mr · 2002. 2. 20. · adeler a tv erhver vsf or skerpr ojekt ef 698 imm-phd-2001-86 issn 0909-3192...

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Hemodynamic simulation of the heart using a 2D model and MR data Pernille Thorup Adeler ATV Erhvervsforskerprojekt EF 698 IMM-PHD-2001-86 ISSN 0909-3192 ISBN 87-88306-13-5 c 2001 by Pernille Thorup Adeler Printed by IMM, DTU Bookbinder Hans Meyer

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Page 1: MR · 2002. 2. 20. · Adeler A TV Erhver vsf or skerpr ojekt EF 698 IMM-PHD-2001-86 ISSN 0909-3192 ISBN 87-88306-13-5 c 2001 by Pernille Thorup Adeler Printed by IMM, DTU Bookbinder

Hem

od

ynam

icsi

mu

lati

on

of

the

hea

rtu

sin

ga

2Dm

od

el

and

MR

dat

a

Per

nill

eT

ho

rup

Ad

eler

AT

VE

rhve

rvsf

ors

kerp

roje

ktE

F69

8

IMM

-PH

D-2

001-

86

ISS

N09

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ISB

N87

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2001

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Page 2: MR · 2002. 2. 20. · Adeler A TV Erhver vsf or skerpr ojekt EF 698 IMM-PHD-2001-86 ISSN 0909-3192 ISBN 87-88306-13-5 c 2001 by Pernille Thorup Adeler Printed by IMM, DTU Bookbinder

Hem

odyn

amics

imul

atio

noft

hehe

artu

sing

a2D

mod

elan

dM

Rda

ta.

Per

nille

Tho

rup

Ade

ler

Aug

ust2

001

Pre

face

Thi

sth

esis

issu

bmitt

edin

part

ialf

ulfil

men

toft

here

quire

men

tsfor

the

Ph.

D.d

e-gr

eeat

the

Tech

nica

lUni

vers

ityof

Den

mar

k(D

TU

).T

hepr

ojec

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iste

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yth

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cade

myo

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ence

s(AT

V)

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cial

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rT

rade

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ing

whi

chth

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ato

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.5m

onth

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ve.

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asca

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twith

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rs:

Mat

h-Te

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ps,I

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mat

ics

and

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hem

atic

alM

odel

ling

(IM

M)

atD

TU

,an

dS

kejb

yS

ygeh

us,A

rhus

Uni

vers

ityH

ospi

tal.

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now

ledg

emen

ts

Firs

tofa

llIw

ould

like

toth

ankm

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perv

isor

s,who

alli

nth

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ario

usw

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ave

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spr

ojec

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cobs

en,R

oski

lde

Uni

vers

ity,h

asbe

ena

won

derf

ulan

din

spiri

ngsu

perv

isor

and

cow

orke

r.I

wou

ldno

thav

eob

tain

edas

good

akn

owle

dgeo

fthe

2Dm

odel

and

itspr

ogra

mm

ingc

odew

ithou

thim

.Je

s-pe

rLar

sen,

Mat

h-Te

ch,w

asth

ein

itiat

orof

the

proj

ecta

ndha

salw

ays

give

nm

eve

ryhe

lpfu

lgui

danc

eand

idea

sfor

furt

herw

ork.

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cent

Alla

nB

arke

r,fo

rmer

lyof

IMM

has

give

nm

eve

ryth

orou

ghan

dus

eful

feed

back

onm

yw

ritte

nm

ate-

rial.

Writ

ing

the

thes

isw

ould

have

been

chao

ticw

ithou

this

advi

ce.E

rikM

orre

Ped

erse

n,Won

Yon

gK

iman

dK

imH

oulin

d,S

kejb

yS

ygeh

us,h

ave

help

edm

eun

ders

tand

the

MR

tech

niqu

eand

give

nm

eus

eful

feed

back

onth

em

odel

from

am

edic

alpo

into

fvi

ew.

Kim

Hou

lind

mus

tals

obe

than

ked

for

his

sugg

estio

nsco

ncer

ning

the

inve

stig

atio

noft

hedi

asto

licfu

nctio

nof

the

vent

ricle

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wou

ldlik

eto

expr

essm

ysp

ecia

lgra

titud

eto

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rlesS

.Pes

kina

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avid

M.

McQ

ueen

both

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oura

ntIn

stitu

teof

Mat

hem

atic

alS

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ces,N

ewY

ork

Uni

vers

ity.

Iam

inde

bted

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antin

gm

eac

cess

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eso

urce

code

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eart

mod

elsb

utev

enm

ore

for

the

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uida

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tion

Page 3: MR · 2002. 2. 20. · Adeler A TV Erhver vsf or skerpr ojekt EF 698 IMM-PHD-2001-86 ISSN 0909-3192 ISBN 87-88306-13-5 c 2001 by Pernille Thorup Adeler Printed by IMM, DTU Bookbinder

ii they

have

give

nm

eth

roug

hout

the

entir

epr

ojec

tand

part

icul

arly

durin

gm

yst

ayat

the

Cou

rant

Inst

itute

inth

efa

llof

1998

.I

also

wan

tto

than

kal

lmy

colle

ague

satM

ath-

Tech

and

IMM

for

givi

ngm

ew

onde

rful

wor

king

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ronm

ents

thro

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utth

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urye

ars.

Fin

ally

,I

wan

tto

give

my

war

mes

tthan

ksto

my

fam

ily,

espe

cial

lym

yhu

s-ba

ndO

lean

dou

rson

Mag

nus,

for

allt

heir

love

and

supp

ort.

Bag

svæ

rd,A

ugus

t200

1

Per

nille

Tho

rup

Ade

ler

Abs

trac

t

Com

puta

tiona

lmod

elso

fthe

bloo

dflo

win

the

hear

tare

aus

eful

tool

for

stud

ying

the

func

tioni

ngof

the

hear

t.T

hepu

rpos

eof

this

thes

isis

toac

hiev

ea

bette

run

ders

tand

ingo

fhe

mod

ynam

icso

fth

eno

rmal

and

dise

ased

hear

tsth

roug

hth

eus

eofa

com

puta

tiona

lmod

elan

dm

agne

ticre

sona

nce(M

R)

data

.W

epr

esen

ta2D

com

puta

tiona

lmod

elof

the

bloo

dflo

win

the

left

side

ofth

ehe

art.

The

wor

kis

base

don

Pes

kina

ndM

cQue

en’s

2Dm

odel

dim

ensi

oned

toda

taon

the

dog

hear

t,w

hich

we

impr

ove

and

adju

stus

ing

phys

iolo

gica

lkno

wl-

edge

and

MR

velo

city

data

toac

hiev

ea

mod

elof

the

hum

anhe

art.

The

impr

ove-

men

tsre

quire

chan

ging

the

geom

etry,

the

timin

g,th

em

echa

nica

lactiv

atio

nof

the

hear

tmus

cula

ture

,and

the

afte

rload

.Fur

ther

mor

e,we

intr

oduc

eate

ther

ingo

fthe

othe

rwis

efre

ely

float

ing

hear

t.W

eev

alua

teth

em

odel

from

aco

mpu

tatio

nalan

dm

odel

ling

poin

tofv

iew

and

find

ase

tofr

easo

nabl

epar

amet

erva

lues

.Thi

sis

our

refe

renc

emod

el,w

hich

give

srep

rese

ntat

ivesi

mul

atio

nres

ults

.W

eco

mpa

rea

sim

ulat

ionu

sing

ourr

efer

ence

mod

elw

ithan

MR

velo

city

data

seto

btai

nedf

rom

ahe

alth

yhu

man

.T

heco

mpa

rison

isca

rrie

dou

tfor

the

in-

trav

entr

icul

arve

loci

tyfie

ldan

dth

eve

loci

tytim

ecu

rves

over

the

mitr

alrin

gan

dac

ross

the

aort

icou

tflow

trac

t.T

heco

mpa

rison

betw

eenv

eloc

ityfie

lds

show

sa

reas

onab

lyfai

rag

reem

entin

the

gene

ralfl

owpa

ttern

:aw

ide

inflo

wje

t,th

efo

r-m

atio

nof

anan

terio

rvor

tex

durin

gfil

ling,

and

anou

tflow

jett

hrou

ghth

eou

tflow

trac

t.T

here

ares

omed

isag

reem

entsin

the

deta

iledfl

owpa

ttern

,inpa

rtic

ular

with

rega

rdto

the

vort

expa

ttern

s.T

heve

loci

tytim

ecu

rves

from

the

sim

ulat

ion

show

good

agre

emen

twith

MR

data

.T

hetim

ing

inth

esi

mul

atio

nis

prac

tical

lyth

esa

mea

sin

the

MR

data

,whi

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med

iffer

ence

sbet

wee

nthe

shap

esan

dm

axim

umva

lues

ofth

eve

loci

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rves

.W

eus

eou

r2D

mod

elto

perf

orm

inve

stig

atio

nsof

cert

ain

mec

hani

smsin

-vo

lved

inhe

artd

isea

sesa

ffect

ing

the

dias

tolic

func

tioni

ngof

the

hear

t.To

beab

leto

sim

ulat

epat

holo

gica

lcon

ditio

nsw

eim

prov

eth

em

odel

for

the

mec

hani

-ca

lact

ivat

ion

ofth

ehe

artm

uscl

e.W

efin

dth

atit

isno

tpos

sibl

eto

succ

essf

ully

Page 4: MR · 2002. 2. 20. · Adeler A TV Erhver vsf or skerpr ojekt EF 698 IMM-PHD-2001-86 ISSN 0909-3192 ISBN 87-88306-13-5 c 2001 by Pernille Thorup Adeler Printed by IMM, DTU Bookbinder

iv sim

ulat

ean

isch

emic

apic

alre

gion

byle

tting

the

rela

xatio

nbe

slow

erin

the

apic

alre

gion

.How

ever

,we

are

able

tosu

cces

sful

lymod

ela

glob

alis

chem

icle

ftve

ntri-

cle

thro

ugha

slow

erre

laxa

tiono

fthe

entir

eve

ntric

lean

dto

mod

ela

myo

card

ial

infa

rctio

naf

fect

ing

the

apex

byle

tting

the

apic

alre

gion

bein

activ

e.In

both

ofth

esec

ases

the

sim

ulat

ion

resu

ltsco

mpa

rew

ellw

ithcl

inic

ally

obse

rved

data

ondo

gsan

dhu

man

s.W

epr

esen

tPes

kina

ndM

cQue

en’s3D

mod

elof

the

entir

ehum

anhe

arta

ndth

ene

arby

grea

tves

sels

.We

perf

orm

asi

mul

atio

nw

ithth

em

odel

,whe

rew

ead

just

the

timin

gto

beth

esa

mea

sin

ourr

efer

ence

2Dm

odel

.Unf

ortu

nate

ly,th

ere

sults

dono

tcom

pare

very

wel

lwith

MR

data

.In

part

icul

ar,t

heflo

wan

dve

loci

tyov

erth

em

itral

ring

are

noti

ngo

odag

reem

ent,a

ndth

epr

essu

rein

the

vent

ricle

sis

far

too

high

.F

urth

erm

ore,

the

3Dm

odel

isco

mpu

tatio

nally

very

dem

andi

ng.T

his,

toge

ther

with

the

disa

gree

men

twith

MR

data

,mak

esit

unfe

asib

leto

use

the

3Dm

odel

asa

tool

fori

nves

tigat

ingt

hehe

mod

ynam

icso

fthe

hear

t.How

ever

,the

3Dm

odel

give

sins

ight

into

the

vort

expa

ttern

inth

ele

ftve

ntric

le.A

clea

rvor

tex

ring

isfo

rmed

belo

wth

em

itral

valv

edu

ring

fillin

g,an

din

acu

t-aw

ayvi

ewth

isrin

gis

seen

astw

odi

stin

ctvo

rtic

es,s

imila

rto

the

vort

ices

form

edin

our2

Dm

odel

.

Res

ume

pada

nsk

Com

pute

rmod

elle

rafbl

odst

røm

ning

enih

jert

eter

etny

ttigt

værk

tøjti

lat

stud

ere

hjer

tets

funk

tion.

Form

alet

med

denn

eafh

andl

inge

rato

pna

enbe

dref

orst

aels

efo

rdet

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eog

dets

ygeh

jert

eshæ

mod

ynam

ikved

atan

vend

een

com

pute

rmod

elog

mag

netis

kres

onan

s(MR

)da

ta.

Vi

præ

sent

erere

n2D

com

pute

rmod

elafb

lods

trø

mni

ngen

ide

nve

nstr

esid

eaf

hjer

tet.

Arb

ejde

terb

aser

etpa

Pes

kino

gM

cQue

en’s2D

mod

eldi

men

sion

eret

tilda

tafo

rhun

dehj

erte

t.Den

nem

odel

forb

edre

rog

ænd

rerv

ived

brug

affy

siol

o-gi

skvi

den

ogM

Rha

stig

heds

datafo

rder

ved

atop

naen

mod

elaf

detm

enne

skelig

ehj

erte

.For

bedr

inge

rnek

ræve

ratg

eom

etrie

n,tid

sfor

løbe

t,den

mek

anis

keak

tive-

ring

afhj

erte

mus

kula

ture

nog

udlø

bsbe

tinge

lser

neænd

res.

Yde

rmer

eint

rodu

-ce

rerv

ien

fast

gøre

lsea

fdet

elle

rsfr

itfly

dend

ehje

rte.

Vie

valu

erer

mod

elle

nud

fra

etbe

regn

ings

-og

mod

elle

rings

ssig

tsyns

punk

tog

finde

rher

ved

etsæ

taf

para

met

ervæ

rdie

r.

Det

teer

vore

sref

eren

cem

odel

,derg

iver

repr

æse

ntat

ivesi

mu-

lerin

gsre

sulta

ter.

Vis

amm

enlig

neren

sim

uler

ingm

edre

fere

ncem

odel

lenm

edet

MR

hast

ighe

ds-

data

sætfra

etra

skm

enne

ske.S

amm

enlig

ning

enud

føre

sfor

deti

ntra

vent

rikul

ære

hast

ighe

dsfe

ltog

forh

astig

heds

kurve

rove

rmitr

alrin

geno

gpa

tvæ

rsaf

udlø

bstr

ag-

ten

ved

aort

a.S

amm

enlig

ning

enm

elle

mha

stig

heds

felte

rnevi

ser

enfo

rnuf

tigov

eren

sste

mm

elsei

detg

ener

elle

flow

nste

r:en

bred

indl

øbs

jet,d

anne

lsen

afen

ante

riorh

virv

elve

dfy

ldni

ngog

enud

løbs

jetg

enne

mud

løbs

trag

tenv

edao

rta.

Der

erdo

gvi

sseu

over

enss

tem

mel

serid

etde

talje

rede

flow

nste

r,spe

ciel

tmed

hens

yntil

hvirv

elm

øns

tret

.Has

tighe

dsku

rvern

efra

sim

uler

inge

nvis

ergo

dov

er-

enss

tem

mel

semed

MR

data

.Tid

sfor

løbe

tisi

mul

erin

gene

rsto

rtse

tdet

sam

me

som

iMR

data

,men

sder

eraf

vige

lser

mel

lem

form

enpa

ogm

axim

umvæ

rdie

rne

afha

stig

heds

kurve

rne.

Vib

enyt

terv

ores

2Dm

odel

tilat

udfø

reen

unde

rsø

gels

eafbe

stem

temek

anis

-m

er,d

erop

træ

derv

edhj

erte

sygd

omm

e,der

pavi

rker

den

dias

tolis

kefu

nktio

naf

hjer

tet.

Fora

tkun

nesi

mul

ered

isse

pato

logi

ske

tilst

ande

forb

edre

rvim

odel

lena

f

Page 5: MR · 2002. 2. 20. · Adeler A TV Erhver vsf or skerpr ojekt EF 698 IMM-PHD-2001-86 ISSN 0909-3192 ISBN 87-88306-13-5 c 2001 by Pernille Thorup Adeler Printed by IMM, DTU Bookbinder

vi den

mek

anis

keak

tiver

ing

afhj

erte

mus

kula

ture

n.Vi

finde

r,at

deti

kke

erm

ulig

tsu

cces

fuld

tat

sim

uler

een

iskæ

mis

kapi

kalr

egio

nve

dat

lade

den

apik

ale

re-

gion

rela

kser

elan

gsom

mer

e.T

ilge

ngæ

ldka

nvi

med

succ

essi

mul

eree

ngl

obal

iskæ

mis

kven

stre

vent

rikel

ved

atla

dehe

leve

ntrik

len

rela

kser

elang

som

mer

e,og

vika

nsi

mul

ere

etm

yoka

rdie

infa

rkt,

derr

amm

erap

ex,

ved

atla

dede

nap

ikal

ere

gion

være

inak

tiv.

Ibe

gge

diss

etilf

æld

eer

derg

odov

eren

sste

mm

elsem

elle

msi

mul

erin

gsre

sulta

terog

klin

isk

obse

rvere

deda

tafr

aba

dehu

ndeo

gm

enne

sker.

Vi

præ

sent

ererP

eski

nog

McQ

ueen

’s3D

mod

elaf

hele

detm

enne

skelig

ehj

erte

ogde

nærm

estes

tore

kar.

Vi

udfø

rere

nsi

mul

erin

gm

edm

odel

len,

hvor

tidsf

orlø

bete

rdet

sam

mes

omi

vore

s2D

refe

renc

emod

el.D

esvæ

rree

rder

ikke

engo

dov

eren

sste

mm

elsem

elle

msi

mul

erin

gsre

sulta

terog

MR

data

.S

peci

elt

flow

etog

hast

ighe

deno

ver

mitr

alrin

gen

pass

erik

kego

dt,o

gtr

ykke

tive

ntrik

-le

rnee

ralt

for

højt.

Yde

rmer

eer3

Dm

odel

lenm

eget

bere

gnin

gskr

æve

nde.

Det

te,

sam

men

hold

tmed

den

darli

gesa

mm

enlig

ning

med

MR

data

,gø

rdet

umul

igta

tan

vend

e3D

mod

elle

nsom

etvæ

rktø

jtil

unde

rsø

gels

eafhj

erte

tshæ

mod

ynam

ik.

Til

geng

æld

kan

3Dm

odel

len

give

inds

igti

hvirv

elm

øns

tret

ide

nve

nstr

even

-tr

ikel

.D

erda

nnes

enty

delig

hvirv

elrin

gun

derm

itral

klap

penv

edfy

ldni

ng,o

gi

etsn

itge

nnem

hjer

tets

esde

nner

ing

som

todi

stin

kte

hvirv

ler,

svar

ende

tilde

tohv

irvle

r,de

rdan

nesi

2Dm

odel

len.

Con

tent

s

Pre

face

i

Abs

trac

tiii

Res

ume

pada

nsk

v

List

offig

ures

xi

1In

trod

uctio

n1

1.1

Hea

rtsi

mul

atio

ns.

..

..

..

..

..

..

..

..

..

..

..

..

.1

1.2

MR

scan

ning

..

..

..

..

..

..

..

..

..

..

..

..

..

..

41.

3U

sing

sim

ulat

ions

and

MR

data

toge

ther

..

..

..

..

..

..

..

41.

4O

utlin

eof

thes

is.

..

..

..

..

..

..

..

..

..

..

..

..

..

5

2P

hysi

olog

yan

dan

atom

yof

the

hear

t7

2.1

Inte

rnal

anat

omy

..

..

..

..

..

..

..

..

..

..

..

..

..

82.

2F

unct

ioni

ngof

the

hear

t..

..

..

..

..

..

..

..

..

..

..

.10

2.3

Con

duct

ions

yste

mof

the

hear

t..

..

..

..

..

..

..

..

..

.11

2.4

Mus

cle

phys

iolo

gy.

..

..

..

..

..

..

..

..

..

..

..

..

13

32D

hear

tmod

elus

ing

the

imm

erse

dbo

unda

rym

etho

d17

3.1

Gen

eral

desc

riptio

noft

hem

odel

..

..

..

..

..

..

..

..

..

173.

2C

ontin

uous

form

ulat

ion

..

..

..

..

..

..

..

..

..

..

..

.18

3.2.

1S

ourc

esan

dsi

nks

..

..

..

..

..

..

..

..

..

..

..

203.

3D

iscr

etef

orm

ulat

ion

..

..

..

..

..

..

..

..

..

..

..

..

243.

3.1

Dis

cret

equa

ntiti

es.

..

..

..

..

..

..

..

..

..

..

243.

3.2

Dif

fere

nceo

pera

tors

and

disc

rete

funct

ion

..

..

..

.25

3.3.

3D

iscr

etiz

atio

nofe

quat

ions

ofm

otio

n.

..

..

..

..

..

27

Page 6: MR · 2002. 2. 20. · Adeler A TV Erhver vsf or skerpr ojekt EF 698 IMM-PHD-2001-86 ISSN 0909-3192 ISBN 87-88306-13-5 c 2001 by Pernille Thorup Adeler Printed by IMM, DTU Bookbinder

viii

Con

tent

s

3.3.

4D

iscr

eteW

indk

esse

lmod

elfo

rth

eao

rtic

sink

..

..

..

.28

3.3.

5B

ound

aryf

orce

s.

..

..

..

..

..

..

..

..

..

..

.31

3.3.

6T

heac

tivat

ion

func

tion

..

..

..

..

..

..

..

..

..

.35

3.3.

7To

polo

gyan

din

itial

geom

etry

ofth

ehe

art.

..

..

..

..

383.

4O

utlin

eof

algo

rithm

..

..

..

..

..

..

..

..

..

..

..

..

40

4E

valu

atio

nof

the

2Dm

odel

434.

1S

imul

atio

nout

put.

..

..

..

..

..

..

..

..

..

..

..

..

.43

4.1.

1H

eart

boun

dary

confi

gura

tiona

ndflu

idm

arke

rs.

..

..

.44

4.1.

2V

eloc

ityfie

ld.

..

..

..

..

..

..

..

..

..

..

..

.44

4.1.

3P

ress

urefi

eld

..

..

..

..

..

..

..

..

..

..

..

..

494.

2T

hesc

alin

gfac

tor

...

..

..

..

..

..

..

..

..

..

..

..

504.

3P

erio

dicb

ound

aryc

ondi

tions

..

..

..

..

..

..

..

..

..

..

564.

4Te

ther

ingo

fthe

hear

t.

..

..

..

..

..

..

..

..

..

..

..

.60

4.5

The

Win

dkes

selm

odel

..

..

..

..

..

..

..

..

..

..

..

.66

4.6

Dis

trib

uted

sour

cesa

ndsi

nks

..

..

..

..

..

..

..

..

..

..

694.

7S

imul

atio

nove

rsev

eral

hear

tcyc

les

..

..

..

..

..

..

..

..

714.

8C

oncl

usio

ns.

..

..

..

..

..

..

..

..

..

..

..

..

..

..

75

5C

ompa

ring

the

2Dm

odel

with

anM

Rda

tase

t77

5.1

The

MR

data

..

..

..

..

..

..

..

..

..

..

..

..

..

..

775.

2V

eloc

ityfie

lds

..

..

..

..

..

..

..

..

..

..

..

..

..

..

795.

3V

eloc

itytim

epr

ofile

s.

..

..

..

..

..

..

..

..

..

..

..

.85

5.4

Dis

cuss

iona

ndco

nclu

sion

s..

..

..

..

..

..

..

..

..

..

.89

6S

imul

atin

gpa

thol

ogic

alhe

artc

ondi

tions

936.

1M

edic

alba

ckgr

ound

..

..

..

..

..

..

..

..

..

..

..

..

946.

1.1

Mec

hani

smsd

urin

gea

rlyfil

ling

..

..

..

..

..

..

..

946.

1.2

Path

olog

ical

hear

tcon

ditio

ns.

..

..

..

..

..

..

..

.94

6.1.

3V

eloc

ityin

dexe

s.

..

..

..

..

..

..

..

..

..

..

.96

6.1.

4T

ime

cons

tant

ofre

laxa

tion.

..

..

..

..

..

..

..

..

996.

1.5

Reg

ions

ofth

eve

ntric

le.

..

..

..

..

..

..

..

..

.99

6.2

The

new

activ

atio

nfu

nctio

n.

..

..

..

..

..

..

..

..

..

..

100

6.2.

1T

heor

igin

alm

odel

..

..

..

..

..

..

..

..

..

..

.10

16.

2.2

The

new

impl

emen

tatio

n.

..

..

..

..

..

..

..

..

.10

26.

2.3

Tim

eco

nsta

ntof

rela

xatio

n..

..

..

..

..

..

..

..

.10

66.

3C

alib

ratin

gthe

mod

el.

..

..

..

..

..

..

..

..

..

..

..

.10

66.

3.1

Vel

ocity

profi

lesa

long

tran

sver

selin

es.

..

..

..

..

..

106

6.3.

2G

radu

alac

tivat

ion

..

..

..

..

..

..

..

..

..

..

.10

86.

3.3

Reg

iona

lact

ivat

ion

..

..

..

..

..

..

..

..

..

..

.11

4

Con

tent

six

6.4

Sim

ulat

ions

ofpa

thol

ogic

alhe

artc

ondi

tions

..

..

..

..

..

..

120

6.4.

1S

low

rela

xatio

noft

heve

ntric

le.

..

..

..

..

..

..

.12

16.

4.2

Slo

wre

laxa

tiono

fapi

calr

egio

n.

..

..

..

..

..

..

.12

66.

4.3

Api

calr

egio

nin

activ

e.

..

..

..

..

..

..

..

..

..

129

6.5

Con

clus

ions

..

..

..

..

..

..

..

..

..

..

..

..

..

..

.13

4

7T

he3D

hear

tmod

el13

77.

1D

escr

iptio

noft

hem

odel

..

..

..

..

..

..

..

..

..

..

..

137

7.1.

1E

quat

ions

ofm

otio

n.

..

..

..

..

..

..

..

..

..

.13

87.

1.2

Com

puta

tiona

lmet

hod

..

..

..

..

..

..

..

..

..

.14

07.

1.3

Initi

alge

omet

ry.

..

..

..

..

..

..

..

..

..

..

..

142

7.2

Res

ults

..

..

..

..

..

..

..

..

..

..

..

..

..

..

..

..

143

7.3

Dis

cuss

ion.

..

..

..

..

..

..

..

..

..

..

..

..

..

..

.14

8

8C

oncl

usio

nsan

dsu

gges

tions

149

8.1

Sum

mar

yofc

oncl

usio

ns.

..

..

..

..

..

..

..

..

..

..

.14

98.

2S

ugge

stio

nsfo

rfu

ture

wor

k.

..

..

..

..

..

..

..

..

..

..

151

App

endi

x15

3

AM

agne

ticre

sona

nceim

agin

g15

3A

.1B

asic

sofM

RI

..

..

..

..

..

..

..

..

..

..

..

..

..

..

153

A.1

.1E

xcita

tion

..

..

..

..

..

..

..

..

..

..

..

..

..

155

A.1

.2R

elax

atio

n.

..

..

..

..

..

..

..

..

..

..

..

..

156

A.1

.3P

ulse

sequ

ence

s..

..

..

..

..

..

..

..

..

..

..

.15

8A

.2Im

agin

gm

etho

ds.

..

..

..

..

..

..

..

..

..

..

..

..

.16

1A

.2.1

Slic

ese

lect

iong

radi

ent.

..

..

..

..

..

..

..

..

..

162

A.2

.2P

hase

enco

ding

grad

ient

..

..

..

..

..

..

..

..

..

163

A.2

.3R

ead-

outg

radi

ent.

..

..

..

..

..

..

..

..

..

..

.16

3A

.2.4

Imag

ing

sequ

ence

s..

..

..

..

..

..

..

..

..

..

.16

4A

.2.5

Mot

ion

artif

acts

..

..

..

..

..

..

..

..

..

..

..

.16

7A

.3V

eloc

itym

easu

rem

ents.

..

..

..

..

..

..

..

..

..

..

..

168

Bib

liogr

aph

y17

1

Page 7: MR · 2002. 2. 20. · Adeler A TV Erhver vsf or skerpr ojekt EF 698 IMM-PHD-2001-86 ISSN 0909-3192 ISBN 87-88306-13-5 c 2001 by Pernille Thorup Adeler Printed by IMM, DTU Bookbinder

List

ofF

igur

es

2.1

The

-fou

rcha

mbe

redh

eart

isdi

vide

din

totw

opa

rts,

the

left

and

right

side

s.

..

..

..

..

..

..

..

..

..

..

..

..

..

..

.8

2.2

Dra

win

gof

ahe

arts

plit

perp

endi

cula

rtoth

ein

terv

entr

icul

arse

ptum

92.

3T

hero

otao

rtic

pres

sure

,vent

ricul

arpr

essu

re,a

tria

lpre

ssur

e,ar

-te

riali

nflow

,to

tali

nflow

toth

ehe

art,

atria

lvol

ume,

vent

ricul

arvo

lum

ean

dve

ntric

ular

outfl

ow.

..

..

..

..

..

..

..

..

..

112.

4S

chem

aticr

epre

sent

atio

noft

heco

nduc

tions

yste

mof

the

hear

t..

122.

5S

chem

aticr

epre

sent

atio

nofa

sect

iono

fare

laxe

dan

dco

ntra

cted

fibril

..

..

..

..

..

..

..

..

..

..

..

..

..

..

..

..

.13

2.6

Act

ion

pote

ntia

land

cont

ract

ilem

echa

nica

lresp

onse

ofa

card

iac

mus

clefi

ber

..

..

..

..

..

..

..

..

..

..

..

..

..

..

.14

3.1

Com

puta

tiona

ldom

ain

andi

nitia

lhea

rtbo

unda

ryco

nfigu

ratio

n

.

..

..

..

..

..

..

..

..

..

..

..

..

..

..

..

193.

2A

nel

ectr

ican

alog

ueto

the

linea

rres

ista

ncem

odel

..

..

..

..

233.

3D

iagr

amof

thre

e-el

emen

tWin

dkes

selm

odel

coup

ledt

odi

ode

valv

e24

3.4

Plo

toft

hefu

nctio

n

..

..

..

..

..

..

..

..

..

..

..

263.

5S

ketc

hof

the

mus

cula

rmod

el.

..

..

..

..

..

..

..

..

..

.34

3.6

Act

ivat

ion

asfu

nctio

nof

time

..

..

..

..

..

..

..

..

..

..

373.

7M

odifi

edin

itial

hear

tgeo

met

ry.

..

..

..

..

..

..

..

..

..

39

4.1

Hea

rtbo

unda

ryan

dflu

idm

arke

rsfr

omth

ere

fere

nces

imul

atio

n.

454.

2V

eloc

ityfie

ldan

dhea

rtbou

ndar

ycon

figur

atio

nfro

mth

ere

fere

nce

sim

ulat

ion

..

..

..

..

..

..

..

..

..

..

..

..

..

..

..

464.

3V

eloc

itytim

epr

ofile

atth

em

itral

valv

efo

rth

ere

fere

nces

imul

atio

n47

4.4

Vel

ocity

time

profi

leac

ross

the

outfl

owtr

actf

orth

ere

fere

nces

im-

ulat

ion

..

..

..

..

..

..

..

..

..

..

..

..

..

..

..

..

484.

5S

ourc

eflow

time

profi

lefo

rth

ere

fere

nces

imul

atio

n.

..

..

..

48

Page 8: MR · 2002. 2. 20. · Adeler A TV Erhver vsf or skerpr ojekt EF 698 IMM-PHD-2001-86 ISSN 0909-3192 ISBN 87-88306-13-5 c 2001 by Pernille Thorup Adeler Printed by IMM, DTU Bookbinder

xii

List

offig

ures

4.6

Pre

ssur

etim

epr

ofile

for

the

refe

renc

esim

ulat

ion

..

..

..

..

.49

4.7

Tim

eva

riatio

nofv

entr

icul

arpr

essu

reand

activ

atio

nfo

rth

ere

fer-

ence

sim

ulat

ion

..

..

..

..

..

..

..

..

..

..

..

..

..

.50

4.8

Vel

ocity

field

and

hear

tbou

ndar

yat

s,w

ith

0.0

4,0.

1,0.

3an

d0.

5.

..

..

..

..

..

..

..

..

..

..

..

..

..

514.

9V

eloc

ityfie

ldan

dhe

artb

ound

arya

t

s,w

ith

0.0

4,0.

1,0.

3an

d0.

5.

..

..

..

..

..

..

..

..

..

..

..

..

..

524.

10V

eloc

ityfie

ldan

dhe

artb

ound

arya

t

s,w

ith

0.0

4,0.

1,0.

3an

d0.

5.

..

..

..

..

..

..

..

..

..

..

..

..

..

534.

11P

ress

ureti

me

profi

lefo

r

0.0

4,0.

1an

d0.

5.

..

..

..

..

..

544.

12V

eloc

itytim

epr

ofile

atth

em

itral

valv

efo

r

0.0

4,0.

1an

d0.

5.

554.

13V

eloc

itytim

epr

ofile

acro

ssth

eao

rtic

outfl

owtr

actf

or

0.0

4,0.

1an

d0.

5.

..

..

..

..

..

..

..

..

..

..

..

..

..

..

.55

4.14

Hea

rtbo

unda

ryfr

oma

refe

renc

esim

ulat

ion

and

from

asi

mul

a-tio

nw

itha

larg

eco

mpu

tatio

naldo

mai

n.

..

..

..

..

..

..

.57

4.15

Pre

ssur

etim

epr

ofile

from

asi

mul

atio

nwith

ala

rge

com

puta

tiona

ldo

mai

nand

from

the

refe

renc

esim

ulat

ion

..

..

..

..

..

..

.58

4.16

Vel

ocity

time

profi

leat

the

mitr

alva

lve

from

asi

mul

atio

nwith

ala

rge

com

puta

tiona

ldom

aina

ndfr

omth

ere

fere

nces

imul

atio

n.

.59

4.17

Vel

ocity

time

profi

leac

ross

the

aort

icsi

nkfr

oma

sim

ulat

ionw

itha

larg

eco

mpu

tatio

naldo

mai

nand

from

the

refe

renc

esim

ulat

ion

.59

4.18

Sou

rcefl

owtim

epr

ofile

sfr

oma

sim

ulat

ion

with

ala

rge

com

pu-

tatio

nald

omai

nand

from

are

fere

nces

imul

atio

n.

..

..

..

..

.60

4.19

Vel

ocity

field

and

hear

tbou

ndar

ycon

figur

atio

nfro

ma

sim

ulat

ion

with

note

ther

ingo

fthe

hear

t.

..

..

..

..

..

..

..

..

..

.61

4.20

Vel

ocity

field

andh

eartb

ound

aryc

onfig

urat

ionf

rom

the

refe

renc

esi

mul

atio

n.

..

..

..

..

..

..

..

..

..

..

..

..

..

..

.62

4.21

Pre

ssur

etim

epr

ofile

from

asi

mul

atio

nw

ithno

teth

erin

gof

the

hear

tand

from

the

refe

renc

esim

ulat

ion

..

..

..

..

..

..

..

634.

22V

eloc

itytim

epr

ofile

atth

em

itral

valv

efr

oma

sim

ulat

ionw

ithno

teth

erin

gand

from

the

refe

renc

esim

ulat

ion

..

..

..

..

..

..

644.

23S

ourc

eflow

time

profi

lefr

oma

sim

ulat

ion

with

note

ther

inga

ndfr

omth

ere

fere

nces

imul

atio

n..

..

..

..

..

..

..

..

..

..

654.

24In

itial

geom

etry

ofth

edo

ghe

art

..

..

..

..

..

..

..

..

..

674.

25P

ress

uret

ime

profi

lefr

oma

sim

ulat

ion

with

outt

heW

indk

esse

lm

odel

..

..

..

..

..

..

..

..

..

..

..

..

..

..

..

..

684.

26P

ress

ureti

me

profi

lefr

oma

sim

ulat

ionw

ithth

eW

indk

esse

lmod

el68

4.27

Pre

ssur

etim

epr

ofile

durin

g4

cycl

es.

..

..

..

..

..

..

..

.73

4.28

Vel

ocity

time

profi

ledu

ring

4cy

cles

atth

em

itral

ring

..

..

..

.73

List

offig

ures

xiii

4.29

Vel

ocity

time

profi

ledu

ring

4he

artc

ycle

sacr

osst

heao

rtic

sink

.74

4.30

Sou

rcefl

owtim

epr

ofile

durin

g4

hear

tcyc

les

..

..

..

..

..

.74

5.1

Vel

ocity

field

and

hear

tbou

ndar

yfro

mM

Rm

easu

rem

entsa

ndre

fere

nces

imul

atio

n..

..

..

..

..

..

..

..

..

..

..

..

.80

5.2

Vel

ocity

field

and

hear

tbou

ndar

yfro

mM

Rm

easu

rem

entsa

ndre

fere

nces

imul

atio

n..

..

..

..

..

..

..

..

..

..

..

..

.81

5.3

Vel

ocity

field

and

hear

tbou

ndar

yfro

mM

Rm

easu

rem

entsa

ndre

fere

nces

imul

atio

n..

..

..

..

..

..

..

..

..

..

..

..

.82

5.4

Vel

ocity

time

profi

leat

the

mitr

alrin

gfr

omM

Rda

taan

dsi

mul

atio

n87

5.5

Vel

ocity

time

profi

leac

ross

the

aort

icou

tflow

trac

tfro

mM

Rda

taan

dsi

mul

atio

n.

..

..

..

..

..

..

..

..

..

..

..

..

..

.88

6.1

Vel

ocity

profi

leal

ong

six

lines

from

ahe

alth

yper

son

..

..

..

.97

6.2

Pea

kve

loci

tyfr

omM

Rm

easu

rem

entso

fhe

alth

ype

rson

sand

AM

Ipa

tient

s.

..

..

..

..

..

..

..

..

..

..

..

..

..

.98

6.3

Vel

ocity

inde

xfr

omM

Rm

easu

rem

entso

fhe

alth

ype

rson

sand

AM

Ipa

tient

s.

..

..

..

..

..

..

..

..

..

..

..

..

..

.98

6.4

Tim

ede

layf

rom

MR

mea

sure

men

tsofh

ealth

yper

sons

and

AM

Ipa

tient

s.

..

..

..

..

..

..

..

..

..

..

..

..

..

..

..

986.

5M

Rim

agew

ithth

efiv

ere

gion

soft

heve

ntric

ular

wal

lind

icat

ed.

996.

6Ill

ustr

atio

nof

the

num

berin

goft

helin

ksin

the

two

chai

nsin

the

atriu

man

dth

eve

ntric

le.

..

..

..

..

..

..

..

..

..

..

..

103

6.7

The

five

regi

onso

fthe

vent

ricul

arhe

artw

alla

tini

tialt

ime

..

..

106

6.8

The

six

lines

whe

resp

atia

lvel

ocity

profi

lesa

reco

mpu

tedd

urin

gdi

asto

le.

..

..

..

..

..

..

..

..

..

..

..

..

..

..

..

108

6.9

Hea

rtbo

unda

ryfr

oma

sim

ulat

ion

with

grad

uala

ctiv

atio

nan

dfr

omth

ere

fere

nces

imul

atio

n.

..

..

..

..

..

..

..

..

..

.11

06.

10H

eart

boun

dary

from

asi

mul

atio

nw

ithgr

adua

lact

ivat

ion

and

from

the

refe

renc

esim

ulat

ion

..

..

..

..

..

..

..

..

..

..

111

6.11

Vel

ocity

time

profi

leat

the

mitr

alva

lve

from

asi

mul

atio

nw

ithgr

adua

lact

ivat

ion

and

from

the

refe

renc

esim

ulat

ion.

..

..

..

.11

26.

12V

eloc

itytim

epr

ofile

atth

eao

rtic

outfl

owtr

actf

rom

asi

mul

atio

nw

ithgr

adua

lact

ivat

ion

and

from

the

refe

renc

esim

ulat

ion

..

..

.11

26.

13F

low

time

profi

lefo

rth

em

itral

sour

cean

daor

ticsi

nkfr

oma

sim

-ul

atio

nw

ithgr

adua

lact

ivat

ion

and

from

the

refe

renc

esim

ulat

ion

.11

36.

14V

eloc

itytim

epr

ofile

atth

em

itral

valv

efr

oma

sim

ulat

ion

whe

re

"!#$ % &'() an

dfr

omth

ere

fere

nces

imul

atio

n..

..

..

..

115

6.15

Vel

ocity

profi

leal

ongs

ixlin

esfr

oma

sim

ulat

iono

fahe

alth

yhum

an11

6

Page 9: MR · 2002. 2. 20. · Adeler A TV Erhver vsf or skerpr ojekt EF 698 IMM-PHD-2001-86 ISSN 0909-3192 ISBN 87-88306-13-5 c 2001 by Pernille Thorup Adeler Printed by IMM, DTU Bookbinder

xiv

List

offig

ures

6.16

Pea

kvel

ocity

from

asi

mul

atio

nofa

heal

thyp

erso

n.

..

..

..

.11

86.

17V

eloc

ityin

dex

from

asi

mul

atio

nofa

heal

thyp

erso

n.

..

..

..

118

6.18

Tim

ede

layf

rom

asi

mul

atio

nofa

heal

thyp

erso

n.

..

..

..

..

118

6.19

Vel

ocity

field

atth

etim

eof

PV

atth

eM

LT

line

..

..

..

..

..

119

6.20

Tim

eva

riatio

nof

pres

sure

diff

eren

cebe

twee

natr

ium

and

vent

ri-cl

efr

oma

sim

ulat

iono

fahe

alth

yhum

an.

..

..

..

..

..

..

120

6.21

Vel

ocity

profi

lesf

rom

asi

mul

atio

nwhe

reve

ntric

ular

rela

xatio

nis

slow

..

..

..

..

..

..

..

..

..

..

..

..

..

..

..

..

..

122

6.22

Pea

kvel

ocity

from

asi

mul

atio

nw

here

the

vent

ricul

arac

tivat

ion

issl

ow.

..

..

..

..

..

..

..

..

..

..

..

..

..

..

..

.12

36.

23V

eloc

ityin

dex

from

asi

mul

atio

nwhe

reth

eve

ntric

ular

rela

xatio

nis

slow

..

..

..

..

..

..

..

..

..

..

..

..

..

..

..

..

123

6.24

Tim

ede

layf

rom

asi

mul

atio

nw

here

the

vent

ricul

arre

laxa

tioni

ssl

ow.

..

..

..

..

..

..

..

..

..

..

..

..

..

..

..

..

123

6.25

Vel

ocity

field

atth

etim

eof

PV

atth

eM

LT

line

from

asi

mul

atio

nw

here

the

vent

ricul

arre

laxa

tioni

ssl

ow.

..

..

..

..

..

..

.12

46.

26T

ime

varia

tion

ofpr

essu

redi

ffer

ence

betw

eena

triu

man

dve

ntri-

cle

from

asi

mul

atio

nwhe

reth

eve

ntric

ular

rela

xatio

nis

slow

..

.12

56.

27V

eloc

itypr

ofile

sfro

ma

sim

ulat

ionw

here

the

apic

alre

laxa

tioni

ssl

ow.

..

..

..

..

..

..

..

..

..

..

..

..

..

..

..

..

127

6.28

Pea

kvel

ocity

from

asi

mul

atio

nwhe

reth

eap

ical

rela

xatio

nis

slow

128

6.29

Vel

ocity

inde

xfr

oma

sim

ulat

ionw

here

the

apic

alre

laxa

tioni

ssl

ow12

86.

30T

ime

dela

yfro

ma

sim

ulat

ionw

here

the

apic

alre

laxa

tioni

ssl

ow.

128

6.31

Vel

ocity

field

atth

etim

eof

PV

atth

eM

LT

line

from

asi

mul

atio

nw

here

the

apic

alre

laxa

tioni

ssl

ow.

..

..

..

..

..

..

..

..

129

6.32

Tim

eva

riatio

nof

pres

sure

diff

eren

cebe

twee

natr

ium

and

vent

ri-cl

efr

oma

sim

ulat

ionw

here

the

apic

alre

laxa

tioni

ssl

ow.

..

..

129

6.33

Vel

ocity

field

and

hear

tbou

ndar

yfro

ma

sim

ulat

ion

whe

reth

eap

ical

regi

onis

inac

tive.

..

..

..

..

..

..

..

..

..

..

..

130

6.34

Vel

ocity

profi

lesf

rom

asi

mul

atio

nw

here

the

apic

alre

gion

isin

-ac

tive

..

..

..

..

..

..

..

..

..

..

..

..

..

..

..

..

131

6.35

Pea

kvel

ocity

from

asi

mul

atio

nwhe

reth

eap

ical

regi

onis

inac

tive

132

6.36

Vel

ocity

inde

xfr

oma

sim

ulat

ionw

here

the

apic

alre

gion

isin

activ

e132

6.37

Tim

ede

layf

rom

asi

mul

atio

nwhe

reth

eap

ical

regi

onis

inac

tive

.13

26.

38T

ime

varia

tion

ofpr

essu

redi

ffer

ence

betw

eena

triu

man

dve

ntri-

cle

from

asi

mul

atio

nwhe

reth

eap

ical

regi

onis

inac

tive

..

..

..

134

7.1

Initi

alge

omet

ryof

the

3Dhe

art.

..

..

..

..

..

..

..

..

..

142

7.2

Cut

-aw

ayvi

ewof

the

initi

alfib

erco

nfigu

ratio

n.

..

..

..

..

.14

3

List

offig

ures

xv

7.3

Flo

wtim

epr

ofile

atth

em

itral

and

aort

icva

lve

..

..

..

..

..

.14

57.

4V

eloc

itytim

epr

ofile

atth

eao

rtic

valv

e.

..

..

..

..

..

..

..

146

7.5

Vel

ocity

time

profi

leat

the

mitr

alva

lve

..

..

..

..

..

..

..

.14

67.

6C

ut-a

way

view

ofth

ehe

artd

urin

gea

rlyve

ntric

ular

dias

tole

..

..

147

7.7

Sec

tiont

hrou

ghth

ele

ftve

ntric

lesh

owin

gst

ream

lines

ofve

ntric

-ul

arfil

ling

..

..

..

..

..

..

..

..

..

..

..

..

..

..

..

147

A.1

Asp

inni

ngnu

cleu

swith

itsdi

pole

vect

or* whe

nno

exte

rnal

mag

-ne

ticfie

ldis

appl

ied

..

..

..

..

..

..

..

..

..

..

..

..

.15

4A

.2P

rece

ssio

nof

the

dipo

leve

ctor

ofa

spin

ning

nucl

eusa

bout

anex

tern

alm

agne

ticfie

ld

+ ..

..

..

..

..

..

..

..

..

..

.15

4A

.3S

pira

lling

mot

ion

ofth

em

agne

tizat

ionv

ecto

rdur

ing

anR

Fpu

lse

.15

5A

.4T

hetim

eva

riatio

nof

the

leng

thof

the

mag

netiz

atio

nvec

tord

ur-

ing

rela

xatio

n.

..

..

..

..

..

..

..

..

..

..

..

..

..

.15

7A

.5D

epha

sing

ofsp

insa

ftera

90

, puls

e.

..

..

..

..

..

..

..

.15

7A

.6T

ime

varia

tion

ofth

eF

ID.

..

..

..

..

..

..

..

..

..

..

.15

8A

.7T

hesp

inec

hose

quen

ce.

..

..

..

..

..

..

..

..

..

..

..

159

A.8

Tim

eva

riatio

nof

the

MR

sign

alam

plitu

dedu

ring

asp

inec

hose

quen

ces.

..

..

..

..

..

..

..

..

..

..

..

..

..

..

.16

0A

.9T

rans

vers

erel

axat

ionc

urve

for

two

tissu

esw

ithdi

ffer

ent

-/. values

161

A.1

0A

sinc

wav

epu

lsea

ndits

Four

iert

rans

form

..

..

..

..

..

..

162

A.1

1M

Rsp

ectr

uman

dco

rres

pond

ingg

rey

scal

eim

age

..

..

..

..

.16

4A

.12

The

grad

ient

echo

sequ

ence

..

..

..

..

..

..

..

..

..

..

.16

6A

.13

Imag

esfr

oma

card

iacM

RI

with

velo

city

enco

ding

..

..

..

..

169

Page 10: MR · 2002. 2. 20. · Adeler A TV Erhver vsf or skerpr ojekt EF 698 IMM-PHD-2001-86 ISSN 0909-3192 ISBN 87-88306-13-5 c 2001 by Pernille Thorup Adeler Printed by IMM, DTU Bookbinder

Cha

pter

1

Intr

oduc

tion

Hem

odyn

amics

imul

atio

nsof

the

hear

tbas

edon

com

puta

tiona

lmod

elsc

anbe

aus

eful

tool

for

stud

ying

the

norm

alan

dab

norm

alfu

nctio

ning

ofth

ehe

art.

Inth

isap

proa

chm

agne

ticre

sona

nceim

agin

g(M

RI)

can

beus

edbo

thas

am

eans

for

obta

inin

gin

putp

aram

eter

sand

hear

tbou

ndar

ycon

ditio

nsto

the

com

puta

tiona

lm

odel

and

for

eval

uatin

gthe

sim

ulat

ionr

esul

ts.

The

purp

oseo

fth

ew

ork

pres

ente

dinth

isth

esis

isto

achi

eve

abe

tteru

nder

-st

andi

ngof

the

hem

odyn

amic

sof

the

norm

alan

ddi

seas

edhe

arts

usin

ga

com

-pu

tatio

nalm

odel

and

MR

mea

sure

men

ts.The

star

ting

poin

tis

the

exis

ting

two

and

thre

edi

men

sion

alhe

artm

odel

sdev

elop

edby

Cha

rlesS

.Pes

kina

ndD

avid

M.M

cQue

en.

1.1

Hea

rtsi

mul

atio

ns

Pes

kini

nitia

ted

his

wor

kon

hear

tmod

ellin

gin

his

Ph.

D.t

hesi

s(P

eski

n,19

72a)

with

atw

odi

men

sion

al(2

D)

mod

elof

the

bloo

dflo

win

the

left

side

ofa

dog’

she

art.

He

intr

oduc

eda

new

met

hod

for

fluid

-str

uctu

reco

uplin

gca

lled

the

im-

mer

sedb

ound

arym

etho

d.T

heid

eaof

the

imm

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dbou

ndar

ymet

hodi

sth

atth

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mer

sedi

nflu

id,

i.e.t

hehe

artb

ound

aryh

asflu

idon

both

side

san

dth

ebo

unda

ryis

repr

esen

tedin

term

soft

hefo

rces

itex

erts

onth

eflu

id.

Thu

sth

ebo

unda

ryis

sim

ply

asp

ecia

lized

regi

onof

the

fluid

whe

reex

tra

forc

esar

eap

-pl

ied.

The

fluid

dyna

mic

aleq

uatio

nsar

esol

ved

usin

gC

horin

’spr

ojec

tionm

etho

d(C

horin

,196

8).A

draw

back

ofth

ism

etho

dis

that

alll

engt

hsan

dtim

esha

veto

bere

duce

dto

achi

eve

num

eric

alst

abili

ty,w

ithth

ere

sult

that

the

Rey

nold

snu

mbe

ris

redu

cedt

oan

unph

ysio

logi

calva

lue.

Page 11: MR · 2002. 2. 20. · Adeler A TV Erhver vsf or skerpr ojekt EF 698 IMM-PHD-2001-86 ISSN 0909-3192 ISBN 87-88306-13-5 c 2001 by Pernille Thorup Adeler Printed by IMM, DTU Bookbinder

2In

trod

uctio

n

Pes

kinh

asde

velo

peda

ndst

udie

dthe

2Dm

odel

inco

llabo

ratio

nwith

othe

rs,

inpa

rtic

ular

Dav

idM

.McQ

ueen

.Thi

sw

ork

isdo

cum

ente

dby

ase

rieso

fpap

ers:

Pes

kin(

1972

b),P

eski

n(19

75),

Pes

kin(

1977

),P

eski

nand

McQ

ueen

(198

0),P

e-sk

in(1

981)

,McQ

ueen

etal

.(19

82)a

ndP

eski

nand

Prin

tz(1

993)

.The

sepa

pers

,w

hich

desc

ribet

hem

odel

ofa

dog’

she

art,f

orm

the

back

grou

ndfo

rour

wor

kw

ithth

e2D

hear

tmod

el.

Pes

kina

ndM

cQue

en’s

orig

inal

purp

osei

ncr

eatin

gahe

artm

odel

was

toes

-ta

blis

ha

com

pute

rtoo

lfor

stud

ying

the

func

tioni

ngof

the

mitr

alva

lve

(Yel

linet

al.,

1981

;Mei

sner

etal

.,19

85)a

ndfo

rde

sign

inga

ndin

vest

igat

ingp

rost

hetic

hear

tval

ves

for

repl

acem

ento

fth

ena

tura

lmitr

alva

lve

(McQ

ueen

and

Pes

kin,

1983

;McQ

ueen

and

Pes

kin,

1985

).To

geth

erw

ithot

hers

,Pes

kin

has

also

stud

ied

vario

usal

tern

ative

num

eric

alsc

hem

esfo

rth

eso

lutio

nof

the

flow

equa

tions

orfo

rth

etr

eatm

ento

fthe

coup

ling

ofth

ebo

unda

ryfo

rces

toth

eflu

id(M

cCra

cken

and

Pes

kin,

1980

;Bor

gers

and

Pes

kin,

1987

;Tu

and

Pes

kin,

1992

;May

oan

dP

eski

n,19

93).

The

seal

tern

ative

met

hods

are

noti

mpl

emen

tedin

ourv

ersi

onof

the

com

puta

tiona

lmod

el.

The

com

puta

tiona

lmet

hodo

fth

e2D

hear

tmod

elha

ssi

nce

been

expa

nded

to3D

(Gre

enbe

rget

al.,

1987

;Pes

kin

and

McQ

ueen

,198

9;M

cQue

enan

dP

e-sk

in,1

989)

,and

the

wor

kof

Pes

kina

ndM

cQue

enha

scul

min

ated

ina

3Dm

odel

ofth

een

tire

hum

anhe

arta

ndne

arby

grea

tves

sels(

Pes

kin,

1989

;Pes

kina

ndM

c-Q

ueen

,199

2;P

eski

nand

McQ

ueen

,199

3b;P

eski

nand

McQ

ueen

,199

3a;P

eski

nan

dM

cQue

en,1

994;

Pes

kina

ndM

cQue

en,1

995;

Pes

kina

ndM

cQue

en,1

996;

Dav

is,1

995;

McQ

ueen

and

Pes

kin,

2000

).In

the

late

stw

ork

with

the

3Dm

odel

(McQ

ueen

and

Pes

kin,

1997

;McQ

ueen

and

Pes

kin,

2000

)the

num

eric

alm

etho

dfo

rso

lvin

gth

eflu

iddy

nam

ical

equa

tions

hasb

eenc

hang

ed,e

limin

atin

gth

ere

-du

ctio

noft

heR

eyno

ldsn

umbe

r.Sin

ceth

ein

trod

uctio

noft

hefu

ll3D

hear

tmod

el,

Pes

kina

ndM

cQue

enha

vest

oppe

dwor

kon

the

2Dm

odel

and

are

com

plet

elyf

o-cu

sedo

nth

e3D

mod

el.T

he3D

mod

el,h

owev

er,i

sve

ryde

man

ding

with

resp

ect

toco

mpu

tatio

nalpo

wer

(McQ

ueen

and

Pes

kin,

1997

).In

fact

,itw

ould

have

been

too

dem

andi

ngfo

rth

epr

ojec

trep

orte

din

this

thes

is,a

ndit

was

deci

dedt

ous

em

ainl

yth

e2D

mod

el.

The

imm

erse

dbou

ndar

ymet

hodh

asbe

enst

udie

dand

used

byot

hers

.Bey

eran

dLe

Veq

ue(1

992)

stud

ied

the

accu

racy

ofva

rious

num

eric

alap

prox

imat

ions

toth

eflu

idbo

unda

ryco

uplin

gin

aon

e-di

men

sion

almod

elus

ing

the

imm

erse

dbo

unda

rym

etho

d,an

din

Bey

er(1

992)

the

met

hodw

asus

edfo

ra

mod

elof

the

coch

lea(

inne

rear

).S

tock

iean

dW

etto

n(1

995)

pres

ente

dast

abili

tyan

alys

isof

the

equa

tions

for

the

imm

erse

dbou

ndar

ymet

hod.

Lem

mon

,Yog

anat

hana

ndco

wor

kers

have

used

the

prin

cipl

esof

the

imm

erse

dbo

unda

rym

etho

dto

cons

truc

tthei

row

n3D

mod

elof

the

left

side

ofth

ehe

art.

In

1.1

Hea

rtsi

mul

atio

ns3

Ves

iera

ndY

ogan

atha

n(199

2)th

em

etho

dis

valid

ated

byco

mpa

rison

betw

eent

heco

mpu

tatio

nalre

sults

for

am

odel

ofth

eflo

wth

roug

ha

flexi

ble

tube

and

anap

-pr

oxim

atea

naly

ticso

lutio

n.In

Yog

anat

hane

tal.

(199

4)th

e3D

mod

elof

the

flow

inth

ele

ftve

ntric

ledu

ring

part

ofsy

stol

eis

pres

ente

d,and

som

ecom

paris

onsw

ithex

perim

enta

lresu

ltsar

ere

port

ed.T

his

mod

elis

used

inY

ogan

atha

neta

l.(1

995)

tost

udyt

hesy

stol

ican

terio

rmitr

alva

lve

mot

ion

synd

rom

e.In

allo

fthe

sepa

pers

the

grou

pus

esth

esa

men

umer

ical

met

hoda

sorig

inal

lyus

edby

Pes

kina

ndM

c-Q

ueen

.As

men

tione

dabo

ve,t

his

met

hodi

sno

tabl

eto

com

pute

atph

ysio

logi

cal

Rey

nold

snu

mbe

rs.I

nLe

mm

onan

dY

ogan

atha

n(19

98)t

hegr

oup

chan

gedt

henu

mer

ical

met

hodt

ore

duce

the

com

puta

tiona

ldem

ands

ofth

em

odel

and

tobe

able

toco

mpu

teat

phys

iolo

gica

lRey

nold

snum

bers

.Thi

sw

asfu

rthe

rexp

loite

din

Lem

mon

and

Yog

anat

han(2

000b

)whe

rea

3Dm

odel

ofth

eflo

wth

roug

hthe

left

hear

tdur

ing

dias

tole

was

pres

ente

dand

eval

uate

dby

com

paris

onsto

clin

ical

data

.T

his

dias

tolic

3Dm

odel

isus

edin

Lem

mon

and

Yog

anat

han(2

000a

)tosi

mul

ate

path

olog

ical

cond

ition

sand

ther

ebyi

nves

tigat

ethe

dias

tolic

func

tion

ofth

ehe

art.

The

imm

erse

dbou

ndar

ymet

hodi

ssp

ecia

linth

ew

ayit

mod

elst

hein

tera

ctio

nbe

twee

nthe

fluid

flow

and

the

tissu

esof

the

hear

t.A

noth

erap

proa

chis

tole

tth

em

ovem

ento

fth

ebo

unda

rybe

give

nin

adva

nce

inde

pend

ently

ofth

eflo

w.

Inth

isap

proa

chon

lyth

ere

sulti

ngflo

wof

the

fluid

has

tobe

com

pute

d.T

hem

etho

dof

pred

eter

min

edbo

unda

rym

otio

nw

asca

rrie

dou

tin

Geo

rgia

dis

etal

.(1

992)

fora

nid

ealiz

edve

ntric

ular

geom

etry

inth

efo

rmof

aco

ntra

ctin

gelli

psoi

d.In

Tayl

oret

al.(

1993

),Ta

ylor

and

Yam

aguc

hi(1

995b

),Ta

ylor

and

Yam

aguc

hi(1

995a

)and

Tayl

oret

al.(

1996

)it

was

done

for

a3D

geom

etry

cons

truc

tedu

sing

aca

stof

ado

g’s

hear

ttake

nin

the

dias

tolic

phas

ewith

anas

sum

edm

ovem

ento

fth

eve

ntric

ular

wal

l.F

urth

erm

ore,

Sch

oeph

oers

teret

al.

(199

3;19

94)u

sed2

Dci

ne-a

ngio

grap

hicim

ages

tode

term

inet

hehe

artw

allb

ound

aryi

nbo

tha

heal

thy

and

adi

seas

ed(c

oron

arya

rter

ydis

ease

)left

vent

ricle

and

subs

eque

ntlyc

ompu

ted

the

flow

durin

gsy

stol

e.T

hey

expa

nded

thei

rm

etho

dto

asi

mpl

esp

heric

al3D

vent

ricle

inG

onza

leza

ndS

choe

phoe

rste

r(199

6),w

here

they

also

inve

stig

ated

the

effe

ctof

abno

rmal

wal

lmot

ion

onth

eflo

wpa

ttern

.In

Din

gan

dS

choe

phoe

rste

r(1

997)

they

used

cine

-ang

iogr

amsto

cons

truc

ta3D

syst

olic

mod

elof

the

left

vent

ricle

assu

min

gcirc

ular

cros

ssec

tions

.T

hem

etho

dof

pred

eter

min

edbo

unda

rym

otio

nha

sals

obe

enus

edin

com

-bi

natio

nw

ithM

Rsc

anni

ngda

ta.J

ones

and

Met

axas

(199

8)us

edM

RI

SPA

MM

togi

veth

ehe

artb

ound

aryc

onfig

urat

ionf

ora

flow

mod

elof

the

left

vent

ricle

.M

RI

SPA

MM

allo

ws

trac

king

ofm

ater

ialp

oint

son

the

hear

tand

give

san

accu

-ra

tere

pres

enta

tiono

fthe

left

vent

ricul

arm

otio

nfr

omen

d-di

asto

leto

end-

dias

tole

(Par

ket

al.,

1996

).S

aber

etal

.(20

01)u

seda

nato

mic

aldat

aobt

aine

dby

MR

scan

-ni

ngto

cons

truc

tam

odel

ofth

ele

ftve

ntric

leus

ing

mov

ing

mes

hes.T

heir

mod

el

Page 12: MR · 2002. 2. 20. · Adeler A TV Erhver vsf or skerpr ojekt EF 698 IMM-PHD-2001-86 ISSN 0909-3192 ISBN 87-88306-13-5 c 2001 by Pernille Thorup Adeler Printed by IMM, DTU Bookbinder

4In

trod

uctio

n

sim

ulat

esth

ebl

ood

flow

durin

ga

full

card

iacc

ycle

exce

ptfo

rth

ela

tedi

asto

le.

1.2

MR

scan

ning

The

curr

ents

tate

ofth

em

agne

ticre

sona

nce(

MR

)te

chni

quea

llow

sth

ede

ter-

min

atio

nof

3Dve

loci

tyfie

lds

for

the

flow

inth

ehu

man

hear

t(e.

g.H

oulin

det

al.,

1994

;Kim

etal

.,19

95;W

alke

reta

l.,19

96).

InH

oulin

det

al.(

1994

)and

Kim

etal

.(1

995)

the

thre

eco

mpo

nent

sof

the

bloo

dve

loci

tyfie

ldin

asi

ngle

slic

e(t

helo

ng-a

xis

plan

e)w

asob

tain

edin

patie

ntsw

ithis

chem

iche

artd

isea

sean

din

norm

alsu

bjec

ts,re

spec

tivel

y.F

rom

thes

evel

ocity

data

they

extr

actv

eloc

-ity

time

curv

esat

cert

ain

posi

tions

,e.g

.ove

rthe

mitr

alrin

g.F

urth

erm

ore,

Kim

etal

.(19

95)q

uant

ified

the

left

vent

ricle

vort

exse

endu

ring

dias

tole

.Wal

kere

tal.

(199

6)m

easu

redth

eth

ree

dim

ensi

onal

bloo

dve

loci

tyfie

ldin

mul

tiple

slic

esin

the

hum

anhe

art.

Inal

loft

hese

thre

epap

ersq

ualit

ative

desc

riptio

nsof

the

bloo

dflo

war

eal

sogi

ven.

Rec

ently

,MR

scan

ning

hasb

eenu

sedi

nth

eas

sess

men

tofth

edi

asto

licfu

nc-

tioni

ngof

the

left

vent

ricle

.Hou

lind

etal

.(19

99)i

nves

tigat

edth

eag

e-de

pend

ent

chan

gesin

the

bloo

dve

loci

tydi

strib

utio

ndu

ring

early

fillin

g.In

trav

entr

icul

arflo

wha

sbe

enco

rrel

ated

with

dise

asea

ndis

ofim

port

ance

toca

rdio

logi

stas

apo

ssib

lem

eans

ofdi

agno

sis(

Wal

kere

tal.,

1996

).In

Hou

lind

(200

1b)t

hech

ange

sinea

rlydi

asto

licbl

ood

flow

patte

rnsi

ndi

s-ea

sedh

eart

s(e.

g.fr

omac

utem

yoca

rdia

linfa

rctio

n)ar

einv

estig

ated

ands

oar

ethe

chan

gesin

velo

city

profi

leso

btai

neda

long

tran

sver

selin

esin

the

left

vent

ricle

attim

esju

stpr

iort

oan

dafte

rthe

occu

rren

ceof

the

peak

velo

city

atth

em

itral

leafl

ettip

s.E

xam

inin

gth

epe

akve

loci

ty(t

hem

agni

tude

and

the

time

ofoc

curr

ence

)at

such

lines

give

sins

ight

into

the

dias

tolic

func

tioni

ngof

the

hear

t.E

spec

ially

the

rela

xatio

nof

the

left

vent

ricle

(whi

chis

redu

cedd

urin

gce

rtai

nhe

artc

ondi

tions

)in

fluen

cest

hedi

asto

licfu

nctio

ning

ofth

ehe

art,

and

this

isre

flect

edin

the

flow

patte

rndu

ring

fillin

g.H

owev

er,a

tpre

sent

note

very

mec

hani

smre

spon

sibl

efor

the

obse

rved

chan

gesin

the

bloo

dflo

wpa

ttern

iskn

own.

1.3

Usi

ngsi

mul

atio

nsan

dM

Rda

tato

geth

er

Com

puta

tiona

lmod

elso

fth

ehe

arta

reve

ryus

eful

assi

mul

atio

nto

ols,

whe

reth

eus

ere.

g.ca

nte

stth

ena

tura

land

path

olog

ical

func

tioni

ngof

the

hear

t.In

aco

mpu

tatio

nalm

odel

the

effe

ctso

fdiff

eren

tpar

amet

ersc

anbe

inve

stig

ated

inde

-pe

nden

tlyan

dco

mbi

ned.

But

for

thes

emod

elto

betr

ustw

orth

yth

ere

sults

have

tobe

valid

ated

.The

type

ofM

Rm

easu

rem

entsp

rese

nted

ine.

g.K

imet

al.(

1995

)

1.4

Out

line

ofth

esis

5

are

idea

lfor

valid

atio

nof

mod

elso

fth

ebl

ood

flow

inth

ehe

art,

sinc

eth

eyar

em

easu

rem

entso

fthe

bloo

dve

loci

tyfie

ldw

hich

isth

ety

pica

lout

putf

rom

aco

m-

puta

tiona

lmod

el.N

atur

ally,

deriv

edqu

antit

ies,

such

asve

loci

tytim

ecu

rves

,can

also

beco

mpa

redb

etw

eenm

odel

and

MR

mea

sure

men

ts.C

ompu

tatio

nalm

od-

els

ofth

ebl

ood

flow

inth

ehe

arth

ave

not,

toou

rkn

owle

dge,

prev

ious

lybe

enva

lidat

edin

deta

ilby

com

paris

onsto

MR

velo

city

field

data

.T

hepo

ssib

ility

ofco

mbi

ning

MR

mea

sure

men

tsand

com

puta

tiona

lhear

tmod

-el

sto

obta

ina

com

pute

rtool

fors

tudy

ingt

hefu

nctio

ning

ofth

ehu

man

hear

tisth

em

otiv

atio

nfo

rou

rwor

k.W

est

artw

ithP

eski

nand

McQ

ueen

’s2D

hear

tmod

elof

ado

g’s

hear

tand

thro

ugh

the

use

ofM

Rda

taan

dge

nera

lphy

siol

ogic

alan

dan

atom

ical

know

ledg

eadj

ustit

tore

pres

enta

hum

anhe

art.

The

n,th

em

odel

and

itssi

mul

atio

nres

ults

are

eval

uate

dand

com

pare

dwith

MR

data

.Thi

s2D

hum

anhe

artm

odel

can

then

beus

edto

stud

ycer

tain

mec

hani

smsa

ffect

ing

the

dias

tolic

func

tioni

ngof

the

hear

tund

erpa

thol

ogic

alco

nditi

ons.

1.4

Out

line

ofth

esis

The

thes

isis

orga

nize

dasf

ollo

ws:

Cha

pter

1T

his

intr

oduc

tion.

Cha

pter

2D

escr

iptio

noft

heph

ysio

logy

and

anat

omyo

fthe

hear

t.T

hech

apte

rin

trod

uces

the

read

erto

the

nece

ssar

yphy

siol

ogic

alba

ckgr

ound

know

ledg

ean

dte

rmsu

sedi

nth

esu

bseq

uentc

hapt

ers.

Cha

pter

3O

ur2D

mod

elof

the

left

side

ofth

ehu

man

hear

tisde

scrib

edin

both

the

cont

inuo

usan

dth

edi

scre

teca

se,a

ndth

eco

mpu

tatio

nalp

roce

dure

isgi

ven.

The

impr

ovem

entsa

ndch

ange

snee

dedto

tran

sfor

mP

eski

nand

Mc-

Que

en’s

orig

inal

2Dm

odel

ofa

dog’

she

artt

oth

atof

ahu

man

hear

tare

argu

edfo

ran

dde

scrib

ed.

Cha

pter

4E

valu

atio

nof

the

2Dm

odel

from

Cha

pter

3.C

erta

inco

mpu

tatio

nal

andm

odel

linga

spec

tsoft

hem

odel

aree

valu

ated

andt

hepr

oper

adju

stm

ent

ofm

odel

para

met

ersis

foun

d.

Cha

pter

5C

ompa

rison

ofth

e2D

mod

elfr

omC

hapt

er4

with

anM

Rda

tase

tof

the

velo

city

field

inth

ehu

man

hear

t.T

hein

trav

entr

icul

arve

loci

tyfie

ldan

dve

loci

tytim

ecu

rves

atth

em

itral

ring

and

atth

eao

rtic

outfl

owtr

acta

reco

mpa

redw

ithco

rres

pond

ingM

Rda

ta.

Page 13: MR · 2002. 2. 20. · Adeler A TV Erhver vsf or skerpr ojekt EF 698 IMM-PHD-2001-86 ISSN 0909-3192 ISBN 87-88306-13-5 c 2001 by Pernille Thorup Adeler Printed by IMM, DTU Bookbinder

6In

trod

uctio

n

Cha

pter

6T

he2D

mod

elfr

omC

hapt

er4

isus

edto

sim

ulat

ecer

tain

mec

hani

sms

ofea

rlyfil

ling

ofth

ele

ftve

ntric

leun

derp

atho

logi

calc

ondi

tions

.Thi

sre

-qu

iresi

mpr

ovin

gth

em

odel

for

the

rela

xatio

nand

cont

ract

iono

fth

ehe

art

wal

l.T

heim

prov

edm

odel

isth

ense

tup

tosi

mul

atea

heal

thyh

uman

,and

path

olog

ical

cond

ition

sare

sim

ulat

edby

alte

ring

the

rela

xatio

nan

dco

n-tr

actio

nof

the

vent

ricle

.

Cha

pter

7D

escr

iptio

nof

Pes

kina

ndM

cQue

en’s

3Dm

odel

ofth

een

tire

hear

t.T

here

sults

from

asi

mul

atio

nwith

the

mod

elar

ebrie

flyco

mpa

redw

ithM

Rda

ta.

Cha

pter

8T

heco

nclu

sion

sof

the

thes

isar

esu

mm

ariz

edan

dre

com

men

datio

nsfo

rfu

ture

wor

kar

epr

esen

ted.

App

endi

xA

Intr

oduc

tion

toth

em

agne

ticre

sona

nceim

agin

gte

chni

que.

Thi

sap

pend

ixpr

ovid

esth

ere

ader

with

back

grou

ndin

form

atio

non

how

the

MR

data

used

inth

eth

esis

isob

tain

ed.

Cha

pter

2

Phy

siol

ogy

and

anat

omy

ofth

ehe

art

Thi

sch

apte

rpro

vide

san

intr

oduc

tiont

oth

eph

ysio

logy

and

anat

omyo

fthe

hear

tes

sent

ialfo

rund

erst

andi

ngth

esu

bseq

uentc

hapt

erso

fthi

sth

esis

.Itis

part

lyba

sed

onO

lufs

enet

al.(

2001

),an

dw

eus

eGan

ong(

1993

),To

rtor

a(1

999)

and

Guy

ton

(199

1)as

refe

renc

es.

The

hear

tisth

epu

mp

that

driv

esth

ebl

ood

flow

inth

eca

rdio

vasc

ular

syst

emby

perio

dic

cont

ract

iona

ndre

laxa

tiono

fth

ehe

artm

uscl

es.T

heca

rdio

vasc

ular

syst

emco

nsis

tsof

two

part

s,th

esy

stem

ican

dpu

lmon

aryc

ircui

ts,c

onne

cted

via

the

left

and

right

hear

tcha

mbe

rs.F

rom

the

left

side

ofth

ehe

artb

lood

ispu

mpe

din

toth

esy

stem

icci

rcui

tth

roug

hth

eao

rta.

The

syst

emic

circ

ulat

ion

tran

spor

tsan

ddi

strib

utes

esse

ntia

lsubs

tanc

esto

the

tissu

esan

dit

rem

oves

bypr

oduc

tsof

met

abol

ism

.Inth

em

uscl

esan

dtis

sues

oxyg

enis

part

ially

exch

ange

dwith

carb

ondi

oxid

e.A

sa

resu

ltsth

ebl

ood

ispa

rtly

deox

ygen

ated

whe

nit

retu

rnst

oth

erig

htsi

deof

the

hear

tthro

ught

wo

big

vein

s(th

esu

perio

rand

infe

riorv

enac

ava)

.The

right

side

ofth

ehe

artp

umps

the

bloo

din

toth

epu

lmon

aryc

ircul

atio

n.H

ere

the

part

lyde

oxyg

enat

edbl

ood

isca

rrie

dto

the

lung

tissu

esw

here

carb

ondi

oxid

eis

exch

ange

dwith

oxyg

enan

dth

ebl

ood

then

retu

rnst

oth

ele

ftsi

deof

the

hear

tth

roug

hfou

rpul

mon

aryv

eins

(tw

ofr

omea

chlu

ng).

Page 14: MR · 2002. 2. 20. · Adeler A TV Erhver vsf or skerpr ojekt EF 698 IMM-PHD-2001-86 ISSN 0909-3192 ISBN 87-88306-13-5 c 2001 by Pernille Thorup Adeler Printed by IMM, DTU Bookbinder

8P

hysi

olog

yand

anat

omy

ofth

ehe

art

2.1

Inte

rnal

anat

omy

The

hear

tcon

sist

sof

four

cham

bers

assh

own

inF

igur

e2.

1.T

hele

ftve

ntric

lean

dle

ftat

rium

cons

titut

ethe

left

side

ofth

ehe

arta

ndth

erig

htve

ntric

lean

drig

htat

rium

cons

titut

ethe

right

side

ofth

ehe

art.

The

left

and

right

side

sof

the

hear

tare

sepa

rate

dby

ase

ptum

.T

heat

riaar

edi

vide

dby

the

inte

ratr

ials

eptu

man

dth

eve

ntric

lesa

rese

para

tedb

yth

ein

-te

rven

tric

ular

sept

um.T

heat

riove

ntric

ular

open

ing

conn

ects

each

atriu

mto

itsco

rres

pond

ingv

entr

icle

.Thi

sop

enin

gis

surr

ound

edby

arin

gof

fibro

sust

issu

e,th

ean

nulu

sfibr

osus

.The

low

erpa

rtof

the

hear

tisca

lledt

heap

exw

hile

the

uppe

rbr

oade

ndof

the

hear

tisca

lled

the

base

,see

Fig

ure

2.2.

The

hear

twal

lsco

nsis

tofm

uscl

etis

sued

enot

edth

em

yoca

rdiu

m.T

heth

ick-

ness

ofth

em

yoca

rdiu

mva

rieso

vert

hehe

arta

ndin

crea

sesw

ithw

orkl

oad.

The

atria

dole

ssw

ork

than

the

vent

ricle

s.C

onse

quen

tlyth

eat

rialw

alls

are

thin

ner,

appr

oxim

atel

y2m

m.

The

right

vent

ricle

isex

pose

dto

the

pres

sure

ofth

epu

l-

Fig

ure

2.1:

The

four

-cha

mbe

redh

eart

isdi

vide

din

totw

opa

rts,

the

left

and

right

side

s.B

oth

part

scon

sist

ofa

vent

ricle

and

anat

rium

.The

left

side

ofth

ehe

artis

anat

omic

ally

larg

erth

anth

erig

htsi

de.F

rom

Rid

eout

(199

1).

2.1

Inte

rnal

anat

omy

9

Fig

ure

2.2:

Dra

win

gof

ahe

arts

plit

perp

endi

cula

rtoth

ein

terv

entr

icul

arse

ptum

.A

dapt

edfr

omN

ette

r(19

91).

mon

ary

circ

ulat

ion

and

has

aw

all

thic

knes

sof

abou

t5m

m.

The

grea

test

wal

lth

ickn

ess,

abou

t15

mm

,bel

ongs

toth

ele

ftve

ntric

lew

hich

ejec

tsbl

ood

into

the

entir

esy

stem

icci

rcul

atio

n.T

hebl

ood

flow

inth

ehe

arti

sun

idire

ctio

nald

ueto

two

sets

ofva

lves

,the

atrio

vent

ricul

arva

lves

and

the

sem

iluna

rval

ves.

The

atrio

vent

ricul

arva

lves

are

loca

tedb

etw

eene

acha

triu

man

dve

ntric

le.T

hese

milu

narv

alve

sare

foun

din

the

open

ingb

etw

eene

achv

entr

icle

and

itsco

rres

pond

ingo

utflo

war

tery

.V

alve

sare

notf

ound

atth

eve

nous

inle

tsin

toth

eat

ria,s

eeF

igur

e2.

2.T

heat

riove

ntric

ular

valv

esco

nsis

tofl

eafle

ts(c

usps

)with

atr

iang

ular

shap

e.T

herig

hthe

artc

ham

berc

onta

inst

hree

leafl

etsa

ndco

nseq

uent

lythe

valv

eis

de-

note

dthe

tric

uspi

dva

lve.

The

valv

ein

the

left

cham

berc

onta

inst

wo

leafl

etsa

ndis

thus

refe

rred

toas

the

bicu

spid

valv

e(o

rm

ore

com

mon

lyth

em

itral

valv

e).

Leafl

ette

ndon

s,al

soca

lled

the

chor

daet

endi

neae

,are

foun

dun

dere

achv

alve

.T

hey

orig

inat

efro

mth

epa

pilla

rym

uscl

esth

atar

elo

cate

don

the

inne

rsur

face

ofea

chve

ntric

le.W

hen

the

atriu

mco

ntra

ctst

hele

aflet

shan

gsla

ckin

the

vent

ricle

,bu

twhe

nth

eve

ntric

leco

ntra

ctst

hele

aflet

sare

push

edto

geth

ercl

osin

gth

eat

ri-ov

entr

icul

arop

enin

g.T

hech

orda

eten

dine

aese

cure

the

leafl

ets,

prev

entin

gth

emfr

omm

ovin

gin

toth

eat

rium

durin

gth

eco

ntra

ctio

noft

heve

ntric

le.

The

sem

iluna

rval

ves

prev

entb

lood

from

flow

ing

back

into

the

hear

tafte

rej

ectio

nint

oth

ear

terie

s.E

ach

ofth

ese

milu

narv

alve

scon

sist

soft

hree

cres

cent

shap

edle

aflet

s.T

hese

leafl

etsh

ave

noch

orda

eten

dine

ae.T

hey

are

dila

ted

with

Page 15: MR · 2002. 2. 20. · Adeler A TV Erhver vsf or skerpr ojekt EF 698 IMM-PHD-2001-86 ISSN 0909-3192 ISBN 87-88306-13-5 c 2001 by Pernille Thorup Adeler Printed by IMM, DTU Bookbinder

10P

hysi

olog

yand

anat

omy

ofth

ehe

art

bloo

dan

dcl

oset

heop

enin

gwhe

nth

epr

essu

rein

the

arte

ryex

ceed

sthe

pres

sure

inth

eve

ntric

le.T

herig

htse

milu

narv

alve

isca

lled

the

pulm

onar

yval

ve,w

hile

the

left

sem

iluna

rval

veis

calle

dth

eao

rtic

valv

e.

2.2

Fun

ctio

ning

ofth

ehe

art

The

time

cour

seof

ahe

artp

erio

dcan

roug

hlyb

edi

vide

din

toan

activ

eph

asea

nda

rela

xed

phas

e,te

rmed

syst

olea

nddi

asto

le,re

spec

tivel

y.T

herig

htan

dlef

tsid

esof

the

hear

twor

kal

mos

tsyn

chro

nous

ly,m

eani

ngth

atth

eyco

ntra

ctan

drel

axal

mos

tat

the

sam

etim

e.W

hen

dias

tole

begi

nsth

epu

lmon

arya

ndao

rtic

valv

esar

ecl

osed

,bec

ause

the

pres

sure

inth

ear

terie

sexc

eeds

the

pres

sure

inth

eve

ntric

les.

The

tric

uspi

dan

dm

itral

valv

ear

eop

en,a

ndth

eve

nous

bloo

dflo

ws

thro

ugh

the

atria

and

fills

the

rela

xed

vent

ricle

s.T

hent

heat

riaco

ntra

ct(a

tria

lsys

tole

)thus

incr

easi

ngth

eflo

wto

the

vent

ricle

san

dca

usin

gthe

pres

sure

inth

eve

ntric

lest

oris

e.S

hort

lyaf

ter,

vent

ricul

arsy

s-to

lese

tsin

resu

lting

ina

pres

sure

rise

that

caus

esth

etr

icus

pid

and

mitr

alva

lves

tocl

ose.

Thu

sth

eve

ntric

lesc

ontr

actis

ovol

umic

ally

.T

his

ends

whe

nth

eve

n-tr

icul

arpr

essu

reeq

uals

the

arte

rialp

ress

ure,

atw

hich

poin

tthe

pulm

onar

yand

aort

icva

lves

open

and

bloo

dflo

ws

into

the

arte

rials

yste

m.T

hepu

lmon

arya

ndao

rtic

valv

esdo

noto

pen

atth

esa

met

ime

inth

etw

osi

deso

fth

ehe

art.

The

pulm

onar

yval

vein

the

right

side

open

swhe

nth

epr

essu

rein

the

right

vent

ricle

exce

eds1

0m

mH

gan

dth

eao

rtic

valv

ein

the

left

side

open

swhe

nth

epr

essu

rein

the

left

vent

ricle

exce

eds8

0m

mH

g.T

heop

enin

goft

hepu

lmon

arya

ndao

rtic

valv

esm

arks

the

onse

tofe

ject

ion.

The

pulm

onar

yand

aort

icva

lves

clos

ewhe

nve

ntric

ular

pres

sured

rops

belo

war

teria

lpre

ssur

eand

initi

ates

the

next

isov

olum

ical

rela

xatio

npha

sean

da

furt

her

fall

inve

ntric

ular

pres

sure

.Whe

nth

eve

ntric

ular

pres

sure

falls

belo

wth

eat

rial

pres

sure

,the

tric

uspi

dan

dm

itral

valv

esop

enan

dth

ebl

ood

that

hase

nter

edth

eat

rium

durin

gve

ntric

ular

syst

olefl

ows

into

the

vent

ricle

s(th

ispe

riod

isca

lledt

hera

pidl

yfil

ling

phas

e),a

nda

new

hear

tcyc

lest

arts

.T

heam

ount

ofbl

ood

ejec

tedb

yea

chve

ntric

lepe

rstr

oke

isab

out7

0m

l.T

heej

ectio

nfra

ctio

n(t

hepe

rcen

tage

ofth

eve

ntric

ular

volu

me

ejec

teda

teac

hstr

oke)

isab

out6

5%(G

anon

g,19

93).

Car

diac

outp

utis

defin

edas

the

amou

ntof

bloo

dej

ecte

dfro

mth

ele

ftve

ntric

lein

toth

eas

cend

inga

orta

.In

are

stin

gad

ultt

his

isap

prox

imat

ely5

l/min

(70

ml

0 72be

ats/

min

)(G

anon

g,199

3).

The

pum

ping

hear

trep

eatst

his

cour

sedu

ring

each

beat

with

atim

epe

riod

ofap

prox

imat

ely0

.8si

nre

stin

ghum

ans.

Fig

ure

2.3

show

sve

ntric

ular

pres

sure

and

2.3

Con

duct

ion

syst

emof

the

hear

t11

Fig

ure

2.3:

The

root

aort

icpr

essu

re,ve

ntric

ular

pres

sure

,atria

lpre

ssur

e,art

eria

lin

flow

,tot

alin

flow

toth

ehe

art,a

tria

lvol

ume,

vent

ricul

arvo

lum

ean

dve

ntric

ular

outfl

ow.

The

vert

ical

fully

draw

nan

dda

shed

lines

indi

cate

valv

ecl

osur

ean

dop

enin

gs,re

spec

tivel

y.F

rom

Noo

rder

graa

f(19

78).

flow

curv

esth

atar

ere

pres

enta

tivefo

ra

norm

alhu

man

left

vent

ricle

.

2.3

Con

duct

ion

syst

emof

the

hear

t

The

cont

ract

iono

fthe

hear

tisin

itiat

edby

elec

tric

alst

imul

atio

n.T

hese

elec

tric

alim

puls

esar

espr

eadt

oal

lpar

tsof

the

myo

card

ium

byth

eco

nduc

tions

yste

m.T

heco

nduc

tions

yste

mco

nsis

tof

the

sino

atria

l(S

A)

node

,the

atrio

vent

ricul

ar(A

V)

node

,the

atrio

vent

ricul

arbu

ndle

(orb

undl

eof

His

),th

ebu

ndle

bran

ches

,and

the

cond

uctin

gfibe

rsca

lledP

urki

njefi

bers

,see

Fig

ure2

.4.A

llpa

rtso

fthe

cond

uctio

nsy

stem

are

able

tose

ndou

tper

iodi

cim

puls

esw

ithou

tneu

rals

timul

atio

n.T

his

isca

lled

auto

mat

ism

.T

heS

Ano

deis

asm

allm

asso

fmus

cula

rfibe

rslo

cate

din

the

myo

card

ium

ofth

erig

htat

rium

near

the

inflo

wof

the

supe

riorv

enac

ava,

seeF

igur

e2.

4.T

heS

A

Page 16: MR · 2002. 2. 20. · Adeler A TV Erhver vsf or skerpr ojekt EF 698 IMM-PHD-2001-86 ISSN 0909-3192 ISBN 87-88306-13-5 c 2001 by Pernille Thorup Adeler Printed by IMM, DTU Bookbinder

12P

hysi

olog

yand

anat

omy

ofth

ehe

art

Fig

ure

2.4:

Sch

emat

icrep

rese

ntat

iono

fthe

cond

uctio

nsys

tem

ofth

ehe

art.F

rom

Tort

ora

(199

9).

node

gene

rate

simpu

lses

fast

erth

anth

eot

herp

arts

ofth

eco

nduc

tions

yste

man

dth

usin

itiat

esea

chhe

artb

eatan

dco

ntro

lsth

efr

eque

ncy

ofth

ehe

artr

ate.

The

impu

lses

from

the

SA

node

reac

hthe

atria

first

,cau

sing

them

toco

ntra

ct.

The

velo

city

ofco

nduc

tioni

nth

eat

rialm

uscl

eis

betw

een0

.3m

/san

d1.

0m

/s(G

uyto

n,19

91).

Late

rthe

impu

lses

reac

hthe

AV

node

.The

AV

node

islo

cate

din

the

inte

ratr

ials

eptu

m,s

eeF

igur

e2.

4.T

heA

Vno

deco

nduc

tssl

owly

,i.e

.the

impu

lses

are

dela

yed(

appr

oxim

atel

y0.1

3s,

Guy

ton,

1991

)in

the

AV

node

.Thi

sal

low

sfo

rth

eat

riato

empt

ythe

irbl

ood

(by

cont

ract

ion)

into

the

vent

ricle

sbef

ore

the

vent

ricle

ssta

rtto

cont

ract

.Fro

mth

eA

Vno

deth

eim

puls

esar

ese

ntth

roug

hth

ebu

ndle

ofH

is.

The

bund

leof

His

isth

eon

lyel

ectr

ical

conn

ectio

nbet

wee

nth

eat

riaan

dve

ntric

les.

The

bund

leof

His

bran

ches

into

two,

one

bran

chgo

ing

toth

erig

htve

ntric

lean

dth

eot

herg

oing

toth

ele

ftve

ntric

le.B

oth

bran

ches

goin

the

dire

ctio

nof

the

apex

ofth

ehe

arta

ndsu

bdivi

dein

toa

com

plex

netw

ork

ofP

urki

nje

fiber

s,se

eFig

ure

2.4.

The

latte

rstim

ulat

esve

ntric

ular

cont

ract

ion.

The

cont

ract

ions

tart

satt

heap

exan

dth

ensp

read

ssup

erio

rlyto

war

dth

eba

seof

the

hear

t.T

heco

nduc

tionv

eloc

ityin

the

Pur

kinj

efib

ers

isve

ryfa

st(a

ppro

xim

atel

y1.

5–4.

0m/s

)and

the

elec

tric

alim

puls

esre

acht

heen

tire

inne

rsur

face

ofth

eve

n-tr

icle

sal

mos

tsim

ulta

neou

sly.

The

nth

eim

puls

esm

ove

thro

ugh

the

vent

ricul

arm

uscl

esto

war

dth

eou

ters

urfa

ceof

the

hear

twith

ave

loci

tyof

appr

oxim

atel

y0.

3-0.

5m/s

.

2.4

Mus

cle

phys

iolo

gy13

2.4

Mus

cle

phys

iolo

gy

The

hear

tpum

psby

the

cont

ract

iono

fits

mus

clefi

bers

.The

hear

thas

aco

mpl

exge

omet

ricst

ruct

urew

ithm

uscl

esly

ing

ina

com

plic

ated

patte

rn.T

heca

rdia

cmus

-cl

eits

elfc

onsi

stso

fin

divi

dual

mus

clefi

bers

,or

myo

cyte

s,w

hich

are

the

smal

l-es

tfun

ctio

nalu

nits

inth

em

uscl

estr

uctu

re.E

ach

mus

clefi

beri

sap

prox

imat

ely

# * m

long

with

adi

amet

erof

# * m

.T

hem

uscl

efibe

rsbr

anch

and

inte

rdig

itate

,but

each

fiber

isa

com

plet

euni

tsur

roun

dedb

ya

cell

mem

bran

e.M

uscl

efib

ers

cont

ain

anu

mbe

rof

fibril

spl

aced

inpa

ralle

l,eac

hof

whi

chis

subd

ivide

dby

the

Z-li

nes

into

bloc

ksca

lleds

arco

mer

es.The

sarc

omer

essho

wal

-te

rnat

ingl

ight

and

dark

band

s,du

eto

para

llelb

undl

esof

thic

kan

dth

infil

amen

ts.

The

top

pane

lof

Fig

ure

2.5

show

sa

piec

eof

afib

rilw

ithits

char

acte

ristic

stria

ted

patte

rn,a

nda

sarc

omer

egoi

ngfr

omon

eZ

line

toan

othe

r.A

tth

eZ

Thi

n fil

amen

t

Thi

ck fi

lam

ent

Z li

neZ

line

Sar

com

ere

Z li

neZ

line

Z li

neZ

line

Rel

axed

Con

trac

ted

Fib

ril −

rel

axed

Fig

ure

2.5:

Top

pane

lsho

ws

ase

ctio

nof

are

laxe

dfib

rilw

ithits

char

acte

ristic

strip

edpa

ttern

.T

hest

riped

patte

rnfo

llow

sfr

omth

ebu

ndle

sof

inte

rdig

itatin

gth

ick

and

thin

filam

ents

how

nin

the

mid

dle

pane

l.T

helo

wer

pane

lsho

ws

the

cont

ract

edst

atew

here

the

Zlin

esm

oves

clos

erto

geth

er.

Page 17: MR · 2002. 2. 20. · Adeler A TV Erhver vsf or skerpr ojekt EF 698 IMM-PHD-2001-86 ISSN 0909-3192 ISBN 87-88306-13-5 c 2001 by Pernille Thorup Adeler Printed by IMM, DTU Bookbinder

14P

hysi

olog

yand

anat

omy

ofth

ehe

art

lines

the

sarc

otub

ular

syst

emis

loca

ted.

Itco

nsis

tsof

the

sarc

opla

smicr

etic

ulum

(whi

chco

ntai

nsa

Ca. 1 re

servo

ir)an

dth

eT

syst

em.B

oth

ofth

esea

rees

sent

ial

for

cont

ract

iono

fthe

mus

clefi

bers

,see

belo

w.

Inth

em

iddl

epa

nelin

Fig

ure

2.5

the

inte

rdig

itatin

gth

ick

and

thin

filam

ents

are

show

nw

hen

the

fiber

isin

are

laxe

dst

ate.

Whe

na

mus

clefi

berc

ontr

acts

the

thin

filam

ents

slid

eov

erth

eth

ick

filam

ents

.The

leng

thof

the

thic

kfil

amen

tsis

cons

tant

,whe

reas

the

Zlin

esm

ove

clos

erto

geth

erw

hen

the

mus

clec

ontr

acts

and

fart

hera

part

whe

nit

isst

retc

hed.

As

the

mus

cles

hort

ens,t

heth

infil

amen

tsfr

omth

eop

posi

teen

dsof

the

sarc

omer

eapp

roac

heac

hoth

eran

dev

entu

ally

over

lap.

The

botto

mpa

nelo

fF

igur

e2.

5sh

ows

the

slid

edth

ick

and

thin

filam

ents

ina

cont

ract

edst

ate,

whe

reth

eth

infil

amen

tsar

eno

tyet

over

lapp

ing.

Con

trac

tiono

fth

em

uscl

efib

ers

isin

itiat

edby

ach

ange

inth

epo

tent

ialo

fth

ece

llm

embr

anes

urro

undi

ngth

efib

er.

Car

diac

cells

resp

ondt

oan

elec

tric

alst

imul

usby

prod

ucin

gcha

nges

inth

eio

nco

nduc

tanc

esand

inth

epo

tent

ialo

fthe

irm

embr

ane.

Ifth

est

imul

usis

suffi

cien

tlyst

rong

anac

tion

pote

ntia

lisge

nera

ted,

whi

chin

aca

rdia

cmus

clei

sre

spon

sibl

efor

initi

atin

gco

ntra

ctio

n(D

espo

poul

osan

dS

ilber

nagl

,199

1).

Fig

ure

2.6

show

sa

typi

cala

ctio

npo

tent

ialo

fa

card

iac

mus

cle.

Car

diac

cells

have

are

stin

gpo

tent

ialo

fab

out-

90m

V.A

suffi

cien

tlyst

rong

010

020

030

040

0

0100

−900

time

[ms]

over

shoo

t

depolarization

repolarization

plat

eau

mec

hani

cal

resp

onse

contraction [%]

membrane potential [mV]

Fig

ure

2.6:

Act

ion

pote

ntia

l(so

lidcu

rve)

and

cont

ract

ilem

echa

nica

lresp

onse

(dot

tedc

urve

)ofa

card

iacm

uscl

efibe

rplo

tted

onsa

met

ime

axis

.

2.4

Mus

cle

phys

iolo

gy15

stim

ulus

prod

uces

anac

tion

pote

ntia

lby

first

redu

cing

the

rest

ingm

embr

anep

o-te

ntia

lto

ale

ssne

gativ

eva

lue

(dep

olar

izat

ion)

.Dep

olar

izat

ionp

roce

edsr

apid

lyan

dex

hibi

tsan

over

shoo

t,see

Fig

ure

2.6.

Thi

sis

follo

wed

bya

plat

eaub

efor

ethe

mem

bran

epot

entia

lret

urns

toth

eba

selin

e.T

hede

pola

rizat

ionl

asta

bout

2m

s,bu

tthe

plat

eaup

hase

and

repo

lariz

atio

nlas

t200

ms

orm

ore,

seeF

igur

e2.

6.T

hepr

oces

sby

whi

chde

pola

rizat

iono

fthe

mus

clefi

beri

nitia

tesc

ontr

actio

nis

calle

dex

cita

tion-

cont

ract

ionc

oupl

ing.

The

actio

npo

tent

ialis

tran

smitt

edto

all

fibril

sin

the

fiber

via

the

Tsy

stem

and

ittr

igge

rsth

ere

leas

eof

Ca. 1 fr

omth

esa

rcop

lasm

icret

icul

um.T

heC

a. 1 initi

ates

cont

ract

ion.

The

cont

ract

ilere

spon

seof

card

iacm

uscl

ebeg

ins

just

afte

rthe

star

tof

depo

lariz

atio

nand

last

sabo

ut1.

5tim

esas

long

asth

eac

tion

pote

ntia

l(Gan

ong,

1993

).F

igur

e2.

6sh

ows

the

actio

npo

tent

iala

ndth

eco

rres

pond

ingm

echa

nica

lresp

onse

plot

ted

onth

esa

met

ime

axis

.

Page 18: MR · 2002. 2. 20. · Adeler A TV Erhver vsf or skerpr ojekt EF 698 IMM-PHD-2001-86 ISSN 0909-3192 ISBN 87-88306-13-5 c 2001 by Pernille Thorup Adeler Printed by IMM, DTU Bookbinder

Cha

pter

3

2Dhe

artm

odel

usin

gth

eim

mer

sed

boun

dary

met

hod

Thi

sch

apte

rpre

sent

sour

2di

men

sion

al(2

D)

mat

hem

atic

almod

elof

the

bloo

dflo

win

the

hear

t.T

heor

igin

al2D

mod

el(P

eski

n,19

77)w

asdi

men

sion

edto

data

onth

edo

ghe

art.

InJa

cobs

enet

al.(

2001

)and

Ade

lera

ndJa

cobs

en(2

001)

the

mod

elw

asad

apte

dto

the

hum

anhe

artt

hrou

ghth

eus

eof

MR

data

,apr

oced

ure

that

requ

ired

fittin

gpa

ram

eter

sfor

geom

etry,

timin

g,m

uscu

larc

ontr

actio

nand

afte

rload

.Her

ew

efo

llow

the

pres

enta

tionin

Ade

lera

ndJa

cobs

en(2

001)

and,

inad

ditio

n,in

trod

ucem

odifi

catio

nsre

gard

ingt

ethe

ringa

ndth

em

odel

ofth

epa

pil-

lary

mus

clea

ndch

ords

.

3.1

Gen

eral

desc

riptio

nof

the

mod

el

The

mod

elre

pres

entsa

2Dse

ctio

noft

hele

ftsi

deof

the

hear

t.Thi

sse

ctio

nlie

sin

apl

ane,

the

long

axis

plan

e,w

hich

pass

esth

roug

hthe

apex

ofth

ehe

art,b

isec

tsth

ele

aflet

soft

hem

itral

valv

ean

dcu

tsth

eao

rtic

outfl

owtr

act.

The

mod

elde

scrib

esth

ebl

ood

flow

inan

dth

em

ovem

ento

fthe

left

atriu

man

dth

ele

ftve

ntric

ledu

ring

aca

rdia

ccyc

le,i

nclu

ding

the

mov

emen

tof

the

mitr

alva

lve

conn

ectin

gthe

two

cham

bers

.T

heve

nous

inflo

wto

the

left

hear

tism

odel

ledb

ya

sour

cepl

aced

atth

ece

n-tr

eof

the

atriu

m,a

ndth

eao

rtic

outfl

owis

allo

wed

thro

ugh

asi

nkpl

aced

atth

eou

tflow

trac

tof

the

vent

ricle

.The

mod

elre

pres

entst

hetis

sues

ofth

ehe

art,b

oth

activ

em

uscl

etis

sues

and

pass

iveva

lve

tissu

es,a

sinfi

nite

lyth

in,m

assl

esse

last

ic

Page 19: MR · 2002. 2. 20. · Adeler A TV Erhver vsf or skerpr ojekt EF 698 IMM-PHD-2001-86 ISSN 0909-3192 ISBN 87-88306-13-5 c 2001 by Pernille Thorup Adeler Printed by IMM, DTU Bookbinder

182D

hear

tmod

elus

ing

the

imm

erse

dbo

unda

rym

etho

d

boun

darie

stota

llyim

mer

sedin

bloo

d,i.e

.with

bloo

don

both

side

s.T

hese

boun

d-ar

iest

hen

man

ifest

them

selve

sto

the

fluid

byex

ertin

gfo

rces

onit

and

are

them

-se

lvesm

oved

byth

eflu

idw

ithth

elo

calfl

uid

velo

city

.T

hebe

atin

gof

the

mod

elhe

artis

indu

cedb

ysu

cces

sive

rela

xatio

nand

cont

ract

iono

fthe

elas

ticbo

unda

ries

repr

esen

tingth

ehe

artm

uscl

es.

The

mod

elus

esa

time-

step

ping

proc

edur

eof

the

follo

win

gty

pe:

Fro

ma

know

nhe

artb

ound

aryc

onfig

urat

ion,

the

boun

dary

forc

esar

eup

date

d.O

nth

eba

siso

fthe

sefo

rces

andt

hefo

rces

inth

eflu

id,t

heve

loci

tyan

dpre

ssur

efiel

dsar

eup

date

d.F

inal

ly,t

heve

loci

tyfie

ldis

used

toup

date

the

hear

tbou

ndar

ycon

figu-

ratio

n.

3.2

Con

tinuo

usfo

rmul

atio

n

Inth

ism

odel

the

hear

tisim

mer

sedi

na

box

fille

dw

itha

fluid

ofth

esa

med

ensi

tyan

dvi

scos

ityas

bloo

d.T

hehe

artb

ound

ary(

mus

cula

rwal

land

valv

ele

aflet

s)ar

etr

eate

dasm

assl

esso

ne-d

imen

sion

albou

ndar

iesto

tally

imm

erse

din

fluid

(blo

od)

and

capa

bleo

fex

ertin

gfo

rces

onth

eflu

id.

The

fluid

inth

eca

vitie

sco

nfine

dby

the

hear

tbou

ndar

iesr

epre

sent

sblo

odin

the

hear

tcha

mbe

rs,w

hile

that

outs

ide

repr

esen

tssur

roun

ding

tissu

eand

mas

sofh

eartm

uscl

e.T

hehe

artm

odel

incl

udes

aso

urce

inth

eat

rium

toac

coun

tfor

the

pulm

onar

yven

ousi

nflow

and

asi

nkat

the

aort

icou

tflow

trac

tto

allo

wfo

rej

ectio

nof

bloo

ddu

ring

syst

ole.

Mor

eove

r,si

nce

the

hear

texp

ands

durin

gdi

asto

lean

dco

ntra

ctsd

urin

gsy

stol

e,th

em

odel

also

incl

udes

anex

terio

rsin

k/so

urce

,pla

ceda

long

the

vert

ical

boun

darie

sof

the

dom

ain,

tom

ake

room

for

the

varia

tion

into

talh

eart

volu

me

durin

ga

hear

tbea

t.T

hepo

into

fde

part

uref

orth

eco

ntin

uous

form

ulat

ion

isth

eN

avie

r-S

toke

seq

uatio

nfor

inco

mpr

essi

blefl

uid

flow

and

the

cont

inui

tyeq

uatio

n,in

whi

chth

eun

know

nsar

eth

eflu

idve

loci

tyfie

ld

243 an

dth

esc

alar

pres

sure

field

5 3 ,

with

3 6

deno

tingt

hepo

sitio

nve

ctor

and

deno

tingt

hetim

eva

riabl

e:

78 9 2 9 : 2 ;< 2= < 5:*<.2:>

(3.1

)

< ;2 ? 3

(3.2

)

The

cons

tant

s

7 and

* denot

ethe

fluid

dens

ityan

dvi

scos

ity,r

espe

ctive

ly.

>43

deno

test

hefo

rce

dens

ity(f

orce

peru

nita

reai

n2D

)ex

erte

don

the

fluid

byth

ehe

artb

ound

ary,

and

? 3 re

pres

entst

hear

eaflo

wra

tede

nsity

dist

ribut

ion

ofth

eso

urce

sand

sink

s.T

hefo

rce

field

> isth

eon

lyre

pres

enta

tiono

fth

ehe

art

boun

dary

’sin

fluen

ceon

the

fluid

.T

heco

mpu

tatio

nald

omai

n is

take

nto

be

3.2

Con

tinuo

usfo

rmul

atio

n19

asq

uare

inth

em

odel

,and

the

boun

dary

cond

ition

isth

ere

quire

men

tthat

the

velo

city

and

pres

sure

field

sbe

perio

dicw

ithth

isdo

mai

nasa

perio

d.E

quat

ions

(3.1

)and

(3.2

)are

base

don

assu

mpt

ions

conc

erni

ngth

em

omen

tum

ofth

eflu

idth

aten

ters

orle

aves

the

mod

elat

the

sour

cesa

ndsi

nks.

Flu

idle

avin

gth

em

odel

atsi

nks

take

sits

mom

entu

mw

ithit

asit

leav

esth

em

odel

,whi

leflu

iden

terin

gthe

mod

elat

sour

cesh

asth

esa

mev

eloc

ity(i.

e.sa

mem

omen

tum

)ast

heflu

idat

the

poin

twhe

reit

ente

rs(J

akob

sena

ndN

iss,

2000

).T

hese

assu

mpt

ions

conc

erni

ngso

urce

sand

sink

will

bedi

scus

sedf

urth

erin

the

eval

uatio

nof

the

mod

el(s

eeS

ectio

n4.6

).T

heex

tern

alflu

idfo

rce

dens

ity

> 3 is

ade

lta-f

unct

ionl

ayer

give

nby

>43

@A B 43 C

(3.3

)

whe

reth

efu

nctio

n

, D DE ,

para

met

eriz

esth

ehe

artb

ound

ary(

acl

osed

curv

e)an

d

B de

note

sthe

boun

dary

forc

ede

nsity

with

resp

ectto

,i.e

.

B C is

the

forc

eex

erte

don

the

fluid

bya

piec

eoft

hebo

unda

ryof

leng

th

C abo

ut

.From

this

equa

tioni

tis

seen

that

the

forc

efie

ld

> 3 is

zero

ever

y-w

here

exce

ptat

the

hear

tbou

ndar

ywhe

reit

iseq

ualto

the

forc

ede

nsity

exer

ted

onth

eflu

idby

the

hear

tbou

ndar

y.F

igur

e3.

1sh

ows

the

com

puta

tiona

ldom

ain

with

the

initi

alhe

artb

ound

ary

F dr

awn.

The

choi

ceof

initi

alge

omet

ryw

illbe

disc

usse

dinS

ectio

n3.3

.7.

The

hear

tbou

ndar

yissi

mul

ated

eith

eras

pass

ivetis

suef

ollo

win

gth

eflu

idm

otio

n

0

x

Ω

y

X(s

,t )

aort

a

mitr

alva

lve

vent

ricle

atriu

m

Fig

ure

3.1:

Com

puta

tiona

ldom

ain

and

initi

alhe

artb

ound

aryc

onfig

urat

ion

.

Page 20: MR · 2002. 2. 20. · Adeler A TV Erhver vsf or skerpr ojekt EF 698 IMM-PHD-2001-86 ISSN 0909-3192 ISBN 87-88306-13-5 c 2001 by Pernille Thorup Adeler Printed by IMM, DTU Bookbinder

202D

hear

tmod

elus

ing

the

imm

erse

dbo

unda

rym

etho

d

oras

activ

em

uscl

etis

sue.

Fort

hepa

ssive

elas

ticpa

rtso

fthe

boun

dary,

the

boun

d-ar

yfo

rce

dens

ity

B depe

ndso

nly

onth

ecu

rren

tcon

figur

atio

n

,w

hile

for

the

activ

epa

rts(

sim

ulat

ingm

uscl

es)it

also

depe

ndso

nth

ehi

stor

yof

thro

ught

hetim

ede

velo

pmen

tofi

nter

nalv

aria

bles

(var

iabl

eres

tingl

engt

hs)w

hich

dete

rmin

eth

eco

ntra

ctile

prop

ertie

sof

the

boun

dary.

The

time

deve

lopm

ento

fth

ein

tern

alva

riabl

esis

dete

rmin

edfr

oma

give

nfu

nctio

nof

time,

the

activ

atio

nfu

nctio

n

G

(see

Sec

tions

3.3.

5an

d3.

3.6)

.The

spec

ificf

orm

ofth

ebo

unda

ryfo

rce

dens

ity

B w

illbe

spec

ified

inth

edi

scre

tefo

rmul

atio

nof

the

mod

elin

Sec

tion3

.3.5

.T

heflu

idis

subj

ectto

the

no-s

lipco

nditi

onat

the

hear

tbou

ndar

yand

ther

efor

eth

ebo

unda

rym

oves

with

the

loca

lflui

dve

loci

ty

9 9 2

@ H2 3 3 C 3

(3.4

)

The

mot

ion

ofth

ehe

artb

ound

aryi

sno

tkno

wn

inad

vanc

e,an

dth

usth

eab

ove

equa

tionc

onst

itute

san

equa

tiono

fmot

ion

for

the

hear

tbou

ndar

y.T

heve

loci

tyis

assu

med

tobe

cont

inuo

usac

ross

the

boun

dary

asa

part

ofth

eno

-slip

cond

ition

.T

heab

ove

equa

tions

desc

ribet

heflu

idve

loci

tyfie

ld(a

ndre

late

dqua

ntiti

es)

inan

Eul

eria

nw

ay,

whi

lequ

antit

iesr

elat

edto

the

hear

tbou

ndar

yare

desc

ribed

ina

Lagr

angi

anw

ay.

Itis

seen

that

the

funct

ion

isus

edto

coup

leE

uler

ian

quan

titie

swith

Lagr

angi

anqu

antit

ies.

Ineq

uatio

n(3.

3)th

e

funct

ion

spre

ads

the

Lagr

angi

anhe

artb

ound

aryf

orce

B toth

eE

uler

ian

forc

efie

ld

> ,w

hile

ineq

uatio

n(3

.4)

the

funct

ion

isus

edto

com

pute

the

Lagr

angi

anflu

idve

loc-

ityat

the

boun

dary

2

from

the

Eul

eria

nflu

idve

loci

tyfie

ld

2 3 .

Thi

sco

uplin

gbe

twee

nflui

dan

dbo

unda

ryis

the

hear

toft

heim

mer

sedb

ound

ary

met

hod.

Ital

low

sfo

rth

ein

tera

ctio

nbet

wee

naflu

idan

dan

imm

erse

dbou

ndar

y,w

ithou

tkno

win

gth

em

otio

nof

eith

erin

adva

nce.

Fur

ther

mor

e,by

intr

oduc

ing

this

coup

ling

itis

poss

ible

tose

tup

the

equa

tions

ofm

otio

nfo

rth

eflu

id(t

heN

avie

r-S

toke

sequ

atio

n3.1

and

the

cont

inui

tyeq

uatio

n3.2

)with

outd

istin

guis

h-in

gbe

twee

nEul

eria

nqua

ntiti

esan

dLa

gran

gian

hear

tbou

ndar

yqua

ntiti

es.

3.2.

1S

ourc

esan

dsi

nks

Ven

ousi

nflow

toth

ehe

artis

mod

elle

dby

aso

urce

inth

eat

rium

,whi

leou

tflow

durin

gej

ectio

nis

mod

elle

dby

asi

nkat

the

aort

icou

tflow

trac

t.T

hehe

artc

hang

esar

ea(d

efine

das

the

area

insi

deth

ecl

osed

hear

tbou

ndar

y)du

ring

ahe

artc

ycle

,an

dth

usit

isne

cess

aryto

incl

ude

aso

urce

/sin

kout

side

the

hear

tbou

ndar

yto

acco

mm

odat

ethe

chan

gesin

area

durin

ga

hear

tcyc

le.T

heso

urce

inth

eat

rium

and

the

sink

atth

eao

rtic

outfl

owar

ere

ferr

edto

asth

ein

terio

rsou

rces

and

sink

s,w

hile

the

sour

ce/s

inko

utsi

deth

ehe

artb

ound

aryi

sre

ferr

edto

asth

eex

terio

rso

urce

/sin

k.

3.2

Con

tinuo

usfo

rmul

atio

n21

Den

sity

dist

ribut

ion

The

sour

cesa

ndsi

nks

are

defin

edas

area

swhe

reflu

idca

nen

tero

rle

ave

the

mod

el.T

hey

arei

ncor

pora

tedin

the

mod

elth

roug

hthe

dens

itydi

strib

utio

n

?43

inth

eco

ntin

uity

equa

tion(

3.2)

.T

hede

nsity

dist

ribut

ion

isze

roex

cept

inth

ear

easa

tthe

sour

cesa

ndsi

nks.

Itis

assu

med

tobe

ofth

efo

rm

?43 IKJL M JL 3 N JL :

.PO Q R)I Q MQ 3 N Q

whe

re

S # co

rres

pond

stoth

eso

urce

inth

eat

rium

and

S co

rres

pond

stoth

esi

nkin

the

aort

icou

tflow

trac

t.T

hein

dex

T refer

sto

the

exte

riors

ourc

e/si

nk.

Fur

ther

,

I Q

and

IKJL de

note

the

area

flow

rate

thro

ugh

the

sour

ceor

sink

,po

sitiv

e

I mea

ning

inflo

wan

dne

gativ

e

I mea

ning

outfl

ow.C

onve

rsio

nbet

wee

nar

eaan

dvo

lum

eis

defin

edby

spec

ifyin

ga’t

hick

ness

’oft

heot

herw

ise2

dim

en-

sion

aldo

mai

n

.

M Q and

M JLar

ew

eigh

tfun

ctio

ns(in

dim

ensi

onpe

runi

tare

a)re

pres

entin

gthe

flow

dist

ribut

ion

acro

ssth

eso

urce

sand

sink

s(as

sum

edto

betim

ean

dflo

win

depe

nden

t),an

d

N Q and

N JL de

note

the

curr

entp

ositi

onso

fthe

cent

reof

the

sour

cesa

ndsi

nks(

whi

chm

ove

with

the

hear

t).

The

mat

hem

atic

alreq

uire

men

ton

M Q and

M JL

isth

atth

eybe

cont

inuo

usno

n-ne

gativ

efu

nctio

nssa

tisfy

ing

@ HM Q 3 C 3 # U VW

@ HM JL 3 C 3#

(3.5

)

Inth

em

odel

the

inte

riors

ourc

esan

dsi

nks

are

defin

edon

aqu

adra

ticdo

mai

nof

wid

th

X andth

ew

eigh

tfun

ctio

nsar

ech

osen

tobe

prop

erly

scal

ed‘c

osin

eha

t’fu

nctio

nsof

the

form

M Q 6

Y[Z\ Z]) ^_` # : ab'c d ^e .f

g` #: ab'c d ^e .6fg fo

r

6 hi ^ .^ .j.

othe

rwis

e

The

exte

riorw

eigh

tfun

ctio

nM JL

isde

fined

ona

rect

angu

lard

omai

nof

wid

th

Xk

and

ahe

ight

l equa

ltoth

ehe

ight

ofth

eco

mpu

tatio

naldo

mai

n.

M JL

isa

‘cos

ine

ridge

’oft

hefo

rm

M JL 6

YmZ\ Z4]) ^no` # : ab'c d ^ne .fg

for

6 hi ^n . ^n .j 0i lj

othe

rwis

e

Page 21: MR · 2002. 2. 20. · Adeler A TV Erhver vsf or skerpr ojekt EF 698 IMM-PHD-2001-86 ISSN 0909-3192 ISBN 87-88306-13-5 c 2001 by Pernille Thorup Adeler Printed by IMM, DTU Bookbinder

222D

hear

tmod

elus

ing

the

imm

erse

dbo

unda

rym

etho

d

Sin

ceth

eve

loci

tyfie

ldis

requ

iredt

obe

perio

dict

here

isno

neti

nflow

toth

edo

mai

n

thro

ugh

the

boun

darie

s,so

the

inco

mpr

essi

bilit

yof

the

fluid

impl

ies

that

the

neti

nflow

thro

ught

heso

urce

sand

sink

smus

tals

obe

zero

,i.e.

@ H</;2C3

@ H?43 C 3 IKJL :

.PO Q R)I Q

By

the

abov

eeq

uatio

nwe

have

IKJL

. O Q R)I Q

Thu

swe

can

writ

e

?43

. O Q R)I Q ? Q 3

(3.6

)

whe

re

? Q43 MQ 3 N Q M JL

43 N JL

(3.7

)

The

flow

rate

I Q

isas

sum

edto

bea

func

tion

ofth

esp

acea

vera

geof

the

pres

sure

p Q atth

eso

urce

orsi

nk.

The

pres

sure

can

only

bede

term

ined

upto

aco

nsta

nt,th

usit

only

mak

esse

nset

odi

scus

spre

ssur

ediff

eren

cesr

athe

rtha

nab

solu

tepr

essu

re.T

here

fere

ncep

ress

ureis

chos

ento

beth

esp

acea

vera

geof

the

pres

sure

atth

eex

terio

rsin

k.T

hesp

acea

vera

geof

the

pres

sure

with

resp

ectto

the

wei

ghtf

unct

ionM

Q isthen

defin

edas

follo

ws:

p Q

@ H5 3 M Q 3NQ C3

@ H543 M JL 3 N JL C 3

@ H5 3 ? Q 3 C 3

q 5 ? Q r

Fore

achs

ourc

eand

sink

asp

ecifi

crel

atio

nbet

wee

n

I Q

and

p Q isgi

ven,

mak

ing

the

flow

depe

ndup

onth

epr

essu

re

I Q 5 .

Hen

cein

trod

ucin

gth

isin

equa

tion(

3.6)

the

sour

ce/s

inkte

rm

? can

now

beex

pres

seda

sa

time

vary

ing

func

tion

s 5 of

the

time

vary

ing

pres

sure

field

5 asfo

llow

s:

? 3 s 5 3

. O Q R)I Q 5 ? Q43

(3.8

)

3.2

Con

tinuo

usfo

rmul

atio

n23

Flo

wan

dpr

essu

rere

latio

nfo

rat

rial

sour

ce

The

spec

ific

rela

tion

betw

een

I )

and

p ) for

the

sour

cein

the

atriu

mis

chos

ento

beth

atof

alin

earr

esis

tanc

emod

elpu

mpi

ngag

ains

taco

nsta

ntpr

essu

rere

servo

ir.F

igur

e3.

2sh

ows

anel

ectr

ican

alog

ueof

alin

earr

esis

tanc

emod

el.T

hego

vern

ing

equa

tiona

tthe

atria

lsou

rcei

s

I ) put!vp ) w t!v

(3.9

)

whe

re

p t!v deno

testh

elo

adpr

essu

reatt

heso

urce

and

w t!v den

otes

the

resi

stan

ceag

ains

tthe

flow

thro

ught

heso

urce

.

P 1R

src

P src

Q1

Fig

ure

3.2:

An

elec

tric

anal

ogue

toth

elin

earr

esis

tanc

emod

el.

Flo

wan

dpr

essu

rere

latio

nfo

rao

rtic

sink

Inth

eor

igin

alm

odel

deve

lope

dby

Pes

kint

heao

rtic

sink

was

mod

elle

dby

alin

ear

resi

stan

cem

odel

pum

ping

agai

nsta

cons

tant

pres

sure

rese

rvoir

com

bine

dwith

adi

ode-

like

valv

e,w

hich

open

edth

esi

nkw

hen

the

pres

sure

atth

esi

nkex

ceed

eda

give

nva

lue

for

the

pres

sure

inth

eao

rtaa

ndcl

osed

itag

ainw

hen

the

pres

sure

fell

belo

wth

atva

lue.

We

find

that

the

linea

rres

ista

ncem

odel

with

aco

nsta

ntpr

essu

rere

servo

irfo

rth

ere

latio

nbe

twee

nthe

outfl

owra

tean

dth

epr

essu

regi

vesa

rath

erun

real

is-

ticsh

apeo

fth

eas

soci

ated

pres

sure

vers

ustim

epr

ofile

,with

the

pres

sure

alm

ost

clam

peda

tthe

pres

crib

edco

nsta

ntpr

essu

rein

the

aort

a(se

eSec

tion4

.5).

Am

ore

real

istic

curv

efo

rmis

obta

ined

byco

mbi

ning

the

diod

e-lik

esi

nkw

itha

sim

-pl

eth

ree-

elem

entW

indk

esse

lmod

elof

the

arte

rialim

peda

nce.

The

Win

dkes

sel

mod

elis

also

alin

earr

esis

tanc

emod

elbu

twith

atim

eva

ryin

gpr

essu

rere

servo

ir.S

eeF

igur

e(3

.3)f

orth

eel

ectr

ican

alog

ueof

the

Win

dkes

selm

odel

.Le

t

p . deno

teth

epr

essu

reat

the

aort

icou

tflow

trac

tand

I . the

outfl

owra

teof

the

vent

ricle

.The

inflo

wto

the

Win

dkes

selm

odel

isth

en

I . ,a

ndw

eha

ve

I .

YxZZ\ ZZ4]p . putyQ

w tyQ )

if

p . zputyQ

if

p . putyQ

(3.1

0)

Page 22: MR · 2002. 2. 20. · Adeler A TV Erhver vsf or skerpr ojekt EF 698 IMM-PHD-2001-86 ISSN 0909-3192 ISBN 87-88306-13-5 c 2001 by Pernille Thorup Adeler Printed by IMM, DTU Bookbinder

242D

hear

tmod

elus

ing

the

imm

erse

dbo

unda

rym

etho

d

Rsn

k2

Rsn

k1P s

nk

P 2

C

−Q

2

Fig

ure

3.3:

Dia

gram

ofth

ree-

elem

entW

indk

esse

lmod

elco

uple

dto

diod

eva

lve.

whe

re

w tyQ )

repr

esen

tsthe

prox

imal

arte

rialr

esis

tanc

eto

the

flow

and

whe

reth

epr

essu

re

putyQ m

aybe

view

edas

the

pres

sure

ata

repr

esen

tative

prox

imal

loca

tion

inth

ear

teria

lsys

tem

.Thi

sre

latio

nbe

twee

nflow

and

pres

sure

issi

mila

rto

the

rela

tionf

orth

eat

rials

ourc

e(se

eequ

atio

n3.9

),ex

cept

that

the

load

pres

sure

(

p"tyQ )for

the

aort

icsi

nkis

time

depe

nden

t.

p tyQ is

gove

rned

byth

edi

ffer

entia

lequ

atio

n

|C p tyQ

C I .

p tyQ w tyQ .

(3.1

1)

whe

re

w tyQ .

repr

esen

tsthe

perip

hera

lresi

stan

cean

d

| repr

esen

tsthe

arte

rial

com

plia

nce.

The

com

puta

tiono

fthe

boun

dary

forc

esin

volv

esho

wac

tive

andp

assiv

etis

sue

ism

odel

led.

Thi

sis

notd

escr

ibed

onth

eco

ntin

uous

leve

lbut

onth

edi

scre

tele

vel

(see

Sec

tion3

.3.5

).

3.3

Dis

cret

efo

rmul

atio

n

The

solu

tion

ofth

eco

ntin

uous

mod

elde

scrib

edin

the

prev

ious

sect

ioni

sdo

neby

disc

retiz

inga

llqu

antit

iesa

ndeq

uatio

nsof

mot

ion

and

then

solv

ing

the

disc

rete

equa

tions

bya

time-

step

ping

proc

edur

e.

3.3.

1D

iscr

ete

quan

titie

s

We

disc

retiz

ethe

squa

redo

mai

n

usin

ga

squa

re

0 gr

idof

poin

tsw

ith

~ 6 de

notin

gth

edi

stan

cebe

twee

nnei

ghbo

urin

gpoi

nts.

Tim

eis

divi

ded

into

inte

rval

sof

leng

th

,an

dth

epa

ram

eter

inte

rval

for

the

boun

dary

isdi

vide

din

tosu

bint

erva

lsof

leng

th

.Thu

sth

ein

depe

nden

tvaria

bles

are

3.3

Dis

cret

efo

rmul

atio

n25

rest

ricte

dto

the

valu

es

3 3 ~ ~ ,

an

d S ,w

here

,

,

and

S are

inte

gers

.H

ence

atea

chtim

ele

vel

w

eha

veth

efie

ldqu

antit

ies

2y ,

5y and

>y

defin

edon

the

grid

poin

ts,i.

e., 2y

2 ~ ~

5y 5 ~ ~

>y > ~ ~

for

# .

The

boun

dary

confi

gura

tion

y attim

ele

vel

isde

fined

asa

finite

se-

quen

ceof

poin

ts,n

otne

cess

arily

coin

cidi

ngw

ithth

egr

idpo

ints

,with

asso

ciat

edbo

unda

ryfo

rce

dens

ities

.Thu

s y Q S

By Q$ B S

for

S # ,wh

ere

denot

esth

enu

mbe

rof

boun

dary

poin

tsin

the

dis-

cret

izat

iona

ndw

here

By Q deno

tesa

boun

dary

forc

era

ther

than

afo

rce

dens

ity.

3.3.

2D

iffer

ence

oper

ator

san

ddi

scre

te

K func

tion

The

diff

eren

tiale

quat

ions

inth

eco

ntin

uous

form

ulat

ion

ared

iscr

etiz

edby

repl

ac-

ing

the

diff

eren

tialo

pera

tors

bydi

ffer

ence

oper

ator

s.T

hece

nter

ed,fo

rwar

dan

dba

ckwa

rddi

ffer

ence

sinth

e

and

6 direct

ions

are

used

.The

sear

ede

fined

for

afu

nctio

n

onth

edo

mai

ngrid

asfo

llow

s:

L

1) () ~

1) ()~

1 L

1) ~

1

1) ~

( L

() ~

(

() ~

Inad

ditio

nto

thes

e,a

diff

eren

ceop

erat

or

L ap

prox

imat

ingt

heco

ntin

uous

oper

ator

< isne

eded

.Thi

sdi

ffer

ence

oper

ator

isob

tain

edth

roug

hthe

useo

fthe

follo

win

gap

prox

imat

ion

tothe

-fun

ctio

n(P

eski

nand

Prin

tz,1

993)

:

3 6

for3

6

(3.1

2)

Page 23: MR · 2002. 2. 20. · Adeler A TV Erhver vsf or skerpr ojekt EF 698 IMM-PHD-2001-86 ISSN 0909-3192 ISBN 87-88306-13-5 c 2001 by Pernille Thorup Adeler Printed by IMM, DTU Bookbinder

262D

hear

tmod

elus

ing

the

imm

erse

dbo

unda

rym

etho

d

-3h

-2h

-h

h2h

3h

0.1

0.2

0.3

0.4

0.5

Fig

ure

3.4:

Plo

toft

hefu

nctio

n

.

whe

re

# ~` # : ab' ~g if

D~

if

z~

(3.1

3)

Fig

ure

3.4

show

sa

plot

ofth

e

func

tion.

Whe

nth

e

func

tion

isus

edth

ear

gum

entis

ofth

efo

rm

3 ,w

here

isa

boun

dary

poin

ttha

tdoe

snot

nece

ssar

ilyco

inci

dew

itha

grid

poin

t.T

hevi

rtue

sof

this

choi

ceof

func

tion

are

give

nin

Pes

kin(

1977

).In

Pe-

skin

and

McQ

ueen

(199

6),B

eyer

and

LeV

eque

(199

2)an

dB

eyer

(199

2)va

rious

alte

rnat

ivest

oth

isch

oice

have

been

stud

ied.

The

vect

ordi

ffer

ence

oper

ator

L th

atap

prox

imat

esth

eco

n-tin

uous

oper

ator

< can

bede

fined

asfo

llow

s(s

eeP

eski

nand

Prin

tz(1

993)

and

Tho

rup

(199

7)): L

6

O Ln nk

6k k

66k

(3.1

4)

6

O Ln nk

6k k

66k

(3.1

5)

with

:N Re . R (e .

@e . (e . :N CN

6 6: Re . R (e .

6 @e . (e . 6: C

3.3

Dis

cret

efo

rmul

atio

n27

The

oper

ator

wor

ksin

the

follo

win

gw

ay:

5y L5y 5y ;2y Ly L: y

whe

re

2y y Ly .

3.3.

3D

iscr

etiz

atio

nof

equa

tions

ofm

otio

n

The

Nav

ier-

Sto

kese

quat

ion(

3.1)

and

the

cont

inui

tyeq

uatio

n(3.

2)ar

edis

cret

ized

follo

win

ga

sche

mea

dapt

edfr

omA

.Cho

rin(1

968;

1969

),se

ePes

kin(

1972

b),P

e-sk

in(1

972a

)and

Pes

kin(

1977

).T

his

intr

oduc

esth

efr

actio

nals

tepv

eloc

ityfie

lds

2y1)/ ,

2y1) ) an

d

2y1)/. fo

und

for

give

n

2y and

>y byso

lvin

gin

succ

essi

onth

eeq

uatio

ns

72y1) 2y >y

(3.1

6)

78 2y1)/) 2y1)/

: y L L2y1) )= *1 L( L2y1)/)

(3.1

7)

78 2y1)/. 2y1)/)

: y 2y1)/.= *1 ( 2y1)/.

(3.1

8)

The

n2y1)

and

5y1)ar

efo

und

byso

lvin

gth

esy

stem

78 2y1) 2y1) .

= : 5y1)

(3.1

9)

;2y1) sy 5y1)

(3.2

0)

Her

e

isth

eve

ctor

diff

eren

ceop

erat

orde

fined

abov

e,an

d

s y 5y1) is

obta

ined

from

adi

scre

tizat

iono

fequ

atio

n(3.

8),

sy 5y1)

. O Q R)Iy Q 5y1) ?y Q

(3.2

1)

whe

re

? y Q isfo

und

byth

edi

scre

tizat

iono

fequ

atio

n(3.

7)

?y QM Qy Q M JL y JL

(3.2

2)

Fort

heso

urce

inth

eat

rium

we

have

acco

rdin

gto

equa

tion(

3.9)

Iy ) 5y1)

put!vpy ) w t!v

put!vq 5y1) ? y)r w t!v

(3.2

3)

Page 24: MR · 2002. 2. 20. · Adeler A TV Erhver vsf or skerpr ojekt EF 698 IMM-PHD-2001-86 ISSN 0909-3192 ISBN 87-88306-13-5 c 2001 by Pernille Thorup Adeler Printed by IMM, DTU Bookbinder

282D

hear

tmod

elus

ing

the

imm

erse

dbo

unda

rym

etho

d

base

don

the

disc

rete

inne

rpro

duct

q 5 ?r

O ~. 5 ?

whe

reth

esu

mm

atio

nis

over

the

grid

poin

tsof

the

dom

ain.

We

note

that

the

sour

ce/s

inkfu

nctio

n

? isde

fined

andc

ontin

uous

ever

ywhe

rein

,whi

leth

epr

es-

sure

5 isonly

defin

edon

the

grid

poin

ts.W

eal

sono

teth

atth

ech

oice

ofw

eigh

tfu

nctio

ns

M Q is

such

that

the

disc

rete

anal

ogue

ofth

eno

rmal

izat

ionc

ondi

tion

(3.5

)hol

dsfo

ral

ltra

nsla

teso

fM Q .Fo

rthe

trea

tmen

toft

heao

rtic

sink

seeS

ectio

n3.

3.4. Equ

atio

n(3

.3)

for

the

coup

ling

ofth

ebo

unda

ryfo

rces

toth

eflu

idis

dis-

cret

ized

usin

gth

eap

prox

imat

iont

oth

ede

ltafu

nctio

ngi

ven

by(3

.12)

and

(3.1

3).

The

disc

retiz

edve

rsio

nofe

quat

ion(

3.3)

then

read

s

>y

O QBy S 43 y S

O QBy Q 43 y Q

(3.2

4)

The

calc

ulat

iono

fthe

boun

dary

forc

es

By Q isdi

scus

sedin

Sec

tion3

.3.5

.F

inal

ly,

equa

tion(

3.4)

coup

ling

the

fluid

mot

ion

toth

ebo

unda

rym

otio

nis

disc

retiz

edus

ing

the

sam

eapp

roxi

mat

iont

oth

ede

ltafu

nctio

n,i.e

.

y1) Qy Q: 2y1) Q

y Q: O 2y1) 3 y Q~.

(3.2

5)

Inso

lvin

gth

edi

scre

teeq

uatio

nsit

isne

cess

aryto

redu

ceal

llen

gths

and

times

bya

fact

or

( D# )

toen

sure

num

eric

alst

abili

ty.

The

scal

ingr

educ

esth

eR

eyno

lds

num

ber,

whi

chis

equi

vale

ntto

rais

ing

the

visc

osity

ofth

eflu

idby

afa

ctor

of

#$ .Ano

ther

effe

ctof

the

scal

ingi

sth

atth

ebo

unda

ryla

yero

fthe

fluid

isra

ised

bya

fact

orof

#$ .The

scal

ingi

sdi

scus

sedin

Sec

tion4

.2.

Fur

ther

deta

ilsof

the

solu

tion

ofth

edi

scre

tized

equa

tions

ofm

otio

nca

nbe

foun

din

Tho

rup

(199

7).

3.3.

4D

iscr

ete

Win

dkes

selm

odel

for

the

aort

icsi

nk

The

rela

tion

betw

eenfl

owan

dpr

essu

refo

rth

eW

indk

esse

lmod

elat

the

aort

icou

tflow

isfo

und

bydi

scre

tizin

gthe

equa

tions

ofth

ism

odel

inS

ectio

n3.2

.1.

3.3

Dis

cret

efo

rmul

atio

n29

Equ

atio

n(3.

11)f

orth

epr

essu

re

p t!v isdi

scre

tized

acco

rdin

gto

anim

plic

itE

uler

met

hoda

sfol

low

s:

py tyQpy () tyQ

I y . |p y tyQ | w ty

Q .W

eus

e

#

and

here,b

ecau

sew

ene

edan

expr

essi

onfo

r

I y . .Thi

seq

uatio

nm

aybe

solv

edfo

r

p y tyQ : py tyQ

py () tyQ# : $| w tyQ .

$ |# : $| w tyQ .Iy .

(3.2

6)

Inse

rtin

g(3.

10)i

nto

(3.2

6)an

dso

lvin

gfo

r

p y tyQ we

get

py tyQY[ZZZZZ\ ZZZZZ]py () tyQ: ¡ ¢£p y .

# : £

if

py .zpy tyQ

py () tyQ # : ¡ _£

if

py .py tyQ

(3.2

7)

whe

re

w () w () tyQ ):w () tyQ . a

nd

py .q 5y1) ? y .r .F

rom

rela

tions

(3.1

0)an

d(3

.26)

we

dedu

ceth

at

py .zpy tyQ

ifan

don

lyif

py .zpy () tyQ # :

/ ¡ _£

(3.2

8)

Inse

rtin

g(3

.27)

and

(3.2

8)in

to(3

.10)

we

obta

inth

efo

llow

ing

rela

tion

betw

een

I y . and

p y . ata

give

ntim

ele

vel

:

Iy .

YmZZ4ZZZZZZZZ\ ZZZZZZZ4ZZZ]p y .py () tyQ # :

/ ¡ _£

w tyQ )# : £

# : / ¡ _£

if

p y .zpy () tyQ # :

¡ _£

if

p y .py () tyQ # :

¡ _£

(3.2

9)

Hen

ceat

each

time

leve

l

forwhi

chth

eva

lve

isop

en,th

erei

sa

linea

rpre

ssur

e-flo

wre

latio

nbe

twee

n

py . and

I y . (com

pare

with

equa

tion(

3.23

)for

the

sour

ce

Page 25: MR · 2002. 2. 20. · Adeler A TV Erhver vsf or skerpr ojekt EF 698 IMM-PHD-2001-86 ISSN 0909-3192 ISBN 87-88306-13-5 c 2001 by Pernille Thorup Adeler Printed by IMM, DTU Bookbinder

302D

hear

tmod

elus

ing

the

imm

erse

dbo

unda

rym

etho

d

inth

eat

rium

).T

heap

pare

ntre

sist

ance

toth

eflo

w(t

hede

nom

inat

orin

the

abov

eex

pres

sion

)isco

nsta

ntin

time,

butt

hepr

essu

re

p y tyQ aga

inst

whi

chth

ehe

artis

pum

ping

varie

swith

time.

Whe

nth

eva

lues

of

p y . and

I y . are

com

pute

dfro

mth

ein

tera

ctio

nwith

the

hear

tmod

elth

enth

epr

essu

re

p"tyQ sho

uldb

eup

date

dacc

ordi

ngto

the

follo

win

gfo

rmul

a

py tyQY[ZZZZZ\ ZZZZZ]py .:w tyQ )Iy .

if

p y .zpy () tyQ # :

/ ¡ _£

py () tyQ # : / ¡ _£

if

p y .py () tyQ # :

/ ¡ _£

(3.3

0)

The

abov

em

odel

for

the

aort

icsi

nkgi

vesr

ise

toth

efo

llow

ing

algo

rithm

for

upda

tingt

hepr

essu

rean

dou

tflow

rate

from

time

leve

l

#

totim

ele

vel

andfo

rco

ntro

lling

the

open

inga

ndcl

osin

gof

the

valv

e

1.C

ompu

tea

prel

imin

aryu

pdat

eof

p tyQ acc

ordi

ngto

p y tyQpy () tyQ # :

/ ¡ _£.

2.C

ompu

teth

epr

essu

re

p y . from

the

hear

tmod

elus

ing

rela

tions

hip(

3.29

)be

twee

npre

ssur

eand

flow

ineq

uatio

n(3.

21)f

orth

eso

urce

/sin

kterm

s :If

the

valv

eis

open

use

Iy .

p y .p y tyQ

w tyQ ) # : $ w|$ #: $ w tyQ .|

othe

rwis

e

Iy .

3.If

p y .zp y tyQ a

ndth

eva

lve

isno

tope

n,th

enth

eva

lve

shou

ldbe

open

.T

huso

pent

heva

lve

byob

tain

ingt

heflo

w

I y . throu

gha

reco

mpu

tingo

fthe

pres

sure

p y . from

the

hear

tmod

elus

ing

the

first

ofth

etw

opr

essu

re-fl

owre

latio

nshi

psin

(3.2

9).

4.If

p y .p y tyQ a

ndth

eva

lve

isop

en,th

enth

eva

lve

shou

ldbe

clos

ed.C

lose

the

valv

eby

reco

mpu

tingt

hepr

essu

re

p y . usin

gth

ese

cond

pres

sure

-flow

rela

tions

hipi

n(3

.29)

.

3.3

Dis

cret

efo

rmul

atio

n31

5.C

ompu

teth

eco

rrec

tval

ueof

p y tyQ acc

ordi

ngto

(3.3

0):

Ifth

eva

lve

isop

enth

en

py tyQpy .:w tyQ )Iy .

Oth

erw

isen

ofu

rthe

rupd

atin

gis

need

ed.

The

actu

alch

oice

ofW

indk

esse

lpar

amet

ers(

| ,w tyQ )

and

w tyQ . )ar

edi

s-cu

ssed

inS

ectio

n4.5

.

3.3.

5B

ound

ary

forc

es

Now

we

turn

toth

ede

scrip

tiono

fthe

boun

dary

forc

esat

the

disc

rete

leve

l.

The

link

form

alis

m

The

posi

tion

ofth

ehe

artb

ound

aryi

sde

fined

byits

confi

gura

tionv

ecto

r

) ¤ ¥

cons

istin

gof

the

posi

tion

vect

ors

Q forth

ebo

unda

rypo

ints

.T

hebo

unda

ryfo

rces

are

mod

elle

dasa

risin

gfr

omel

astic

sprin

gs,c

alle

dlin

ks,c

onne

ctin

gthe

sebo

unda

rypo

ints

.T

hese

tofa

lllin

ksis

deno

ted

¦ .Let

deno

tea

link

conn

ectin

gbou

ndar

ypoi

nt

S whi

chha

spos

ition

vect

or

Q with

boun

dary

poin

t

§ whi

chha

spos

ition

vect

or¨ .Th

enit

isa

prop

erty

ofth

em

odel

that

the

forc

e

B Q on

the

poin

t

S due

toth

elin

k

,ata

nygi

ven

time

leve

l,is

ofth

efo

rm

B QB Q -c ¨ Qf

¨ Q

¨ Q

(3.3

1)

whe

reth

efu

nctio

n

- give

sthe

tens

ioni

nlin

k

vers

usits

leng

th

E ¨ Q .

Not

eth

atsu

pers

crip

t does

notd

enot

eatim

est

ep.T

heel

astic

prop

ertie

sof

the

boun

dary

are

thus

defin

edat

each

time

leve

lby

ase

tof

leng

th-t

ensi

onre

latio

ns

- - E ,

one

for

each

link.

The

mod

elfo

rth

esel

engt

h-te

nsio

nrel

atio

nsis

give

nbe

low

.T

heto

talb

ound

aryf

orce

By Q onbo

unda

rypo

int

S isno

wgi

ven

by

By QB Q y O © ª

« ¡¬B Qy

(3.3

2)

whe

re

¦ Q denot

esth

ese

tofa

lllin

ksw

hich

have

the

boun

dary

poin

t

S ason

eof

itsen

dpo

ints

.Mor

eth

anon

elin

kca

nco

nnec

tagi

ven

pair

ofpo

ints

.

Page 26: MR · 2002. 2. 20. · Adeler A TV Erhver vsf or skerpr ojekt EF 698 IMM-PHD-2001-86 ISSN 0909-3192 ISBN 87-88306-13-5 c 2001 by Pernille Thorup Adeler Printed by IMM, DTU Bookbinder

322D

hear

tmod

elus

ing

the

imm

erse

dbo

unda

rym

etho

d

How

ever

,the

boun

dary

forc

esac

tual

lyap

plie

dto

the

fluid

are

notc

ompu

ted

dire

ctly

byev

alua

ting

equa

tion(

3.32

).In

stea

dan

impl

icit

met

hod,

actu

ally

anim

plic

itfr

actio

nals

tep

met

hod,

isus

edto

ensu

renu

mer

ical

stab

ility

.T

hefo

rces

are

notc

ompu

tedf

rom

the

final

boun

dary

confi

gura

tion

y1)

butf

rom

aco

nfig-

urat

ion

­ defin

edim

plic

itly

asfo

llow

s:

­ Qy Q: 2­ Q

2­ 2y : >­

whe

re

2­ QO 2­ 43 y Q~.

(3.3

3)

>­ O QB­ Q 3 y Q

(3.3

4)

B­ QB Q ­ ) ­ ¤¥

Not

eth

ateq

uatio

n(3.

33)i

sof

the

sam

efor

mas

the

last

term

ineq

uatio

n(3.

25)

and

equa

tion(

3.34

)is

ofth

esa

mef

orm

aseq

uatio

n(3.

24).

By

subs

titut

ioni

nth

eab

ove

five

equa

tions

we

find

the

follo

win

gno

n-lin

ear

syst

em(P

eski

n,19

77;T

horu

p,19

97)

­ Qk Q:®B Q­ ) ­ ¤¥ S #

(3.3

5)

whe

re

k Qy Q: 2y Q

(whi

chis

know

nat

time

leve

l

:# )an

dw

here

® isch

osen

soth

at

­ Q isan

appr

oxim

atio

nto

y1) Q .InP

eski

n(19

81)

® isch

osen

tobe

; $ ~. . .F

inal

ly,e

quat

ion(

3.35

)can

beso

lved

byN

ewto

n’s

met

hod

for

­ Q (Pes

kin

and

McQ

ueen

,198

0;T

horu

p,19

97),

and

the

forc

esap

plie

dto

the

fluid

are

give

nby

B­ QB Q ­ ) ­ ¤¥ ,i

.e.i

neq

uatio

n(3.

24)i

nser

t

B­ Qin

stea

dof

By Q .P

assiv

etis

sue

mod

el

The

hear

tval

vesa

ndth

eou

tflow

trac

tare

esse

ntia

llyel

astic

tissu

eand

thes

epar

tsof

the

hear

tbou

ndar

yare

ther

efor

emod

elle

dby

linea

rspr

ings

.The

leng

th-t

ensi

onre

latio

nin

the

links

mod

ellin

gth

eva

lves

is(P

eski

n,19

77)

- E ¯ °± E E E zE

E E

3.3

Dis

cret

efo

rmul

atio

n33

whe

re°±

isth

est

iffne

ssan

d

E isthe

rest

ing

leng

th.I

tis

seen

that

the

tens

ion

isne

ver

nega

tive,

soth

eel

emen

tissl

ack

whe

nits

leng

this

less

than

the

rest

-in

gle

ngth

.T

his

mea

nsth

atth

ele

aflet

scan

resi

stte

nsio

nbu

tno

tcom

pres

sion

(McQ

ueen

etal

.,19

82).

InP

eski

nand

McQ

ueen

(198

0)pr

osth

etic

hear

tval

ves

wer

em

odel

ledb

ych

angi

ngth

ele

ngth

tens

ionr

elat

ion

toal

low

for

resi

stan

ceto

com

pres

sion

.T

hete

nsio

n

-­ ina

link

betw

eent

hebo

unda

rypo

ints

­ Q and

­ ¨ inth

ebo

unda

ryco

nfigu

ratio

n

­ is

-­ ¯ °± E­ E E­ zE

E­ E

(3.3

6)

whe

reth

ein

stan

tane

ousle

ngth

ofth

elin

kis

E­ ­ ¨­ Q .T

here

stin

glen

gth

E iscom

pute

dast

hele

ngth

ofth

elin

kat

the

initi

altim

e.

Mus

cula

rm

odel

Alin

kre

pres

entin

gam

uscu

larfi

beri

sm

odel

leda

stw

olin

ears

prin

gsin

para

llel,

one

ofw

hich

,the

activ

epa

rt,h

asa

varia

ble

rest

ing

leng

th,s

eeF

igur

e3.

5.T

heva

riabl

ere

stin

gle

ngth

ism

odel

led

bya

cont

ract

ileel

emen

tinse

riesw

ithth

elin

ears

prin

g.T

his

rest

ing

leng

this

cont

rolle

din

asp

ecifi

cway

byth

ele

ngth

ofth

elin

kE ,i

tste

nsio

n

- ,and

agi

ven

func

tion

oftim

e

G mod

ellin

gthe

activ

atio

nle

velo

fth

em

uscl

e.T

hesp

ring

inth

eac

tive

part

isde

note

dthe

serie

sele

men

t.T

hesp

ring

inpa

ralle

lwith

the

activ

epa

rt,a

ndw

hich

cons

titut

esth

epa

ssive

part

,is

calle

dth

epa

ralle

lele

men

t.T

hete

nsio

n

-­ ina

mus

cula

rlink

inth

ebo

unda

ryco

nfigu

ratio

n

­ isth

esu

mof

the

pass

ivean

dth

eac

tive

part -­

-­³²:-­ ^

(3.3

7)

The

tens

ioni

nth

epa

ssive

part

isfo

und

sim

ilarly

toth

epa

ssive

tissu

emod

elab

ove.

Thu

s

-­³²¯ ° ²J E­ E ²J

if

E­ zE ²J

if

E­ E ²J

(3.3

8)

whe

re° ²J

isth

est

iffne

ss,

E­ isth

ele

ngth

ofth

em

uscu

larli

nkan

d

E ²J isthe

rest

ingl

engt

hof

the

para

llele

lem

ent.° ²J

and

E ²J arefix

edin

time.

The

tens

ioni

nth

eac

tive

part

isgi

ven

by

-­ ^¯ ° tJ E­ Ey1) vJ

if

E­ zE y1) vJ

if

E­ E y1) vJ

(3.3

9)

Page 27: MR · 2002. 2. 20. · Adeler A TV Erhver vsf or skerpr ojekt EF 698 IMM-PHD-2001-86 ISSN 0909-3192 ISBN 87-88306-13-5 c 2001 by Pernille Thorup Adeler Printed by IMM, DTU Bookbinder

342D

hear

tmod

elus

ing

the

imm

erse

dbo

unda

rym

etho

d

L ce

Par

alle

lel

emen

t

Ser

ies

elem

ent

Con

trac

tile

elem

ent

L ce

L−

L

Fig

ure

3.5:

Ske

tch

ofth

em

uscu

larm

odel

with

two

linea

rspr

ings

inpa

ralle

l,one

ofw

hich

isco

nnec

tedin

serie

sto

aco

ntra

ctile

elem

ent.

whe

re° tJ

isth

est

iffne

ssof

the

serie

sele

men

tand

E vJ isth

ele

ngth

ofth

eco

n-tr

actil

eel

emen

t.W

hen

we

com

pare

this

expr

essi

onw

ithth

eex

pres

sion

for

the

tens

ioni

nth

epa

ssive

part

abov

e,w

ese

etha

tthe

leng

thof

the

cont

ract

ileel

emen

t

E vJ has

the

func

tion

ofa

rest

ingl

engt

h.S

ince

E vJ varie

sin

time,

we

can

thin

kof

the

activ

epa

rtas

alin

ears

prin

gw

itha

varia

bler

estin

glen

gth

give

nby

E vJ .In

the

cont

inuo

usfo

rmul

atio

nof

the

mod

elth

eve

loci

tyof

cont

ract

iono

fthe

cont

ract

ileel

emen

tisgo

vern

edby

the

follo

win

gco

mbi

natio

nof

adi

ffer

entia

leq

uatio

nand

anal

gebr

aice

quat

ion

YmZZ\ ZZ]C E vJ C

´"µ^L G ;G ° E - ^

° E :- ^

if

G ¶

E vJE

if

G

(3.4

0)

whe

re

´"µ^L and°

are

mus

clep

aram

eter

sand

G isa

give

nfu

nctio

nof

time

calle

dth

eac

tivat

ion

func

tion.

For

deta

ilson

the

activ

atio

nfu

nctio

nse

eS

ec-

tion

3.3.

6.A

tco

nsta

ntac

tivat

ion

G andle

ngth

E the

equi

libriu

mva

lue

ofth

eac

tive

ten-

sion

is

- ^G° E °tJ EE vJ ,so

the

max

imum

valu

eof

G compa

tible

with

non-

nega

tive

rest

ingl

engt

h

E vJ is

G °tJ$ °

.Cha

ract

eris

ticof

the

mod

elis

that

the

appr

oach

toth

iseq

uilib

rium

isfa

ster

atsm

alle

ract

ivat

ion

leve

lsdu

eto

the

G

inth

ede

nom

inat

orin

the

expr

essi

onin

(3.4

0).

Equ

atio

n(3.

40),

with

the

activ

atio

nde

pend

ence

,isa

gene

raliz

atio

nof

Hill

’seq

uatio

nfor

the

velo

city

ofco

ntra

ctio

nof

ate

tani

zedm

uscl

e.T

hem

odel

abov

e

3.3

Dis

cret

efo

rmul

atio

n35

iskn

own

asH

ill’s

thre

eele

men

tmod

el,s

eech

apte

rs9

and

10of

Fun

g(1

993)

.In

the

case

of

Gy1) ¶ th

ete

nsio

n

-­ ^ inth

elin

kca

nbe

foun

dfr

omth

esy

stem

-­ ^° tJ E­ Ey1) vJ

Ey1) vJEy vJ ´ µ^L Gy1)Gy1) °E­ -­ ^

° E ­ :- ­ ^

Com

bini

ngth

esee

quat

ions

and

solv

ing

for

-­ ^ gives

-­ ^# ° tJ` | · + ¸ ·:+:|.· |g

(3.4

1)

whe

re

· ´ µ^L8 # Gy1):#=

+ ° E­

° tJ| E­ Ey vJ: ´ µ^L

Sin

cebo

th· an

d

+ are

posi

tive,

itis

seen

that

for

| D th

ete

nsio

n

-­ ^D .

Thi

sco

rres

pond

sto

E y1) vJzE­ in

whi

chca

seth

ete

nsio

n

-­ ^ shoul

dbe

zero

(see

equa

tion(

3.39

)).T

hus

we

can

set

-­ ^ if

| D w

ithou

thav

ing

toco

mpu

te

E y1) vJdi

rect

ly.

3.3.

6T

heac

tivat

ion

func

tion

The

activ

atio

nfu

nctio

n

G whi

chw

asin

trod

uced

for

the

mus

cula

rlink

abov

eis

the

driv

ing

forc

eof

the

hear

tmod

el.T

heac

tivat

ion

func

tion

mod

elst

here

leas

eof

Ca. 1 (P

eski

n,20

01),

whi

chin

itiat

esth

eco

ntra

ctio

nofh

eartm

uscl

easm

entio

ned

inS

ectio

n2.

4.T

hus

the

activ

atio

nfu

nctio

nde

term

ines

the

time

cour

sein

the

mod

el,i.

e.th

eco

ntra

ctio

nand

rela

xatio

noft

hehe

artm

uscl

e.W

ede

scrib

eher

eth

efo

rmof

the

activ

atio

nfu

nctio

nas

itw

asin

the

orig

inal

mod

elby

Pes

kina

ndM

cQue

en.W

eha

veal

soim

plem

ente

dane

wfo

rmof

the

activ

atio

nfu

nctio

n,bu

tth

isis

the

topi

cof

Cha

pter

6an

dw

illno

tbe

disc

usse

dhe

re. The

time

cour

seof

the

hear

tcyc

leis

dete

rmin

edby

the

follo

win

gpa

ram

eter

s:he

artr

ate,

onse

tand

dura

tion

times

ofat

riala

ndve

ntric

ular

syst

ole

rela

tive

tohe

artp

erio

d,an

dex

cita

tion

and

rela

xatio

nrat

eco

nsta

nts(s

eebe

low

).T

hem

odel

sets

the

initi

altim

eof

the

sim

ulat

ion

inth

eea

rlyve

ntric

ular

dias

tole

durin

gth

e

Page 28: MR · 2002. 2. 20. · Adeler A TV Erhver vsf or skerpr ojekt EF 698 IMM-PHD-2001-86 ISSN 0909-3192 ISBN 87-88306-13-5 c 2001 by Pernille Thorup Adeler Printed by IMM, DTU Bookbinder

362D

hear

tmod

elus

ing

the

imm

erse

dbo

unda

rym

etho

d

isov

olum

icre

laxa

tionp

hase

ofth

eve

ntric

le.T

heac

tivat

ion

func

tion

G isde

-fin

edin

sepa

ratew

ays

indi

asto

lean

dsy

stol

eand

isdi

ffer

entf

orth

elin

ksin

the

atriu

m,t

heve

ntric

lean

dth

epa

pilla

rym

uscl

e.D

urin

gdi

asto

leth

eac

tivat

ion

func

tion

G isde

fined

asa

solu

tion

toa

dif-

fere

ntia

lequ

atio

noft

hefo

rm

C G C "!G

whe

re

u! denot

esa

rela

xatio

nrat

eco

nsta

nt.D

urin

gsy

stol

e

G isde

fined

asa

solu

tion

toa

casc

aded

seto

fdiff

eren

tiale

quat

ions

ofth

efo

rm

C G ­ C J G µ^LG ­

C G C J G ­G

whe

re

J denot

esan

exci

tatio

nra

teco

nsta

ntan

d

G µ^L

deno

testh

elim

iting

valu

eof

the

activ

atio

nfu

nctio

n.T

heac

tivat

ion

func

tion

G insyst

olei

sch

osen

asth

eso

lutio

nto

ase

cond

orde

req

uatio

nbec

ause

itgi

ves

asm

ooth

tran

sitio

nto

the

syst

olic

phas

e,w

here

asth

eau

xilia

ryfu

nctio

n

G ­ hasa

mor

eab

rupt

upst

roke

.In

addi

tion,

the

activ

atio

nfu

nc-

tion

isre

quire

dto

beco

ntin

uous

for

the

who

lehe

artp

erio

d.T

here

isa

diff

eren

tse

tof

cons

tant

sfor

the

atriu

man

dth

eve

ntric

le,b

utth

esa

mes

etis

used

for

the

vent

ricle

and

the

papi

llary

mus

cle.

The

initi

alva

lues

ofth

eac

tivat

ion

func

tion

are

diff

eren

tfor

allt

hree

type

sofl

inks

.In

Pes

kina

ndM

cQue

en’sor

igin

alm

odel

the

cons

tant

sfort

heac

tivat

ion

func

-tio

nw

ere

sett

om

atch

ado

g’s

hear

t.S

ince

itis

oura

imto

mak

ea

sim

ulat

ion

ofth

em

odel

rese

mbl

ethe

MR

data

ofa

hum

anw

ech

ange

the

timin

gpa

ram

eter

sfo

rth

eac

tivat

ion

func

tion.

We

choo

seon

esp

ecifi

cset

ofM

Rm

easu

rem

entsa

ndus

eit

asth

eba

sisf

orou

rmod

ifica

tiono

fth

em

odel

.The

leng

thof

the

hear

tcy-

cle,

0.93

6m

s,is

foun

das

the

peak

tope

aktim

e(2

6in

terv

als

of36

ms

dura

tion

t t Jy¹ ! JG µ^LG

[ms]

[ms]

[ms

() ][m

s

() ]

G

atriu

m0.

362

0.46

61/

551/

751.

50

vent

ricle

0.54

50.

851

1/55

1/21

4.9

1.07

pap.

mus

c.0.

545

0.85

11/

551/

214.

90.

107

Tabl

e3.

1:T

imin

gs(o

nset

time

ofsy

stol

e

t anden

dtim

eof

syst

ole

t Jy¹ ),rat

eco

nsta

nts,l

imiti

ngva

lues

,and

initi

alva

lues

for

the

activ

atio

nfu

nctio

ns.I

nitia

ltim

efo

rm

odel

is

.

3.3

Dis

cret

efo

rmul

atio

n37

each

)inth

eM

Rre

cord

ingo

fthe

aort

icou

tflow

velo

city

ata

cent

ralre

gion

inth

eou

tflow

jet

atth

ele

velo

fth

eao

rtic

valv

e.T

heM

Rda

tado

esno

tdire

ctly

give

the

timin

gfo

rth

eco

ntra

ctio

nof

the

hear

t,bu

tby

com

parin

gvel

ocity

profi

les

atth

em

itral

ring

and

the

aort

icou

tflow

trac

tfro

mth

esi

mul

atio

nand

from

the

MR

reco

rdin

g,th

eco

nsta

ntsc

anbe

dete

rmin

edby

tria

land

erro

r.T

hese

are

aslis

ted

inTa

ble

3.1.

Fig

ure

3.6

show

sth

eac

tivat

ion

func

tions

for

the

vent

ricle

,atr

ium

and

papi

llary

mus

clef

oron

ehe

artc

ycle

.T

hedi

ffer

entia

lequ

atio

nsha

vean

alyt

icso

lutio

ns(s

eeS

ectio

n6.2

.1),

buti

nth

epr

ogra

mth

edi

ffer

entia

lequ

atio

nsar

eso

lved

with

suffi

cien

tacc

urac

yby

anim

plic

itE

uler

met

hod.

Indi

asto

lew

eha

ve

Gy1)Gy u!Gy1)

and

insy

stol

e

Gy1) ­Gy ­ J G µ^LGy1) ­

Gy1)Gy J

Gy1) ­Gy1)

0.2

0.4

0.6

0.8

1

012345

i j

Fig

ure

3.6:

Act

ivat

ion

asfu

nctio

nof

time

for

the

vent

ricle

(dot

ted)

,atr

ium

(das

hed)

and

papi

llary

mus

cle(

solid

),th

ela

tteri

sin

dist

ingu

isha

blefr

omth

eve

n-tr

icul

arcu

rve

insy

stol

e.

Page 29: MR · 2002. 2. 20. · Adeler A TV Erhver vsf or skerpr ojekt EF 698 IMM-PHD-2001-86 ISSN 0909-3192 ISBN 87-88306-13-5 c 2001 by Pernille Thorup Adeler Printed by IMM, DTU Bookbinder

382D

hear

tmod

elus

ing

the

imm

erse

dbo

unda

rym

etho

d

3.3.

7To

polo

gyan

din

itial

geom

etry

ofth

ehe

art

The

geom

etric

para

met

ersd

eter

min

ethe

size

and

shap

eof

the

mod

elhe

arta

tth

ein

itial

time

ofsi

mul

atio

n.T

hein

itial

geom

etry

isso

mew

hati

deal

ized

,bei

ngco

mpo

sedo

fstr

aigh

t-lin

eseg

men

tsan

dci

rcul

arar

cs.T

his

geom

etry

isof

cour

sech

ange

ddur

ing

asi

mul

atio

nofa

card

iacc

ycle

.W

eus

efou

rkey

para

met

ersfo

rth

ege

omet

ry:th

edi

amet

erof

the

mitr

alrin

g(2

.97

cm),

the

diam

eter

ofth

eao

rtic

outfl

owtr

act(

2.58

cm),

the

angl

ebe

twee

nth

eset

wo

(45

, ),an

dthe

leng

thof

the

vent

ricle

(5.4

2cm

).T

hedi

amet

erva

lues

are

read

off

from

the

wid

ths

ofth

ein

flow

and

outfl

owje

tsin

the

MR

reco

rdin

gsan

dth

enin

crea

sedb

y10

%so

that

the

wid

thso

fthe

mea

sure

dand

sim

ulat

edin

/out

flow

jets

appe

arap

prox

imat

elyt

hesa

me

durin

gth

eir

initi

alph

ases

.Suc

hin

crea

seis

nece

ssar

yinor

dert

oco

mpe

nsat

efor

the

incr

ease

dthi

ckne

ssof

the

boun

dary

laye

r.T

hein

crea

sedth

ickn

essis

due

toth

esc

alin

goft

hevi

scos

itym

entio

nedi

nS

ectio

n3.3

.3an

dto

the

size

ofth

ere

gion

ofin

fluen

ceof

the

boun

dary

laye

ron

the

fluid

resu

lting

from

the

chos

ensp

atia

lreso

lutio

n.T

hean

gula

rval

ue,w

hich

issl

ight

lyon

the

high

side

,isch

osen

tom

ake

the

sim

ulat

edin

flow

jetd

irect

ion

fitth

em

easu

redo

neat

the

time

ofea

rlype

akin

flow

.T

hele

ngth

ofth

eve

ntric

leis

chos

enla

rge

enou

ghso

that

itca

nw

ithst

andc

ontr

actio

nunt

ilth

een

dof

syst

ole.

Fig

ure

3.7

show

sth

efin

alm

odifi

edin

itial

geom

etry.

The

boun

dary

poin

tsar

econ

nect

edby

links

repr

esen

tingm

uscl

esan

dcon

nec-

tive

tissu

es.T

his

link

stru

ctur

e,th

eto

polo

gyof

the

mod

elhe

art,i

sfix

edth

roug

h-ou

tthe

cycl

e.In

addi

tion

toth

eso

-cal

ledp

hysi

calb

ound

aryp

oint

s,th

ebo

unda

ryin

clud

eson

evi

rtua

lpoi

ntw

hich

isno

tmov

eddi

rect

lyby

the

fluid

buti

sus

edas

anin

terc

onne

ctio

npoi

ntbe

twee

nphy

sica

lpoi

nts.

Link

sco

nnec

tingt

hebo

unda

rypo

ints

may

beei

ther

activ

eor

pass

ive,s

eese

ctio

n3.3

.5.

Agi

ven

pair

ofpo

ints

may

beco

nnec

tedb

ym

ore

than

one

link.

The

boun

dary

poin

tsar

eco

nnec

teda

long

the

wal

land

inad

ditio

nby

cros

slin

ks.

Cro

sslin

ksar

ene

eded

tosi

mul

ate

circ

umfe

rent

ials

tres

sesin

the

mod

elhe

art

sinc

eth

em

odel

ison

ly2D

.The

links

them

selve

sdo

noti

nter

fere

with

the

fluid

,ex

cept

thro

ught

hefo

rces

they

exer

ton

thei

rend

poin

ts.

Inth

eor

igin

alm

odel

cros

slin

ksco

nnec

tthe

stra

ight

part

soft

heve

ntric

leto

each

othe

r.A

lso

conn

ecte

dby

cros

slin

ksar

eth

est

raig

htpa

rts

ofth

eou

tflow

trac

t.To

acco

mm

odat

ethe

mod

elto

are

alis

tichu

man

left

vent

ricle

we

incr

ease

the

stiff

ness

para

met

erso

fthe

cros

slin

ksin

the

stra

ight

part

ofth

eve

ntric

lean

din

trod

ucec

ross

links

inth

eci

rcul

arpa

rtof

the

vent

ricle

,see

Fig

ure

3.7.

Cro

sslin

ksem

anat

efrom

apo

inta

tthe

botto

mof

the

vent

ricle

toth

evi

rtua

lpo

inta

ndfr

omth

evi

rtua

lpoi

ntto

the

end

poin

tsof

the

valv

ele

aflet

s.T

helin

kfr

omth

eve

ntric

lew

allt

oth

evi

rtua

lpoi

ntre

pres

entst

hetw

opa

pilla

rym

uscl

es

3.3

Dis

cret

efo

rmul

atio

n39

Source

Sink

Atrium

Ventricle

Exteriorsink/source

Valveleaflets

Outflow

tract

Papillarymuscle

Chords

Virtualpoint

Fig

ure

3.7:

Mod

ified

initi

alhe

artg

eom

etry

with

cros

slin

ksan

dlin

ksal

ong

hear

tw

alls

how

nas

full

lines

.

(see

Fig

ure

3.7)

,whi

chin

the

real

hear

tpro

trud

efr

omth

ehe

artw

all

atpo

ints

abov

ean

dbe

low

the

plan

ein

whi

chth

em

odel

resi

des.

The

yar

ere

pres

ente

dinth

em

odel

byth

eirc

omm

onpr

ojec

tiono

nto

this

plan

e.In

the

orig

inal

mod

elth

epa

pilla

rym

uscl

ewas

conn

ecte

dto

the

apex

ofth

ehe

art(

Pes

kin,

1977

).To

im-

prov

eth

em

ovem

ento

fthe

mitr

alva

lve

we

mov

eth

epo

intt

ow

hich

the

papi

llary

mus

clei

sco

nnec

tedu

pal

ong

the

ante

riorw

all.

The

links

from

the

virt

ualp

oint

sto

the

tips

ofth

ele

aflet

repr

esen

tthe

chor

ds,c

hord

aete

ndin

eae,w

hich

arep

assiv

etis

sue.

All

activ

elin

ksar

edou

bled

bya

corr

espo

ndin

gpas

sive

link,

buts

omep

airs

ofpo

ints

are

conn

ecte

donl

yby

apa

ssive

link,

cf.

Sec

tion3

.3.5

onbo

unda

ryfo

rces

.T

helin

ksin

the

outfl

owtr

acta

ndth

eas

soci

ated

cros

slin

ksar

eal

lpas

sive.

Als

oth

elin

ksin

the

valv

ele

aflet

sand

the

links

repr

esen

tingth

ech

ords

are

pass

ive.

Inth

eor

igin

alm

odel

the

hear

twas

free

lyflo

atin

gin

the

surr

ound

ingd

omai

n,w

hich

resu

ltedi

nex

cess

ive(n

on-p

hysi

olog

ical

)mov

emen

tsdu

ring

the

ejec

tion

phas

e.D

ueto

are

coil

effe

ctfr

omth

eej

ectio

nth

ehe

artw

ould

star

taro

ta-

tion

chan

ging

itsal

ignm

entin

spac

eand

begi

na

tran

slat

ione

vent

ually

mov

ing

itth

roug

hth

ebo

unda

ry.To

over

com

ethi

spr

oble

mw

ete

ther

the

hear

tby

linea

r

Page 30: MR · 2002. 2. 20. · Adeler A TV Erhver vsf or skerpr ojekt EF 698 IMM-PHD-2001-86 ISSN 0909-3192 ISBN 87-88306-13-5 c 2001 by Pernille Thorup Adeler Printed by IMM, DTU Bookbinder

402D

hear

tmod

elus

ing

the

imm

erse

dbo

unda

rym

etho

d

sprin

gs(p

assiv

elin

ks)t

oa

seto

ffixe

dpo

ints

.Afte

rtry

ing

diff

eren

tarr

ange

men

tsw

ech

oose

tote

ther

the

stra

ight

part

ofth

eou

tflow

trac

tto

fixed

poin

tssi

tuat

edat

the

initi

alpo

sitio

nof

the

outfl

owtr

act.

Thi

sim

prov

esth

em

otio

nof

the

hear

tdu

ring

ahe

artc

ycle

cons

ider

ably,

even

thou

ghit

isst

illm

oret

han

that

ofa

natu

ral

hum

anhe

art(

seeC

hapt

er4)

.

3.4

Out

line

ofal

gorit

hm

The

prev

ious

sect

ions

have

desc

ribed

diff

eren

tpar

tsof

the

2Dhe

artm

odel

.The

over

alla

imof

the

mod

elis

toco

mpu

teth

eve

loci

tyfie

ld

2y1) ,the

pres

sure

field

5y1)

and

the

hear

tbou

ndar

ycon

figur

atio

n

y1)

attim

ele

vel

:# base

don

the

sam

equa

ntiti

esat

the

prev

ious

time

leve

l

.Theal

gorit

hmis

asfo

llow

s:

1.C

ompu

teth

ebo

unda

ryfo

rce

B­ Q asfol

low

s:

(a)

Com

pute

the

frac

tiona

lste

pbou

ndar

ycon

figur

atio

n

­ byso

lvin

g

­ Qk Q:®B Q­ ) ­ ¤¥ S #

(3.3

5)

whe

re

k Qy Q: 2y Q .

(b)

Com

pute

the

tens

ion

-­ inth

ebo

unda

ryba

sedo

nth

eco

nfigu

ratio

n

­ asde

scrib

edin

Sec

tion3

.3.5

for

the

pass

ivetis

sueu

sing

equa

tion

(3.3

6)an

dfo

rth

em

uscu

larti

ssue

usin

geq

uatio

ns(3

.37)

–(3.

41).

(c)

Com

pute

B­ Q using

B­ QB­ Q ­ O © ª

« ¡¬B Q­

(3.3

2)

whe

re

B Q­ -­c ­ ¨­ Qf

­ ¨­ Q

­ ¨­ Q

(3.3

1)

2.D

istr

ibut

eth

ebo

unda

ryfo

rce

B­ Q tothe

Eul

eria

ngrid

,i.e

.com

pute

the

forc

efie

ld

>y usin

g

>y O QB­ Q 43 y Q

(3.2

4)

3.C

ompu

teth

eve

loci

tyfie

ld

2y1)

and

the

pres

sure

field

5y1)by

solv

ing

the

Nav

ier-

Sto

kese

quat

iona

ndth

eco

ntin

uity

equa

tiona

sfol

low

s:

3.4

Out

line

ofal

gorit

hm41

(a)

Suc

cess

ively

solv

efo

rth

efr

actio

nals

tep

velo

citie

s

2y1)/ ,

2y1)/)

and

2y1) . us

ing

72y1) 2y >y

(3.1

6)

78 2y1)/) 2y1)/

: y L L2y1) )= *1 L( L2y1)/)

(3.1

7)

78 2y1)/. 2y1)/)

: y 2y1)/.= *1 ( 2y1)/. (3

.18)

(b)

Sol

ve

78 2y1) 2y1) .

= : 5y1)

(3.1

9)

;2y1) sy 5y1)

(3.2

0)

for

2y1)an

d

5y1)us

ing sy 5y1

) . O Q R)Iy Q 5y1) ?y Q

(3.2

1)

?y QM Qy Q M JL y JL

(3.2

2)

Her

e

I y ) 5y1) is

give

nby

equa

tion(

3.23

)for

the

atria

lsou

rce,

whi

leth

eco

mpu

tatio

nof

I y . forth

eao

rtic

sink

isas

desc

ribed

onpp

.30–

31S

ectio

n3.3

.4.

4.C

ompu

teth

ehe

artb

ound

aryc

onfig

urat

ion

y1) Qy Q: O 2y1) 3 y Q~.

(3.2

5)

Page 31: MR · 2002. 2. 20. · Adeler A TV Erhver vsf or skerpr ojekt EF 698 IMM-PHD-2001-86 ISSN 0909-3192 ISBN 87-88306-13-5 c 2001 by Pernille Thorup Adeler Printed by IMM, DTU Bookbinder

Cha

pter

4

Eva

luat

ion

ofth

e2D

mod

el

Thi

sch

apte

rpre

sent

sthe

eval

uatio

nof

the

2Dhe

artm

odel

.Firs

twe

pres

entth

ety

pica

lout

putf

rom

asi

mul

atio

nwith

the

mod

el.W

eev

alua

tetw

oge

nera

lasp

ects

ofth

eim

mer

sedb

ound

arym

etho

d(as

itis

pres

ente

dinth

isth

esis

):th

ein

fluen

ceof

the

scal

ing

fact

or

andth

ein

fluen

ceof

the

perio

dic

boun

dary

cond

ition

s.F

urth

erm

ore,

som

easp

ectso

fth

em

odel

rela

teds

peci

fical

lyto

the

sim

ulat

ion

ofth

ehe

arta

reev

alua

ted,

e.g.

the

teth

erin

gof

the

hear

t,the

Win

dkes

selm

odel

and

the

mod

ellin

gof

dist

ribut

edso

urce

sand

sink

s.

4.1

Sim

ulat

ion

outp

ut

The

mai

nou

tput

from

asi

mul

atio

ncon

sist

soft

hree

varia

bles

:the

hear

tbou

ndar

yco

nfigu

ratio

n

,the

velo

city

field

2 andth

epr

essu

refie

ld

5 .From

each

ofth

ese

seve

ralo

ther

varia

bles

can

bede

rived

.T

here

sults

pres

ente

dinth

isch

apte

rare

from

asi

mul

atio

nof

the

mod

elde

-sc

ribed

inC

hapt

er3,

with

the

follo

win

gse

tting

s:12

8

0 128

grid

,299

52tim

est

eps

perh

eart

cycl

e,t

hele

ngth

ofa

hear

tcyc

leis

0.93

6s,

# ,a

ndth

eto

tals

im-

ulat

ion

time

is2

hear

tcyc

les(

i.e.1

.872

s).W

ew

illre

fert

oth

isas

ourr

efer

ence

sim

ulat

ion.

Thi

sch

oice

ofpa

ram

eter

setti

ngsw

illbe

disc

usse

dinth

efo

llow

ing

sect

ions

.Inth

isse

ctio

nwe

only

pres

entth

ere

sults

,leav

ing

the

disc

ussi

onof

them

tola

ters

ectio

ns.

Page 32: MR · 2002. 2. 20. · Adeler A TV Erhver vsf or skerpr ojekt EF 698 IMM-PHD-2001-86 ISSN 0909-3192 ISBN 87-88306-13-5 c 2001 by Pernille Thorup Adeler Printed by IMM, DTU Bookbinder

44E

valu

atio

nof

the

2Dm

odel

4.1.

1H

eart

boun

dary

confi

gura

tion

and

fluid

mar

ker

s

Ate

acht

ime

step

the

hear

tbou

ndar

ycon

figur

atio

n

iskn

own

andc

anbe

plot

ted.

We

also

com

pute

the

mot

ion

ofso

mefl

uid

mar

kers

.The

sear

epl

aced

initi

ally

atea

chgr

idpo

inti

nth

ein

terio

rof

the

hear

tand

mov

edac

cord

ingt

oth

eve

loci

tyfie

ldat

each

time

step

.No

new

mar

kers

are

intr

oduc

edas

fluid

ente

rsth

em

odel

thro

ugh

the

sour

ces,

nora

rem

arke

rsre

mov

edas

fluid

leav

esth

roug

hth

esi

nks.

The

mar

kers

dono

taffe

ctth

eflu

idm

otio

nan

dar

eon

lyus

edfo

rou

tput

.A

nan

imat

iono

fthe

hear

tbou

ndar

ycon

figur

atio

nand

fluid

mar

kers

toge

ther

isa

very

help

fult

ooli

nth

ein

vest

igat

iono

fasi

mul

atio

n.S

ince

itis

notp

ossi

ble

tosh

owth

ishe

re,w

esh

owin

stea

din

Fig

ure

4.1

apl

otof

the

hear

tbou

ndar

yco

nfigu

ratio

nand

the

fluid

mar

kers

atsi

xeq

uidi

stan

ttim

esdu

ring

the

seco

ndhe

artc

ycle

.F

rom

the

hear

tbou

ndar

ycon

figur

atio

nthe

leng

thof

the

mitr

alrin

gan

dth

edi

stan

cebe

twee

nmitr

alva

lve

leafl

ettip

sar

eco

mpu

ted.

Fur

ther

mor

e,w

eco

m-

pute

the

area

ofth

eat

rium

and

ofth

eve

ntric

le.T

hetim

eva

riatio

nof

thes

efou

rqu

antit

iesc

anbe

used

inth

ein

vest

igat

iono

fasi

mul

atio

n.

4.1.

2V

eloc

ityfie

ld

The

velo

city

field

isvi

sual

ized

thro

ugha

velo

city

vect

orfie

ldpl

ot.T

osi

mpl

ifyth

epl

ot,o

nly

asu

bset

ofth

efu

llve

loci

tyfie

ldis

plot

ted.

Mor

epr

ecis

ely,

rega

rdle

ssof

the

spat

iald

iscr

etiz

atio

nuse

dfor

asi

mul

atio

n,th

eve

loci

tyfie

ldis

plot

ted

only

ona

32

0 32gr

id.

Inth

eup

perl

eft

corn

erof

each

velo

city

field

plot

aun

itsi

zeve

ctor

corr

espo

ndin

gto

ale

ngth

of1.

25cm

and

ave

loci

tyof

1m

/sis

plot

ted.

Fur

ther

mor

e,th

ehe

artb

ound

aryc

onfig

urat

ion

ispl

otte

d.F

igur

e4.

2sh

ows

apl

otof

the

velo

city

field

and

the

hear

tbou

ndar

ycon

figur

atio

natt

hesa

mes

ixeq

uidi

stan

ttim

esas

inF

igur

e4.

1.E

ven

thou

ghve

loci

tyve

ctor

sare

seen

tocr

oss

the

hear

tbou

ndar

y,th

isdo

esno

tmea

nth

atflu

idis

leak

ing

thro

ugh

the

wal

ls.

Rat

her,t

his

isa

cons

eque

nceof

the

hear

tbou

ndar

ymov

ing

with

the

fluid

velo

city

.F

rom

the

velo

city

field

we

can

com

pute

velo

city

time

profi

les

atgi

ven

posi

-tio

ns;t

his

isth

etim

eva

riatio

nof

the

velo

city

over

agi

ven

line

segm

ento

rat

agi

ven

poin

t.W

eha

vefo

cuse

don

velo

city

time

profi

lesa

tthe

mitr

alrin

g,be

twee

nth

em

itral

leafl

ettip

s,an

dac

ross

the

aort

icou

tflow

trac

tbel

owth

eao

rtic

sink

.W

eco

mpu

teth

em

eanv

eloc

itytim

epr

ofile

sast

hem

eanv

eloc

ity(w

ithre

spec

tto

spac

e)ov

era

line

segm

entr

elat

ive

toth

ehe

artb

ound

ary,

i.e.i

na

refe

renc

efr

ame

mov

ing

with

the

hear

t.E

.g.t

heve

loci

tytim

epr

ofile

over

the

mitr

alrin

gis

the

spat

ialm

eanv

eloc

ityov

erth

em

itral

ring

rela

tive

toth

em

ovin

gm

itral

ring.

Fur

ther

mor

e,w

elo

okat

the

velo

city

time

profi

leof

the

cent

reve

loci

ty,w

hich

issi

mpl

yth

eve

loci

tyco

mpo

nent

norm

alto

the

line

segm

enta

tthe

cent

repo

into

f

4.1

Sim

ulat

ion

outp

ut45

Time0.936

Time1.092

Time1.248

Time1.404

Time1.560

Time1.716

Fig

ure

4.1:

Hea

rtbo

unda

ryan

dflu

idm

arke

rsat

six

equi

dist

antti

mes

durin

gth

ese

cond

hear

tcyc

le.

The

first

time

(0.9

36s)

isat

the

onse

tof

the

seco

ndhe

art

cycl

ein

early

dias

tole

,whi

leth

ela

sttim

e(1

.716

s)is

atth

een

dof

the

seco

ndhe

artc

ycle

durin

gve

ntric

ular

syst

ole.

Page 33: MR · 2002. 2. 20. · Adeler A TV Erhver vsf or skerpr ojekt EF 698 IMM-PHD-2001-86 ISSN 0909-3192 ISBN 87-88306-13-5 c 2001 by Pernille Thorup Adeler Printed by IMM, DTU Bookbinder

46E

valu

atio

nof

the

2Dm

odel

Time0.936

Time1.092

Time1.248

Time1.404

Time1.560

Time1.716

Fig

ure4

.2:V

eloc

ityfie

ldan

dhea

rtbou

ndar

ycon

figur

atio

nats

ixeq

uidi

stan

ttimes

durin

gth

ese

cond

hear

tcyc

le.T

hefir

sttim

e(0

.936

s)is

atth

eon

seto

fthe

seco

ndhe

artc

ycle

inea

rlydi

asto

le,w

hile

the

last

time

(1.7

16s)

isat

the

endo

fthe

seco

ndhe

artc

ycle

durin

gve

ntric

ular

syst

ole.

4.1

Sim

ulat

ion

outp

ut47

the

line

segm

ent.

The

cent

reve

loci

tyis

repo

rted

asth

eve

loci

tyre

lativ

eto

the

com

puta

tiona

lgrid

,i.e

.in

are

fere

ncef

ram

efix

edin

spac

e.In

all

the

plot

sof

velo

city

time

profi

lesw

edr

awve

rtic

alda

shed

lines

atth

een

dtim

eof

each

hear

tcy

cle,

i.e.i

nou

rref

eren

cesi

mul

atio

nth

elin

esar

edr

awn

at

san

dat

# %º s.

Fig

ure

4.3

show

sth

eve

loci

tytim

epr

ofile

ofth

em

eanv

eloc

ityov

erth

em

itral

ring

andb

etw

eent

hem

itral

leafl

ettip

sdu

ring

2he

artc

ycle

s.F

igur

e4.4

show

sth

eve

loci

tytim

epr

ofile

ofth

em

eanv

eloc

ityac

ross

the

aort

icou

tflow

trac

t(be

low

the

aort

icsi

nk)d

urin

g2

hear

tcyc

les.

Fro

mth

eve

loci

tyfie

ldw

eca

nals

oobt

ainfl

owda

taov

era

give

nlin

ese

gmen

t.F

low

isco

mpu

tedb

yth

em

eanv

eloc

ityov

erth

elin

ese

gmen

tmul

tiplie

dby

the

leng

thof

the

line

segm

ent.

Thi

sgi

ves

aflo

win

the

dim

ensi

onof

area

pert

ime,

whi

chis

the

natu

rald

imen

sion

offlo

win

a2D

mod

el.

Toco

nver

tare

aflow

tovo

lum

eflow

we

mul

tiply

bya

unifo

rmth

ickn

essc

orre

spon

ding

to1/

4of

the

com

-pu

tatio

nald

omai

n.W

eco

mpu

teth

etim

eva

riatio

nof

the

volu

me

flow

over

the

mitr

alrin

g,be

twee

nthe

leafl

ettip

s,an

dac

ross

the

aort

icou

tflow

trac

t(be

low

the

aort

icsi

nk).

The

mod

elna

tura

llygi

ves

the

volu

me

flow

thro

ugh

the

sour

cesa

ndsi

nks

inth

em

odel

,see

e.g.

equa

tion(

3.9)

for

the

flow

thro

ught

heat

rials

ourc

e.T

hetim

eva

riatio

nof

the

flow

thro

ugh

the

atria

lsou

rcea

ndth

eao

rtic

sink

are

plot

ted

in

0.25

0.5

0.75

11.25

1.5

1.75

2t[s]

-40

-200

20

40

60

velocity[cm/s]

Fig

ure

4.3:

Vel

ocity

time

profi

leof

the

mea

nvel

ocity

(cm

/s)o

vert

hem

itral

ring

(sol

id)a

ndbe

twee

nthe

leafl

ettip

s(d

ashe

d).

Page 34: MR · 2002. 2. 20. · Adeler A TV Erhver vsf or skerpr ojekt EF 698 IMM-PHD-2001-86 ISSN 0909-3192 ISBN 87-88306-13-5 c 2001 by Pernille Thorup Adeler Printed by IMM, DTU Bookbinder

48E

valu

atio

nof

the

2Dm

odel

0.25

0.5

0.75

11.25

1.5

1.75

2t[s]

0

20

40

60

80

velocity[cm/s]

Fig

ure

4.4:

Vel

ocity

time

profi

leof

the

mea

nve

loci

ty(c

m/s

)acr

osst

heao

rtic

outfl

owtr

act(

belo

wth

eao

rtic

sink

).

0.25

0.5

0.75

11.25

1.5

1.75

2t[s]

-600

-400

-2000

200

sourceflow[cm^3/s]

Fig

ure

4.5:

Flo

wtim

epr

ofile

for

the

flow

(cm

» /s)

thro

ugh

the

mitr

also

urce

(das

hed)

and

the

aort

icsi

nk(s

olid

).

4.1

Sim

ulat

ion

outp

ut49

Fig

ure

4.5.

Inth

efig

ure

vert

ical

dash

edlin

esat

the

end

time

ofea

chhe

artc

ycle

are

also

incl

uded

.

4.1.

3P

ress

ure

field

The

mod

elgi

vest

hepr

essu

refiel

d

543 asou

tput

,and

this

canb

epl

otte

dasa

sur-

face

plot

,aco

ntou

rplo

t,or

ade

nsity

plot

,whe

reth

eco

lour

ofa

cell

corr

espo

nds

toth

eva

lue

ofth

epr

essu

refie

ldat

inth

atce

ll.T

hepr

essu

refie

ldis

nots

moo

thdu

eto

the

num

eric

alm

etho

dsus

ed(P

eski

n,20

01).

Thu

san

aver

agin

gpro

cedu

reis

nece

ssar

ybef

orei

tca

nbe

plot

ted.

The

non-

smoo

thpr

essu

refie

lddo

esno

taf-

fect

the

com

puta

tiono

fthe

velo

city

field

,sin

ceon

lyth

egr

adie

ntof

the

pres

sure

field

isus

edin

the

com

puta

tions

and

this

issm

ooth

.P

lots

ofth

epr

essu

refie

ldis

notv

ery

usef

ul,s

ince

the

pres

sure

field

insi

deth

ehe

arti

sra

rely

know

n.It

ism

ore

usef

ulto

com

pute

the

time

varia

tion

ofth

epr

essu

reat

agi

ven

posi

tion,

e.g.

over

asm

alls

quar

ein

the

atriu

mor

the

vent

ricle

,sim

ilarly

toth

eco

mpu

tatio

noft

hepr

essu

reat

aso

urce

asde

scrib

edin

Sec

tion3

.2.1

.F

igur

e4.6

depi

ctst

hetim

eva

riatio

noft

hepr

essu

reata

squa

rein

the

vent

ricle

,in

the

atriu

m,a

ndat

the

aort

icsi

nk.T

hepr

essu

reat

the

aort

icsi

nkco

rres

pond

sto

p . ineq

uatio

n(3.

10).

Inth

efig

ure

vert

ical

dash

edlin

esar

edr

awn

atth

een

d

0.25

0.5

0.75

11.25

1.5

1.75

2t[s]

10

20

30

40

50

60

pressure[mmHg]

Fig

ure

4.6:

Pre

ssur

etim

epr

ofile

for

the

pres

sure

(mm

Hg)

inth

eve

ntric

le(s

olid

),at

rium

(dot

ted)

and

atth

eao

rtic

sink

(das

hed)

.

Page 35: MR · 2002. 2. 20. · Adeler A TV Erhver vsf or skerpr ojekt EF 698 IMM-PHD-2001-86 ISSN 0909-3192 ISBN 87-88306-13-5 c 2001 by Pernille Thorup Adeler Printed by IMM, DTU Bookbinder

50E

valu

atio

nof

the

2Dm

odel

0.25

0.5

0.75

11.25

1.5

1.75

2t

[s]

Fig

ure

4.7:

Tim

eva

riatio

nof

vent

ricul

arpr

essu

re(s

olid

)and

vent

ricul

arac

tiva-

tion

(das

hed)

show

non

sam

etim

eax

isan

dsc

aled

toac

hiev

eth

esa

mem

axim

umle

vel.

time

ofea

chhe

artc

ycle

.T

heve

ntric

ular

pres

sure

varia

tion

follo

ws

clos

ely

the

vent

ricul

arac

tivat

ion

curv

e.T

his

isill

ustr

ated

inF

igur

e4.

7w

here

both

the

time

varia

tion

ofth

eve

n-tr

icul

arpr

essu

rean

dth

eve

ntric

ular

activ

atio

nar

esh

own

onth

esa

met

ime

axis

and

scal

edto

achi

eve

the

sam

emax

imum

leve

l.W

eex

ploi

tthi

sfe

atur

ein

Cha

p-te

r6.

4.2

The

scal

ing

fact

or

¼

The

scal

ing

fact

or

isuse

dto

scal

eall

times

and

leng

thst

oac

hiev

enu

mer

ical

stab

ility

ofth

eflu

idso

lver

ata

reas

onab

lecom

puta

tiona

ltime.

Pes

kini

ntro

duce

dth

esc

alin

gfac

tor

inhis

orig

inal

2Dm

odel

(Pes

kin,

1972

a).H

ela

terc

hang

edth

eflu

idso

lver

ina

subs

eque

nt3D

mod

elan

dth

usre

mov

edth

ene

edfo

rsc

alin

g(La

ian

dP

eski

n,20

00;M

cQue

enan

dP

eski

n,20

00).

But

sinc

ethe

2Dm

odel

still

uses

the

old

fluid

solv

er,t

hene

edfo

r

isstill

pres

ent,a

ndit

isim

port

antto

inve

stig

ate

the

influ

ence

of

onthe

sim

ulat

ionr

esul

ts.

We

belie

veth

atth

esc

alin

gw

ith

doesh

ave

anin

fluen

ceon

the

flow

,si

nce

scal

inga

llle

ngth

sand

times

by

( D# )c

orre

spon

dsto

scal

ingt

hevi

scos

ity

4.2

The

scal

ing

fact

or

51

#

Time

0.234

Time

0.234

Time

0.234

Time

0.234

Fig

ure

4.8:

Vel

ocity

field

and

hear

tbou

ndar

yat

s,w

ith

0.0

4,0.

1,0.

3an

d0.

5.

with

#$ ,thu

seffe

ctiv

ely

low

erin

gth

eR

eyno

ldsn

umbe

r.Pes

kin(

1977

)jus

tified

the

intr

oduc

tiono

f

bythe

com

para

tive

phys

iolo

gyof

the

hear

tofd

iffer

entm

am-

mal

s:he

arts

ofdi

ffer

entm

amm

alsa

rero

ughl

ysc

aled

mod

elso

feac

hoth

er.

Thi

sis

the

argu

men

tfor

Pes

kin’s

hypo

thes

istha

tess

entia

lfeat

ures

ofth

ebl

ood

flow

inth

ehe

arta

reno

tver

yse

nsitiv

eto

the

Rey

nold

snum

ber(

Pes

kin,

1977

).To

inve

stig

atet

hein

fluen

ceof

wemak

e6

sim

ulat

ions

vary

ing

only

the

valu

eof

.Thesi

mul

atio

nsar

eper

form

edon

a25

6gr

idw

ith29

952t

ime

step

sper

hear

tcy

cle

and

ato

talc

ompu

tatio

ntim

eof

1he

artc

ycle

.T

he

values

are:

0.04

,0.1

,0.

2,0.

3,0.

4an

d0.

5.

0.0

4w

asth

eor

igin

alva

lue

inth

eco

dew

ere

ceive

d

Page 36: MR · 2002. 2. 20. · Adeler A TV Erhver vsf or skerpr ojekt EF 698 IMM-PHD-2001-86 ISSN 0909-3192 ISBN 87-88306-13-5 c 2001 by Pernille Thorup Adeler Printed by IMM, DTU Bookbinder

52E

valu

atio

nof

the

2Dm

odel

#

Time

0.546

Time0.546

Time

0.546

Time0.546

Fig

ure

4.9:

Vel

ocity

field

and

hear

tbou

ndar

yat

s,w

ith

0.0

4,0.

1,0.

3an

d0.

5.

from

Pes

kin.

Toco

mpu

teat

values

clos

erto

1it

isne

cess

aryto

com

pute

ona

finer

grid

.U

nfor

tuna

tely,

we

coul

dno

tcom

pute

afu

llhe

artc

ycle

with

# .

On

a51

2gr

idw

eca

nco

mpu

teap

prox

imat

ely2

/3of

ahe

artc

ycle

.We

belie

veth

ata

#si

mul

atio

ncan

beac

com

plis

hedo

nly

ona

1064

grid

,and

unfo

rtun

atel

ywe

did

not

have

suffi

cien

ttim

efo

rth

is.I

tis

oure

xper

ienc

etha

tit

isno

tpos

sibl

eto

com

pute

afu

llhe

artc

ycle

ona

256

grid

with

a

value

high

erth

an0.

5.N

ote

thou

gh,th

atit

isno

tpos

sibl

eto

com

plet

e2he

artc

ycle

son

a25

6gr

id.

We

plot

the

velo

city

field

from

the

6si

mul

atio

nsto

com

pare

the

over

allp

ictu

re

4.2

The

scal

ing

fact

or

53

#

Time

0.936

Time

0.936

Time

0.936

Time

0.936

Fig

ure

4.10

:Vel

ocity

field

and

hear

tbou

ndar

yat

s,

with

0.0

4,0.

1,0.

3an

d0.

5.

ofth

eve

loci

tyfie

ld.

Fig

ures

4.8–

4.10

show

the

velo

city

field

at

s,

san

d

s,re

spec

tivel

y.E

ach

figur

eco

ntai

nspl

ots

from

the

sim

ulat

ions

with

0.0

4,0.

1,0.

3an

d0.

5.T

heflo

win

Fig

ure

4.8

occu

rsdu

ring

the

fillin

gof

the

vent

ricle

,and

itis

seen

that

the

flow

patte

rnis

gene

rally

the

sam

e,th

ough

the

vort

ices

beco

mem

ore

dis-

tinct

as

increas

es.The

hear

tbou

ndar

ycon

figur

atio

nis

prac

tical

lyth

esa

mea

tall

4

values

.The

flow

inF

igur

e4.

9oc

curs

durin

gat

rials

ysto

leju

stbe

fore

vent

ric-

ular

syst

ole.

Als

ohe

reit

isse

enth

atth

evo

rtic

esar

emor

edi

stin

ctw

ithin

crea

sing

,andth

ein

trav

entr

icul

arve

loci

tyin

crea

sesw

ith

.Furth

erm

ore,

we

seet

hata

s

Page 37: MR · 2002. 2. 20. · Adeler A TV Erhver vsf or skerpr ojekt EF 698 IMM-PHD-2001-86 ISSN 0909-3192 ISBN 87-88306-13-5 c 2001 by Pernille Thorup Adeler Printed by IMM, DTU Bookbinder

54E

valu

atio

nof

the

2Dm

odel

increas

es,th

reev

ortic

esar

epr

esen

tinth

eve

ntric

le.T

his

isve

rydi

fficu

ltto

see

at

0.0

4.E

ven

thou

ghth

eve

loci

tyfie

ldis

diff

eren

tinsi

deth

ehe

art,t

hehe

art

boun

dary

ispr

actic

ally

the

sam

efor

all4

values

.T

heflo

win

Fig

ure

4.10

occu

rsat

the

end

ofth

ehe

artc

ycle

.W

ese

etha

tat

0.0

4it

ispo

ssib

leto

seeo

nein

trav

entr

icul

arvo

rtex

,w

hile

at

0.1

,0.3

and

0.5

two

vort

ices

arep

rese

nt.N

ote

that

avo

rtex

isfo

rmed

atth

eao

rtic

outfl

owtr

acta

saco

nseq

uenc

eofth

esi

mpl

ege

omet

ryof

this

trac

t.T

heco

mpa

rison

ofve

loci

tyfie

ldsi

ndic

ates

that

the

orig

inal

choi

ceof

0.04

isno

topt

imal

,sin

ceat

0.0

4th

evo

rtex

stru

ctur

eis

notc

aptu

redv

ery

wel

l.To

furt

here

luci

date

the

influ

ence

of

weplo

tpre

ssur

etim

epr

ofile

s,ve

loci

tytim

epr

ofile

sand

sour

ceflo

wtim

epr

ofile

sfro

mth

esi

mul

atio

nsw

ith

0.0

4,0.

1an

d0.

5.F

igur

e4.

11sh

ows

the

pres

suret

ime

profi

lefo

rthe

vent

ricle

,atr

ium

and

aort

icsi

nk.T

heve

loci

tycu

rves

for

0.1

and

0.5

areq

uite

sim

ilar,

whi

lefo

r

0.0

4th

em

axim

umle

velf

orth

eve

ntric

ular

curv

eis

too

low

and

the

max

imum

leve

lat

the

aort

icsi

nkis

too

high

.We

belie

veth

atth

elo

wer

max

imum

leve

loft

heao

rtic

sink

pres

sure

isre

late

dto

the

form

atio

nof

the

vort

exin

the

aort

icou

tflow

trac

tas

seen

inF

igur

e4.

10.

Fig

ure

4.12

show

sth

eve

loci

tytim

epr

ofile

atth

em

itral

ring

and

betw

eent

hem

itral

leafl

ettip

s,w

hile

Fig

ure

4.13

show

sth

eve

loci

tytim

epr

ofile

acro

ssth

eao

rtic

sink

.F

rom

Fig

ure

4.12

we

seet

hatt

heve

loci

tyov

erth

em

itral

ring

isno

t

#

0.2

0.4

0.6

0.8

t[s]

10

20

30

40

50

60

pressure[mmHg]

0.2

0.4

0.6

0.8

t[s]

10

20

30

40

50

60

pressure[mmHg]

0.2

0.4

0.6

0.8

t[s]

10

20

30

40

50

60

pressure[mmHg]

Fig

ure4

.11:

Pre

ssur

etim

epr

ofile

fort

hepr

essu

re(m

mH

g)in

the

vent

ricle

(sol

id),

atriu

m(d

otte

d)an

dat

the

aort

icsi

nk(d

ashe

d),w

ith

(le

ft),

#

(mid

dle)

and

(r

ight

).

4.2

The

scal

ing

fact

or

55

#

0.2

0.4

0.6

0.8

t[s]

-40

-200

20

40

60

velocity[cm/s]

0.2

0.4

0.6

0.8

t[s]

-40

-200

20

40

60

velocity[cm/s]

0.2

0.4

0.6

0.8

t[s]

-40

-200

20

40

60

velocity[cm/s]

Fig

ure

4.12

:V

eloc

itytim

epr

ofile

ofth

em

ean

velo

city

(cm

/s)o

ver

the

mitr

alrin

g(s

olid

)and

betw

eent

hele

aflet

tips

(das

hed)

,with

(le

ft),

#

(mid

dle)

and

(r

ight

).

#

0.2

0.4

0.6

0.8

t[s]

0

20

40

60

80

100

velocity[cm/s]

0.2

0.4

0.6

0.8

t[s]

0

20

40

60

80

100

velocity[cm/s]

0.2

0.4

0.6

0.8

t[s]

0

20

40

60

80

100

velocity[cm/s]

Fig

ure

4.13

:Vel

ocity

time

profi

leof

the

mea

nvel

ocity

(cm

/s)a

cros

sthe

aort

icou

tflow

trac

tbel

owth

eao

rtic

sink

,with

(le

ft),

# (m

iddl

e)an

d

(r

ight

).

Page 38: MR · 2002. 2. 20. · Adeler A TV Erhver vsf or skerpr ojekt EF 698 IMM-PHD-2001-86 ISSN 0909-3192 ISBN 87-88306-13-5 c 2001 by Pernille Thorup Adeler Printed by IMM, DTU Bookbinder

56E

valu

atio

nof

the

2Dm

odel

affe

cted

very

muc

hby

incr

easi

ng

value:

peak

valu

esar

eal

mos

tthe

sam

eand

the

time

varia

tion

issi

mila

r,th

ough

mor

eos

cilla

tions

are

seen

as

increa

ses.

Not

eth

atfo

r

0.5

the

velo

city

over

the

mitr

alrin

gis

zero

atap

prox

imat

ely

º

sbe

twee

nthe

two

forw

ard

peak

s.A

sw

esh

alls

eein

the

com

paris

onbe

twee

nthe

mod

elan

dMR

mea

sure

men

tsinC

hapt

er5,

this

isa

desi

rabl

efea

ture

.Fo

rth

eve

loci

tybe

twee

nthe

leafl

ettip

sth

etim

eva

riatio

nis

sim

ilar,

whi

leth

efo

rwar

dpe

akve

loci

tiesa

rehi

gher

with

incr

easi

ng

value.

For

0.5

we

see

ane

gativ

eve

loci

tybe

twee

nthe

two

forw

ard

peak

s,an

dfo

ral

l

values

we

seea

nega

tive

velo

city

peak

follo

win

gth

ese

cond

forw

ard

peak

.The

latte

ris

rela

tedt

oth

ecl

osur

eoft

hem

itral

valv

e.F

igur

e4.1

3sho

ws

that

the

gene

rala

ortic

velo

city

profi

leis

sim

ilarf

ordi

ffer

ent

values

.As

seen

fort

hem

itral

velo

city

the

osci

llatio

nsar

emor

epro

noun

cedw

ithin

crea

sing

value

and

the

peak

valu

ein

crea

ses.

Gen

eral

ly,w

ese

etha

tthe

scal

ingf

acto

r

doesh

ave

anin

fluen

ceon

the

flow

patte

rn.It

does

notc

hang

ethe

over

allfl

owpa

ttern

,but

loca

ldiff

eren

cesa

rese

en.

The

intr

aven

tric

ular

velo

city

incr

ease

swith

incr

easi

ng

valuea

ndth

evo

rtex

for-

mat

ion

ism

ore

dist

inct

.F

urth

erm

ore,

the

max

imum

pres

sure

sach

ieved

inth

eve

ntric

lean

dat

the

aort

icsi

nkar

eal

soaf

fect

ed.

Whe

nth

em

odel

isus

edfo

rph

ysio

logi

calin

vest

igat

ions

the

user

isin

tere

sted

inas

shor

tasi

mul

atio

ntim

eas

poss

ible

whi

lest

illob

tain

ing

reas

onab

lycor

rect

resu

lts.A

shor

tsim

ulat

ion

time

requ

iresa

smal

lval

ueof

.Asim

ulat

ion

with

0.5

ispo

ssib

leon

a25

6(o

rfine

r)gr

id,w

hile

asi

mul

atio

nw

ith

0.1

can

run

ona

128

grid

with

2995

2tim

est

eppe

rhea

rtcy

cle,

and

asi

mul

atio

nw

ith

ca

nru

non

a64

grid

with

2808

time

step

sper

hear

tcyc

le.

Bas

edon

our

com

paris

onsb

etw

eens

imul

atio

nsw

ithdi

ffer

ent

values

and

cons

ider

ings

imul

atio

ntim

es,w

ebe

lieve

that

0.1

isa

good

choi

ce.A

t

0.1

the

pres

sure

time

varia

tion

and

the

velo

city

time

profi

les

are

clos

eto

thos

eat

0.5

,and

the

flow

patte

rnin

side

the

hear

tissi

mila

rto

the

flow

patte

rnse

enat

0.5

.In

Tho

rup

(199

7)it

was

conc

lude

dtha

t

0.0

4w

asa

good

choi

ce,

butt

hein

vest

igat

iont

here

was

perf

orm

edw

ithth

em

odel

befo

reth

ete

ther

ingo

fth

ehe

artw

asim

plem

ente

d.It

turn

sou

ttha

tthe

teth

erin

gdec

reas

esth

est

abili

tyof

the

mod

el.

4.3

Per

iodi

cbo

unda

ryco

nditi

ons

Inth

em

odel

the

hear

tispl

aced

ina

com

puta

tiona

ldom

ainw

ithpe

riodi

cbou

ndar

yco

nditi

ons.

Thi

sm

eans

that

ifth

ehe

artm

oves

past

one

boun

dary

itw

illap

pear

atth

eop

posi

tebo

unda

ry.A

nex

ampl

eofs

ucha

situ

atio

ncan

bese

enin

Fig

ure

4.1

4.3

Per

iodi

cbo

unda

ryco

nditi

ons

57

Time0.156

Time0.312

Time0.468

Time0.624

Time0.780

Time0.936

Fig

ure

4.14

:Hea

rtbo

unda

ryat

six

equi

dist

antti

mes

durin

ga

hear

tcyc

lefr

omth

ere

fere

nces

imul

atio

n(

½ )an

dfr

oma

sim

ulat

ion

with

ala

rge

com

puta

tiona

ldo-

mai

n(

¾ ).F

ield

ofvi

ewis

iden

tical

toth

eco

mpu

tatio

naldo

mai

noft

here

fere

nce

sim

ulat

ion.

Page 39: MR · 2002. 2. 20. · Adeler A TV Erhver vsf or skerpr ojekt EF 698 IMM-PHD-2001-86 ISSN 0909-3192 ISBN 87-88306-13-5 c 2001 by Pernille Thorup Adeler Printed by IMM, DTU Bookbinder

58E

valu

atio

nof

the

2Dm

odel

at

#

s.F

urth

erm

ore,

ifth

edi

men

sion

ofth

ehe

arte

xcee

dsth

edo

mai

ndi

men

sion

the

hear

twill

over

lap

itsel

f.To

dete

rmin

ethe

influ

ence

ofth

epe

riodi

cbo

unda

ryco

nditi

onsw

em

ake

asi

mul

atio

nw

here

the

hear

tis

imm

erse

din

ala

rge

com

puta

tiona

ldom

ain

(on

a51

2gr

id),

but

whe

real

lpa

ram

eter

valu

esde

term

inin

gthe

initi

alse

tup

ofth

ehe

art(

incl

udin

gth

esi

ze)a

reid

entic

alto

ourr

efer

ence

sim

ulat

ion.

InF

igur

e4.

14th

ehe

artb

ound

aryc

onfig

urat

ionf

rom

the

sim

ulat

ion

with

the

larg

eco

mpu

tatio

naldo

mai

nand

from

the

refe

renc

esim

ulat

ioni

sde

pict

ed.W

ese

ea

smal

ldev

iatio

nbe

twee

nthe

two

hear

tbou

ndar

ycon

figur

atio

n.T

here

isha

rdly

any

diff

eren

cebe

twee

nthe

pres

sure

time

profi

less

eeni

nF

igur

e4.

15or

betw

een

the

velo

city

time

profi

les

atth

em

itral

ring

and

betw

eent

hele

aflet

sdep

icte

din

Fig

ure

4.16

.F

igur

e4.

17sh

ows

the

velo

city

time

profi

lefo

rth

eao

rtic

outfl

owtr

act,

whi

leF

igur

e4.

18sh

ows

the

flow

time

profi

lesf

orth

em

itral

sour

ceflo

wan

dth

eao

rtic

sink

flow

.In

both

ofth

esefi

gure

swe

find

smal

ldis

crep

anci

esbe

twee

nthe

resu

ltsfr

omth

ere

fere

nces

imul

atio

nand

from

the

sim

ulat

ionw

itha

larg

eco

mpu

tatio

nal

dom

ain.

Fro

mF

igur

e4.1

8w

ese

etha

tthe

aort

icsi

nkop

ensa

ndcl

oses

atth

esa

me

time

inth

etw

osi

mul

atio

nsan

dth

atth

epe

akin

flow

thro

ugh

the

sour

cean

dth

e

larg

edo

mai

nre

fere

nce

0.2

0.4

0.6

0.8

t[s]

10

20

30

40

50

60

pressure8mmHg]

0.2

0.4

0.6

0.8

t[s]

10

20

30

40

50

60

pressure[mmHg]

Fig

ure

4.15

:P

ress

uret

ime

profi

les

for

the

pres

sure

(mm

Hg)

inth

eve

ntric

le(s

olid

),at

rium

(dot

ted)

and

atth

eao

rtic

sink

(das

hed)

from

asi

mul

atio

nw

itha

larg

eco

mpu

tatio

naldo

mai

n(le

ft)an

dfr

omth

ere

fere

nces

imul

atio

n(rig

ht).

4.3

Per

iodi

cbo

unda

ryco

nditi

ons

59

larg

edo

mai

nre

fere

nce

0.2

0.4

0.6

0.8

t[s]

-40

-200

20

40

60

velocity[cm/s]

0.2

0.4

0.6

0.8

t[s]

-40

-200

20

40

60

velocity[cm/s]

Fig

ure4

.16:

Vel

ocity

time

profi

lefo

rthe

mea

nvel

ocity

(cm

/s)o

vert

hem

itral

ring

and

betw

eent

hele

aflet

tips

from

asi

mul

atio

nwith

ala

rge

com

puta

tiona

ldom

ain

(left)

and

from

the

refe

renc

esim

ulat

ion(

right

).

larg

edo

mai

nre

fere

nce

0.2

0.4

0.6

0.8

t[s]

0

20

40

60

80

velocity[cm/s]

0.2

0.4

0.6

0.8

t[s]

0

20

40

60

80

velocity[cm/s]

Fig

ure

4.17

:Vel

ocity

time

profi

lefo

rth

em

eanv

eloc

ity(c

m/s

)acr

osst

heao

rtic

outfl

owtr

actb

elow

the

aort

icsi

nkfr

oma

sim

ulat

ion

with

ala

rge

com

puta

tiona

ldo

mai

n(le

ft)an

dfr

omth

ere

fere

nces

imul

atio

n(rig

ht).

Page 40: MR · 2002. 2. 20. · Adeler A TV Erhver vsf or skerpr ojekt EF 698 IMM-PHD-2001-86 ISSN 0909-3192 ISBN 87-88306-13-5 c 2001 by Pernille Thorup Adeler Printed by IMM, DTU Bookbinder

60E

valu

atio

nof

the

2Dm

odel

larg

edo

mai

nre

fere

nce

0.2

0.4

0.6

0.8

t[s]

-600

-400

-2000

200

sourceflow[cm^3/s]

0.2

0.4

0.6

0.8

t[s]

-600

-400

-2000

200

sourceflow[cm^3/s]

Fig

ure

4.18

:Flo

wtim

epr

ofile

sfor

the

flow

(cm

» /s)t

hrou

ghth

em

itral

sour

cean

dao

rtic

sink

from

asi

mul

atio

nw

itha

larg

eco

mpu

tatio

nald

omai

nan

dfr

omth

ere

fere

nces

imul

atio

n.

peak

outfl

owfr

omth

esi

nkis

the

sam

e.W

eco

nclu

deth

atre

sults

from

the

hear

tmod

elar

eno

tinfl

uenc

edsi

gnifi

cant

lyby

the

perio

dic

boun

dary

cond

ition

s.H

owev

er,

for

visu

alre

ason

sitw

ould

bede

sira

blei

fth

eco

mpu

tatio

nald

omai

nw

asa

little

bit

larg

erto

allo

wth

ehe

art

tost

ayin

side

the

dom

ain

durin

ga

full

sim

ulat

ion.

Thi

sw

ould

mea

nth

atth

eco

mpu

tatio

nssh

ould

bepe

rfor

med

eith

eron

the

sam

egrid

size

butw

itha

slig

htly

smal

lerh

eart

(giv

ing

aco

arse

rreso

lutio

noft

hehe

art)

oron

afin

ergr

idw

ithth

ehe

arts

ize

iden

tical

toth

esi

zeat

the

coar

segr

id(g

ivin

gap

prox

imat

ely

. times

asm

uch

com

puta

tiona

ltime,

beca

useth

enu

mbe

rofg

ridpo

ints

hast

obe

apo

wer

of2)

.S

ince

the

resu

ltsar

eno

taffe

cted

byth

epe

riodi

cbo

unda

ryco

nditi

ons,

we

have

chos

enno

tto

chan

geth

egr

idsi

zeor

the

hear

tdim

ensi

on.

4.4

Tet

herin

gof

the

hear

t

Inth

eor

igin

alm

odel

the

hear

tfloa

tedf

reel

yin

the

com

puta

tiona

ldom

ain,

andt

his

resu

ltedi

nno

n-ph

ysio

logi

calm

ovem

ents

,esp

ecia

llydu

ring

the

ejec

tion

phas

ew

hen

atr

ansl

atio

nwou

ldbe

gin

and

even

tual

lym

ove

the

hear

tthro

ught

hebo

und-

ary.

Fig

ure

4.19

show

sth

eve

loci

tyfie

ldan

dhe

artb

ound

aryc

onfig

urat

iona

t4

4.4

Teth

erin

gof

the

hear

t61

Time

0.624

Time

0.936

Time

1.248

Time

1.872

Fig

ure

4.19

:Vel

ocity

field

and

hear

tbou

ndar

ycon

figur

atio

natf

ourt

imes

durin

gtw

ohe

artc

ycle

sfro

ma

sim

ulat

ionw

ithno

teth

erin

goft

hehe

art.

times

durin

g2

hear

tcyc

leso

fasi

mul

atio

nwhe

reth

ehe

artis

nott

ethe

red.

Inth

efir

stfr

ame

inF

igur

e4.

19it

isse

enth

atth

ehe

artm

oves

thro

ugh

the

uppe

rbou

ndar

y.W

hile

from

the

seco

ndfr

ame

(at

s),w

hich

isat

the

end

ofth

efir

sthe

artc

ycle

,it

isse

enth

atth

ehe

arth

asbe

gun

tom

ove

thro

ught

helo

wer

boun

dary.

Thi

sde

velo

pmen

tisev

encl

eare

rinth

eth

irdfr

ame.

Inth

ela

stfr

ame,

atth

een

dof

the

seco

ndhe

artc

ycle

,the

hear

tisag

aini

ntac

tins

idet

hefie

ldof

view

.T

hus

durin

gtw

ohe

artc

ycle

sth

ehe

artm

oves

adi

stan

ceco

rres

pond

ing

toth

esi

zeof

the

com

puta

tiona

ldom

ain.

Tore

stra

inth

ehe

artf

rom

mov

ing,

we

teth

ered

itto

ase

tof

fixed

poin

tsas

desc

ribed

inS

ectio

n3.3

.7.I

nF

igur

e4.

20th

eve

loci

tyfie

ldan

dhe

artb

ound

ary

confi

gura

tionf

rom

asi

mul

atio

nwhe

reth

ehe

artis

teth

ered

ares

how

nfo

rthe

sam

e

Page 41: MR · 2002. 2. 20. · Adeler A TV Erhver vsf or skerpr ojekt EF 698 IMM-PHD-2001-86 ISSN 0909-3192 ISBN 87-88306-13-5 c 2001 by Pernille Thorup Adeler Printed by IMM, DTU Bookbinder

62E

valu

atio

nof

the

2Dm

odel

Time

0.624

Time0.936

Time

1.248

Time1.872

Fig

ure

4.20

:Vel

ocity

field

and

hear

tbou

ndar

ycon

figur

atio

natf

ourt

imes

durin

gtw

ohe

artc

ycle

sfro

mth

ere

fere

nces

imul

atio

n.

times

asin

Fig

ure

4.19

Fig

ure

4.20

show

sth

atth

ete

ther

ing

wor

ksef

ficie

ntly

inke

epin

gth

ehe

art

inpl

ace.

The

hear

tisal

low

edto

mov

ea

little

,bu

tnot

too

muc

h.F

urth

erm

ore,

we

see

that

the

flow

field

inth

ehe

arti

sno

tver

ydi

ffer

entf

rom

that

ina

hear

tw

ithno

teth

erin

g,ex

cept

durin

gou

tflow

thro

ught

heao

rtic

sink

(the

first

fram

eat

s)

.In

the

sam

efra

me

we

seet

hatw

ithth

ete

ther

ingt

hein

trav

entr

icul

arflo

wfie

ldis

dom

inat

edby

anou

tflow

jet

from

the

vent

ricle

tow

ard

the

aort

icsi

nk,w

hile

inth

esi

mul

atio

nwith

outt

ethe

ringt

hein

trav

entr

icul

arflo

wfie

ldse

ems

calm

eran

dex

hibi

tsa

vort

exbe

twee

nthe

ante

riorw

alla

ndth

em

itral

leafl

ets.

The

teth

erin

ghas

also

intr

oduc

edos

cilla

tions

inbo

thth

eat

rium

and

the

vent

ricle

.The

osci

llatio

nsof

the

atriu

mca

nbe

seen

whe

nco

mpa

rings

ucce

ssive

plot

sof

the

4.4

Teth

erin

gof

the

hear

t63

note

ther

ing

0.25

0.5

0.75

11.25

1.5

1.75

2t[s]

10

20

30

40

50

60

pressure[mmHg]

refe

renc

e

0.25

0.5

0.75

11.25

1.5

1.75

2t[s]

10

20

30

40

50

60

pressure[mmHg]

Fig

ure4

.21:

Pre

ssur

etim

epr

ofile

fort

hepr

essu

re(m

mH

g)in

the

vent

ricle

(sol

id),

atriu

m(d

otte

d)an

dat

the

aort

icsi

nk(d

ashe

d)fr

oma

sim

ulat

ionw

ithno

teth

erin

gof

the

hear

t(to

p)an

dfr

omth

ere

fere

nces

imul

atio

n(bo

ttom

).

hear

twal

l.T

his

isno

tsee

nin

the

plot

ssh

own

here

beca

useth

eyar

eto

ofa

rapa

rtin

time.

The

osci

llatio

nsof

the

vent

ricle

are

best

seen

whe

nan

anim

atio

nof

the

pict

ures

ispe

rfor

med

.To

furt

here

xam

inet

hein

fluen

ceof

the

teth

erin

gwe

com

pare

dthe

time

varia

-tio

nof

the

pres

sure

,velo

city

and

flow

from

the

two

sim

ulat

ions

.

Page 42: MR · 2002. 2. 20. · Adeler A TV Erhver vsf or skerpr ojekt EF 698 IMM-PHD-2001-86 ISSN 0909-3192 ISBN 87-88306-13-5 c 2001 by Pernille Thorup Adeler Printed by IMM, DTU Bookbinder

64E

valu

atio

nof

the

2Dm

odel

note

ther

ing

0.25

0.5

0.75

11.25

1.5

1.75

2t[s]

-40

-200

20

40

60

velocity[cm/s]

refe

renc

e

0.25

0.5

0.75

11.25

1.5

1.75

2t[s]

-40

-200

20

40

60

velocity[cm/s]

Fig

ure

4.22

:Vel

ocity

time

profi

lefo

rth

em

eanv

eloc

ity(c

m/s

)att

hem

itral

ring

(sol

id)a

ndbe

twee

nthe

leafl

ettip

s(d

ashe

d)fr

oma

sim

ulat

ion

with

note

ther

ing

ofth

ehe

art(

top)

and

from

the

refe

renc

esim

ulat

ion(

botto

m).

Fig

ure

4.21

show

sth

etim

eva

riatio

nof

the

pres

sure

.Itis

seen

that

the

max

-im

umle

velf

orth

eve

ntric

ular

pres

sure

issl

ight

lyhi

gher

with

outt

hete

ther

ing,

whi

leth

em

axim

umpr

essu

rele

velf

orth

eao

rtic

sink

ishi

gher

inth

ese

cond

cy-

cle

with

teth

erin

g.A

part

from

that

,the

time

varia

tion

ofth

epr

essu

resa

reve

rysi

mila

r.

4.4

Teth

erin

gof

the

hear

t65

note

ther

ing

0.25

0.5

0.75

11.25

1.5

1.75

2t[s]

-600

-400

-2000

200

sourceflow[cm^3/s]

refe

renc

e

0.25

0.5

0.75

11.25

1.5

1.75

2t[s]

-600

-400

-2000

200

sourceflow[cm^3/s]

Fig

ure

4.23

:F

low

time

profi

lefo

rth

eflo

w(c

m

» /s)

thro

ugh

the

mitr

also

urce

(das

hed)

and

the

aort

icsi

nk(s

olid

)fr

oma

sim

ulat

ion

with

note

ther

ing

ofth

ehe

art(

top)

and

from

the

refe

renc

esim

ulat

ion(

botto

m).

InF

igur

e4.

22th

eve

loci

tytim

epr

ofile

sfo

rth

em

itral

ring

and

betw

eent

hele

aflet

tips

ares

how

n.E

spec

ially

inth

efir

stcy

cle

diff

eren

cesb

etw

eent

heve

loci

typr

ofile

sex

ist:

the

peak

forw

ard

velo

city

inth

epr

ofile

sin

the

sim

ulat

ion

with

note

ther

ing

iscl

early

high

erth

anin

the

sim

ulat

ion

with

teth

erin

g.F

urth

erm

ore,

the

shap

eoft

heve

loci

typr

ofile

durin

gth

efir

stpe

akis

wid

erw

ithte

ther

ingt

han

Page 43: MR · 2002. 2. 20. · Adeler A TV Erhver vsf or skerpr ojekt EF 698 IMM-PHD-2001-86 ISSN 0909-3192 ISBN 87-88306-13-5 c 2001 by Pernille Thorup Adeler Printed by IMM, DTU Bookbinder

66E

valu

atio

nof

the

2Dm

odel

with

out.

Inth

ese

cond

cycl

eth

eve

loci

typr

ofile

sfr

omth

etw

osi

mul

atio

nsar

em

uch

mor

esi

mila

r.F

igur

e4.

23sh

ows

the

time

varia

tiono

fthe

flow

thro

ught

hem

itral

sour

cean

dao

rtic

sink

.T

hepe

akou

tflow

issl

ight

lyla

rger

inth

esi

mul

atio

nw

ithte

ther

ing

than

inth

esi

mul

atio

nw

ithno

teth

erin

g,bu

tthe

shap

esof

the

profi

les

are

sim

i-la

r.In

the

sim

ulat

ion

with

teth

erin

gthe

flow

thro

ugh

the

mitr

also

urce

beco

mes

nega

tive,

indi

catin

gth

atbl

ood

isflo

win

gba

ckth

roug

hthe

mitr

also

urce

.Thi

sis

nota

nun

phys

iolo

gica

lfeat

ure,

sinc

ethe

pres

surei

nsid

ethe

hear

tcan

besu

chth

atbl

ood

leav

esth

roug

hthe

pulm

onar

yvei

ns(t

hepu

lmon

aryv

eins

have

nova

lves

topr

even

tthi

s).

The

intr

oduc

tiono

ftet

herin

gpre

vent

sthe

hear

tfrom

mov

ing

too

muc

hw

ith-

outs

igni

fican

tlych

angi

ngth

eflo

wpa

ttern

.The

time

varia

tion

ofth

epr

essu

reis

alm

ostth

esa

me,

whi

leso

med

iffer

ence

sare

seen

inth

eve

loci

tyan

dso

urce

flow

profi

les.

Fort

heve

loci

typr

ofile

sthe

mai

ndi

ffer

ence

sare

inth

efir

sthe

artc

ycle

.S

ince

prev

entin

gth

ehe

artf

rom

mov

ing

arou

ndin

the

com

puta

tiona

ldom

ain

isa

maj

orim

prov

emen

t,we

conc

lude

that

the

teth

erin

gof

the

hear

tissu

cces

sful

,ev

enth

ough

som

echa

nges

are

intr

oduc

edin

the

resu

ltsw

eha

vem

adet

his

part

ofth

em

odel

.

4.5

The

Win

dkes

selm

odel

The

Win

dkes

selm

odel

for

the

afte

rload

ofth

ehe

artw

asin

trod

uced

inJa

cobs

en(1

999)

and

eval

uate

din

both

Jaco

bsen

(199

9)an

dA

dele

rand

Jaco

bsen

(200

1).

We

incl

ude

here

asu

mm

aryo

fth

atev

alua

tion

toco

mpl

etet

hede

scrip

tiona

ndev

alua

tiono

four

2Dm

odel

.T

heW

indk

esse

lmod

elw

asin

trod

uced

toim

prov

eth

eou

tflow

cond

ition

sat

the

aort

icsi

nk.

Orig

inal

ly,

the

outfl

oww

asde

term

ined

bya

linea

rre

sist

ance

mod

el(s

imila

rto

the

onef

orth

eat

rials

ourc

e),bu

tthi

sga

vean

unre

alis

ticpr

essu

re

onse

tsys

t.en

dsy

st.

u! JG µ^LG

[ms]

[ms]

[ms

() ][m

s

() ]

G

atriu

m0.

347

0.42

21/

601/

542.

00

vent

ricle

0.44

70.

547

1/60

1/15

4.9

1.07

pap.

mus

c.0.

447

0.54

71/

601/

154.

90.

107

Tabl

e4.

1:T

imin

gs,r

ate

cons

tant

s,lim

iting

valu

esan

din

itial

valu

esfo

rth

eac

ti-va

tion

func

tions

for

the

dog

hear

t(M

cQue

enet

al.,

1982

).

4.5

The

Win

dkes

selm

odel

67

10

20

30

40

50

60

10

20

30

40

50

60

Fig

ure4

.24:

Initi

alge

omet

ryof

the

dog

hear

t,com

pare

with

Fig

ure3

.7.N

ote

that

the

hear

tisno

ttet

here

dto

any

fixed

poin

ts.

time

profi

leat

the

sink

,whe

reth

epr

essu

rew

asal

mos

tcla

mpe

datt

hepr

escr

ibed

cons

tant

pres

sure

inth

eao

rta.

Toin

vest

igat

ethe

influ

ence

ofth

eW

indk

esse

lm

odel

conn

ecte

dtoth

eao

rtic

sink

,we

mad

eaco

mpa

rison

betw

eena

sim

ulat

ion

with

Pes

kin’s

orig

inal

mod

elan

da

sim

ulat

ion

whe

reth

eon

lym

odifi

catio

nin

-tr

oduc

edis

the

Win

dkes

selm

odel

.P

eski

n’sor

igin

alm

odel

isba

sedo

na

dog’

she

art,

i.e.n

one

ofth

eim

prov

emen

tspr

esen

tede

arlie

rin

this

thes

isto

mak

eth

em

odel

hum

anw

ere

impl

emen

ted.

The

leng

thof

ado

g’s

hear

tcyc

lew

asta

ken

tobe

0.67

5s.

The

para

met

ersfo

rth

eac

tivat

ion

func

tion

are

liste

din

Tabl

e4.

1an

dth

ein

i-tia

lge

omet

ryfo

rth

edo

g’s

hear

tis

show

nin

Fig

ure

4.24

(com

pare

thes

ewith

Tabl

e3.

1an

dF

igur

e3.

7fo

rth

em

odifi

edm

odel

).N

ote

that

the

leng

thsc

ales

are

nott

hesa

mei

nth

em

odel

ofa

dog’

she

art(

Fig

ure

3.7)

and

inth

em

odifi

edm

odel

(Fig

ure

4.24

):fo

rth

edo

g’s

hear

tthe

leng

thof

the

com

puta

tiona

ldom

ain

corr

espo

ndsto

7.35

cm,w

hile

inou

rmod

ified

mod

elit

corr

espo

ndsto

13cm

.F

igur

e4.

25sh

ows

pres

sure

sfrom

asi

mul

atio

nof

ado

g’s

hear

twith

outt

heW

indk

esse

lmod

elov

er3

cycl

es.I

tis

appa

rent

that

the

mod

elop

erat

esat

apr

es-

sure

whi

chis

only

abou

t1/2

ofth

atof

the

phys

iolo

gica

llyco

rrec

tpre

ssur

efor

ado

g,w

hich

corr

espo

ndsto

appr

oxim

atel

y1/3

ofth

ehu

man

case

.Not

eth

atth

epr

essu

reatt

heao

rtic

sink

ishe

ldat

anal

mos

tcon

stan

tleve

lwhe

nthe

sink

isop

en.

Page 44: MR · 2002. 2. 20. · Adeler A TV Erhver vsf or skerpr ojekt EF 698 IMM-PHD-2001-86 ISSN 0909-3192 ISBN 87-88306-13-5 c 2001 by Pernille Thorup Adeler Printed by IMM, DTU Bookbinder

68E

valu

atio

nof

the

2Dm

odel

0.5

11.5

2

Time [s]

0

10

20

30

40

Fig

ure

4.25

:P

ress

uret

ime

profi

ledu

ring

thre

ehe

artc

ycle

sfo

rth

epr

essu

re(m

mH

g)in

the

vent

ricle

(sol

id),

atriu

m(d

otte

d)an

dat

the

aort

icsi

nk(d

ashe

d)fr

oma

sim

ulat

ionw

ithou

tthe

Win

dkes

selm

odel

.

0.5

11.5

2

Time [s]

0

10

20

30

40

Fig

ure

4.26

:P

ress

uret

ime

profi

ledu

ring

thre

ehe

artc

ycle

sfo

rth

epr

essu

re(m

mH

g)in

the

vent

ricle

(sol

id),

atriu

m(d

otte

d),a

tthe

aort

icsi

nk(lo

ngda

shed

)an

dth

elo

adpr

essu

re

p tyQ (sho

rtda

shed

)from

asi

mul

atio

nwith

the

Win

dkes

sel

mod

el.

4.6

Dis

trib

uted

sour

cesa

ndsi

nks

69

How

ever

,the

atria

lpre

ssur

eisap

prox

imat

elya

tthe

phys

iolo

gica

lleve

l.F

igur

e4.

26sh

ows

the

pres

sure

profi

lesc

orre

spon

ding

toth

osei

nF

igur

e4.

25,

butw

ithth

eou

tflow

thro

ught

heao

rtic

sink

dete

rmin

edby

the

Win

dkes

selm

odel

.T

hefig

ure

also

incl

udes

the

time

varia

tion

ofth

elo

adpr

essu

re

p"tyQ intr

oduc

edin

equa

tion(

3.10

).T

heva

lues

ofth

eW

indk

esse

lpar

amet

ersa

read

apte

dfro

mC

appe

lloet

al.(

1995

)as

follo

ws:

Sin

ceth

em

odel

oper

ates

ata

pres

sure

of1/

3of

the

phys

iolo

gica

lleve

lsus

edin

Cap

pello

etal

.(19

95),

the

valu

esfo

rth

ere

-si

stan

cesa

redi

vide

dby

3w

hile

the

com

plia

ncei

sm

ultip

lied

by3.

Thu

sth

eW

indk

esse

lpar

amet

ersa

re:

w tyQ ) ,w tyQ .

0.8

mm

Hg/

(cm

» /s)

and

| 1.5

cm

» /mm

Hg.

The

intr

oduc

tion

ofth

eW

indk

esse

lmod

eldo

esno

tcha

nget

heve

ntric

ular

pres

sure

sign

ifica

ntly,

but

the

pres

sure

atth

eao

rtic

sink

isno

long

ercl

ampe

dto

anal

mos

tcon

stan

tval

ue.

Rat

her,

itva

ries

ina

mor

eph

ysio

logi

calr

ealis

ticw

ay.

The

time

inte

rval

durin

gw

hich

the

aort

icsi

nkis

open

isla

rger

whe

nth

eW

indk

esse

lmod

elis

intr

oduc

ed.

The

resu

ltspr

esen

tedh

ere

show

that

the

pres

sure

profi

leat

the

aort

icou

t-flo

wtr

acti

sco

nsid

erab

lyim

prov

edth

roug

hthe

useo

faW

indk

esse

lmod

elra

ther

than

alin

earr

esis

tanc

emod

elco

uple

dto

aco

nsta

ntpr

essu

rere

servo

ir.Ja

cob-

sen

(199

9)al

sore

port

sth

atit

does

not

mak

ea

sign

ifica

ntdi

ffer

ence

whe

ther

ano

n-lin

earc

ompl

ianc

e(i.e

.apr

essu

rede

pend

entco

mpl

ianc

e)is

used

.Bas

edon

thes

ein

vest

igat

ions

we

ther

efor

ech

ose

toim

plem

enta

Win

dkes

selm

odel

with

aco

nsta

ntco

mpl

ianc

ein

the

hear

tmod

el.

Afte

rim

plem

entin

gall

ofou

rm

odifi

catio

nsin

the

mod

el,w

ead

just

edth

eW

indk

esse

lpar

amet

ersb

ased

ona

com

paris

onof

sim

ulat

ions

and

MR

data

.We

ende

dwith

the

follo

win

gpa

ram

e-te

rcho

ice:

w tyQ ) #

mm

Hg/

(cm

» /s),

w tyQ . m

mH

g/(c

m

» /s)a

nd| cm

» /mm

Hg.

4.6

Dis

trib

uted

sour

cesa

ndsi

nks

The

wor

kpr

esen

tedin

this

sect

ionw

aspe

rfor

med

byJa

kobs

enan

dN

iss

(200

0)ba

sedo

nan

unpu

blis

hedn

oteb

yP

eski

n(19

98).

We

incl

udeh

erea

brie

fsum

mar

yof

Jako

bsen

and

Nis

s’s

(200

0)w

ork.

Whe

ndis

trib

uted

sour

cesa

ndsi

nksw

erei

ntro

duce

din

the

hear

tmod

el(P

eski

n,19

77)t

hest

anda

rdco

ntin

uity

equa

tione

xpre

ssin

ginc

ompr

essi

bilit

y

< ;2

was

mod

ified

to

< ;2 ?

Page 45: MR · 2002. 2. 20. · Adeler A TV Erhver vsf or skerpr ojekt EF 698 IMM-PHD-2001-86 ISSN 0909-3192 ISBN 87-88306-13-5 c 2001 by Pernille Thorup Adeler Printed by IMM, DTU Bookbinder

70E

valu

atio

nof

the

2Dm

odel

whe

re

? (dep

endi

ngon

both

time

and

spac

e)ex

pres

sesth

edi

strib

utio

nof

the

sour

cesa

ndsi

nks,

asde

scrib

edin

Sec

tion3

.2.1

.Thi

sw

asdo

new

ithou

tmod

ifyin

gth

em

omen

tum

equa

tion(

the

Nav

ier-

Sto

kese

quat

ion)

78 9 2 9 : 2 ;< 2= < 5 *<.2:>

even

thou

ghth

ede

rivat

ion

ofth

eN

avie

r-S

toke

sequ

atio

nis

base

don

the

cont

inu-

ityeq

uatio

n.A

ssum

ptio

nsab

outt

hem

omen

tum

atth

eso

urce

sand

sink

sha

veto

bem

ade

toco

rrec

tlyde

rive

the

mom

entu

meq

uatio

nwith

the

mod

ified

form

ofth

eco

n-tin

uity

equa

tion.

At

asi

nkit

isas

sum

edth

atflu

idle

avin

gth

em

odel

take

sits

mom

entu

mw

ithit.

At

aso

urce

one

can

eith

eras

sum

ethat

fluid

ente

rsth

em

odel

with

nove

loci

ty(a

ndth

usw

ithno

mom

entu

mbe

caus

ethe

fluid

isin

com

pres

sibl

ean

dho

mog

eneo

us)or

that

fluid

ente

rsw

ithth

esa

mev

eloc

ityas

the

fluid

atth

eso

urce

.The

form

eras

sum

ptio

nwas

prop

osed

byP

eski

n(19

98),

whi

leJa

kobs

enan

dN

iss

(200

0)pr

opos

edth

ela

tter.

The

diff

eren

cebe

twee

nder

ivin

gth

em

o-m

entu

meq

uatio

nbas

edon

the

form

eror

the

latte

rass

umpt

ionc

once

rnin

gflui

den

terin

gthe

mod

elis

inth

ete

rmde

scrib

ingt

hech

ange

inm

omen

tum

caus

edby

the

sour

cesa

ndsi

nks.

Thi

sdi

ffer

ence

isde

scrib

edbe

low

,w

ere

fert

oJa

kobs

enan

dN

iss

(200

0)fo

rde

tails

.To

beab

lede

scrib

einfl

owan

dou

tflow

sepa

rate

lythe

follo

win

gar

ede

fined

?1 ? if

? ¶

if

? D

? ( if

? z? if

?

Thu

s

?1 desc

ribes

the

dist

ribut

ion

ofin

flow

thro

ugh

sour

ces,a

nd

? ( desc

ribes

the

dist

ribut

ion

ofou

tflow

thro

ughs

inks

.W

ithth

eas

sum

ptio

nsth

atflu

iden

terin

gth

em

odel

has

nom

omen

tum

and

fluid

leav

ing

the

mod

elta

kes

itsm

omen

tum

with

it,th

ech

ange

inm

omen

tum

rela

tedt

oth

eso

urce

sand

sink

sis

@ ¿ 7? (C·

whe

re

· isa

fixed

area

.Usi

ngth

isin

the

deriv

atio

nof

the

mom

entu

meq

uatio

ngi

ves

78 9 2 9 : 2 ;< 2= < 5 *<.2:> ?12

Thu

sthe

mom

entu

meq

uatio

nsis

nott

hest

anda

rdN

avie

r-S

toke

sequ

atio

n.

4.7

Sim

ulat

ion

over

seve

ralh

eart

cycl

es71

With

the

assu

mpt

ions

that

fluid

ente

rsth

em

odel

with

the

sam

evel

ocity

(i.e.

sam

emom

entu

m)a

sth

eflu

idat

the

sour

cean

dflu

idle

avin

gth

em

odel

take

sits

mom

entu

mw

ithit,

the

chan

gein

mom

entu

mre

late

dto

the

sour

cesa

ndsi

nks

beco

mes

@ ¿ 7?C·

Usi

ngth

iste

rmin

the

deriv

atio

nof

the

mom

entu

meq

uatio

nlea

dsto

the

follo

win

geq

uatio

n:

78 9 2 9 : 2 ;< 2= < 5 *<.2:>

Thi

sis

the

stan

dard

Nav

ier-

Sto

kese

quat

ion,

even

thou

ghth

eco

ntin

uity

equa

tion

was

noti

nst

anda

rdfo

rm.

Thi

ssh

ows

that

the

useo

fthe

stan

dard

Nav

ier-

Sto

kese

quat

iont

oget

herw

ithth

eno

n-st

anda

rdcon

tinui

tyeq

uatio

ndoe

snot

lead

toin

cons

iste

ncie

sinth

em

odel

,bu

tis

base

don

sens

ible

assu

mpt

ions

conc

erni

ngth

eflu

iden

terin

gthe

mod

el.

The

sede

rivat

ions

are

nots

peci

ficto

the

hear

tmod

el,b

utar

eva

lidfo

ran

arbi

-tr

ary

fluid

dyna

mic

alm

odel

with

dist

ribut

edso

urce

sand

sink

s.In

the

case

ofth

ehe

artm

odel

,itis

nece

ssar

ytodi

scus

swhi

chof

the

two

assu

mpt

ions

conc

erni

ngth

eflu

iden

terin

gthe

mod

elis

corr

ect.

Sin

cebl

ood

ente

rsth

eat

rium

durin

gbo

thdi

asto

lean

dsy

stol

e,w

ebe

lieve

itw

ould

beun

phys

iolo

gica

ltoas

sum

ethat

bloo

den

ters

the

hear

twith

the

sam

evel

ocity

asth

ebl

ood

alre

adyi

nth

eat

rium

has.

Itis

mor

eco

rrec

tto

assu

met

hatb

lood

ente

rsw

itha

low

erve

loci

ty.

Thu

sw

ebe

lieve

that

none

ofth

est

ated

assu

mpt

ions

abou

tflui

den

terin

gthe

mod

elar

eco

rrec

t,but

the

assu

mpt

iont

hatt

heflu

iden

terin

gthe

mod

elha

sno

velo

city

mig

htbe

clos

erto

the

phys

iolo

gica

llyco

rrec

tsitu

atio

n.Ja

kobs

enan

dN

iss

(200

0)ex

amin

eth

edi

ffer

ence

sinsi

mul

atio

nre

sults

(par

-tic

ular

lyth

eve

loci

tyfie

ld)

betw

eent

hetw

oeq

uatio

nsof

mom

entu

mde

scrib

edab

ove.

The

yfin

dth

atth

erea

reon

lym

inor

diff

eren

cesin

the

velo

city

field

,pro

b-ab

lydu

eto

the

fact

that

the

velo

city

ofth

eflu

idat

the

sour

ces,w

here

fluid

ente

rsth

em

odel

,issm

all.

We

conc

lude

that

even

thou

ghdi

ffer

enta

ssum

ptio

nsab

outth

eflu

iden

terin

gthe

mod

elle

adto

diff

eren

tmom

entu

meq

uatio

ns,th

isdo

esno

tlea

dto

maj

ordi

ffer

ence

sinth

esi

mul

atio

nres

ults

.Thu

swe

dono

tfind

itne

cess

aryto

incl

ude

the

new

form

ofth

em

omen

tum

equa

tioni

nth

em

odel

.

4.7

Sim

ulat

ion

over

seve

ralh

eart

cycl

es

Whe

nth

em

odel

isus

edfo

rph

ysio

logi

cale

xper

imen

tsan

dco

mpa

rison

sitis

im-

port

antto

dete

rmin

eatw

hich

poin

tthe

mod

elbe

com

espe

riodi

c.T

his

can

bede

-

Page 46: MR · 2002. 2. 20. · Adeler A TV Erhver vsf or skerpr ojekt EF 698 IMM-PHD-2001-86 ISSN 0909-3192 ISBN 87-88306-13-5 c 2001 by Pernille Thorup Adeler Printed by IMM, DTU Bookbinder

72E

valu

atio

nof

the

2Dm

odel

term

ined

bym

akin

ga

sim

ulat

iono

verm

any

hear

tcyc

lesa

ndex

amin

ing

atw

hich

poin

tthe

mod

elbe

com

es(p

ract

ical

ly)p

erio

dicf

rom

one

hear

tcyc

leto

the

next

.W

hen

dete

rmin

ingt

heap

prop

riate

hear

tcyc

lenu

mbe

r,it

isal

sone

cess

ary

toco

nsid

erth

eco

mpu

tatio

ntim

e.Fo

rou

rref

eren

cesi

mul

atio

ntw

ohe

artc

ycle

sta

keap

prox

imat

ely3

1/2

hour

sto

com

pute

ona

700

MH

zP

entiu

mIII

proc

esso

r.W

hen

perf

orm

ing

phys

iolo

gica

lexp

erim

ents

itis

our

expe

rienc

etha

t,be

caus

eof

the

com

plex

ityof

the

mod

el,m

any

sim

ulat

ions

are

need

edbe

fore

the

corr

ect

setti

ngof

the

mod

elis

achi

eved

.Thu

sash

ortc

ompu

tatio

ntim

eis

very

impo

rtan

t.W

em

ake

aru

nw

ithth

ere

fere

ncem

odel

over

15he

artc

ycle

s.It

isev

iden

tfr

omth

ere

sults

that

the

outp

utbe

com

es(p

ract

ical

ly)p

erio

dic

with

inth

efir

st4

hear

tcyc

les.

We

dono

tsee

that

the

outp

utbe

com

espe

rfec

tlype

riodi

c,no

teve

nw

ithin

15he

artc

ycle

s,e.

g.th

eam

plitu

deso

fesp

ecia

llyth

eve

loci

tyan

dflow

time

profi

lesv

ary

alit

tle.

Fig

ure

4.27

show

sth

epr

essu

retim

epr

ofile

s,F

igur

e4.

28th

eve

loci

tytim

epr

ofile

atth

em

itral

ring,

Fig

ure

4.29

the

velo

city

time

profi

leac

ross

the

aort

icou

tflow

trac

tand

Fig

ure

4.30

the

sour

cesfl

owpr

ofile

,in

allc

ases

for

the

first

4he

artc

ycle

sofo

urre

fere

nces

imul

atio

n.F

rom

Fig

ure

4.27

itis

seen

that

the

pres

sure

inth

eat

rium

issl

ight

lydi

ffer

ent

inth

efir

stcy

cle

than

inth

efo

llow

ing,

the

vent

ricul

arpr

essu

reis

prac

tical

lyth

esa

me,

whi

leth

em

axim

umle

velo

fthe

pres

surea

tthe

aort

icsi

nkin

crea

sess

light

lydu

ring

the

four

hear

tcyc

les.

The

shap

eoft

hem

itral

velo

city

profi

le(F

igur

e4.

28)

isdi

ffer

enti

nth

efir

stcy

cle

than

inth

efo

llow

ing

ones

:the

first

peak

ishi

gher

and

the

shap

edur

ing

that

peak

isw

ider

.F

urth

erm

ore,

from

the

seco

ndcy

cle

and

onw

ard

thre

efo

rwar

dpe

aksa

repr

esen

t.T

hefir

stpe

aksl

ight

lyde

crea

ses

durin

gth

ela

stth

reec

ycle

splo

tted.

The

diff

eren

cebe

twee

nthe

first

cycl

ean

dth

efo

llow

ing

cycl

esar

ecl

osel

yrel

ated

toth

efa

ctth

atth

em

odel

begi

nsw

ithth

eflu

idbe

ing

atre

st.

InF

igur

e4.

29it

isse

enth

atth

eve

loci

typr

ofile

acro

ssth

eao

rtic

trac

tfro

mth

eth

irdan

dfo

urth

hear

tcyc

lesa

reve

rysi

mila

r.In

the

first

two

cycl

esth

epe

akve

loci

tyis

high

er,a

ndth

esh

apeo

fthe

curv

eis

slig

htly

diff

eren

tinth

efir

stcy

cle

com

pare

dto

the

follo

win

gcy

cles

.T

heflo

wth

roug

hth

eat

rials

ourc

efro

mth

ese

cond

,third

and

four

thhe

artc

ycle

isve

rysi

mila

r,w

hile

min

ordi

ffer

ence

sexi

stbe

twee

nthe

first

cycl

ean

dth

efo

llow

ing

cycl

es.F

orth

eflo

wth

roug

hth

eao

rtic

sink

we

seet

hesa

met

ende

ncie

sasf

orth

eve

loci

tyac

ross

the

aort

icou

tflow

trac

t:th

eth

irdan

dfo

urth

hear

tcyc

les

are

very

sim

ilar.

The

shap

eof

the

curv

ein

the

seco

ndcy

cle

issi

mila

rto

the

shap

ein

the

third

and

four

th,b

utth

epe

akou

tflow

isla

rger

and

for

the

first

cycl

eth

esh

apes

how

ssm

alld

iffer

ence

scom

pare

dto

the

follo

win

gcy

cles

and

the

peak

outfl

owis

larg

erth

anin

the

third

and

four

thcy

cles

.W

eco

nclu

deth

atit

isre

ason

ablet

ota

keth

ere

sults

from

the

seco

ndhe

art

4.7

Sim

ulat

ion

over

seve

ralh

eart

cycl

es73

0.5

11.5

22.5

33.5

t[s]

0

10

20

30

40

50

60

pressure[mmHg]

Fig

ure

4.27

:Pre

ssur

etim

epr

ofile

durin

g4

hear

tcyc

lesf

orth

epr

essu

re(m

mH

g)in

the

vent

ricle

(sol

id),

atriu

m(d

otte

d)an

dat

the

aort

icsi

nk(d

ashe

d).

0.5

11.5

22.5

33.5

t[s]

-40

-200

20

40

velocity[cm/s]

Fig

ure

4.28

:V

eloc

itytim

epr

ofile

durin

g4

hear

tcyc

les

for

the

mea

nve

loci

ty(c

m/s

)att

hem

itral

ring.

Page 47: MR · 2002. 2. 20. · Adeler A TV Erhver vsf or skerpr ojekt EF 698 IMM-PHD-2001-86 ISSN 0909-3192 ISBN 87-88306-13-5 c 2001 by Pernille Thorup Adeler Printed by IMM, DTU Bookbinder

74E

valu

atio

nof

the

2Dm

odel

0.5

11.5

22.5

33.5

t[s]

-200

20

40

60

80

velocity[cm/s]

Fig

ure

4.29

:V

eloc

itytim

epr

ofile

durin

g4

hear

tcyc

les

for

the

mea

nve

loci

ty(c

m/s

)acr

osst

heao

rtic

outfl

owtr

actb

elow

the

aort

icsi

nk.

0.5

11.5

22.5

33.5

t[s]

-600

-400

-2000

sourceflow[cm^3/s]

Fig

ure

4.30

:Flo

wtim

epr

ofile

durin

g4

hear

tcyc

lesf

orth

eflo

w(c

m» /s

)thr

ough

the

mitr

also

urce

(das

hed)

and

the

aort

icsi

nk(s

olid

).

4.8

Con

clus

ions

75

cycl

ew

hen

phys

iolo

gica

lexp

erim

ents

are

carr

ied

outw

ithth

em

odel

.T

his

isba

sedo

nth

ego

odco

mpa

rison

betw

eent

here

sults

from

the

seco

ndhe

artc

ycle

andt

hefo

llow

ing

third

andf

ourt

hcy

cles

and

onth

ene

edto

run

man

ysi

mul

atio

nsw

hen

expe

rimen

tsar

eca

rrie

dou

t.T

hus

choo

sing

the

seco

ndan

dno

tthe

third

cycl

ere

duce

sthe

com

puta

tiona

ltime.

4.8

Con

clus

ions

We

have

seen

that

the

scal

ingf

acto

r

hasan

influ

ence

onth

eflo

wpa

ttern

insi

deth

ehe

art.

Itdo

esno

tcha

nget

heov

eral

lflow

patte

rn,b

utlo

cald

iffer

ence

sare

seen

.Com

parin

gthe

sim

ulat

ion

resu

ltsfr

omsi

mul

atio

nsw

ithdi

ffer

ent

values

and

taki

ngth

eco

mpu

tatio

nalti

me

into

acco

unt,w

eha

vech

osen

0.1

asa

good

choi

ce.T

heflo

wpa

ttern

rese

mbl

esw

ellt

heflo

wpa

ttern

seen

inth

e

0.5

sim

ulat

ion

and

the

time

varia

tion

ofpr

essu

rean

dm

eanv

eloc

ities

are

sim

ilart

oth

oseo

btai

neda

t

0.5

.W

eha

vein

vest

igat

edth

ein

fluen

ceof

the

perio

dic

boun

dary

cond

ition

sby

embe

ddin

gthe

hear

tina

larg

erco

mpu

tatio

naldo

mai

nand

com

parin

git

with

our

refe

renc

esim

ulat

ion.

Thi

sco

mpa

rison

show

edon

lym

inor

diff

eren

cesb

etw

een

the

sim

ulat

ions

.Thu

sw

eco

nclu

deth

atth

epe

riodi

cbo

unda

ryco

nditi

onsd

ono

tin

fluen

ceth

ere

sults

and

the

size

ofth

eco

mpu

tatio

nald

omai

nin

rela

tion

toth

ech

osen

hear

tdim

ensi

onis

reas

onab

le.

We

exam

ined

the

cons

eque

nceso

ftet

herin

gthe

hear

ttoa

seto

ffixe

dpo

ints

asde

scrib

edin

Sec

tion3

.3.7

byco

mpa

rings

imul

atio

nsw

ithan

dw

ithou

ttet

herin

g.W

efo

und

that

the

teth

erin

gsuc

cess

fully

prev

ente

dthe

unph

ysio

logi

calm

ovem

ent

ofth

ehe

arta

ndon

lyin

trod

uced

afe

wch

ange

sinth

ere

sults

.W

eha

vesh

owed

that

the

impl

emen

tedW

indk

esse

lmod

elfo

rth

eou

tflow

thro

ught

heao

rtic

sink

impr

oves

the

shap

eof

the

pres

sure

curv

efo

rth

epr

essu

reat

the

aort

icsi

nkw

ithou

tint

rodu

cing

sign

ifica

ntch

ange

sinth

eve

loci

tyfie

ld.

We

have

com

pare

dthe

resu

ltsfr

omth

efir

st15

hear

tcyc

les

ofou

rref

eren

cesi

mul

atio

nand

foun

dth

atit

isac

cept

ablet

ous

ethe

resu

ltsfr

omth

ese

cond

cycl

ein

expe

rimen

tsw

ithth

em

odel

.The

first

cycl

eis

cons

ider

ablyd

iffer

entf

rom

the

follo

win

gcy

cles

,whi

leth

ere

sults

from

the

seco

ndcy

cle

are

clos

eto

thos

efro

mth

efo

llow

ing

cycl

es.

The

inve

stig

atio

nspe

rfor

med

inth

isch

apte

rsho

wth

atth

ere

sults

from

the

seco

ndhe

artc

ycle

ofa

refe

renc

esim

ulat

ionc

ompu

tedo

na

128

grid

with

2995

2tim

est

epsp

erhe

artc

ycle

,with

0.1,

andw

ithal

loth

erpa

ram

eter

sasd

escr

ibed

inC

hapt

er3,

are

the

resu

ltsfr

omth

e2D

hear

tmod

elth

atsh

ould

beta

ken

asre

pres

enta

tive.

Page 48: MR · 2002. 2. 20. · Adeler A TV Erhver vsf or skerpr ojekt EF 698 IMM-PHD-2001-86 ISSN 0909-3192 ISBN 87-88306-13-5 c 2001 by Pernille Thorup Adeler Printed by IMM, DTU Bookbinder

Cha

pter

5

Com

parin

gth

e2D

mod

elw

ithan

MR

data

set

The

ultim

ate

eval

uatio

noft

hehe

artm

odel

isa

com

paris

onbe

twee

nmod

elre

sults

and

mea

sure

men

tsper

form

edon

ahu

man

,whi

chin

ourc

asea

reM

Rm

easu

re-

men

ts.

Thi

sch

apte

rispa

rtly

base

don

Jaco

bsen

etal

.(2

001)

and

Ade

lera

ndJa

cobs

en(2

001)

.H

owev

er,

we

have

chan

gedt

hein

itial

geom

etry

and

the

teth

-er

ing

sinc

eth

ere

sults

pres

ente

dinth

em

entio

nedp

aper

s,an

dhe

rew

eco

mpa

reou

rnew

mod

elre

sults

with

the

sam

eMR

data

set.

The

new

initi

alge

omet

ryan

dte

ther

inga

reth

osed

escr

ibed

inS

ectio

n3.3

.7.

The

com

paris

onfa

llsin

totw

opa

rts,

each

repr

esen

tedb

yits

type

ofda

ta:

À Veloc

ityfie

lds

and

hear

twal

lbou

ndar

y.

À Veloc

itypr

ofile

satt

hem

itral

ring

and

atth

eao

rtic

outfl

owtr

act.

5.1

The

MR

data

We

useM

Rda

tafr

oma

stud

yin

Kim

etal

.(19

95)c

ondu

cted

on26

heal

thyv

ol-

unte

ers,

18m

enan

d8

wom

en.T

heir

mea

nag

ew

as25

year

s(in

ara

ngef

rom

21to

30ye

ars)

.The

volu

ntee

rsha

dno

know

nca

rdia

cor

syst

emic

dise

ases

.For

the

com

paris

onw

ithou

rsi

mul

ated

hear

tmod

el,o

neof

the

26se

tsof

MR

data

was

chos

en.S

eeA

ppen

dix

Afo

ran

expl

anat

iono

fth

ete

chni

calit

ieso

fth

eM

Rm

etho

d.

Page 49: MR · 2002. 2. 20. · Adeler A TV Erhver vsf or skerpr ojekt EF 698 IMM-PHD-2001-86 ISSN 0909-3192 ISBN 87-88306-13-5 c 2001 by Pernille Thorup Adeler Printed by IMM, DTU Bookbinder

78C

ompa

ring

the

2Dm

odel

with

anM

Rda

tase

t

Inth

eM

Rda

taco

llect

ing

proc

ess,

aco

nven

tiona

lspi

nec

hose

quen

cew

asus

edfo

ra

coro

nalim

ageo

fthe

hear

tfollo

wed

bya

sing

lean

gula

tiont

hrou

ghth

eao

rtic

valv

ean

dth

eap

exof

the

hear

ttoyi

eld

alo

ngax

isvi

ewof

the

left

vent

ricle

.In

Kim

etal

.(19

95)t

helo

ngax

ispl

aneo

fthe

left

vent

ricle

was

chos

enbe

caus

eitco

ntai

nsbo

thth

eao

rtic

outfl

owan

dth

em

itral

inflo

w,a

swel

last

hele

ftve

ntric

lean

dle

ftat

rium

.Fo

rth

eco

mpa

rison

betw

eenM

Rda

taan

dm

odel

,the

long

axis

plan

eis

wel

lsui

ted

sinc

eit

isco

nsis

tent

with

the

com

puta

tiona

lpla

neof

the

2Dm

odel

.Im

agea

cqui

sitio

nwas

pros

pect

ively

trig

gere

dby

the

Rw

ave

ofth

eel

ectr

ocar-

diog

ram

,so

the

first

reco

rded

fram

ew

as8

ms

afte

rthe

Rw

ave.

Thi

sco

rres

pond

sap

prox

imat

elyt

oth

etim

eof

clos

ureo

fthe

mitr

alva

lve.

The

intr

acar

diac

flow

velo

city

mea

sure

men

tswer

eobt

aine

dusi

ngth

est

anda

rdF

LAG

(Flo

wA

djus

tedG

radi

ents

)seq

uenc

e,whi

chis

desc

ribed

inG

roen

andD

ijk(1

987)

.The

reco

rdin

gsw

erec

ondu

cted

ina

squa

re40

cmfie

ldof

view

with

anin

-pl

aner

esol

utio

nof3

.125

mm

0 3.12

5m

mgi

ving

anim

aged

slic

eof

128

0 128

voxe

ls(v

olum

eel

emen

ts).

The

follo

win

gpa

ram

eter

setti

ngsw

ere

used

for

the

flow

mea

sure

men

ts:45

degr

eesfl

ipan

gle,

9.5

ms

echo

time,

7.1

ms

acqu

isiti

ontim

e,an

d10

mm

slic

eth

ickn

ess.

The

velo

city

sens

itivity

was

sett

opr

oduc

eam

axim

umph

ases

hift

ata

velo

city

of

Á 1.25

m/s

to

Á 1.67

m/s

toav

oid

alia

sing

.V

eloc

ityen

codi

ngw

aspe

rfor

med

inal

lthr

eesp

atia

ldire

ctio

nsto

prod

ucet

hree

-di

men

sion

alve

loci

tyin

form

atio

nfr

omea

chvo

xeli

nsid

eth

efie

ldof

view

.T

hetim

ene

eded

for

the

quan

titat

iveve

loci

tyac

quis

ition

s(us

ing

EC

Gga

ting

toav

oid

mot

ion

artif

acts

)was

15to

20m

info

rea

chsu

bjec

t,dep

endi

ngon

the

hear

trat

e.T

hepr

oced

urer

esul

tedi

nth

ere

cord

edM

Rda

tabe

ing

aver

aged

over

768

hear

tbe

ats.

For

the

26ex

amin

edpe

rson

sthe

tem

pora

lreso

lutio

nwas

28m

s

Á 3.8

ms

(mea

n

Á stan

dard

devi

atio

n(S

D))

with

25-3

2fr

ames

perc

ardi

accy

cle.

For

the

spec

ificM

Rse

twith

whi

chth

eco

mpa

rison

was

carr

iedo

ut,t

hete

mpo

ralre

solu

-tio

nw

as36

ms

with

26fr

ames

perc

ardi

accy

cle

givi

nga

tota

llen

gth

ofth

ehe

art

cycl

eof

936

ms.

The

tota

lrec

ordi

ngtim

ew

as11

52m

s,i.e

.app

roxi

mat

ely

#) Âhe

artc

ycle

s.T

heac

cura

cyof

quan

titat

iveflo

wm

easu

rem

entsb

yth

eM

Rph

aset

echn

ique

depe

ndso

nth

esu

ppre

ssio

nof

artif

acts

.T

heve

loci

tym

apsw

ere

corr

ecte

dfor

poss

ible

linea

rpha

seer

rors

resu

lting

from

eddy

curr

ents

inth

em

agne

ticfie

ld.I

nad

ditio

n,m

aski

ngof

rand

omno

isei

nth

est

atio

nary

tissu

ewas

done

.Bot

hpr

oce-

dure

swer

eper

form

edby

ase

mi-a

utom

ateds

oftw

arep

rogr

am,w

hich

isde

scrib

edin

deta

ilin

Wal

kere

tal.

(199

3).

An

MR

data

setc

onsi

stso

fthe

thre

e-di

men

sion

alvel

ocity

info

rmat

ioni

nea

chvo

xela

ndth

em

odul

usim

age

atea

chtim

efr

ame.

The

mod

ulus

imag

eco

ntai

nsin

form

atio

non

the

MR

sign

alam

plitu

de,w

hich

depe

ndse

.g.o

nth

esp

ecifi

ctis

sue

5.2

Vel

ocity

field

s79

and

the

velo

city

ofth

eflo

win

the

voxe

l.T

hem

odul

usim

age

isdi

spla

yeda

sa

grey

-sca

lepi

ctur

ean

dca

n,as

such

,be

used

toro

ughl

yde

term

inet

hein

tern

alan

atom

yand

also

the

mag

nitu

deof

the

flow

.For

the

com

paris

onw

ithth

e2D

hear

tm

odel

we

wer

eonl

yin

tere

sted

inth

ein

-pla

neco

mpo

nent

soft

heve

loci

ty.T

hein

-pl

anev

eloc

ityco

mpo

nent

scan

bedi

spla

yeda

svel

ocity

field

vect

ors.

Pre

sent

ing

the

velo

city

field

plot

supe

rimpo

sedo

nth

eco

rres

pond

ingm

odul

usim

ages

how

sbo

thth

em

agni

tude

and

the

dire

ctio

nof

the

bloo

d.It

isal

sopo

ssib

leat

each

time

fram

eto

extr

actv

eloc

ityin

form

atio

nfr

omon

eor

seve

ralv

oxel

s,an

dth

isca

nbe

used

topl

ota

velo

city

profi

le(v

eloc

ityas

func

tion

oftim

e)at

asp

ecifi

cpl

ace

inth

eim

aged

slic

e.In

the

velo

city

field

plot

we

show

belo

ww

eha

vein

dica

ted

the

voxe

lsfr

omw

hich

velo

city

info

rmat

ion

isex

trac

tedt

oca

lcul

atev

eloc

itytim

epr

ofile

s.

5.2

Vel

ocity

field

s

The

star

tingt

ime

ofth

eM

Rda

tais

diff

eren

tfro

mth

atof

the

sim

ulat

ion.

The

nat-

ural

star

toft

heM

Rda

tais

atth

ecl

osur

eoft

hem

itral

valv

e,w

hile

the

sim

ulat

ion

star

tsin

early

vent

ricul

ardi

asto

le.W

eha

vech

osen

tosh

owal

lres

ults

acco

rdin

gto

the

time

cour

seof

the

sim

ulat

ion,

i.e.s

tart

ing

with

early

vent

ricul

ardi

asto

le,

and

have

shift

edth

eve

loci

tieso

fth

eM

Rm

easu

rem

entsfr

omth

efir

stcy

cle,

ac-

cord

ingl

y.T

hem

atch

ingw

asdo

neby

sync

hron

izin

gthe

time

ofth

eea

rlype

akve

loci

ty(a

lso

calle

dth

eE

peak

)inth

efir

sthe

artc

ycle

inth

eve

loci

tytim

epr

ofile

ofth

ece

ntre

velo

city

atth

em

itral

ring

inth

em

odel

with

the

time

ofth

eE

peak

inth

eve

loci

tytim

epr

ofile

atth

em

itral

ring

inth

eM

Rda

ta.

InF

igur

es5.

1–5.

3th

eve

loci

tyfie

ldis

show

nat

8di

ffer

entt

imes

durin

ga

hear

tcyc

leas

velo

city

vect

orsa

long

with

the

hear

twal

lbou

ndar

y.W

eha

veus

edth

ere

sults

from

the

seco

ndhe

artc

ycle

ofth

em

odel

,so

the

sim

ulat

ion

time

runs

from

sto

# %º s.

Inth

em

odel

,the

hear

twal

lbo

unda

ryis

com

pute

dand

isth

eref

oree

asily

plot

ted.

Inth

eM

Rda

ta,th

ein

terio

roft

hehe

art

boun

dary

(not

the

valv

ele

aflet

s)w

asm

anua

llytr

aced

from

plot

sof

the

velo

city

field

supe

rimpo

sedo

nth

em

odul

usim

age.

The

boun

dary

isgi

ven

aw

idth

equa

ltoth

esp

atia

lreso

lutio

noft

heM

Rm

easu

rem

ents

,i.e.3

.125

mm

.We

emph

asiz

ethat

the

dete

rmin

atio

nof

the

inte

riorb

ound

aryf

rom

the

MR

data

isra

ther

unce

rtai

nan

dth

atit

shou

ldbe

only

take

nas

anin

dica

tion

ofits

posi

tion.

We

begi

nw

itha

desc

riptio

nof

the

resu

ltsin

Fig

ures

5.1–

5.3.

Thi

sw

illgi

vean

intr

oduc

tiont

oth

etim

ese

quen

ceof

ahe

artc

ycle

and

prov

ide

the

basi

sfor

our

com

paris

on.

Ea

rly

mitr

ali

nflo

w.

The

resu

ltsst

artw

ithth

eea

rlym

itral

inflo

w.

The

mitr

al

Page 50: MR · 2002. 2. 20. · Adeler A TV Erhver vsf or skerpr ojekt EF 698 IMM-PHD-2001-86 ISSN 0909-3192 ISBN 87-88306-13-5 c 2001 by Pernille Thorup Adeler Printed by IMM, DTU Bookbinder

80C

ompa

ring

the

2Dm

odel

with

anM

Rda

tase

t

MR

sim

ulat

ion

Time R+512 ms

Time1.0660

à ÄÅÇÆÈÉÉ s

Time R+620 ms

Time1.1700

à ÄÅÇÆÅÊ È s

Time R+728 ms

Time1.2740

à ÄÅÇÆËÊÌ s

Fig

ure

5.1:

Vel

ocity

field

and

hear

tbou

ndar

yfro

mM

Rm

easu

rem

ents(l

eft)

and

refe

renc

esim

ulat

ion

(rig

ht)

atth

ree

times

durin

ga

hear

tcyc

lech

arac

teriz

edby

:ea

rlype

akm

itral

inflo

w(t

op),

tem

pora

rym

axim

alan

terio

rvor

tex

inth

eM

Rda

ta(m

iddl

e)an

da

decl

inei

nin

flow

(bot

tom

).

5.2

Vel

ocity

field

s81

MR

sim

ulat

ion

Time R+836 ms

Time1.3910

à ÄÅÇÆÍÎÅ s

Time R+8 ms

Time1.4950

à ÄÅÇÆÌÎÏ s

Time R+80 ms

Time1.5600

ÅÇÆÏÉÈ

s

Fig

ure

5.2:

Vel

ocity

field

and

hear

tbou

ndar

yfro

mM

Rm

easu

rem

ents(l

eft)

and

refe

renc

esim

ulat

ion

(rig

ht)

atth

ree

times

durin

ga

hear

tcyc

lech

arac

teriz

edby

:at

rials

ysto

lein

sim

ulat

ion(

top)

,clo

sure

ofm

itral

valv

e(m

iddl

e)an

dea

rlyao

rtic

outfl

ow(b

otto

m).

Page 51: MR · 2002. 2. 20. · Adeler A TV Erhver vsf or skerpr ojekt EF 698 IMM-PHD-2001-86 ISSN 0909-3192 ISBN 87-88306-13-5 c 2001 by Pernille Thorup Adeler Printed by IMM, DTU Bookbinder

82C

ompa

ring

the

2Dm

odel

with

anM

Rda

tase

t

MR

sim

ulat

ion

Time R+152 ms

Time1.6380

à ÄÅÇÆÉÍÐ s

Time R+332 ms

Time1.8200

à ÄÅÇÆÐËÈ s

Fig

ure

5.3:

Vel

ocity

field

and

hear

tbou

ndar

yfro

mM

Rm

easu

rem

ents(l

eft)

and

refe

renc

esim

ulat

ion

(rig

ht)

attw

otim

esdu

ring

ahe

artc

ycle

char

acte

rized

by:

peak

aort

icou

tflow

inM

Rda

ta(t

op)

and

the

time

just

befo

recl

osur

eof

aort

icva

lve

inM

Rda

taan

dju

staf

tera

ortic

sink

clos

urei

nsi

mul

atio

n(bo

ttom

).

inflo

wty

pica

llyha

stw

ope

aksd

urin

ga

hear

tcyc

le,t

heea

rlype

ak,a

lso

refe

rred

toas

the

Epe

ak,a

ndth

ela

teat

rialp

eak,

refe

rred

toas

the

Ape

ak.(

Inth

ese

cond

hear

tcyc

leof

the

sim

ulat

ion,

thou

gh,th

reep

eaks

ares

een.

We

disc

ussth

isbe

low

).In

Fig

ure

5.1

atth

etim

eof

the

Epe

ak(1

.066

s),a

wid

ein

flow

jeti

sse

enin

both

MR

data

and

sim

ulat

ion.

Inth

eM

Rda

tath

eje

tis

wid

eran

dre

ache

sdee

per

into

the

vent

ricle

com

pare

dto

that

ofth

esi

mul

atio

n.In

both

the

MR

data

and

sim

ulat

ion,

the

begi

nnin

gof

form

atio

nof

avo

rtex

isse

enat

the

leafl

ettip

s,th

ean

terio

rvor

tex

iscl

early

seen

inth

esi

mul

atio

n.(T

hele

aflet

sare

nots

how

nin

the

MR

data

).In

the

sim

ulat

ion

avo

rtex

isal

read

ypre

sent

deep

erin

the

vent

ricle

,

5.2

Vel

ocity

field

s83

this

vort

exw

asfo

rmed

inth

efir

sthe

artc

ycle

and

notd

estr

oyed

.M

idd

iast

ole.

Inth

eM

Rda

taan

dsim

ulat

iona

t1.1

70s

(Fig

ure5

.1),

the

inflo

wha

sdec

reas

edan

din

the

sim

ulat

ions

emi-c

losu

reoft

hem

itral

valv

eis

seen

.Als

o,th

eflo

wpa

ttern

inth

eM

Rda

tasu

gges

tstha

tthe

mitr

alva

lve

isin

ase

mic

lose

dpo

sitio

n.In

the

MR

data

ala

rge

vort

exha

sdev

elop

edin

the

ante

riorp

arto

fth

eve

ntric

le,w

hile

ther

eis

only

ahi

ntof

apo

ster

iorv

orte

x.T

heflo

wpa

ttern

issi

mila

rin

the

uppe

rpar

toft

heve

ntric

lein

the

sim

ulat

ion:

two

vort

ices

arec

lear

lyse

en,a

larg

ean

terio

rvor

tex

and

asm

alle

rpos

terio

rone

.B

utin

the

low

erpa

rtof

the

vent

ricle

,clo

seto

the

apex

,a

third

vent

ricle

isal

sopr

esen

t.A

t1.

274

s(F

igur

e5.

1)th

ein

flow

hasf

urth

erde

clin

edin

both

MR

data

and

sim

ulat

ion,

but

the

vort

ices

ares

tillp

rese

ntat

low

eran

gula

rvel

ocity

.In

the

MR

data

the

post

erio

rvo

rtex

isha

rdly

dete

ctab

le.

La

tefil

ling

.A

t1.

391

s(F

igur

e5.

2)th

ein

flow

thro

ugh

the

mitr

alrin

gin

the

sim

ulat

ion

hasi

ncre

ased

,and

the

third

peak

(the

Ape

ak)o

fth

em

itral

inflo

wis

onits

way

.T

his,

ofco

urse

,sho

uld

have

been

the

seco

ndpe

ak,a

poin

ttha

tis

disc

usse

dinS

ectio

n5.3

.In

cont

rast

,onl

ya

hint

ofth

eA

peak

isse

enin

the

MR

data

.The

pres

ence

ofth

ean

terio

rvor

tex

inth

eM

Rda

tais

rath

erva

guea

tthi

stim

e,w

hile

itis

still

clea

rin

the

sim

ulat

ion,

alon

gw

ithbo

thth

epo

ster

iora

ndap

ical

vort

ices

.No

post

erio

rvor

tex

isde

tect

ablei

nth

eM

Rda

ta.

Mitr

alv

alv

ecl

osu

re.

Inbo

thth

eM

Rda

taan

dsi

mul

atio

n,th

em

itral

valv

eis

clos

ing

at1.

495

s(F

igur

e5.

2).

The

mitr

alva

lve

isno

tsho

wn

expl

icitl

yin

the

MR

data

,but

the

flow

patte

rnre

veal

stha

tthe

valv

eis

clos

ing.

Inth

eM

Rda

taa

rota

tiona

lflow

patte

rnfil

ling

upth

eve

ntric

leis

disc

erni

ble,

buti

tis

nota

clea

rvo

rtex

,w

hile

inth

esi

mul

atio

nbo

thth

ean

terio

rand

post

erio

rvor

tices

are

still

pres

ent.T

heap

ical

vort

exis

hard

lyde

tect

able

.Ve

ntr

icu

lars

ysto

le.T

heea

rlyao

rtic

outfl

owpa

ttern

near

the

outfl

owtr

acta

t1.

560

s(F

igur

e5.

2)is

sim

ilari

nth

eM

Rda

taan

dth

esi

mul

atio

n.D

eepe

rinth

eve

ntric

leth

eve

loci

tiesa

rehi

gher

inth

esi

mul

atio

ntha

nis

appa

rent

from

the

MR

data

.Fur

ther

mor

e,the

flow

from

mos

toft

heve

ntric

lein

the

sim

ulat

ionc

onve

rges

tow

ard

the

outfl

owtr

act.

Bas

edon

the

posi

tion

ofth

ehe

artw

allo

fth

eve

ntric

lein

the

sim

ulat

ion

(whe

nco

mpa

redt

oth

epr

evio

ustim

efr

ame)

,itis

seen

that

the

vent

ricul

arsy

stol

eha

sse

tin.

Thi

sis

notc

lear

from

the

hear

twal

lpo

sitio

nin

the

MR

data

,but

sinc

eaor

ticou

tflow

ispr

esen

tthe

vent

ricul

arsy

stol

emus

thav

est

arte

d.In

Fig

ure

5.3

at1.

638

sth

eao

rtic

outfl

owve

loci

tyha

sinc

reas

edin

both

MR

data

ands

imul

atio

n.F

rom

the

velo

city

profi

less

how

nin

the

follo

win

gse

ctio

nit

can

bese

enth

atth

isis

the

time

ofpe

akao

rtic

outfl

owve

loci

tyac

cord

ingt

oth

eM

Rda

taan

dju

staf

terp

eakv

eloc

ityac

cord

ingt

osi

mul

atio

n.T

heco

nver

ging

ofth

eve

ntric

ular

flow

tow

ard

the

outfl

owtr

actf

rom

mos

tpar

tsof

the

vent

ricle

isst

illm

ostc

lear

lyse

enin

the

sim

ulat

ion.

Inth

esi

mul

ated

flow

field

the

artifi

cial

Page 52: MR · 2002. 2. 20. · Adeler A TV Erhver vsf or skerpr ojekt EF 698 IMM-PHD-2001-86 ISSN 0909-3192 ISBN 87-88306-13-5 c 2001 by Pernille Thorup Adeler Printed by IMM, DTU Bookbinder

84C

ompa

ring

the

2Dm

odel

with

anM

Rda

tase

t

term

inat

iono

fth

eou

tflow

trac

tcau

sesa

back

flow

alon

gth

ean

terio

rsid

eof

the

trac

tand

the

form

atio

nof

avo

rtex

.E

nd

ofs

ysto

le.T

heflo

wpa

ttern

at1.

820

s(F

igur

e5.

3)sh

ows

that

the

aort

icva

lve

isst

illop

enin

the

MR

data

,but

the

aort

icsi

nkis

clos

edin

the

sim

ulat

ion.

Fro

mth

eve

loci

typr

ofile

sin

the

follo

win

gse

ctio

nit

isse

enth

atth

isis

just

befo

reva

lve

clos

urea

ccor

ding

toth

eM

Rda

taan

dju

staf

terv

alve

clos

urei

nth

esi

mul

a-tio

n.T

hevo

rtex

seen

inth

eou

tflow

trac

toft

hesi

mul

atio

nis

ofco

urse

anar

tifac

tof

the

mod

el,a

ndth

eve

ntric

ular

vort

exse

enin

the

sim

ulat

ionw

illaf

fect

the

flow

patte

rnof

the

follo

win

ghe

artc

ycle

,asw

esa

win

the

first

time

fram

es(F

igur

e5.1

)of

this

hear

tcyc

le.

The

abov

eco

mpa

rison

betw

eent

heve

loci

tyfie

ldsf

rom

the

MR

mea

sure

men

tsan

dth

esi

mul

atio

nsh

ows

are

ason

ablea

gree

men

tinth

ege

nera

lflow

patte

rn.A

diff

eren

cein

velo

city

field

sis

seen

inth

ew

idth

ofth

ein

flow

jet(

from

atriu

mto

vent

ricle

).T

heflo

wpa

ttern

sals

odiff

erw

ithre

spec

ttoth

esi

zeof

the

vent

ricle

,the

vent

ricle

inth

esi

mul

atio

nbei

ngla

rger

than

inth

eM

Rda

ta.T

his

isa

cons

eque

nce

ofth

em

odel

bein

g2D

.The

entir

eex

pans

iont

akes

plac

ein

the

cons

ider

edpl

ane,

and

topr

oduc

ethe

right

outfl

owth

eve

ntric

leha

sto

expa

ndm

ore.

The

larg

erve

ntric

lem

ight

bean

expl

anat

ionf

orth

ecl

eare

rfor

mat

ion

ofa

post

erio

rvor

tex

and

the

mor

epr

omin

enta

nter

iorv

orte

xin

the

sim

ulat

ion.

The

flow

field

sfr

omth

esi

mul

atio

nar

eaf

fect

edby

the

sim

ple

aort

icva

lve

(sin

kco

uple

dthr

ough

adi

ode

toa

Win

dkes

selm

odel

).To

geth

erw

ithth

ete

rmi-

natio

noft

heou

tflow

trac

t,th

eao

rtic

sink

resu

ltsin

the

form

atio

nofa

vort

exat

the

sink

,whi

chof

cour

seis

nots

eeni

nth

eM

Rda

ta.F

urth

erm

ore,t

hete

ther

ingo

fthe

mod

elhe

arth

asel

imin

ated

the

exce

ssive

mov

emen

tof

the

hear

t,bu

tit

hasa

lso

intr

oduc

edos

cilla

tions

inbo

thth

eat

rium

and

the

vent

ricle

(see

Sec

tion4

.4)a

ndth

isaf

fect

sthe

flow

field

inan

unph

ysio

logi

calw

ay.T

heos

cilla

tions

ofth

eat

rium

can

bese

enw

hen

com

parin

gsuc

cess

ivepl

ots

ofth

ehe

artw

all.

Thi

sis

nots

een

inth

epl

ots

show

nhe

rebe

caus

ethey

are

too

fara

part

intim

e.T

heos

cilla

tions

ofth

eve

ntric

lear

ebe

stse

enw

hen

anan

imat

iono

fthe

pict

ures

ispe

rfor

med

.Inad

ditio

n,th

ete

ther

ingr

estr

icts

the

mod

elto

mov

emen

tsalo

ngth

eax

isof

the

out-

flow

trac

t.To

geth

erw

ithth

edy

nam

icso

fthe

mitr

alrin

g(v

aria

tion

inle

ngth

),th

ere

stric

tion

due

toth

ete

ther

ingr

esul

tsin

the

vent

ricle

axis

bein

gal

mos

talig

ned

with

the

axis

ofth

eou

tflow

trac

tins

tead

ofha

ving

the

angl

ewe

intr

oduc

edin

the

initi

alge

omet

ry.T

hepa

pilla

rym

uscl

e(m

odel

ledb

ya

link

betw

eena

virt

ualp

oint

insi

deth

ele

ftve

ntric

lean

da

poin

ton

the

post

erio

rhea

rtw

all)

resu

ltsin

anun

phys

iolo

gica

lsh

apeo

fth

eap

exof

the

left

vent

ricle

(see

Fig

ure

5.2

at

#

s).

Thi

sdi

stor

tion

affe

ctst

heflo

wpa

ttern

and

mak

esth

eag

reem

entle

ssgo

od.

Inou

rear

lierr

epor

tedc

ompa

rison

sbet

wee

nmod

elan

dM

Rda

ta(A

dele

rand

5.3

Vel

ocity

time

profi

les

85

Jaco

bsen

,2001

;Jac

obse

neta

l.,20

01)w

em

oved

the

teth

erin

gpoi

ntof

the

pap-

illar

ym

uscl

eto

the

vent

ricul

arw

all

upal

ong

the

post

erio

rwal

lto

prev

entt

hefo

rmat

ion

ofth

epo

ster

iorv

orte

x.B

utth

isre

sulte

din

ave

ryst

rong

(and

unph

ys-

iolo

gica

l)co

ntra

ctio

nof

the

post

erio

rwal

land

ina

very

asym

met

ricm

ovem

ent

ofth

em

itral

valv

e.R

egar

ding

the

wor

kde

scrib

edin

this

thes

is,it

was

deci

ded

that

the

mitr

alva

lve

mov

emen

tand

the

cont

ract

iono

fth

eve

ntric

lew

ere

mor

eim

port

antt

han

the

form

atio

nof

the

post

erio

rvor

tex.

The

refo

rew

eno

wte

ther

the

papi

llary

mus

clet

oa

poin

talit

tlebi

tup

alon

gth

ean

terio

rwal

l,as

desc

ribed

inS

ectio

n3.

3.7.

Thi

sde

cisi

onw

aspa

rtic

ular

lym

ade

with

the

sim

ulat

ions

for

Cha

pter

6in

min

d.G

ener

ally,

we

have

obta

ined

age

omet

ryw

hich

ism

ore

corr

ectc

ompa

redt

oa

hum

anle

ftve

ntric

leth

anth

atin

the

orig

inal

mod

el,b

utth

ege

omet

ryis

still

sim

-pl

ified

.W

eha

veac

hiev

eda

corr

ectle

ngth

scal

eoft

hele

ftve

ntric

leby

chan

ging

the

diam

eter

ofth

em

itral

ring

and

the

diam

eter

ofth

eou

tflow

trac

t.T

hech

ange

sof

the

cros

slin

ksim

prov

edth

eco

ntro

lof

the

mov

emen

tof

the

vent

ricle

wal

ldur

ing

the

hear

tcyc

le,t

husc

hang

ingt

heal

mos

tcirc

ular

form

ofth

eve

ntric

lein

the

orig

inal

mod

elto

the

mor

ere

alis

ticel

onga

tedf

orm

inth

epr

esen

tm

odel

.W

ithth

isse

tof

mod

ifica

tions

,whi

chm

ustb

eco

nsid

ered

asm

inim

al,w

eof

cour

sedi

dno

tobt

ain

(nor

did

we

expe

ctto

)acl

osem

atch

betw

eent

hesi

mul

ated

and

mea

sure

dhea

rtw

allg

eom

etrie

sdur

ing

the

vario

usph

ases

ofth

ehe

artc

ycle

.

5.3

Vel

ocity

time

profi

les

Fro

mth

eve

loci

tyfie

lds

ofbo

thth

eM

Rda

taan

dsi

mul

atio

nwe

cane

xtra

ctve

loc-

ities

atch

osen

spat

ialp

ositi

ons.

For

the

MR

data

we

only

have

26tim

esov

era

hear

tcyc

lew

here

we

can

extr

actv

eloc

ityin

form

atio

n,w

here

asfo

rth

esi

mul

atio

nw

eha

ve29

952t

imes

.A

part

from

the

purp

oseo

fcom

parin

gthe

velo

city

atch

osen

spat

ialp

ositi

ons,

the

velo

city

profi

les

can

also

beus

edto

eval

uate

the

timin

gof

the

sim

ulat

ion

com

pare

dto

MR

mea

sure

men

ts.W

eha

veno

exac

tmea

sure

men

tsof

the

time

ofon

seta

ndth

edu

ratio

nof

vent

ricul

aran

dat

rials

ysto

le(s

eeS

ectio

n3.3

.6)d

ueto

the

limite

dqu

ality

ofth

eE

CG

durin

gth

eM

Rsc

an,b

utby

com

parin

gthe

velo

city

profi

lest

hetim

ing

para

met

ersc

anbe

eval

uate

d.T

hein

-an

dou

tflow

velo

city

profi

lesf

rom

the

MR

data

are

obta

ined

byav

er-

agin

gth

eve

loci

tyov

er2

fixed

voxe

lsat

the

cent

reof

the

left

vent

ricul

arou

tflow

trac

tatt

hele

velo

fth

eao

rtic

valv

e,an

dov

era

squa

reof

4fix

edvo

xels

near

the

cent

reof

the

mitr

alrin

g.T

hese

voxe

lare

indi

cate

din

the

velo

city

field

plot

sin

Page 53: MR · 2002. 2. 20. · Adeler A TV Erhver vsf or skerpr ojekt EF 698 IMM-PHD-2001-86 ISSN 0909-3192 ISBN 87-88306-13-5 c 2001 by Pernille Thorup Adeler Printed by IMM, DTU Bookbinder

86C

ompa

ring

the

2Dm

odel

with

anM

Rda

tase

t

Fig

ures

5.1–

5.3.

At

the

outfl

owtr

actt

heve

rtic

alco

mpo

nent

isre

cord

ed(s

eere

f-er

ence

fram

ein

Fig

ure5

.1),

whi

leat

the

mitr

alrin

git

isth

eco

mpo

nentm

akin

gan

angl

eof3

0

, with

the

vert

ical

.Bec

ause

ofth

esm

allm

ovem

ento

fth

ehe

artw

all,

noat

tem

ptis

mad

eto

trac

eth

em

ovem

ents

ofth

ehe

artin

choo

sing

thes

evox

els

and

thus

the

velo

citie

sar

eco

mpu

tedw

ithre

spec

ttoa

refe

renc

efra

me

fixed

insp

ace.

The

extr

acte

dvel

ociti

esar

e’m

ean

cent

re’v

eloc

ities

,whi

char

ea

com

bi-

natio

nof

am

eanv

eloc

ityov

eran

da

cent

reve

loci

tyat

the

rele

vant

posi

tion.

Itw

ould

bedi

fficu

ltto

com

pute

the

mea

nvel

ocity

over

the

entir

eou

tflow

trac

tor

over

the

entir

em

itral

ring

beca

useth

epo

ster

iorw

alli

sno

tkno

wn

for

the

aort

icou

tflow

trac

tand

the

ante

riorb

orde

ris

notk

now

nfo

rth

em

itral

ring.

Itis

also

diffi

cult

tore

port

the

cent

reve

loci

ty(a

tone

voxe

l)be

caus

ethe

velo

city

osci

llate

sfr

omon

evo

xelt

oth

ene

xtov

erth

eao

rtic

outfl

owtr

act.

The

sear

eou

rrea

sons

for

repo

rtin

gam

eanc

entr

evel

ocity

for

the

MR

data

.Fo

rth

esi

mul

atio

nw

ere

port

both

am

eana

nda

cent

reve

loci

ty(a

sdes

crib

edin

Sec

tion4

.1)t

obe

able

toco

mpa

reth

em

ean

cent

reve

loci

tyof

the

MR

data

with

both

type

sofv

eloc

ities

.F

igur

e5.

4sh

ows

the

time

cour

seof

the

inflo

wve

loci

tyat

the

mitr

alrin

gex

-tr

acte

dfro

mbo

thth

eM

Rm

easu

rem

entsa

ndth

esi

mul

atio

n.O

utflo

wve

loci

tiesa

tth

eao

rtic

outfl

owtr

acta

resh

own

inF

igur

e5.

5.T

hem

atch

ingo

fth

esi

mul

atio

nan

dM

Rda

tapl

aced

the

R-p

eaki

nth

eE

CG

ofth

eM

Rda

taat

1.48

6s

and

this

isin

dica

tedb

ya

vert

ical

dash

edlin

ein

Fig

ures

5.4

and

5.5.

Fig

ure

5.4

show

sth

atat

the

mitr

alrin

gth

ere

isa

reas

onab

leagr

eem

entb

e-tw

een

MR

data

and

sim

ulat

ion

resu

ltsfo

rbo

thth

ece

ntre

and

the

mea

nvel

ocity

inth

ebe

ginn

ing

ofth

ehe

artc

ycle

durin

gea

rlyfil

ling,

but

the

early

max

imum

(pea

kE)v

eloc

ityis

high

erin

the

MR

data

than

inth

esi

mul

atio

n(f

orbo

thm

ean

and

cent

reva

lues

).It

isob

tain

edat

the

sam

etim

ebe

caus

eof

the

mat

chin

gof

sim

ulat

ion

and

MR

data

.The

upst

roke

ofth

eE

peak

ofth

esi

mul

atio

nre

sults

isve

rysi

mila

r,w

hile

the

dow

nstr

oke

isfa

ster

for

the

mea

ntha

nth

ece

ntre

velo

city

,bu

tbot

hth

eup

stro

kean

dth

edo

wns

trok

em

atch

the

MR

data

fairl

yw

ell.

The

MR

data

show

sne

gativ

eflo

wve

loci

tybe

twee

nthe

Epe

akan

dth

eA

peak

,and

this

isno

tsee

nin

the

sim

ulat

ion.

On

the

cont

rary,

the

sim

ulat

ion

show

sa

forw

ard

peak

.Thi

sco

uld

bedu

eto

anin

corr

ectm

ovem

ento

fth

em

itral

valv

ele

aflet

sin

the

sim

ulat

ion,

whi

chm

ight

beca

used

byth

eth

ree

vent

ricul

arvo

rtic

es,b

ecau

seth

evo

rtic

esaf

fect

the

mitr

alva

lve

mov

emen

t.B

utth

em

itral

valv

em

ovem

entis

diffi

cult

toju

dge

sinc

eit

isno

tdet

ecte

dinth

eM

Rm

easu

rem

ents

.Alte

rnat

ivel

y,th

epe

akco

uld

beca

used

byan

inco

rrec

tact

ivat

ion

leve

loft

hem

uscl

emod

el(s

eeS

ectio

n3.3

.6).

The

Ape

akin

the

mitr

alin

flow

isca

used

byth

eon

seto

fatr

ials

ysto

le.A

tria

lsy

stol

ecan

beha

rdto

dete

ctin

the

MR

mea

sure

men

ts,be

caus

eitoc

curs

atth

een

d

5.3

Vel

ocity

time

profi

les

87

200

400

600

800

Time [msec]

-0.4

-0.20

0.2

0.4

0.6

Velocity [m/s]

Ventricular inflow - mitral valve

11.2

1.4

1.6

1.8

t[s]

-0.4

-0.20

0.2

0.4

0.6

velocity[m/s]

Fig

ure

5.4:

Vel

ocity

time

profi

lefo

rve

loci

ty(m

/s)

over

the

mitr

alrin

gfr

omM

Rda

ta(t

op)

and

from

sim

ulat

ion

(bot

tom

).F

rom

the

sim

ulat

ion

both

cent

re(d

ashe

d)an

dm

ean(

solid

)vel

ocity

isin

clud

ed.

ofea

chM

Rre

cord

ing.

The

last

part

ofan

MR

reco

rdin

gwill

besm

eare

dout

be-

caus

ethe

final

mea

sure

men

tisan

aver

ageo

ver7

68he

artb

eats

whi

chea

chm

ight

vary

inhe

artc

ycle

leng

th.T

his

cane

xpla

inw

hyth

epe

akA

velo

city

(thi

rdpe

akin

the

sim

ulat

ion

curv

es)i

sm

uch

high

erin

the

sim

ulat

ion

than

inth

eM

Rda

ta.A

sse

enin

Fig

ure

5.4,

the

sim

ulat

ions

how

sa

clea

ratr

ials

ysto

le.A

lthou

ghth

em

ea-

sure

men

tssho

won

lya

very

vagu

eatr

ials

ysto

le,th

isoc

curs

atap

prox

imat

elyt

hesa

met

ime

inth

esi

mul

atio

nand

MR

mea

sure

men

ts,co

nfirm

ing

the

timin

gof

the

atria

lsys

tole

inth

em

odel

.The

MR

data

show

noba

ckflo

wat

the

time

ofcl

osur

eof

the

mitr

alva

lve

(bet

wee

n1.4

94an

d1.5

30s)

,in

cont

rast

tobo

thve

loci

tiesf

rom

the

sim

ulat

ion.

Thi

sco

uld

bea

cons

eque

nceof

the

aver

agin

goft

heM

Rda

ta,o

rit

coul

dbe

caus

edby

the

coar

setim

ere

solu

tioni

nth

eM

Rm

easu

rem

ents

.Inot

her

Page 54: MR · 2002. 2. 20. · Adeler A TV Erhver vsf or skerpr ojekt EF 698 IMM-PHD-2001-86 ISSN 0909-3192 ISBN 87-88306-13-5 c 2001 by Pernille Thorup Adeler Printed by IMM, DTU Bookbinder

88C

ompa

ring

the

2Dm

odel

with

anM

Rda

tase

t

MR

mea

sure

men

ts(not

show

n)th

isdi

spla

cem

entba

ckflo

wha

sbee

ncle

arly

seen

.F

igur

e5.

5sh

ows

the

velo

city

time

profi

leac

ross

the

aort

icou

tflow

trac

tfro

mbo

thth

eM

Rda

taan

dth

esi

mul

atio

n.It

isse

enth

atth

eou

tflow

thro

ught

heao

rtic

trac

tsta

rtsa

tapp

roxi

mat

elyt

hesa

met

ime

inth

eM

Rda

taan

dth

esi

mul

atio

n(f

orbo

thve

loci

tiesr

epor

ted)

.Thu

swe

can

conc

lude

that

the

onse

tofv

entr

icul

arsy

stol

ein

the

sim

ulat

ion

isco

rrec

t.T

hefo

rmof

the

curv

eis

muc

hw

ider

for

the

MR

data

,but

the

outfl

owth

roug

hth

etr

acte

ndsa

tapp

roxi

mat

elyt

hesa

me

time

inbo

thth

eM

Rda

taan

dth

esi

mul

atio

n.T

hem

axim

umou

tflow

velo

city

isob

tain

edea

rlier

inth

esi

mul

atio

nth

anin

the

MR

data

,sug

gest

ingt

hatt

heon

set

ofve

ntric

ular

dias

tole

coul

dbe

furt

heri

mpr

oved

.

200

400

600

800

Time [msec]

-0.20

0.2

0.4

0.6

0.81

Velocity [m/s]

Ventricular outflow - aortic valve

11.2

1.4

1.6

1.8

t[s]

0

0.2

0.4

0.6

0.81

velocity[m/s]

Fig

ure

5.5:

Vel

ocity

time

profi

lefo

rve

loci

ty(m

/s)a

cros

sthe

aort

icou

tflow

trac

tfr

omM

Rda

ta(t

op)

and

from

sim

ulat

ion

(bot

tom

).F

rom

the

sim

ulat

ion

both

cent

re(d

ashe

d)an

dm

ean(

solid

)vel

ocity

isin

clud

ed.

5.4

Dis

cuss

iona

ndco

nclu

sion

s89

Apr

imar

yef

fect

ofth

eus

eoft

heW

indk

esse

lmod

elis

that

we

obta

ina

sim

u-la

ted

aort

icou

tflow

profi

lew

hich

repr

oduc

esa

char

acte

ristic

feat

ureo

fth

em

ea-

sure

done

,nam

elyt

hatt

heup

stro

keha

sadu

ratio

nofa

bout

one

half

ofth

atof

the

dow

nstr

oke.

As

men

tione

dabo

ve,t

heac

tual

shap

eoft

hesi

mul

ated

outfl

owcu

rve

does

note

xact

lym

atch

the

mea

sure

done

.Fur

ther

adju

stm

ento

fthe

load

para

m-

eter

smig

htac

hiev

ea

bette

ragr

eem

ent,b

utth

em

uscu

larm

odel

behi

ndth

ehe

art

mod

elis

also

invo

lved

inth

esi

mul

ated

profi

lean

dthe

refo

resh

ould

bein

volv

edin

the

tuni

ngpr

oces

sasw

ell.

Itw

asal

sofo

und

that

the

shap

eoft

heou

tflow

profi

lew

asse

nsitiv

eto

the

stre

ngth

and

geom

etry

ofth

ete

ther

ing.

Itsh

ould

beno

tedt

hati

nth

epr

evio

usly

repo

rted

com

paris

onsb

etw

eenm

odel

and

MR

data

(Jac

obse

neta

l.,20

01;A

dele

rand

Jaco

bsen

,2001

)res

ults

from

the

first

hear

tcyc

lew

ere

com

pare

dwith

the

MR

data

and

seve

ralo

fth

epa

ram

eter

sw

ere

adju

sted

toac

hiev

ea

good

com

paris

onbe

twee

nthe

first

hear

tcyc

lean

dth

eM

Rda

ta.W

hen

we

late

rinv

estig

ated

whi

chhe

artc

ycle

best

repr

esen

tsape

riodi

cre

sultf

rom

the

mod

el(s

eeS

ectio

n4.7

),w

edi

dno

tcha

nget

hepa

ram

eter

setti

ngs

fort

hem

odel

,and

this

expl

ains

why

the

com

paris

onpr

esen

tedh

erei

sno

tasg

ood

asth

eon

ew

eha

vepr

evio

usly

repo

rted

.The

mod

elco

uld

befu

rthe

radj

uste

dto

mak

eth

ese

cond

hear

tcyc

lebe

tterc

ompa

redto

MR

data

.Unf

ortu

nate

ly,tim

eha

sno

tallo

wed

usto

doth

is.

5.4

Dis

cuss

iona

ndco

nclu

sion

s

The

com

paris

onof

the

velo

city

field

sfro

mth

eM

Rm

easu

rem

entsa

ndth

esi

mul

a-tio

nsh

ows

afa

irqu

alita

tive

agre

emen

tinth

ege

nera

lflow

patte

rn:a

wid

ein

flow

jet,

the

form

atio

nof

ado

min

anta

nter

iorv

orte

xfil

ling

the

vent

ricle

,and

anou

t-flo

wje

tin

the

aort

icou

tflow

trac

t.A

diff

eren

cein

velo

city

field

sis

seen

inth

ew

idth

ofth

ein

flow

jet(

from

atriu

mto

vent

ricle

)and

inth

esi

zeof

the

vent

ricle

.C

ompa

rison

ofth

evo

rtex

patte

rnsin

the

mid

dias

tolic

phas

ecou

ldin

dica

teth

ata

mor

eco

mpl

ex3D

flow

patte

rnis

pres

entin

the

mea

sure

dven

tric

leth

anth

atpr

e-di

cted

from

the

sim

ple

2Dm

odel

.Thi

sis

supp

orte

dby

resu

ltsfr

omth

e3D

mod

elpr

esen

tedin

Cha

pter

7.In

the

3Dm

odel

we

seet

hata

vort

exrin

gis

form

eddu

r-in

gfil

ling

(see

Fig

ure

7.6)

,and

whe

nlo

okin

gat

this

vort

exrin

gin

acu

t-aw

ayvi

ew(F

igur

e7.

7)it

hast

hesh

apeo

ftw

ovo

rtic

es,s

imila

rto

thos

esee

nin

the

2Dm

odel

.Fur

ther

,the

sim

ulat

ion

show

sth

ree

vort

ices

inth

eve

ntric

le,w

here

asth

eM

Rda

tash

ows

atm

ostt

wo.

The

third

vort

exis

are

sult

ofth

evo

rtex

inth

epr

e-vi

ous

hear

tcyc

leno

tbei

ngde

stroy

edbe

fore

the

onse

tofd

iast

ole.

Inth

eM

Rda

tano

vort

exis

pres

enta

tthe

end

ofa

hear

tcyc

le.T

heth

irdvo

rtex

inth

esi

mul

atio

nis

unph

ysio

logi

cal,a

ndit

wou

ldim

prov

eth

em

odel

cons

ider

ably

ifit

coul

dbe

Page 55: MR · 2002. 2. 20. · Adeler A TV Erhver vsf or skerpr ojekt EF 698 IMM-PHD-2001-86 ISSN 0909-3192 ISBN 87-88306-13-5 c 2001 by Pernille Thorup Adeler Printed by IMM, DTU Bookbinder

90C

ompa

ring

the

2Dm

odel

with

anM

Rda

tase

t

rem

oved

.Rem

ovin

gth

isvo

rtex

mig

htim

prov

eth

em

ovem

ento

fthe

mitr

alva

lve

and

cons

eque

ntlya

lso

rem

ove

the

third

peak

inm

itral

velo

city

profi

le.

Gen

eral

ly,w

ese

eth

atth

evo

rtex

patte

rnis

mor

edi

stin

ctin

the

sim

ulat

ion

and

the

velo

citie

sin

the

vort

ices

are

larg

er.

Thi

sis

part

lyre

late

dto

the

form

ofth

eve

ntric

lean

dth

em

itral

valv

em

otio

nin

the

sim

ulat

ion.

Bec

ause

the

mod

elis

2D,v

entr

icul

arex

pans

ionh

asto

take

plac

ein

the

cons

ider

edpl

ane,

resu

lting

inan

over

size

vent

ricle

.F

urth

erm

ore,

the

vent

ricle

isst

illto

oci

rcul

arin

form

,ev

enth

ough

we

have

impr

oved

this

byad

just

ing

the

cros

slin

ks.

The

mot

ion

ofth

em

itral

valv

eis

notc

ompl

etel

yco

rrec

t;it

shou

ldop

enup

mor

ean

dth

epo

ster

iorl

eafle

tsho

uld

actu

ally

touc

hth

epo

ster

iorv

entr

icul

arw

all.

The

latte

rw

ould

prob

ably

prev

entt

hefo

rmat

ion

ofth

epo

ster

iorv

orte

x.T

heflo

wfie

lds

from

the

sim

ulat

ion

are

affe

cted

byth

esi

mpl

eao

rtic

valv

e(d

iode

coup

ledt

osi

nk),

resu

lting

inth

efo

rmat

ion

ofa

vort

exat

the

sink

,whi

chof

cour

seis

nots

eeni

nth

eM

Rda

ta.

Fur

ther

mor

e,th

ete

ther

ing

ofth

em

odel

hear

tintr

oduc

esos

cilla

tions

inbo

thth

eat

rium

and

the

vent

ricle

and

this

affe

cts

the

flow

field

inan

unph

ysio

logi

calw

ay.

The

time

ofat

rials

ysto

lese

emsto

bese

trea

sona

blyw

elli

nth

em

odel

,but

this

isdi

fficu

ltto

judg

ebe

caus

eof

the

very

vagu

eatr

ials

ysto

lein

the

MR

data

.The

onse

tof

vent

ricul

arsy

stol

esee

mst

obe

right

,whi

leit

wou

ldpr

obab

lyim

prov

eth

em

odel

ifth

edu

ratio

nof

vent

ricul

arsy

stol

ewas

exte

nded

,thus

lead

ing

toa

late

rons

etof

vent

ricul

ardi

asto

le.

The

velo

city

profi

lesa

tthe

mitr

alrin

gan

daor

ticou

tflow

trac

tfro

msi

mul

atio

nan

dMR

mea

sure

men

tsmat

chre

ason

ablyw

ell.

The

timin

gof

the

velo

city

profi

les

isin

good

agre

emen

t,whe

reas

the

shap

eand

max

imum

valu

esof

the

velo

city

curv

essh

owso

med

iffer

ence

.The

best

agre

emen

tfor

the

mitr

alve

loci

typr

ofile

isin

the

begi

nnin

gof

the

hear

tcyc

le,w

hile

the

best

agre

emen

tfor

the

aort

icpr

ofile

isfr

omth

ebe

ginn

ing

until

max

imum

outfl

owve

loci

ty.

The

depe

nden

ceof

the

sim

ulat

edre

sults

onth

eva

rious

para

met

ersin

the

mod

elis

very

com

plex

,and

we

ares

uret

hata

furt

hera

djus

tmen

tofth

epa

ram

eter

sco

uld

lead

toan

even

bette

ragr

eem

entbe

twee

nsim

ulat

edan

dm

easu

redv

eloc

-ity

data

.Pa

ram

eter

sof

part

icul

arim

port

ance

inth

isre

gard

are

the

dura

tion

ofve

ntric

ular

syst

ole,

the

exci

tatio

nan

dre

laxa

tionp

aram

eter

s,and

the

Win

dkes

sel

and

mus

clep

aram

eter

s.How

ever

,the

com

paris

onsh

ows

that

desp

iteth

ege

omet

-ric

alco

nstr

aint

spos

edby

the

2Dm

odel

ling

ofa

3Dph

enom

enon

,are

ason

able

agre

emen

tisob

tain

edbe

twee

nsim

ulat

edan

dm

easu

redre

sults

.T

heco

mpa

rison

supp

ortst

heco

ncep

tofc

ombi

neds

imul

atio

nand

MR

stud

ies

toin

vest

igat

ethe

flow

inth

ehe

arta

ndits

inte

ract

ionw

ithth

est

ruct

urea

ndfu

nc-

tion

ofhe

artm

uscl

esan

dhe

artv

alve

s,pr

ovid

edth

atth

elim

itsof

the

mod

elar

eke

ptin

min

d.T

hede

taile

dflow

insi

deth

ehe

arts

houl

dnot

beus

edfo

rin

vest

iga-

5.4

Dis

cuss

iona

ndco

nclu

sion

s91

tions

befo

reth

em

odel

isim

prov

ed,e

spec

ially

with

resp

ectto

the

vort

expa

ttern

.B

ased

onth

eco

mpa

rison

betw

eent

hem

itral

velo

city

profi

les,

itis

just

ified

tous

eth

em

odel

toin

vest

igat

ethe

early

fillin

gof

the

vent

ricle

,par

ticul

arly

the

influ

ence

onth

em

itral

velo

city

profi

le.I

nves

tigat

ions

invo

lvin

gth

eao

rtic

outfl

owve

loci

typr

ofile

sw

ould

also

beju

stifi

ed.

Exp

erim

ents

invo

lvin

gth

eov

eral

lres

pons

eof

the

hear

tto

diff

eren

tsce

nario

sisye

tano

ther

poss

ibili

ty,e

.g.h

owdo

esth

ehe

art

reac

tto

anin

crea

sedr

esis

tanc

einth

eou

tflow

,w

hath

appe

nsif

part

ofth

eve

n-tr

icul

arw

allg

row

sst

iffer

orw

hata

reth

eco

nseq

uenc

esofa

decr

ease

inpa

pilla

rym

uscl

ete

nsio

n?In

answ

erin

gthe

sequ

estio

nson

esh

ould

note

xpec

tto

obta

inth

eco

mpl

etefl

owfie

ldin

side

the

hear

t,but

rath

ersu

chqu

antit

iesa

sth

eca

rdia

cou

tput

,the

form

ofth

eou

tflow

velo

city

profi

le,o

rth

ein

fluen

ceon

the

fillin

gof

the

vent

ricle

.

Page 56: MR · 2002. 2. 20. · Adeler A TV Erhver vsf or skerpr ojekt EF 698 IMM-PHD-2001-86 ISSN 0909-3192 ISBN 87-88306-13-5 c 2001 by Pernille Thorup Adeler Printed by IMM, DTU Bookbinder

Cha

pter

6

Sim

ulat

ing

path

olog

ical

hear

tco

nditi

ons

An

impo

rtan

tpur

pose

ofou

rw

ork

with

the

2Dm

odel

isto

use

itto

stud

yth

ein

fluen

ceof

path

olog

ical

cond

ition

sin

the

hear

t,sp

ecifi

cally

cond

ition

swhi

chca

nbe

rela

tedt

oth

em

echa

nica

lactiv

atio

nof

the

hear

tmus

cle.

The

bloo

dflo

wpa

ttern

chan

gesw

hen

apa

tient

suffe

rsfr

oma

hear

tdis

ease

,re

sulti

ngin

e.g.

ade

crea

sein

the

ejec

tion

frac

tion

ora

redu

cedfi

lling

velo

city

.M

echa

nism

sinvo

lved

inhe

artd

isea

sesh

ave

been

inve

stig

ated

byth

eus

eof

dif-

fere

ntm

easu

ringte

chni

ques

(one

ofth

embe

ingM

R).

Thi

sha

sled

toth

ede

finiti

onof

inde

xeso

fthe

bloo

dve

loci

tyto

char

acte

rizeth

ele

ftve

ntric

ular

dias

tolic

func

-tio

n.S

ever

alst

udie

shav

efo

cuse

don

the

early

dias

tolic

fillin

g,an

dsi

ncew

eha

vefo

und

are

ason

ablyg

ood

com

paris

onbe

twee

nthe

mod

elan

dM

Rda

tain

exac

tlyth

eea

rlyfil

ling

phas

e,th

em

echa

nism

sresp

onsi

blefo

rth

ech

ange

inflo

wpa

ttern

and

the

velo

city

inde

xes

can

best

udie

din

the

com

pute

rmod

el.H

owev

er,t

obe

able

tosi

mul

atep

atho

logi

calc

ondi

tions

,itis

nece

ssar

yfirs

tto

refin

eth

em

odel

for

the

activ

atio

nof

the

hear

tmus

cle.

The

impr

oved

mod

elca

nth

enbe

used

tost

udys

omeg

ener

alm

echa

nism

sinvo

lved

inhe

artd

isea

ses.

Thi

sch

apte

rbeg

ins

with

the

med

ical

back

grou

ndfo

rim

prov

ing

the

mod

elfo

rth

eac

tivat

ion

ofth

ehe

artm

uscl

ean

dde

scrib

esth

eim

plem

enta

tiono

fth

eim

prov

edac

tivat

ion

func

tion.

The

mod

elpa

ram

eter

sare

then

setu

pto

sim

ulat

ea

heal

thy

hum

an.

Usi

ngth

esem

odel

para

met

ersw

em

ake

anin

vest

igat

iono

fso

meo

fthe

mec

hani

smsin

volv

edin

hear

tdis

ease

sand

com

pare

sim

ulat

ions

ofa

dise

ased

hear

twith

MR

mea

sure

men

ts.

Page 57: MR · 2002. 2. 20. · Adeler A TV Erhver vsf or skerpr ojekt EF 698 IMM-PHD-2001-86 ISSN 0909-3192 ISBN 87-88306-13-5 c 2001 by Pernille Thorup Adeler Printed by IMM, DTU Bookbinder

94S

imul

atin

gpa

thol

ogic

alhe

artc

ondi

tions

6.1

Med

ical

back

grou

nd

Inm

osth

eart

dise

ases

dias

tolic

dysf

unct

iono

ften

coex

ists

with

syst

olic

dysf

unc-

tion.

The

asse

ssm

entof

dias

tolic

func

tion,

or,m

ore

prec

isel

y,th

eas

sess

men

tofle

ftve

ntric

ular

dias

tolic

func

tion,

hasb

eeng

iven

muc

hatte

ntio

n(H

oulin

d,20

01b;

Nis

hiha

raet

al.,

2000

;Oht

eeta

l.,19

99;S

tein

eeta

l.,19

99;S

tuga

arde

tal.,

1994

a;S

tuga

arde

tal.,

1994

b;S

tuga

arde

tal.,

1993

;Yam

amot

oeta

l.,19

95;S

t.G

oar

etal

.,19

91).

As

are

sults

ofre

cent

prog

ress

the

intr

aven

tric

ular

bloo

dflo

wpa

t-te

rnan

dde

rived

bloo

dve

loci

tyin

dexe

scan

now

beus

edto

eval

uate

the

stat

eof

the

dias

tolic

func

tion.

The

intr

aven

tric

ular

bloo

dflo

wpa

ttern

chan

gesin

adi

s-ea

sedh

eart

,but

atpr

esen

tthe

mec

hani

smsre

spon

sibl

efor

this

chan

gear

eno

tco

mpl

etel

yund

erst

ood.

The

com

pute

rmod

elis

ato

olfo

rst

udyi

ngth

esem

echa

-ni

sms.

The

dias

tolic

func

tion

can

beev

alua

tede

.g.b

ym

easu

ringt

hepr

essu

re,th

ew

allt

hick

ness

,the

wal

lmot

ion

orth

ebl

ood

flow

/vel

ocity

.Nat

ural

ly,w

eha

vefo

-cu

sedo

nco

mpa

ringt

hem

odel

with

stud

ieso

fthe

dias

tolic

func

tion

that

areb

ased

onth

ebl

ood

flow

patte

rnor

bloo

dflo

wve

loci

ty.T

hese

stud

iesa

repe

rfor

med

us-

ing

MR

Ior

echo

card

iogr

aphy(

e.g.

colo

urM

-mod

eD

oppl

erte

chni

que)

.We

look

atth

ege

nera

lflow

patte

rndu

ring

early

fillin

gan

dw

eco

mpa

reco

mpu

teda

ndob

serve

dve

loci

tyin

dexe

sder

ived

from

the

intr

aven

tric

ular

velo

city

field

.

6.1.

1M

echa

nism

sdur

ing

early

fillin

g

Inth

eno

rmal

stat

eofe

arly

left

vent

ricul

arfil

ling,

the

rapi

dle

ftve

ntric

ular

rela

x-at

ion

gene

rate

sapr

essu

regr

adie

ntin

the

left

vent

ricle

with

the

high

estp

ress

ure

atth

eba

sean

dth

elo

wes

tpre

ssur

eat

the

apex

.T

hepr

essu

regr

adie

ntdr

ives

the

bloo

den

terin

gatt

hem

itral

valv

eto

war

dth

eap

exof

the

vent

ricle

(Hou

lind

etal

.,20

01).

Inth

edi

seas

edhe

artw

ithdi

asto

licdy

sfun

ctio

nthe

left

vent

ricul

arre

laxa

tioni

ssl

owed

and

the

intr

aven

tric

ular

pres

sure

grad

ient

isre

duce

d(se

ee.g

.S

tein

eeta

l.,19

99).

So,

regi

onal

diff

eren

cesin

rela

xatio

nrat

eaf

fect

the

early

di-

asto

licfu

nctio

n.T

here

duce

dint

rave

ntric

ular

pres

sure

grad

ient

tend

sto

caus

easl

ower

prop

agat

iono

fthe

bloo

dflo

win

toth

eve

ntric

le(H

oulin

det

al.,

2001

).

6.1.

2P

atho

logi

calh

eart

cond

ition

s

The

reex

ists

ever

alst

udie

soft

hedi

asto

licfu

nctio

n,co

verin

ga

rang

eofh

eart

dis-

ease

s,tha

tpro

vide

data

that

canb

eus

edto

dete

rmin

eapp

ropr

iatei

nput

para

met

ers

toth

em

odel

and

toco

mpa

rew

ithsi

mul

atio

nre

sults

.Thi

sse

ctio

ngiv

esa

brie

fde

scrip

tiono

fso

mei

mpo

rtan

thea

rtdi

seas

esan

dth

eiri

nflue

nceo

nth

edi

asto

lic

6.1

Med

ical

back

grou

nd95

func

tion.

Isch

emic

hear

tdis

ease

isa

com

mon

term

fori

nade

quat

eblo

odsu

pply

toan

area

ofth

ehe

artw

all.

Ifth

isis

due

tobl

ocka

geof

the

coro

nary

arte

riesi

tis

calle

dco

rona

ryar

tery

dise

ase,

seeb

elow

.Is

chem

iaca

nbe

both

loca

land

glob

al.I

nth

eca

seof

glob

alis

chem

iath

efil

ling

ofth

eve

ntric

leis

dela

yed

(Stu

gaar

deta

l.,19

94b)

.Loc

alis

chem

iais

ofte

nse

enin

anac

utei

nfar

ctio

n(K

im,

2001

),se

e’A

cute

myo

card

ialin

farc

tion’

belo

w.

Cor

onar

yar

tery

dise

ase(

CA

D)

isth

ena

rrow

ing

ofth

eco

rona

ryar

terie

sca

used

byat

hero

scle

rosi

s.Aco

rona

ryar

tery

isan

arte

ryth

atsu

pplie

sbl

ood

toth

ehe

artm

uscl

e.R

elax

atio

nis

ofte

npr

olon

gedd

urin

gth

isill

ness

(Wei

sset

al.,

1976

;Oht

eet

al.,

1999

)and

the

fillin

gof

the

vent

ricle

isde

laye

d(S

tuga

arde

tal.,

1994

a;S

tuga

arde

tal.,

1993

).

Acu

tem

yoca

rdia

linf

arct

ion

(AM

I),o

ften

refe

rred

toas

ahe

arta

ttack

,isth

ede

ath

ofpa

rtof

the

hear

tmus

cle

due

toa

sudd

enlo

ssof

bloo

dsu

pply.

The

loss

ofbl

ood

supp

lyis

caus

edby

the

com

plet

eblo

ckag

eof

aco

rona

ryar

tery

bya

bloo

dcl

ot.

AM

Iaf

fect

sthe

mot

ion

and

the

rela

xatio

noft

hedi

seas

edpa

rtof

the

hear

twal

l.Ty

pica

lly,t

hem

otio

nof

the

hear

twal

lis

abno

rmal

and

both

the

rela

xatio

nand

the

fillin

gof

the

vent

ricle

isde

laye

d(S

tein

eeta

l.,19

99).

Fur

ther

mor

e,lo

wer

fillin

gpe

akve

loci

ties

are

seen

(Ste

ine

etal

.,19

99;H

oulin

det

al.,

2001

).

Car

diom

yopa

thy

isa

gene

ralte

rmfo

ra

dise

aseo

fth

ehe

artm

uscl

e(t

hem

y-oc

ardi

um).

Hyp

ertr

ophi

cca

rdio

myo

path

y(H

CM

)is

char

acte

rized

byin

crea

sed

grow

th(h

yper

trop

hy)in

the

thic

knes

sof

the

left

vent

ricul

arw

all.

Inth

isca

seth

eej

ectio

nfr

actio

n(s

eeS

ectio

n2.2

)is

ofte

nno

taffe

cted

,bu

tthe

rela

xatio

nis

prol

onge

d(N

ishi

hara

etal

.,20

00).

Dila

ted

card

iom

yopa

thy

(DC

M)

isch

arac

teriz

edby

adi

late

dve

ntric

le.

Thi

sis

ofte

nse

enin

chro

nic

hear

tfai

lure

,whe

rea

glob

aldi

latio

nof

the

vent

ricle

ispr

esen

tand

the

rela

xatio

nis

abno

rmal

(Kim

,200

1).I

nth

eca

seof

DC

Mth

eej

ectio

nfr

actio

nis

decr

ease

dand

the

fillin

gof

the

vent

ricle

isab

norm

al(H

oulin

d,20

01a;

Yam

amot

oeta

l.,19

95;S

t.G

oare

tal.,

1991

).It

isno

tcle

arw

heth

erth

eab

norm

alfil

ling

isca

used

bydi

asto

licor

syst

olic

dysf

unct

iono

fthe

vent

ricle

(Yam

amot

oeta

l.,19

95).

Page 58: MR · 2002. 2. 20. · Adeler A TV Erhver vsf or skerpr ojekt EF 698 IMM-PHD-2001-86 ISSN 0909-3192 ISBN 87-88306-13-5 c 2001 by Pernille Thorup Adeler Printed by IMM, DTU Bookbinder

96S

imul

atin

gpa

thol

ogic

alhe

artc

ondi

tions

6.1.

3V

eloc

ityin

dexe

s

The

dias

tolic

func

tion

can

bede

term

ined

byin

vest

igat

ing(

spat

ial)

velo

city

pro-

files

alon

glin

esac

ross

the

left

vent

ricle

,i.e.

velo

city

profi

lesa

long

lines

perp

en-

dicu

lart

oth

elo

ngax

isof

the

vent

ricle

,atd

iffer

entt

imes

durin

gth

eea

rlyin

flow

.T

his

has

been

done

usin

gbo

thM

RI

(Hou

lind

etal

.,20

01)a

ndpu

lsed

Dop

pler

echo

card

iogr

aphy

(Ste

ine

etal

.,19

99;Y

amam

otoe

tal.,

1995

).Ty

pica

lly3-

6lin

esar

eex

amin

ed.

We

pres

enth

ere

the

met

hodo

fH

oulin

det

al.(

2001

),w

here

six

lines

are

ex-

amin

eddu

ring

anM

Rsc

an.O

nelin

eis

plac

edat

the

leve

lof

the

mitr

alle

aflet

tips

(ML

T)

perp

endi

cula

rtoth

ein

flow

jet.

The

othe

rlin

esar

epl

aced

para

llelt

oth

efir

stlin

ebu

tdis

plac

edei

ther

upst

ream

ordo

wns

trea

mof

the

first

:on

elin

eis

plac

ed2

cmup

stre

am(a

ppro

xim

atel

yatt

hele

velo

fthe

mitr

alrin

g),a

ndlin

esar

epl

aced

1,2,

3an

d4

cmdo

wns

trea

m.T

hese

lines

are

fixed

insp

acea

nddo

not

mov

ew

ithth

ehe

art.

Thi

sis

acce

ptab

lebec

ause

the

mot

ion

ofth

ehe

artis

smal

ldu

ring

dias

tole

.Alo

ngea

chof

thes

elin

esth

eab

solu

teve

loci

tyis

com

pute

dbas

edon

allt

hree

velo

city

com

pone

nts,a

ndth

esp

atia

lvel

ocity

profi

leis

plot

ted.

The

inflo

wje

tis

man

ually

trac

edan

dal

lvel

ociti

esou

tsid

ethe

jeta

rese

tto

zero

.The

velo

city

profi

lesa

reex

amin

edat

5tim

es:t

hetim

eof

Epe

akve

loci

tyat

the

mitr

alle

aflet

tips,

the

time

fram

eprio

rto

this

,and

the

thre

esub

sequ

enttim

efr

ames

.The

time

diff

eren

cebe

twee

nsuc

ceed

ingti

me

fram

esar

eof

the

orde

rof2

5m

s.F

rom

the

velo

city

profi

lest

hree

quan

titie

scan

bede

rived

that

char

acte

rizeth

eve

ntric

ular

dias

tolic

func

tion

(Hou

lind

etal

.,20

01).

The

sear

eth

epe

akve

loc-

ity(P

V),

the

velo

city

inde

x(V

I),

and

the

time

dela

y(T

D).

PV

isth

em

axim

umve

loci

ty(in

both

spac

eand

time)

ata

part

icul

arlin

e.V

Ifo

ra

part

icul

arlin

eis

com

pute

das

the

PV

atth

atlin

ere

lativ

eto

the

PV

atth

elin

eat

the

mitr

alle

aflet

tips.

Fin

ally

,TD

isca

lcul

ated

asth

etim

edi

ffer

ence

betw

eent

ime

ofoc

curr

ence

ofP

Vin

apa

rtic

ular

line

and

time

ofoc

curr

ence

ofP

Vat

the

line

atth

em

itral

leafl

ettip

s.F

igur

e6.1

show

sth

eve

loci

typr

ofile

sfro

ma

heal

thyp

erso

nalo

ngth

esi

xlin

esat

five

times

:27

ms

befo

reP

Vat

the

mitr

alle

aflet

tips,

atth

etim

eof

PV

atth

em

itral

leafl

ettip

s,an

d27

,54

and

81m

saf

tert

hetim

eof

PV

atth

em

itral

leafl

ettip

s.It

isse

enth

atth

eve

loci

typr

ofile

sar

ew

ider

and

low

erfo

rth

elin

escl

oses

tto

the

apex

(the

2,3

and

4cm

lines

).F

urth

erm

ore,

the

figur

esh

ows

that

PV

isob

tain

edal

mos

tatt

hesa

met

ime

atal

lthe

lines

.In

Hou

lind

etal

.(20

01)P

V,V

Ian

dTD

areg

iven

fora

grou

pofh

ealth

yper

sons

and

for

agr

oup

ofA

MI

patie

nts.

Fig

ure

6.2

show

sth

eP

Vat

the

six

lines

from

the

heal

thyg

roup

and

the

AM

Igr

oup.

The

data

are

plot

ted

asth

em

eanv

alue

sw

ithth

est

anda

rdde

viat

ion

show

nas

erro

rbar

s.F

rom

this

figur

eit

iscl

eart

hat

6.1

Med

ical

back

grou

nd97

+4

+3

+2

+1

ML

T -2

-27

ms

PV

ÑÒÓ

27m

s54

ms

81m

s

Fig

ure6

.1:V

eloc

itypr

ofile

sofa

bsol

utev

eloc

ity(m

/s)a

long

six

lines

atfiv

etim

esfr

oma

heal

thyp

erso

nobt

aine

dby

MR

I.P

eakv

eloc

ityin

each

mea

surin

gpos

ition

ism

arke

dby

a

Ô .From

Hou

lind

etal

.(20

01).

the

peak

velo

city

atal

llin

esar

elo

wer

inan

AM

Ipa

tient

than

ina

heal

thyp

erso

n.P

Vis

only

sign

ifica

ntly

low

er(f

rom

ast

atis

tical

poin

tofv

iew

)at

the

3an

d4

cmlin

es(H

oulin

det

al.,

2001

).F

igur

e6.

3sh

ows

the

velo

city

inde

x,V

I,at

the

six

lines

from

the

heal

thya

ndth

eA

MI

grou

p.T

hefig

ure

show

sth

atcl

oset

oth

eap

ex(a

tthe

3an

d4

cmlin

es)

VI

islo

wer

inth

eA

MI

patie

ntst

han

for

the

heal

thyg

roup

.In

Fig

ure

6.4

the

time

dela

y,T

D,

atth

esi

xlin

esis

show

n.T

Dis

mar

kedl

yhi

gher

clos

erto

the

apex

(att

he3

and

4cm

lines

)for

the

AM

Igr

oup

than

for

the

heal

thyg

roup

.All

thes

efig

ures

(Fig

ures

6.1–

6.4)

show

that

inA

MI

patie

ntst

hefil

ling

patte

rndu

ring

early

dias

tole

inth

elo

wer

part

ofth

eve

ntric

leis

chan

gedc

ompa

redto

heal

thyp

erso

ns:

the

fillin

gis

dela

yed,

peak

velo

citie

sare

low

eran

dth

epe

akve

loci

tyat

ML

Tis

notm

aint

aine

ddow

nstr

eam

ofM

LT.

Page 59: MR · 2002. 2. 20. · Adeler A TV Erhver vsf or skerpr ojekt EF 698 IMM-PHD-2001-86 ISSN 0909-3192 ISBN 87-88306-13-5 c 2001 by Pernille Thorup Adeler Printed by IMM, DTU Bookbinder

98S

imul

atin

gpa

thol

ogic

alhe

artc

ondi

tions

-2

01

23

4Distance

from

MLT

[cm]

0.2

0.4

0.6

0.81

PV[m/s]

MR

healthy

MR

AMI

Fig

ure

6.2:

Pea

kve

loci

ty(P

V)

atsi

xlin

esfr

omM

Rm

easu

rem

entso

fhe

alth

yper

sons

(

Õ )an

dA

MI

patie

nts

(

Ö ).D

ataa

resh

own

asth

em

eanv

alue

with

the

stan

dard

devi

atio

n(S

D)a

ser-

rorb

ars.

-2

01

23

4Distance

from

MLT

[cm]

0.2

0.4

0.6

0.81

1.2

1.4

1.6

VI

MR

healthy

MR

AMI

Fig

ure

6.3:

Vel

ocity

inde

x(V

I)at

six

lines

from

MR

mea

sure

men

tsof

heal

thyp

erso

ns(

Õ )an

dA

MI

patie

nts

(

Ö ).D

ataa

resh

own

asth

em

eanv

alue

with

the

stan

dard

devi

atio

n(S

D)a

ser-

rorb

ars.

-2

01

23

4Distance

from

MLT

[cm]

-500

50

100

TD[ms]

MR

healthy

MR

AMI

Fig

ure

6.4:

Tim

ede

lay(

TD

)at

six

lines

from

MR

mea

sure

men

tsof

heal

thyp

er-

sons

(

Õ )an

dA

MI

patie

nts(

Ö ).D

ata

are

show

nas

the

mea

nval

uew

ithth

est

an-

dard

devi

atio

n(S

D)a

serr

orba

rs.

6.1

Med

ical

back

grou

nd99

6.1.

4T

ime

cons

tant

ofre

laxa

tion

The

rela

xatio

nof

the

left

vent

ricle

iscl

osel

yre

late

dto

the

pres

sure

ther

e.W

eiss

etal

.(19

76)s

how

edth

atdu

ring

isov

olum

icre

laxa

tiont

hepr

essu

re-t

imev

aria

tion

follo

ws

anex

pone

ntia

ldec

ay(

×ØÙÚ Û )w

itha

cert

ain

time

cons

tant

Ü ,and

Ü hassu

bseq

uent

lybee

nuse

das

anin

dex

for

the

rela

xatio

n.T

hem

easu

redp

ress

ure-

time

varia

tion

durin

gis

ovol

umic

rela

xatio

nis

fitte

dto

anex

pone

ntia

ldec

ayto

dete

rmin

ethe

time

cons

tant

Ü .P

ress

ureis

mea

sure

dby

inva

sive

met

hods

(not

MR

I).

The

pres

sure

mea

sure

-m

ents

can

bedo

neat

seve

ralp

oint

sin

the

vent

ricle

,thu

sm

akin

git

poss

ible

toob

tain

Ü fordiff

eren

treg

ions

inth

eve

ntric

le.T

ypic

ally

,

Ü isdete

rmin

edfo

rth

eba

sala

ndap

ical

part

s,se

ee.g

.Ste

inee

tal.

(199

9).

6.1.

5R

egio

nsof

the

vent

ricle

Inst

udie

sof

the

left

vent

ricle

the

vent

ricul

arw

alli

sdi

vide

din

tofiv

ere

gion

sof

appr

oxim

atel

ythe

sam

esiz

e(S

chro

eder,

1999

):th

eba

salh

alfo

fthe

ante

riorw

all

regi

on(A

B),

the

apic

alha

lfof

the

ante

riorw

allr

egio

n(A

A),

the

apic

alre

gion

(A),

the

apic

alha

lfof

the

post

erio

rwal

lreg

ion

(PA

),an

dth

eba

salh

alfo

fthe

post

erio

rw

allr

egio

n(P

B).

The

five

regi

onsa

resh

own

onan

MR

imag

ein

Fig

ure

6.5.

A

AoV MiV

Ao LA

RV

AB

AA

PA

PBLV

Fig

ure

6.5:

MR

imag

ewith

the

five

regi

onso

fthe

vent

ricul

arw

alli

ndic

ated

:AB

:ba

salh

alfo

fan

terio

rwal

l,A

A:

apic

alha

lfof

ante

riorw

all,

A:

apex

,PA

:ap

ical

half

ofpo

ster

iorw

all,

PB

:bas

alha

lfof

post

erio

rwal

l.F

urth

erm

ore,

the

posi

tion

ofth

ele

ftve

ntric

le(L

V),

the

left

atriu

m(L

A),

the

right

vent

ricle

(RV

),th

em

itral

valv

e(M

iV),

the

aort

icva

lve

AoV

and

the

aort

a(A

o)ar

ein

dica

ted.

Page 60: MR · 2002. 2. 20. · Adeler A TV Erhver vsf or skerpr ojekt EF 698 IMM-PHD-2001-86 ISSN 0909-3192 ISBN 87-88306-13-5 c 2001 by Pernille Thorup Adeler Printed by IMM, DTU Bookbinder

100

Sim

ulat

ing

path

olog

ical

hear

tcon

ditio

ns

6.2

The

new

activ

atio

nfu

nctio

n

The

prev

ious

sect

ions

how

edth

atin

adi

seas

edhe

artt

here

laxa

tiono

fth

ehe

art

mus

clei

sof

ten

affe

cted

.The

rela

xatio

noft

hehe

artw

allc

anea

sily

beco

ntro

lled

and

chan

gedi

nth

em

odel

thro

ugh

man

ipul

atio

nof

the

para

met

ersd

eter

min

ing

the

activ

atio

nfu

nctio

n.In

the

orig

inal

mod

el,t

hepa

ram

eter

sthat

dete

rmin

ethe

rela

xatio

nand

con-

trac

tion

ofth

ehe

artw

all(

the

para

met

ersin

the

activ

atio

nfu

nctio

n

Ý )arede

fined

sepa

rate

lyfor

the

atriu

man

dve

ntric

le.

Tobe

able

tosi

mul

ate

regi

onal

diff

er-

ence

s,whi

chis

nece

ssar

yinth

epa

thol

ogic

alca

sesa

bove

,the

para

met

ersh

ave

tobe

regi

onal

lygi

ven

rath

erth

angi

ven

for

each

hear

tcha

mbe

ras

aw

hole

.Thi

sis

achi

eved

bydi

vidi

ngth

ehe

artw

alli

nto

five

regi

ons,

sim

ilart

oth

eon

esde

scrib

edin

Sec

tion6

.1.5

.The

para

met

ersd

eter

min

ingt

heac

tivat

ion

func

tion

are

then

de-

fined

with

inea

chre

gion

.T

hese

para

met

ersa

reth

ere

laxa

tiona

ndex

cita

tion,

orco

ntra

ctio

n,tim

eco

nsta

nts

Þuß and

Þuà ,thelim

iting

and

initi

alva

lues

ofth

eac

-tiv

atio

nfu

nctio

n

Ýâáãä

and

Ýå ,th

eon

setti

me

ofsy

stol

e

æèç andth

een

dtim

eof

syst

ole

æèç éàêë

(whi

chis

also

the

onse

ttim

eof

dias

tole

).We

call

this

refin

emen

tof

the

activ

atio

nfu

nctio

na

regi

onal

activ

atio

n.In

addi

tion

tom

akin

git

poss

ible

tosi

mul

atep

atho

logi

calc

ondi

tions

,we

wis

hto

impr

ove

the

activ

atio

nfu

nctio

nfr

oma

gene

ralp

hysi

olog

ical

poin

tof

view

.T

heac

tivat

ion

func

tion

Ýì æí give

sth

etim

eco

urse

ofco

ntra

ctio

nand

rela

xatio

nof

the

hear

tmus

cle.

Ýì æí isa

mod

elfo

rth

ere

leas

eof

Ca

î ï (Pes

kin,

2001

),w

hich

initi

ates

the

mec

hani

calco

ntra

ctio

nofh

eart

mus

cle(

seeS

ectio

n2.4

).T

here

leas

eofC

a

î ï istr

igge

redb

yth

eac

tion

pote

ntia

l,whi

chis

prop

agat

edth

roug

hth

eco

nduc

tions

yste

mof

the

hear

t.S

ince

the

cont

ract

ilere

spon

seof

aca

rdia

cm

uscl

ebe

gins

just

afte

rth

eac

tion

pote

ntia

lhas

reac

hedt

hem

uscl

efib

er,

the

cont

ract

iona

lso

prop

agat

esas

aw

ave

over

the

hear

twal

lwith

the

sam

evel

ocity

field

asth

eel

ectr

ical

impu

lses

.But

this

isno

thow

the

cont

ract

iona

ndre

laxa

tion

are

impl

emen

tedin

the

orig

inal

mod

el.

Inth

eor

igin

alm

odel

the

cont

ract

iono

fthe

hear

twal

locc

urss

imul

tane

ousl

yinth

een

tire

atriu

man

d,af

tera

dela

y,si

mul

tane

ousl

yinth

een

tire

vent

ricle

,bec

ause

æèç isthe

sam

efor

the

entir

eatr

ium

andf

orth

een

tire

vent

ricle

.The

sam

ehol

dsfo

rth

ere

laxa

tioni

nth

eor

igin

alm

odel

,bec

ause

also

æèç éàêë isth

esa

mef

orth

een

tire

atriu

man

dfo

rth

een

tire

vent

ricle

.Cha

ngin

gto

are

gion

alac

tivat

ion

wou

ldst

illno

tbe

phys

iolo

gica

llyco

rrec

t,be

caus

e

æðç and

æðç éàêë wou

ldbe

the

sam

ewith

inea

chre

gion

.T

heph

ysio

logi

cally

corr

ectw

ayto

mod

elth

etim

eco

urse

ofco

n-tr

actio

nan

dre

laxa

tioni

sto

lett

heco

ntra

ctio

nand

rela

xatio

npro

paga

teove

rthe

hear

twal

lwith

afin

iteve

loci

ty.

With

resp

ectto

the

mod

el,t

his

mea

nsth

atth

eon

setti

me

ofsy

stol

e

æðç andth

een

dtim

eof

syst

ole

æðç éàêëar

egi

ven

indi

vidu

ally

6.2

The

new

activ

atio

nfu

nctio

n10

1

for

each

link

inth

ehe

arta

ndno

tfor

agr

oup

oflin

ksto

geth

er.T

his

impr

ovem

ent

ofth

eac

tivat

ion

func

tion

we

call

agr

adua

lact

ivat

ion.

The

grad

uala

ctiv

atio

naf

fect

sth

etim

ing

ofth

eco

ntra

ctio

nand

rela

xatio

n,w

hile

the

regi

onal

activ

atio

naf

fect

sbot

hth

etim

ing

andt

hera

teof

cont

ract

iona

ndre

laxa

tion.

The

grad

uala

ndre

gion

alac

tivat

ions

aren

otco

mpl

emen

taryp

roce

sses

but

can

beus

edto

geth

eror

sepa

rate

ly.If

they

are

used

toge

ther,

the

timin

gis

dete

rmin

edby

the

grad

uala

ctiv

atio

n,an

dth

era

teof

cont

ract

iona

ndre

laxa

tion

are

dete

rmin

edby

the

regi

onal

activ

atio

n.

6.2.

1T

heor

igin

alm

odel

Inth

isse

ctio

nwe

brie

flyre

peat

how

the

activ

atio

nfu

nctio

nis

defin

edin

the

orig

-in

alm

odel

.In

dias

tole

the

gove

rnin

gequ

atio

nfor

the

activ

atio

nfu

nctio

n

Ýì æí is(s

eeS

ec-

tion

3.3.

6)

ñ Ý ñ æò óÞußÝ

with

the

anal

ytic

solu

tion

Ýì æíòÝì æëí ×Ø

ôõö Ù ØÙ ÷ø

whe

reÞ ß isth

ere

laxa

tionr

ate

cons

tant

and

æ ë iseith

erth

eon

setti

me

ofdi

asto

leor

the

star

tingt

ime

ofth

esi

mul

atio

n.In

syst

olet

hego

vern

ing

equa

tions

are

(see

Sec

tion3

.3.6

)

ñ Ýúù ñ æòÞ"àì ÝáãäóÝ ùíüû

ñ Ý ñ æòÞ"àì Ý ùóÝí

with

the

anal

ytic

solu

tion

Ý ùì æíòÝ áãäóìÝ áãäóÝ ùì æèçíí ×Øôýö Ù ØÙÿþø

Ýì æíòÝ áãäóìÝ áãäóÝì æðçííì Þ àì æ óæðçíí ×Øôýö ÙØÙÿþø

whe

re

Þuà isthe

exci

tatio

nra

teco

nsta

nt,

Ý áãä

isth

elim

iting

valu

eof

the

activ

a-tio

nfu

nctio

nan

d

æèç isthe

time

ofon

seto

fsys

tole

.The

equa

tions

are

solv

edw

itha

com

mon

initi

alva

lue

for

the

auxi

liary

func

tion

Ý ù and

the

activ

atio

nfu

nctio

n

Ý :Ý ùì æèçíòÝì æèçí .T

hesi

xpa

ram

eter

sthat

dete

rmin

ethe

time

cour

seof

the

activ

atio

nfu

nctio

nar

e:

Þ ß ,Þ"à ,Ýáãä

,

Ýå òÝì æ òí ,

æðç time

ofon

seto

fsy

stol

eand

æðç éàêë time

ofen

dof

syst

ole(

whi

chis

equa

lto

æ ë thetim

eof

onse

tofd

iast

ole)

.The

reis

one

seto

fpar

amet

ersfo

rth

elin

ksin

the

atriu

m,o

nefo

rth

elin

ksin

the

vent

ricle

and

Page 61: MR · 2002. 2. 20. · Adeler A TV Erhver vsf or skerpr ojekt EF 698 IMM-PHD-2001-86 ISSN 0909-3192 ISBN 87-88306-13-5 c 2001 by Pernille Thorup Adeler Printed by IMM, DTU Bookbinder

102

Sim

ulat

ing

path

olog

ical

hear

tcon

ditio

ns

one

for

the

papi

llary

mus

cle

link.

The

only

dist

inct

ion

betw

eent

hese

tfor

the

vent

ricul

arlin

ksan

dth

atfo

rth

epa

pilla

rym

uscl

elin

kis

the

initi

alva

lue

Ýå .T

heva

lues

ofth

epa

ram

eter

sare

liste

din

Tabl

e3.

1in

Sec

tion3

.3.6

.

6.2.

2T

hene

wim

plem

enta

tion

The

core

ofth

ene

wim

plem

enta

tiono

fthe

activ

atio

nfu

nctio

n

Ý isthat

this

func

-tio

nin

clud

ing

the

six

para

met

ers

Þ"ß ,

Þ"à ,Ý áãä

,

Ýå ,

æðç and

æðç éàêë are

defin

edse

para

telyf

orea

chlin

kin

the

hear

tbou

ndar

y.

Gra

dual

activ

atio

n

Inth

eco

deof

the

orig

inal

mod

el,th

eac

tivat

ion

func

tion

was

give

nby

thre

evar

i-ab

les:

,

and

,re

pres

entin

gthe

activ

atio

nfu

nctio

nin

the

atriu

m,v

entr

icle

and

papi

llary

mus

cle

(cho

rd),

resp

ectiv

ely.

The

seva

riabl

esar

eno

wde

fined

asar

rays

with

inde

x

:

ì í ,

ì í an

d

ì í ,w

here

isan

inde

xto

the

link.

Eac

hof

thes

evar

iabl

esho

lds

only

valu

esof

links

inits

own

dom

ain,

e.g.

for

ì í w

ede

alon

lyw

ithin

dexe

s

tolin

ksth

atar

epa

rtof

the

atria

lhea

rtbo

unda

ry.T

hetw

opa

ram

eter

saffe

cted

byth

egr

adua

lact

ivat

ion

æèç and

æèç éàêë

wer

eorig

-in

ally

defin

edas

cons

tant

varia

bles

for

the

thre

egro

upsa

triu

m,v

entr

icle

and

pap-

illar

ych

ord,

resp

ectiv

ely.

The

yar

eno

w,

sim

ilarly

to

,

and

,de

fined

asar

rays

with

inde

x

,e.g

.the

time

æèç ofons

etof

atria

lsys

tole

,whi

chus

edto

beth

eva

riabl

e

,is

now

ì í .

We

setu

ptw

och

ains

oflin

ks,o

nefo

rth

eat

rium

,

,

and

one

for

the

vent

ricle

,

.

The

seva

riabl

esho

lds

the

inde

x,in

age

omet

rical

lyna

tura

lord

er,

toal

lth

elin

ksin

the

atriu

man

dve

ntric

le,r

espe

ctive

ly.

By

ge-

omet

rical

lyna

tura

lord

erw

em

eant

hat

ì í

and

ì í

hold

inde

xest

one

ighb

ourin

glin

kson

the

hear

tbou

ndar

y.F

igur

e6.

6sh

ows

how

the

two

chai

nsar

ese

tup.

Eac

hcr

ossl

ink

inth

eve

ntric

leis

num

bere

ddire

ctly

afte

rthe

link

alon

gth

erig

ht(p

oste

rior)

boun

dary

with

whi

chit

has

aco

mm

onbo

unda

rypo

int.

We

defin

east

artin

glin

k(

an

d

)

for

each

ofth

ech

ains

,i.e.

and

ar

eth

enu

mbe

rsof

the

links

whe

reth

ew

ave

ofco

ntra

ctio

nor

rela

x-at

ion

star

tsin

each

chai

n,re

spec

tivel

y.Fo

rphy

siol

ogic

alre

ason

sthe

star

tingl

ink

inth

eat

rium

shou

ldbe

atth

epo

sitio

nof

the

SA

node

and

the

star

tingl

ink

inth

eve

ntric

lesh

ould

beat

the

posi

tion

ofth

eA

Vno

de(s

eeS

ectio

n2.3

).N

ext,

we

pres

crib

eave

loci

ty

with

whi

chth

eac

tivat

ion

shou

ldpr

opag

ate

over

the

hear

tbou

ndar

y.T

heve

loci

tydo

esno

thav

eto

beth

esa

mef

orth

eat

rium

6.2

The

new

activ

atio

nfu

nctio

n10

3

aN

Nv

i+1

i+3

i+5

i+4

i+2

12

3

mitr

alrin

g

atriu

mve

ntric

le

12

mitr

alrin

g

i

vN

−v

N − v

N − v

4 2

N − 3

1

a1

N −

N − a

N − a

23

Fig

ure

6.6:

Illus

trat

ion

ofth

enu

mbe

ringo

fth

elin

ksin

the

two

chai

nsin

the

atriu

m(le

ft)an

dth

eve

ntric

le(r

ight

).

ã and

are

the

tota

lnum

bero

flin

ksin

the

chai

ns,re

spec

tivel

y.N

ote,

the

mitr

alrin

gis

mod

elle

dby

two

links

,one

inea

chof

the

chai

ns.

and

the

vent

ricle

,nor

does

itha

sto

beth

esa

mef

oral

llin

ksin

eith

erth

eat

rium

orth

eve

ntric

le.I

nth

efo

llow

ing

we

intr

oduc

eatp

ropa

gatio

nvel

ocity

for

the

atriu

m

ò ã a

nda

prop

agat

ionv

eloc

ityfo

rth

eve

ntric

le

ò .T

heor

etic

ally

the

prop

agat

ionv

eloc

itysh

ould

beeq

ualto

the

velo

city

ofco

nduc

tiono

fthe

elec

tric

alim

puls

esin

the

hear

t(se

eSec

tion2

.3).

Toim

plem

entt

hegr

adua

lact

ivat

ion

func

tion,

the

para

met

ersæðç a

nd

æðç éàêë

shou

ldbe

setf

orea

chlin

kac

cord

ingt

oth

elin

k’s

spat

ialp

ositi

onat

time

æ òæðç

and

æ òæðç éàêë .

How

ever

,to

sim

plify

the

calc

ulat

ions

we

com

pute

æðç and

æðç éàêë

acco

rdin

gto

the

initi

alpo

sitio

nof

the

link.

Tha

tis,

first

we

set

æðç and

æðç éàêë

for

the

star

ting

link

(

an

d

)

inea

chch

ain.

The

n,ba

sedo

nth

epr

opag

a-tio

nve

loci

tyan

dth

edi

stan

cebe

twee

nlin

ksin

the

initi

alhe

artc

onfig

urat

ion,

we

com

pute

æðç and

æðç éàêë

for

the

rest

ofth

elin

ksin

each

chai

n.T

hege

nera

lform

ula

for

the

onse

ttim

eof

syst

ole

æðç fora

link

is

æèçì í òæèçì çÙ ãßÙí

ì í

whe

re

çÙ ãßÙ ise

ither

or

,

isth

epr

opag

atio

nvel

ocity

and

ì í

isth

edi

stan

cebe

twee

nlin

k

and

the

star

tingl

ink

(eith

er

or

).

Typi

cally

,we

have

that

the

dist

ance

ì í

isof

the

form

óçÙ ãßÙ

å ,w

here

å isth

ein

itial

dist

ance

betw

eenn

eigh

bour

ingb

ound

aryp

oint

s.

Page 62: MR · 2002. 2. 20. · Adeler A TV Erhver vsf or skerpr ojekt EF 698 IMM-PHD-2001-86 ISSN 0909-3192 ISBN 87-88306-13-5 c 2001 by Pernille Thorup Adeler Printed by IMM, DTU Bookbinder

104

Sim

ulat

ing

path

olog

ical

hear

tcon

ditio

ns

Thu

s

æðçì í òæðçì çÙ ãßÙí ó çÙ ãßÙ

å

We

assu

met

hatt

hedu

ratio

nof

syst

ole

æèç éë ß

isth

esa

mef

oral

llin

ksin

the

atriu

man

dfo

ral

llin

ksin

the

vent

ricle

(Gan

ong,

1993

).T

hust

hege

nera

lform

ula

for

the

end

time

ofsy

stol

e

æðç éàêë

is

æðç éàêëì íòæðçìíæðç éë ß

Inth

ein

itial

hear

tcon

figur

atio

nthe

dist

ance

betw

eenn

eigh

bour

ingp

oint

sis

å .By

com

putin

gthe

valu

esfo

rthe

links

acco

rdin

gto

thei

rini

tialp

ositi

ons,

we

gett

herig

hton

setti

me

ofsy

stol

e

æðçì í on

lyif

the

dist

ance

betw

eenn

eigh

bour-

ing

poin

tsat

æðçì í is

å .T

his

cond

ition

does

noth

old,

and

we

take

that

into

acco

untw

hen

we

com

pute

æðçì í .

Fort

heat

rium

we

know

that

atth

eon

seto

fsys

tole

æ òæðç

the

dist

ance

betw

een

neig

hbou

ringp

oint

sis

ÙFþò ! å ,

i.e.

åò"ÙFþ .

So

toas

sure

the

corr

ectv

alue

of

æðçì í w

em

ultip

lyth

epr

opag

atio

nvel

ocity

inth

eat

rium

ò

ã by

2.T

hust

heeq

uatio

nsfo

rth

eon

setti

me

ofsy

stol

eand

end

time

ofsy

stol

ein

the

atriu

mar

e

æðçì í òæðçì í ó

å " ã

æðç éàêëì íòæðçì íæðç éë ß

Inth

eve

ntric

leth

edi

stan

cebe

twee

nnei

ghbo

urin

gpoi

ntsa

tthe

onse

tofs

ys-

tole

æ òæðç isa

ppro

xim

atel

y

Ù #ò $$å ,

i.e.

åò $Ùÿþ .

Thu

sw

ene

edto

mul

tiply

the

prop

agat

ionv

eloc

ityin

the

vent

ricle

ò b

y

$ toas

-su

reth

eco

rrec

tval

ueof

æðçì í .

The

onse

tand

end

time

ofsy

stol

efo

ral

lth

elin

ksal

ong

the

left

(ant

erio

r)ve

ntric

ular

wal

l(c

alle

dsh

ortl

inks

)ar

eco

mpu

ted

sim

ilarly

toth

elin

ksin

the

atriu

m,i.

e.

æèçì í òæèçì í ó

å $

æèç éàêëì í òæèçì í æèç éë ß

Her

e

æðçì í ha

sbee

nset

toa

valu

egre

ater

than

æðç forth

ela

stlin

kin

the

atria

lch

ain,

the

diff

eren

cebe

ing

equa

ltoth

ede

layi

nth

eA

Vno

de(s

eeS

ectio

n2.3

).Fo

rth

esh

ortl

inks

alon

gth

erig

htve

ntric

ular

wal

lthe

prin

cipl

eis

the

sam

e,pr

ovid

edw

eta

kein

toac

coun

tthat

ever

yse

cond

inde

xis

anin

dex

toa

cros

slin

k.

6.2

The

new

activ

atio

nfu

nctio

n10

5

Thu

s

æèçì í òæèçì í " ó

å $

æèç éàêëì í òæèçì í æèç éë ß

Ons

etan

dend

time

ofsy

stol

efor

each

cros

slin

kin

the

vent

ricle

area

ssoc

iate

dw

ithth

esh

ortl

inks

alon

gth

erig

htve

ntric

ular

wal

l.T

heva

lues

of

æðç and

æðç éàêë

for

acr

ossl

ink

are

iden

tical

toth

eva

lues

for

the

next

shor

tlink

inth

eve

ntric

ular

chai

n,e.

g.th

esh

ortl

ink

with

inde

x

" an

dth

ecr

ossl

ink

with

inde

x

in

Fig

ure

6.6

have

iden

tical

valu

esof

onse

tand

end

time

ofsy

stol

e.In

sum

mar

ywe

have

that

with

the

grad

uala

ctiv

atio

nth

etim

eco

urse

ofth

eac

tivat

ion

func

tion

isde

term

ined

byth

efo

llow

ing

para

met

ers:t

hest

artin

glin

ks

an

d

,t

heon

setti

mes

ofsy

stol

efor

the

star

ting

links

æèçì í an

d

æèçì í ,

the

velo

citie

s ã a

nd

,and

the

dura

tion

times

ofsy

stol

e

æèç éë ß

inth

eat

rium

and

vent

ricle

.

Reg

iona

lact

ivat

ion

The

regi

onal

activ

atio

nfu

nctio

nis

intr

oduc

edba

sedo

nth

ew

ish

tosi

mul

ater

e-gi

onal

diff

eren

cesin

the

vent

ricul

arac

tivat

ion,

part

icul

arly

inth

eve

ntric

ular

re-

laxa

tion.

Hen

ce,th

isim

prov

emen

toft

heac

tivat

ion

func

tion

affe

ctso

nly

the

acti-

vatio

nfu

nctio

nfo

rth

eve

ntric

ular

links

.Whi

leth

egr

adua

lact

ivat

ion

affe

ctso

nly

æèç andæèç éàêë ,the

regi

onal

activ

atio

naf

fect

sall

six

para

met

ersth

atde

term

inet

heac

tivat

ion

func

tion,

æèç ,æèç éàêë ,

Þ à ,Þuß ,Ýâáãä

and

Ýå .W

ede

finefi

vere

gion

soft

heve

ntric

ular

hear

twal

lofa

ppro

xim

atel

ythe

sam

esi

ze:

regi

on1

alon

gth

eup

pera

nter

iorw

all,

regi

on2

alon

gth

elo

wer

ante

rior

wal

l,re

gion

3al

ong

the

apex

,reg

ion

4al

ong

the

low

erpo

ster

iorw

alla

ndre

gion

5al

ong

the

uppe

rpos

terio

rwal

l.F

igur

e6.

7sh

ows

the

five

regi

ons

atth

ein

itial

time.

The

regi

onsc

orre

spon

dto

the

five

regi

onsp

rese

nted

inS

ectio

n6.1

.4.T

hepa

pilla

rym

uscl

elin

kbe

long

sto

regi

on3.

Inea

chof

the

five

regi

ons

all

the

para

met

ers(

æðç ,æðç éàêë ,

Þ à ,

Þ"ß ,Ýå an

d

Ýáãä )de

term

inin

gthe

activ

atio

nfu

nctio

nar

efix

ed.T

hus

ifw

ech

oose

regi

onal

and

notg

radu

alac

tivat

ion,

the

valu

esof

æðç and

æðç éàêë are

the

sam

ewith

inea

chre

gion

.It

isal

sopo

ssib

leto

have

both

regi

onal

and

grad

uala

ctiv

atio

nat

the

sam

etim

e.In

this

case

æèç and

æèç éàêë areg

iven

byth

egr

adua

lact

ivat

ion

proc

essa

ndth

ere

mai

ning

four

para

met

ersa

rede

term

ined

byth

eva

lue

for

the

give

nre

gion

.We

give

the

valu

esfo

rth

epa

pilla

rym

uscl

elin

kin

depe

nden

tlyof

the

regi

onva

lues

,as

sum

ingc

ondi

tions

whe

reth

epa

pilla

rym

uscl

eact

ivat

ion

isno

taffe

cted

byth

ehe

artd

isea

se.

Page 63: MR · 2002. 2. 20. · Adeler A TV Erhver vsf or skerpr ojekt EF 698 IMM-PHD-2001-86 ISSN 0909-3192 ISBN 87-88306-13-5 c 2001 by Pernille Thorup Adeler Printed by IMM, DTU Bookbinder

106

Sim

ulat

ing

path

olog

ical

hear

tcon

ditio

ns

2

4

1

5

aort

a

valv

em

itral

atriu

m

vent

ricle

3

Fig

ure

6.7:

The

five

regi

onso

fthe

vent

ricul

arhe

artw

alla

tini

tialt

ime.

6.2.

3T

ime

cons

tant

ofre

laxa

tion

InS

ectio

n4.

1.3

we

foun

da

clos

ere

latio

nbe

twee

nthe

time

cour

seof

the

ac-

tivat

ion

func

tion

Ý andth

etim

eco

urse

ofth

eve

ntric

ular

pres

sure

,par

ticul

arly

from

the

begi

nnin

gof

rela

xatio

nun

tilth

em

itral

valv

eop

ens(

see

Fig

ure

4.7)

.F

urth

erm

ore,

the

prev

ious

sect

ions

show

that

durin

gre

laxa

tion

Ý isdesc

ribed

byan

expo

nent

iald

ecay

ofth

efo

rm

×Øô õÙ .

Thi

ssu

ppor

tsth

eus

eof

apr

essu

re-

dete

rmin

edin

dex

(the

time

cons

tant

Ü ofan

expo

nent

iald

ecay

durin

gre

laxa

tion)

for

the

eval

uatio

noft

here

laxa

tion,

asde

scrib

edin

Sec

tion6

.1.4

.Hen

ce,a

ssum

-in

gth

at

Ü ò% Þuß ,w

eca

nus

emea

sure

men

tsoft

hetim

eco

nsta

nt

Ü todete

rmin

e

Þuß inthe

activ

atio

nfu

nctio

n.

6.3

Cal

ibra

ting

the

mod

el

The

para

met

ersd

eter

min

ingt

hetw

oim

prov

emen

tsoft

heac

tivat

ion

func

tion

(gra

d-ua

land

regi

onal

activ

atio

n)ar

ese

tup

tom

atch

ahe

alth

yhum

anby

com

paris

ons

with

MR

data

and

calib

ratio

nsba

sedo

nph

ysio

logi

calk

now

ledg

e.

6.3.

1V

eloc

itypr

ofile

sal

ong

tran

sver

selin

es

Inad

ditio

nto

the

typi

calo

utpu

tfro

mth

em

odel

(see

Sec

tion4

.1)w

eal

solo

okat

spat

ialv

eloc

itypr

ofile

s(of

abso

lute

velo

city

)alo

ngtr

ansv

erse

lines

inth

eve

ntri-

cle

bya

met

hods

imila

rto

that

used

byH

oulin

det

al.(

2001

)for

MR

data

durin

gth

eea

rlyfil

ling

phas

e.W

ede

scrib

edth

atm

etho

din

Sec

tion

6.1.

3.S

ince

we

are

only

inte

rest

edin

the

dias

tolic

fillin

gph

ase,

we

only

inve

stig

atet

heve

loci

typr

ofile

sdu

ring

dias

tole

,but

we

inve

stig

atet

hem

for

alo

nger

time

perio

dan

dat

6.3

Cal

ibra

ting

the

mod

el10

7

smal

lert

ime

inte

rval

s(a

ppro

xim

atel

y13

ms)

than

done

inH

oulin

det

al.(

2001

).W

hen

we

inve

stig

atet

here

sults

from

the

six

lines

,we

look

atth

esp

atia

lve-

loci

typr

ofile

alon

gea

chof

the

lines

atdi

ffer

entt

imes

and

com

pute

PV,

VI

and

TD

for

each

ofth

elin

es(s

eeS

ectio

n6.1

.3fo

ra

defin

ition

ofth

eseq

uant

ities

).B

ecau

sew

ein

vest

igat

ethe

lines

for

alo

nger

time

perio

dth

ando

nein

Hou

lind

etal

.(20

01)w

ear

eab

leto

find

high

erva

lues

ofT

D.

InH

oulin

det

al.

(200

1)th

elin

esar

efix

edin

spac

e,an

dth

isis

reas

onab

lebe

caus

ethe

mot

ion

ofth

ehe

arti

sre

lativ

ely

smal

l.H

owev

er,

inth

em

odel

the

hear

tmot

ion

ism

ore

pron

ounc

ed.T

here

fore

we

exam

inet

hedi

ffer

ence

betw

een

resu

ltsfr

omlin

esfix

edin

spac

eand

resu

ltsfr

omlin

esfo

llow

ing

the

hear

tmot

ion.

The

lines

fixed

insp

acea

rese

tup

sim

ilarly

toth

em

etho

dfor

the

MR

data

:at

the

time

ofpe

akve

loci

tybe

twee

nthe

leafl

ettip

sa

line

ispl

aced

atth

ele

velo

fth

em

itral

leafl

ettip

s(M

LT

)bu

tper

pend

icul

arto

the

inflo

wje

t.A

noth

erlin

eis

plac

edpa

ralle

ltoth

efir

ston

ebu

tdis

plac

ed2

cmup

stre

am,a

ppro

xim

atel

yatt

hele

velo

fth

em

itral

ring.

Fur

ther

mor

e,4

lines

are

plac

edpa

ralle

lto

the

first

line

butd

ispl

aced

1,2,

3an

d4

cmdo

wns

trea

m.T

heto

pro

wof

Fig

ure

6.8

show

sth

eve

loci

tyfie

ld,t

hehe

artb

ound

arya

ndth

esi

xlin

esat

two

times

durin

gth

efir

stcy

cle

ofa

sim

ulat

ionw

here

the

lines

are

fixed

insp

ace.

Fort

helin

esfo

llow

ing

the

hear

tmot

ion

we

take

,ate

acht

ime

step

,the

mitr

alrin

gas

the

basi

clin

e,be

caus

ethis

isa

wel

ldefi

nedl

ine

inth

em

odel

and

the

flow

ispr

actic

ally

perp

endi

cula

rtoth

islin

e.T

hen

we

plac

e5lin

espa

ralle

ltoth

islin

ebu

tdis

plac

ed2,

3,4,

5an

d6

cmdo

wns

trea

m,se

ebot

tom

row

ofF

igur

e6.

8.T

helin

e2

cmdo

wns

trea

mof

the

mitr

alrin

gis

appr

oxim

atel

yatt

hele

velo

fthe

mitr

alle

aflet

tips

and

we

thus

deno

teit

ML

T.T

heco

mpa

rison

betw

eent

here

sults

obta

ined

atlin

esfix

edin

spac

eand

lines

follo

win

gth

ehe

artm

otio

nre

veal

sth

atev

enth

ough

we

only

look

atdi

asto

le(w

here

the

mot

ion

isle

ssth

anin

syst

ole)

,the

hear

tmot

ion

isto

ogr

eatt

oob

-ta

inre

ason

abler

esul

tsfr

omth

elin

esfix

edin

spac

e.E

.g.t

helin

epo

sitio

ned1

cmdo

wns

trea

mof

the

mitr

alle

aflet

tips

mov

esab

ove

the

leve

lof

the

mitr

alle

aflet

tips,

and

the

line

atth

em

itral

ring

ispo

sitio

nedi

nth

em

iddl

eof

the

atriu

m,s

eeto

prig

htpi

ctur

ein

Fig

ure

6.8.

Thu

sw

eco

nclu

deth

atw

esh

ould

choo

selin

esfo

llow

ing

the

hear

tmot

ion.

Sin

ceth

elin

esth

atfo

llow

the

hear

tmot

ion

are

base

don

the

line

atth

em

itral

ring

and

noto

na

line

posi

tione

dper

pend

icul

arto

the

inflo

wje

t,w

eca

nnot

bece

rtai

ntha

tthe

lines

are

perp

endi

cula

rtoth

ein

flow

jet.

Thi

sis

nota

prob

lem

for

the

velo

city

inde

xess

ince

they

areb

ased

onth

em

axim

umof

anab

solu

teve

loci

ty,

butt

hesp

atia

lvar

iatio

noft

heve

loci

tyal

ongt

helin

esm

ight

bedi

ffer

entth

anse

enin

MR

data

obta

ined

byth

em

etho

ddes

crib

edin

Hou

lind

etal

.(20

01).

Page 64: MR · 2002. 2. 20. · Adeler A TV Erhver vsf or skerpr ojekt EF 698 IMM-PHD-2001-86 ISSN 0909-3192 ISBN 87-88306-13-5 c 2001 by Pernille Thorup Adeler Printed by IMM, DTU Bookbinder

108

Sim

ulat

ing

path

olog

ical

hear

tcon

ditio

ns

Line

sfix

edin

spac

e

Time

0.164

Time

0.244

Line

sfo

llow

ing

the

hear

tmot

ion

Time

0.164

Time

0.244

Fig

ure

6.8:

The

six

lines

whe

resp

atia

lvel

ocity

profi

lesa

reco

mpu

tedd

urin

gdi

-as

tole

inth

eca

seof

lines

fixed

insp

ace(

top)

and

lines

follo

win

gth

ehe

artm

otio

n(b

otto

m).

The

pict

ures

inth

ele

ftsi

deis

atth

etim

eof

peak

velo

city

atth

em

itral

leafl

ettip

s.

6.3.

2G

radu

alac

tivat

ion

The

para

met

ersd

eter

min

ingt

hegr

adua

lact

ivat

ion

are:

the

star

tingl

ink

inat

rium

,t

hest

artin

glin

kin

vent

ricle

,t

heon

setti

me

ofsy

stol

efor

the

star

ting

links

æðçì í an

d

æðçì í ,

the

velo

citie

s

and

ã ,the

dura

tion

times

ofsy

stol

e

æðç éë ß

inth

eat

rium

and

inth

eve

ntric

le,a

ndth

eon

set/e

ndtim

esof

syst

ole

for

the

papi

llary

mus

clel

ink.

The

para

met

ersfo

rth

epa

pilla

rym

uscl

elin

kar

ese

tse

para

telyf

rom

the

vent

ricul

arpa

ram

eter

s,bec

ause

ittu

rns

outt

hatt

hem

odel

isve

ryse

nsitiv

eto

the

activ

atio

nof

the

papi

llary

mus

cle.

We

perf

orm

eda

serie

sof

sim

ulat

ions

tode

cide

the

best

setti

ngof

the

pa-

6.3

Cal

ibra

ting

the

mod

el10

9

ram

eter

sfor

the

grad

uala

ctiv

atio

n.W

ede

fine

the

best

setti

ngas

one

that

best

impr

oves

the

com

paris

onw

ithM

Rda

ta(s

eeC

hapt

er5)

with

outi

ntro

duci

ngno

n-ph

ysio

logi

calb

ehav

iour

ofth

ehe

art.

E.g

.it

isim

port

antt

hatt

hem

ovem

ento

fth

em

itral

valv

eis

sym

met

rical

and

nota

sym

met

rical

(see

Ade

lera

ndJa

cobs

en(2

001)

and

Jaco

bsen

etal

.(20

01))

.For

allo

fthe

sim

ulat

ions

we

chos

eto

lett

hedu

ratio

nofs

ysto

lebe

the

sam

easi

nou

rref

eren

cem

odel

,i.e.

æðç éë ßis

0.10

4san

d0.

306

sfo

rth

eat

rium

and

vent

ricle

,res

pect

ively

.Fur

ther

mor

e,

æðç forth

est

artin

glin

ksw

erec

hose

nto

beth

esa

mea

s

æðç inour

refe

renc

emod

el,i.

e.in

the

first

hear

tcy

cle

æðçì íò 0.36

2s

and

æðçì íò 0.54

5s.

The

sim

ulat

ions

indi

cate

that

the

mod

elis

notv

ery

sens

itive

toth

eac

tivat

ion

ofth

eat

rium

,sho

win

gon

lym

inor

diff

eren

cesw

hen

we

chan

geth

eve

loci

ty

ã and

the

star

tingl

ink

.

We

chos

eto

lett

heat

riala

ctiv

atio

npr

opag

ates

ymm

etri-

cally

over

the

hear

twal

lfro

mth

em

idpo

into

nth

eat

rialw

alla

ndw

itha

velo

city

of

ãò 0.5m

/s,w

hich

isph

ysio

logi

cally

corr

ect(

seeS

ectio

n2.3

).

is

not

plac

edat

the

posi

tion

ofth

eS

Ano

de,b

ecau

sea

sym

met

rical

activ

atio

nof

the

atriu

mgi

vesa

mov

emen

toft

hem

itral

valv

eth

atis

slig

htly

mor

esy

mm

etric

al.

The

phys

iolo

gica

llyco

rrec

tvel

ocity

inth

eve

ntric

leis

appr

oxim

atel

y5.0

m/s

,so

ò 5.0m

/s.T

hest

artin

glin

kin

the

vent

ricle

isth

eto

plin

kon

the

ante

rior

wal

l,si

nce

this

isap

prox

imat

elyw

here

the

AV

node

islo

cate

din

the

hear

t,se

eS

ectio

n2.3

.B

ecau

seth

em

odel

star

tsup

from

anun

phys

iolo

gica

lsitu

atio

n(a

llth

ebl

ood

isat

rest

at

æ ò ),

we

chos

eto

lett

here

laxa

tionb

esi

mul

tane

ousin

the

entir

eve

ntric

lein

the

first

hear

tcyc

le.T

hepr

opag

atio

noft

heac

tivat

ion

over

the

vent

ricul

arw

alld

oesn

otch

ange

the

sim

ulat

ionr

esul

tsve

rym

uch,

the

bigg

est

diff

eren

cebe

ing

seen

inth

eou

tflow

thro

ught

heao

rtic

sink

.How

ever

,the

mod

elis

very

sens

itive

toth

eac

tivat

ion

time

ofth

epa

pilla

rym

uscl

elin

k.W

hen

the

papi

llary

mus

clel

ink

isde

fined

aspa

rtof

the

vent

ricul

arlin

kch

ain

and

thus

isac

tivat

edac

cord

ingt

oth

epr

opag

atio

noft

heac

tivat

ion

wav

e,th

ean

-te

riorv

entr

icul

arw

allm

otio

nis

very

abno

rmal

beca

useo

favi

goro

usco

ntra

ctio

nof

this

part

ofth

ew

all.

Thi

sis

beca

uset

hepa

pilla

rym

uscl

eco

ntra

ctsb

efor

eth

epo

ster

iorw

all.

Eve

nif

we

lett

hepa

pilla

rym

uscl

econ

trac

t20

ms

late

r,th

eco

ntra

ctio

noft

hean

terio

rwal

lis

dist

orte

dand

the

mitr

alva

lve

clos

esve

ryas

ym-

met

rical

ly.T

his

can

bese

enin

Fig

ure

6.9

whe

reth

ehe

artb

ound

aryc

onfig

urat

ion

issh

own

attw

otim

esfr

oma

sim

ulat

ionw

ithth

egr

adua

lact

ivat

ion

and

from

the

refe

renc

esim

ulat

iond

escr

ibed

inC

hapt

er4.

The

dist

orte

dcon

trac

tiono

fthe

ante

riorw

alla

ndth

eas

ymm

etric

alclo

sing

ofth

em

itral

valv

eis

seen

beca

useth

epa

pilla

rym

uscl

eis

teth

ered

toa

poin

talo

ngth

ean

terio

rwal

l.In

ourp

revi

ousl

yre

port

edw

ork

(Jac

obse

neta

l.,20

01;A

dele

rand

Jaco

bsen

,2001

)the

papi

llary

mus

clew

aste

ther

edto

apo

inta

long

the

post

erio

rw

all,

and

here

the

cont

ract

iono

fth

epo

ster

iorw

allw

asdi

stor

teda

ndth

em

itral

Page 65: MR · 2002. 2. 20. · Adeler A TV Erhver vsf or skerpr ojekt EF 698 IMM-PHD-2001-86 ISSN 0909-3192 ISBN 87-88306-13-5 c 2001 by Pernille Thorup Adeler Printed by IMM, DTU Bookbinder

110

Sim

ulat

ing

path

olog

ical

hear

tcon

ditio

ns

Time1.5600

Time1.6380

Fig

ure

6.9:

Hea

rtbo

unda

ryat

two

times

durin

ga

hear

tcyc

lefr

oma

sim

ulat

ion

with

grad

uala

ctiv

atio

nw

ith

ò 5.0m

/san

d20

ms

late

ract

ivat

ion

ofpa

pilla

rym

uscl

e(

Ö )an

dfr

omth

ere

fere

nces

imul

atio

n(

& ).

valv

ecl

osed

asym

met

rical

lyto

the

othe

rsid

e.T

hebe

stw

ayto

min

imiz

eth

edi

stor

tion

ofth

ean

terio

rwal

lis

toin

crea

seth

eve

loci

ty

inth

eve

ntric

le.I

fw

ese

t

ò 10.0

m/s

and

lett

hepa

pilla

rym

uscl

eco

ntra

ct10

ms

late

rtha

nit

shou

ldac

cord

ingt

oth

epr

opag

atio

nof

the

activ

atio

nw

ave,

we

obta

inre

ason

ables

imul

atio

nre

sults

.How

ever

,

ò 10.0

m/s

isto

ohi

ghco

mpa

redt

oty

pica

lvel

ociti

esin

the

Pur

kinj

efib

ers

ofap

prox

imat

ely3

.0-

5.0

m/s

(see

Sec

tion2

.3).

Fig

ure

6.10

show

sth

ehe

artb

ound

arya

tsix

times

durin

gth

ese

cond

hear

tcy

cle

from

asi

mul

atio

nwith

ò 10.0

m/s

and

10m

sla

tera

ctiv

atio

nof

the

pap-

illar

ym

uscl

eand

from

the

refe

renc

esim

ulat

ion.

We

sees

omed

iffer

ence

inth

ehe

artb

ound

aryc

onfig

urat

iona

ndna

tura

llyth

ebi

gges

tdiff

eren

ceis

durin

gsy

s-to

le.B

utth

efig

ure

also

show

sa

bette

rcon

trac

tiono

fthe

ante

riorw

allc

ompa

red

toth

ere

sults

inF

igur

e6.

9an

dan

impr

oved

mov

emen

tof

the

mitr

alva

lve

dur-

ing

clos

ing,

thou

ghth

eva

lve

does

notc

lose

assy

mm

etric

ally

asin

the

refe

renc

esi

mul

atio

n.To

furt

herj

udge

the

chan

gesin

sim

ulat

ionr

esul

tsdu

eto

the

grad

uala

ctiv

atio

nw

eco

mpa

repr

essu

retim

epr

ofile

s,ve

loci

tytim

epr

ofile

san

dflo

wtim

epr

ofile

s.T

hepr

essu

retim

epr

ofile

s(n

otsh

own)

show

hard

lyan

ydi

ffer

ence

com

pare

dto

the

refe

renc

esim

ulat

ion.

The

velo

city

time

profi

les

over

the

mitr

alrin

gan

dbe

-tw

een

the

leafl

ettip

sar

esh

own

inF

igur

e6.

11.

The

figur

esh

ows

that

the

peak

velo

citie

sfor

the

mitr

alrin

gpr

ofile

are

low

erin

the

sim

ulat

ion

with

the

grad

ual

6.3

Cal

ibra

ting

the

mod

el11

1

Time1.0920

Time1.2480

Time1.4040

Time1.5600

Time1.7160

Time1.8720

Fig

ure

6.10

:Hea

rtbo

unda

ryat

six

times

durin

ga

hear

tcyc

le.F

rom

asi

mul

atio

nw

ithgr

adua

lact

ivat

ion

with

ò 10.0

m/s

and

10m

sla

tera

ctiv

atio

nof

papi

llary

mus

cle(

Ö )an

dfr

omth

ere

fere

nces

imul

atio

n(

& ).

Page 66: MR · 2002. 2. 20. · Adeler A TV Erhver vsf or skerpr ojekt EF 698 IMM-PHD-2001-86 ISSN 0909-3192 ISBN 87-88306-13-5 c 2001 by Pernille Thorup Adeler Printed by IMM, DTU Bookbinder

112

Sim

ulat

ing

path

olog

ical

hear

tcon

ditio

ns

11.2

1.4

1.6

1.8

t[s]

-40

-200

20

40

60

velocity[cm/s]

11.2

1.4

1.6

1.8

t[s]

-40

-200

20

40

60

velocity[cm/s]

Fig

ure

6.11

:Vel

ocity

time

profi

leof

the

mea

nvel

ocity

(cm

/s)a

tthe

mitr

alrin

g(s

olid

)and

betw

eent

hele

aflet

tips

(das

hed)

from

asi

mul

atio

nw

ithgr

adua

lact

i-va

tion

(left)

and

from

the

refe

renc

esim

ulat

ion(

right

).

11.2

1.4

1.6

1.8

t[s]

0

20

40

60

80

velocity[cm/s]

11.2

1.4

1.6

1.8

t[s]

0

20

40

60

80

velocity[cm/s]

Fig

ure

6.12

:Vel

ocity

time

profi

leof

the

mea

nvel

ocity

(cm

/s)a

cros

sthe

aort

icou

tflow

trac

tbel

owth

eao

rtic

sink

from

asi

mul

atio

nwith

grad

uala

ctiv

atio

n(le

ft)an

dfr

omth

ere

fere

nces

imul

atio

n(rig

ht).

6.3

Cal

ibra

ting

the

mod

el11

3

11.2

1.4

1.6

1.8

t[s]

-600

-400

-2000

200

sourceflow[cm^3/s]

11.2

1.4

1.6

1.8

t[s]

-600

-400

-2000

200

sourceflow[cm^3/s]

Fig

ure

6.13

:F

low

time

profi

lefo

rth

eflo

w(c

m

' /s)

thro

ugh

the

mitr

also

urce

(das

hed)

and

the

aort

icsi

nk(f

ull)

from

asi

mul

atio

nwith

grad

uala

ctiv

atio

n(le

ft)an

dfr

omth

ere

fere

nce(

right

).

activ

atio

nim

plem

ente

d.T

hepe

akin

the

leafl

ettip

profi

leca

used

byth

eat

rialc

on-

trac

tion

ishi

gher

inth

esi

mul

atio

nw

ithth

egr

adua

lact

ivat

ion

and,

asex

pect

ed,

occu

rsla

ter.

Bas

edon

the

com

paris

onbe

twee

nthe

refe

renc

esim

ulat

iona

ndM

Rda

tapr

esen

tedin

Cha

pter

5,w

edo

notw

antt

heat

rials

ysto

leto

bede

laye

d.A

part

from

the

diff

eren

cesa

tthe

peak

s,th

epr

ofile

sar

eco

mpa

rabl

eand

have

sim

ilar

shap

es.

Fig

ure

6.12

show

sth

eve

loci

typr

ofile

acro

ssth

eao

rtic

outfl

owtr

act,

whi

leF

igur

e6.1

3sh

ows

the

flow

thro

ught

hem

itral

sour

cean

daor

ticsi

nk.T

heve

loci

typr

ofile

acro

ssth

eao

rtic

outfl

owtr

acts

how

son

lym

inor

diff

eren

cesc

ompa

redt

oth

ere

fere

nces

imul

atio

n,e.

g.a

slig

htly

low

erpe

akva

lue.

Fro

mth

eso

urce

/sin

kflo

wpr

ofile

sw

ese

eth

atth

eao

rtic

sink

open

sand

clos

essl

ight

lyla

ter

inth

esi

mul

atio

nw

ithth

egr

adua

lact

ivat

ion.

Thi

sis

expe

cted

beca

useo

nset

ofsy

stol

eat

the

first

link

inth

eve

ntric

leis

atth

esa

met

ime

ason

seto

fsys

tole

inth

een

tire

vent

ricle

inth

ere

fere

nces

imul

atio

n.T

hus

the

over

allv

entr

icul

arco

ntra

ctio

nis

dela

yedi

nth

esi

mul

atio

nwith

grad

uala

ctiv

atio

n.F

urth

erm

ore,

the

peak

outfl

owra

teis

less

inth

egr

adua

lact

ivat

ion

sim

ulat

ion

than

inth

ere

fere

nces

imul

atio

n.T

heflo

wth

roug

hthe

mitr

also

urce

show

son

lysm

alld

iscr

epan

cies

,e.g.

the

flow

isne

vern

egat

ive

inth

egr

adua

lact

ivat

ion

sim

ulat

iona

sin

the

refe

renc

esim

ulat

ion.

The

resu

ltspr

esen

tedin

this

sect

ion

show

that

we

obta

inre

ason

abler

esul

ts

Page 67: MR · 2002. 2. 20. · Adeler A TV Erhver vsf or skerpr ojekt EF 698 IMM-PHD-2001-86 ISSN 0909-3192 ISBN 87-88306-13-5 c 2001 by Pernille Thorup Adeler Printed by IMM, DTU Bookbinder

114

Sim

ulat

ing

path

olog

ical

hear

tcon

ditio

ns

only

with

anun

phys

iolo

gica

lpara

met

erset

ting(

ò 10.0

m/s

)and

the

resu

ltsar

eve

ryse

nsitiv

eto

the

activ

atio

nof

the

papi

llary

mus

cle.

Fur

ther

mor

e,th

egr

adua

lac

tivat

ion

only

slig

htly

influ

ence

sthe

sim

ulat

ion

resu

lts,th

usw

ech

oose

nott

ous

egra

dual

activ

atio

n.

6.3.

3R

egio

nala

ctiv

atio

n

Thi

sse

ctio

ndes

crib

esth

em

odel

setu

pfo

rahe

alth

yhum

anw

henw

eus

eonl

yth

ere

gion

alac

tivat

ion.

Thi

sse

tup

invo

lves

the

para

met

ers

Þ"à ,Þ"ß ,Ýå an

d

Ý áãä ,w

hile

æðç and

æðç éàêë

are

unch

ange

dfrom

the

orig

inal

mod

else

tup

(see

Tabl

e3.

1fo

rth

eor

igin

alm

odel

setu

p).

InS

ectio

n6.1

we

saw

that

path

olog

ical

hear

tcon

ditio

nsaf

fect

the

rela

xatio

nof

the

vent

ricul

arhe

artm

uscl

e.T

hust

hepr

imar

ypa

ram

eter

toad

just

isth

ere

lax-

atio

nra

teco

nsta

nt

Þuß forth

eve

ntric

le,w

hich

corr

espo

ndsto

the

reci

proc

alof

the

para

met

er

Ü inphy

siol

ogic

alm

easu

rem

ents

.Adj

ustin

g

Þ ß chang

esth

edu

ratio

ntim

eof

dias

tole

and

cons

eque

ntlyt

hepe

riod

ofth

eac

tivat

ion

func

tion,

whi

chin

turn

mea

nsth

atth

ele

ngth

ofa

hear

tcyc

leis

alte

red.

We

choo

seno

tto

adju

stan

yof

the

othe

rpar

amet

ersfo

rth

eac

tivat

ion

func

tion,

sinc

ew

ew

illlim

itou

rin

vest

igat

ions

toth

eea

rlyfil

ling

phas

ewhi

chis

durin

gre

laxa

tion.

For

ahe

alth

yhu

man

Ü isthe

sam

efor

the

entir

eve

ntric

le,s

oth

ere

are

nore

gion

aldi

ffer

ence

sinth

ere

laxa

tion.

Thu

s

Þ"ß shoul

dbe

the

sam

efor

the

entir

eve

ntric

lein

the

mod

el.

Whe

nco

mpa

ringt

heva

lue

of

Þ ß (% !!(Ø) )

inou

rre

fere

ncem

odel

with

the

reci

proc

alof

mea

sure

dval

ueso

f

Ü forthe

vent

ricle

asa

who

le(i.

e.no

tfor

any

part

icul

arre

gion

inth

eve

ntric

le)it

turn

sout

that

this

valu

eco

rres

pond

stoa

dise

ased

hear

t.T

heva

lues

ofth

eac

tivat

ion

func

tion

para

met

ers

inou

rre

fere

ncem

odel

(see

Tabl

e3.

1)w

ere

notc

hose

nbas

edon

phys

iolo

gica

lkn

owle

dge,

butw

ere

sett

oac

hiev

eth

esa

met

imin

gin

the

mod

elas

inth

eM

Rda

taw

eco

mpa

redth

em

odel

with

.Nis

hiha

raet

al.(

2000

)find

that

inpa

tient

swith

HC

M

Ü is54

* 12m

s(m

ean

* SD

),w

hile

inth

eco

ntro

lgro

upof

heal

thyp

erso

ns

Üis

32

* 7m

s.S

imila

rly,O

hte

etal

.(19

99)fi

ndth

atin

patie

ntsw

ithe.

g.A

MI

Ü is48

.5

* 6m

s,w

hile

Ü forahe

alth

ycon

trol

grou

pis

37.6

* 2.6

ms.

Not

eth

atal

lof

the

stud

iesm

entio

neda

reof

pers

onsw

ithan

agea

roun

d60

year

s.B

ased

onth

ese

mea

sure

men

tsof

Ü wecha

nge

Þ"ß from

%!!(Ø) to

% +,(Ø) .T

hepe

riod

ofth

eac

tivat

ion

func

tion

(and

cons

eque

ntlyt

hele

ngth

ofa

hear

tcyc

le)t

henc

hang

esfr

om0.

936

sto

0.90

9s.

Inre

duci

ngth

edu

ratio

nofd

iast

olet

hele

ngth

ofa

hear

tcy

cle

hasb

eenr

educ

ed,a

ndth

isis

phys

iolo

gica

llyco

rrec

t.To

dete

rmin

ethe

affe

ctof

the

chan

gedr

elax

atio

nrat

e

Þ"ß andth

esh

orte

rhea

rtcy

cle

leng

th,w

eco

mpa

rea

sim

ulat

ion

with

thes

enew

para

met

ersim

plem

ente

dw

ithth

ere

fere

nces

imul

atio

nde

scrib

edin

Cha

pter

4.G

ener

ally

the

resu

ltsar

e

6.3

Cal

ibra

ting

the

mod

el11

5

very

sim

ilar.

We

find

that

the

pres

sure

leve

l(no

tsho

wn)

isra

ised

alit

tlew

ithth

ene

wpa

ram

eter

choi

cean

dth

eve

loci

tytim

epr

ofile

atth

eao

rtic

outfl

ow(n

otsh

own)

issl

ight

lych

ange

d.T

heve

loci

tytim

epr

ofile

satt

hem

itral

valv

ear

eal

soch

ange

d,w

hich

isse

enin

Fig

ure

6.14

.The

wid

thof

the

first

peak

inth

em

itral

ring

profi

leis

wid

eran

dth

em

eanv

eloc

ityov

erth

em

itral

ring

ispr

actic

ally

zero

attw

opo

ints

intim

e.F

rom

the

com

paris

onbe

twee

nthe

refe

renc

esim

ulat

ion

and

MR

data

inC

hapt

er5

we

seet

hatb

oth

ofth

esef

eatu

resa

reim

prov

emen

tsof

the

sim

ulat

ion

resu

lts.I

nth

eve

loci

typr

ofile

betw

eent

hele

aflet

tips

from

the

sim

ulat

ionw

ith

Þ"ßò% +,(Ø) w

ese

eane

gativ

eve

loci

tyju

stbe

fore

æ ò 1.2

s,w

hich

isre

late

dto

the

sem

iclo

sure

ofth

em

itral

valv

e.T

hem

odel

with

the

abov

ede

scrib

edpa

ram

eter

adju

stm

ents(

Þ ß andle

ngth

ofhe

artc

ycle

)w

ere

fert

oas

a’h

ealth

ype

rson

’.In

the

follo

win

gw

eus

eth

ism

odel

setu

pto

stud

ydiff

eren

tmec

hani

smsin

volv

edin

the

early

fillin

gof

the

left

vent

ricle

.The

sem

echa

nism

sare

exam

ined

onth

eba

siso

fvel

ocity

profi

lesa

long

six

tran

sver

selin

esin

the

vent

ricle

asde

scrib

edin

Sec

tion6

.3.1

ando

nth

eba

siso

fth

epr

essu

redi

ffer

ence

betw

eena

triu

man

dve

ntric

le,s

ince

the

pres

sure

grad

ient

isas

sum

edto

bew

hatd

rives

the

bloo

din

toth

eve

ntric

le(s

eeS

ectio

n6.1

.1).

Þ ßò% +,(Ø)

refe

renc

e,

Þ"ßò% !!(Ø)

11.2

1.4

1.6

1.8

t[s]

-40

-200

20

40

60

velocity[cm/s]

11.2

1.4

1.6

1.8

t[s]

-40

-200

20

40

60

velocity[cm/s]

Fig

ure

6.14

:Vel

ocity

time

profi

leof

the

mea

nvel

ocity

(cm

/s)a

tthe

mitr

alrin

g(s

olid

)an

dbe

twee

nthe

leafl

ettip

s(d

ashe

d)fr

oma

sim

ulat

ion

whe

re

Þ"ßò

% +,(Ø) (le

ft)an

dfr

omth

ere

fere

nces

imul

atio

nw

here

Þ ßò%!!(Ø)

(rig

ht).

Page 68: MR · 2002. 2. 20. · Adeler A TV Erhver vsf or skerpr ojekt EF 698 IMM-PHD-2001-86 ISSN 0909-3192 ISBN 87-88306-13-5 c 2001 by Pernille Thorup Adeler Printed by IMM, DTU Bookbinder

116

Sim

ulat

ing

path

olog

ical

hear

tcon

ditio

ns

+4

+3

+2

+1

ML

T

-2

-25

ms

PV

ÑÒÓ

+25

ms

+51

ms

+76

ms

1.01

0s1.

035

s1.

060

s1.

086s

1.11

1s

0.2

0.4

0.6

0.8

0.2

0.4

0.6

0.8

0.2

0.4

0.6

0.8

0.2

0.4

0.6

0.8

0.2

0.4

0.6

0.8

0.2

0.4

0.6

0.8

0.2

0.4

0.6

0.8

0.2

0.4

0.6

0.8

0.2

0.4

0.6

0.8

0.2

0.4

0.6

0.8

0.2

0.4

0.6

0.8

0.2

0.4

0.6

0.8

0.2

0.4

0.6

0.8

0.2

0.4

0.6

0.8

0.2

0.4

0.6

0.8

0.2

0.4

0.6

0.8

0.2

0.4

0.6

0.8

0.2

0.4

0.6

0.8

0.2

0.4

0.6

0.8

0.2

0.4

0.6

0.8

0.2

0.4

0.6

0.8

0.2

0.4

0.6

0.8

0.2

0.4

0.6

0.8

0.2

0.4

0.6

0.8

0.2

0.4

0.6

0.8

0.2

0.4

0.6

0.8

0.2

0.4

0.6

0.8

0.2

0.4

0.6

0.8

0.2

0.4

0.6

0.8

0.2

0.4

0.6

0.8

Fig

ure

6.15

:V

eloc

itypr

ofile

sof

abso

lute

velo

city

(m/s

)alo

ngsi

xlin

esat

five

times

from

asi

mul

atio

nof

ahe

alth

yhum

an.I

fth

eve

loci

typr

ofile

ispl

otte

dat

the

time

ofP

Vat

alin

e,P

Vis

mar

ked

bya

Ô .F

igur

e6.

15sh

ows

the

spat

ialv

eloc

itypr

ofile

s(of

abso

lute

velo

city

)alo

ngth

esi

xtr

ansv

erse

lines

inth

eve

ntric

leat

five

times

:25

ms

befo

reP

Vat

the

mitr

alle

aflet

tips,

atth

etim

eof

PV

atth

em

itral

leafl

ettip

s,an

d25

,51

and

76m

saf

ter

the

time

ofP

Vat

the

mitr

alle

aflet

tips.

The

velo

city

profi

les

inF

igur

e6.

15ar

esi

mila

rto

thos

eof

ahe

alth

yper

son

from

MR

mea

sure

men

tssho

wn

inF

igur

e6.

1.F

igur

e6.

1sh

ows

that

the

velo

city

profi

les

beco

mew

ider

and

decr

ease

inhe

ight

ata

line

astim

ein

crea

ses.

Inth

esi

mul

atio

nw

edo

nots

eea

wid

erpr

ofile

ata

line

astim

ein

crea

ses,b

utth

ere

isa

decr

ease

inhe

ight

.The

MR

data

isav

erag

edov

erm

any

hear

tcyc

les

and

this

coul

dre

sulti

nw

ider

and

low

erpr

ofile

stha

nw

hatt

ypic

ally

occu

rsin

one

spec

ific

hear

tcyc

le.

The

peak

velo

city

isob

tain

edat

the

sam

etim

eat

four

ofth

elin

esin

the

MR

6.3

Cal

ibra

ting

the

mod

el11

7

data

,inth

esi

mul

atio

nthi

sis

true

for

thre

eoft

helin

es.T

hepr

ofile

sfro

mth

eM

Rda

tash

owth

atth

eje

tget

sslig

htly

wid

erfu

rthe

rdow

nin

the

vent

ricle

ata

fixed

time.

The

sim

ulat

ion

show

sth

eop

posi

te:a

slig

htly

narr

ower

jetf

urth

erdo

wn

inth

eve

ntric

leat

afix

edtim

e.F

urth

erm

ore,

inth

esi

mul

atio

nth

eve

loci

typr

ofile

sat

the

2,3

and

4cm

lines

are

tria

ngul

arin

shap

e,th

isis

nott

rue

for

the

MR

data

,ag

aint

his

coul

dbe

aco

nseq

uenc

eofth

eav

erag

ingi

nth

eM

Rda

ta.

Fig

ure

6.16

show

sth

epe

akve

loci

tyP

Vat

the

six

lines

from

the

sim

ulat

ion

alon

gw

ithth

esa

med

ata

from

MR

mea

sure

men

tsof

heal

thyp

erso

ns.T

heM

Rda

taar

eth

esa

mea

sin

Fig

ure

6.2,

soth

eM

Rda

taar

esh

own

asm

ean

valu

ew

ithth

est

anda

rdde

viat

ion

show

nas

erro

rbar

s.T

hefig

ure

show

sth

atP

Vis

gene

rally

high

erin

the

sim

ulat

ion,

exce

ptat

the

ML

Tlin

e.A

tth

elin

esju

stup

-an

ddo

wns

trea

mof

the

ML

Tlin

eP

Vis

with

inth

est

anda

rdde

viat

ion

ofth

eM

Rda

ta,b

utfu

rthe

rdow

nstr

eam

PV

ism

uch

high

erin

the

sim

ulat

ion.

Fur

ther

mor

e,P

Vin

crea

sesd

owns

trea

mof

the

ML

Tlin

ein

the

sim

ulat

ion,

whi

leit

decr

ease

sinth

eM

Rm

easu

rem

ents

.The

latte

ris

prob

ably

rela

tedt

oth

eje

tbec

omin

gnar

row

erfu

rthe

rdow

nin

the

vent

ricle

seen

inth

eve

loci

typr

ofile

sfr

omth

esi

mul

atio

nab

ove,

seeF

igur

e6.

15.I

nth

eM

Rda

tath

eje

tbec

omes

wid

erfu

rthe

rdow

nin

the

vent

ricle

,whi

chle

adst

olo

wer

PV.

The

narr

ower

jeti

nth

esi

mul

atio

nco

uld

bea

resu

ltof

the

vort

exm

otio

n,w

hich

ism

uch

mor

epr

onou

nced

inth

esi

mul

atio

nth

anse

enin

MR

mea

sure

men

ts,se

eSec

tion5

.2.M

ore

pron

ounc

edvo

rtic

esw

ould

leav

ele

ssro

omfo

rth

eje

t,he

reby

mak

ing

itna

rrow

er.

Thi

sag

ain

mig

htbe

are

sulto

fthe

mod

elbe

ing

only

2D,w

hile

the

MR

mea

sure

men

tsare

ofth

efu

ll3D

phen

omen

on.

Fig

ure

6.17

show

sth

eve

loci

tyin

dex

VI

atth

esi

xlin

esfr

omth

esi

mul

atio

nan

dth

eM

Rda

taof

heal

thyp

erso

ns.T

hela

ttera

reid

entic

alto

thos

esh

own

inF

igur

e6.

3.T

heve

loci

tyin

dex

VI

isco

nsid

erab

lyhig

heri

nth

esi

mul

atio

n,be

ing

only

iden

tical

,nat

ural

ly,at

the

ML

Tlin

ew

ithth

eM

Rda

ta.F

urth

erm

ore,

VI

isgr

eate

rthan

1fo

rlin

esdo

wns

trea

mof

ML

T,w

hich

isa

resu

ltofP

Vbe

ing

high

erat

lines

dow

nstr

eam

inth

eve

ntric

leth

anat

the

ML

Tlin

e.F

igur

e6.

18sh

ows

the

time

dela

yTD

atth

esi

xlin

esfr

omth

esi

mul

atio

nand

from

the

MR

data

ofhe

alth

yper

sons

,whi

char

eth

esa

mea

stho

sesh

own

inF

ig-

ure

6.4.

The

figur

esh

ows

that

TD

inth

esi

mul

atio

nis

com

para

blet

oT

Dfr

omth

eM

Rda

ta;o

nly

atth

elin

e2

cmup

stre

amof

the

ML

Tlin

eis

TD

notw

ithin

the

stan

dard

devi

atio

n.T

heva

lue

ofT

Dat

the

3cm

line

from

the

sim

ulat

ion

islo

w(0

ms)

and

resu

ltsin

ale

sssm

ooth

lyin

crea

sing

TD

curv

eas

fort

heM

Rda

ta.T

helo

wva

lue

ofT

Dat

the

3cm

line

isa

resu

ltsof

the

vort

expr

esen

tinth

eve

ntric

lefr

omth

epr

evio

ushe

artc

ycle

(des

crib

edin

Sec

tion5

.2).

Thi

svo

rtex

exte

ndst

hein

flow

jet(

spat

ially

)and

cons

eque

ntlyt

heve

loci

tybe

com

eshi

ghat

anea

rlier

time

low

erin

the

vent

ricle

.Thi

sis

seen

inth

ele

ftpl

otin

Fig

ure

6.19

that

show

sth

e

Page 69: MR · 2002. 2. 20. · Adeler A TV Erhver vsf or skerpr ojekt EF 698 IMM-PHD-2001-86 ISSN 0909-3192 ISBN 87-88306-13-5 c 2001 by Pernille Thorup Adeler Printed by IMM, DTU Bookbinder

118

Sim

ulat

ing

path

olog

ical

hear

tcon

ditio

ns

-2

01

23

4Distance

from

MLT

[cm]

0.2

0.4

0.6

0.81

PV[m/s]

MR

healthy

Healthy

Fig

ure

6.16

:Pea

kvel

ocity

(PV

)att

hesi

xlin

esfr

omM

Rm

easu

rem

entso

fhe

alth

ype

rson

s(

Õ )an

dfr

oma

sim

-ul

atio

nof

ahe

alth

yper

son(

& ).

-2

01

23

4Distance

from

MLT

[cm]

0.2

0.4

0.6

0.81

1.2

1.4

1.6

VI

MR

healthy

Healthy

Fig

ure6

.17:

Vel

ocity

inde

x(V

I)at

the

six

lines

from

MR

mea

sure

men

tsof

heal

thy

pers

ons(

Õ )an

dfr

oma

sim

-ul

atio

nof

ahe

alth

yper

son(

& ).

-2

01

23

4Distance

from

MLT

[cm]

-500

50

100

TD[ms]

MR

healthy

Healthy

Fig

ure

6.18

:Tim

ede

lay(

TD

)at

the

six

lines

from

MR

mea

sure

men

tsofh

ealth

ype

rson

s(

Õ )an

dfr

oma

sim

ulat

iono

fahe

alth

yper

son(

& ).

6.3

Cal

ibra

ting

the

mod

el11

9

2.he

artc

ycle

Time

1.035

1.he

artc

ycle

Time

0.151

Fig

ure

6.19

:Vel

ocity

field

atth

etim

eof

PV

atth

eM

LT

line

inth

ese

cond

hear

tcy

cle

(left)

and

inth

efir

sthe

artc

ycle

(rig

ht).

velo

city

field

atth

etim

eof

PV

atth

eM

LT

line.

Ifth

evo

rtex

was

notp

rese

ntP

Vw

ould

belo

wer

and

TD

wou

ldbe

high

erat

the

3an

d4

cmlin

es.W

eca

nsu

ppor

tth

isby

look

ing

atth

eve

loci

tyfie

ldfr

omth

efir

sthe

artc

ycle

ofth

esi

mul

atio

n,w

here

novo

rtex

ispr

esen

tlow

inth

eve

ntric

le;s

eeth

erig

htpl

otin

Fig

ure

6.19

.F

rom

this

figur

eit

iscl

eart

hatt

heje

tdoe

snot

reac

hasf

arin

toth

eve

ntric

leas

inth

ese

cond

cycl

e.F

igur

e6.2

0sh

ows

the

time

varia

tiono

fthe

pres

sured

iffer

ence

betw

eena

triu

man

dven

tric

le.T

heve

ntric

ular

pres

surei

sm

easu

reda

ppro

xim

atel

y2/3

dow

nin

the

vent

ricle

from

the

mitr

alrin

g,w

hile

the

atria

lpre

ssur

eism

easu

redin

the

mid

dle

ofth

eat

rium

.In

the

sim

ulat

ion

we

find

ape

akpr

essu

redi

ffer

ence

durin

gea

rlyfil

ling

ofap

prox

imat

ely2

mm

Hg

(the

first

peak

inF

igur

e6.

20is

rela

tedt

oea

rlyfil

ling)

.T

hela

rges

tpea

kin

Fig

ure

6.20

isca

used

byat

rials

ysto

le.S

tein

eeta

l.(1

999)

mea

sure

dusi

ngco

lour

M-m

ode

Dop

pler

echo

card

iogr

aphy

the

pres

sure

diff

eren

cebe

twee

nthe

mitr

altip

and

the

apex

and

betw

eent

heat

rium

and

the

mi-

tral

tipdu

ring

early

dias

tole

indo

gs.T

hey

foun

dth

atth

epe

akpr

essu

rediff

eren

cebe

twee

nmitr

altip

and

apex

was

1.9

* 0.9

mm

Hg

and

betw

eena

triu

man

dm

itral

tips

itw

as2.

4

* 0.7

mm

Hg.

Thi

sgi

ves

am

eanv

alue

ofth

epr

essu

redi

ffer

ence

from

atriu

mto

apex

of4.

3m

mH

g.T

hust

hepe

akpr

essu

redi

ffer

ence

inth

esi

m-

ulat

ion

isre

ason

ablec

ompa

redt

om

easu

rem

entsw

hen

we

take

into

acco

untth

ede

viat

ions

inth

em

easu

rem

entsa

ndth

efa

ctth

atth

epr

essu

rele

veli

sto

olo

win

the

mod

el,s

eeS

ectio

n4.5

.T

heag

reem

entof

the

velo

city

profi

les

and

velo

city

inde

xesb

etw

eens

imul

a-tio

nan

dM

Rda

tais

reas

onab

lyfai

r.B

ecau

seof

prev

ious

com

paris

onsb

etw

een

Page 70: MR · 2002. 2. 20. · Adeler A TV Erhver vsf or skerpr ojekt EF 698 IMM-PHD-2001-86 ISSN 0909-3192 ISBN 87-88306-13-5 c 2001 by Pernille Thorup Adeler Printed by IMM, DTU Bookbinder

120

Sim

ulat

ing

path

olog

ical

hear

tcon

ditio

ns

11.2

1.4

1.6

1.8

t[s]

-101234

pressure[mmHg]

Fig

ure

6.20

:Tim

eva

riatio

nof

pres

sure

diff

eren

ce(m

mH

g)be

twee

natr

ium

and

vent

ricle

from

asi

mul

atio

nofa

heal

thyh

uman

.

mod

elan

dM

Rda

ta(C

hapt

er3)

,we

coul

dno

texp

ecti

tto

bebe

tter.

Inth

efo

l-lo

win

gin

vest

igat

ions

we

focu

son

the

rela

tive

chan

gesin

PV,

VI,

TD

andp

ress

ure

diff

eren

cew

hen

we

sim

ulat

ediff

eren

tmec

hani

sms.

6.4

Sim

ulat

ions

ofpa

thol

ogic

alhe

artc

ondi

tions

We

wis

hto

inve

stig

atec

erta

inm

echa

nism

sof

early

dias

tolic

fillin

gus

ing

the

mod

elde

scrib

edin

the

prev

ious

sect

ion.

We

hypo

thes

izet

hata

hear

tdis

ease

whi

chaf

fect

sth

edi

asto

licfu

nctio

nca

nbe

mod

elle

dei

ther

bya

chan

gein

the

rela

xatio

nra

te

Þuß orsi

mpl

yby

letti

nga

regi

onof

the

hear

twal

lbe

inac

tive.

The

form

erco

rres

pond

stoa

chan

gein

Ü seeni

nm

easu

rem

entso

fsev

eral

patie

ntty

pes,

whi

leth

ela

tterc

orre

spon

dsto

am

yoca

rdia

linfa

rctio

n,w

here

part

ofth

ehe

artw

alld

iesd

ueto

abl

ocka

geof

the

coro

nary

arte

riesa

ndsu

bseq

uent

lylose

sits

abili

tyto

cont

ract

and

rela

x.W

ein

clud

eth

rees

cena

riosin

ouri

nves

tigat

ion

1.sl

owre

laxa

tiono

fthe

entir

eve

ntric

le

2.sl

owre

laxa

tiono

fthe

apic

alre

gion

ofth

eve

ntric

le

3.in

activ

e(p

assiv

e)ap

ical

regi

on

6.4

Sim

ulat

ions

ofpa

thol

ogic

alhe

artc

ondi

tions

121

The

first

scen

ario

coul

dha

vebe

enin

vest

igat

edw

ithou

tthe

new

activ

atio

nfu

nctio

nim

plem

ente

din

the

mod

el,b

ecau

seit

corr

espo

ndsto

ach

ange

in

Þuß

for

the

entir

eve

ntric

le.T

his

scen

ario

corr

espo

ndsto

agl

obal

dysf

unct

iono

fth

eve

ntric

le,e

.g.c

ause

dby

agl

obal

isch

emia

.The

seco

ndsc

enar

ioco

rres

pond

stoa

loca

ldys

func

tiono

fth

ehe

artc

ause

dby

anis

chem

icap

ical

regi

ondu

eto

e.g.

CA

Dor

AM

I.T

heth

irdsc

enar

iore

sem

bles

wha

thap

pens

durin

ga

myo

card

ial

infa

rctio

nan

dth

ussh

ould

com

pare

the

best

with

resu

ltsfr

omA

MI

patie

nts.

We

expe

ctto

sees

igni

fican

tcha

nges

insi

mul

atio

nres

ults

inth

eth

isca

se,b

ecau

sean

inac

tive

regi

onis

ave

rydr

astic

chan

geof

the

mod

el.

6.4.

1S

low

rela

xatio

nof

the

vent

ricle

Asl

ower

rela

xatio

nin

the

entir

eve

ntric

leco

rres

pond

stom

odel

ling

adi

seas

edhe

artw

here

the

glob

alfu

nctio

ning

ofth

ehe

artis

redu

ced.

We

achi

eve

asl

ower

rela

xatio

nby

decr

easi

ngth

eva

lue

of

Þuß forth

een

tire

vent

ricle

corr

espo

ndin

gtoan

incr

ease

in

Ü .Nishi

hara

etal

.(20

00)r

epor

t

Ü values

of54

* 12m

sfo

rpa

tient

sw

ithH

CM

,whi

leS

t.G

oare

tal.

(199

1)re

port

Ü values

of59

* 8m

sfo

rpa

tient

sw

ithD

CM

,an

dfin

ally

Oht

eet

al.(

1999

)rep

ortv

alue

sof

47

* 6.3

ms

for

CA

Dpa

tient

s.B

ased

onth

eset

hree

stud

iesw

ead

just

Þ"ß to% $(Ø) co

rres

pond

ing

to

Ü ò 60

ms.

With

Þ"ßò% $(Ø) th

epe

riod

ofth

eac

tivat

ion

func

tion,

and

cons

eque

ntlyt

hele

ngth

ofth

ehe

artc

ycle

,bec

omes

0.94

2s.

Apa

rtfr

omth

ese

adju

stm

ents

,the

para

met

erse

tting

isid

entic

alto

the

refe

renc

esim

ulat

ion.

The

velo

city

profi

lesa

long

the

six

tran

sver

selin

esin

the

vent

ricle

are

show

nin

Fig

ure

6.21

atfiv

etim

es:2

6m

sbe

fore

PV

atth

em

itral

leafl

ettip

s,at

the

time

ofP

Vat

the

mitr

alle

aflet

tips,

and

26,5

2an

d78

ms

afte

rthe

time

ofP

Vat

the

mitr

alle

aflet

tips.

Fro

mth

efig

ure

we

seet

hatt

hesh

apeo

fth

eve

loci

typr

ofile

sha

veno

tcha

nged

com

pare

dto

asi

mul

atio

nofa

heal

thyh

uman

(Fig

ure

6.15

).F

igur

es6.

22–6

.24s

how

the

peak

velo

city

PV,

the

velo

city

inde

xV

I,an

dth

etim

ede

layT

D,r

espe

ctive

ly.I

nea

chof

thes

ethr

eefig

ures

the

corr

espo

ndin

gdat

afr

omM

Rm

easu

rem

entso

fhe

alth

ype

rson

sand

from

asi

mul

atio

nof

ahe

alth

ype

rson

are

incl

uded

.The

data

from

the

MR

mea

sure

men

tsisid

entic

alto

that

ofF

igur

es6.

2–6.

4,w

hile

the

data

from

asi

mul

atio

nofa

heal

thyp

erso

nis

iden

tical

toth

atof

Fig

ures

6.16

–6.1

8.F

rom

both

the

velo

city

profi

lesa

ndth

epl

otof

PV

we

seet

hatt

hepe

akve

loci

-tie

sin

the

pres

ents

imul

atio

nare

low

erth

anin

the

sim

ulat

iono

fahe

alth

yper

son.

The

peak

velo

citie

sst

illha

vea

tend

ency

toin

crea

sefu

rthe

rdow

nstr

eam

ofth

eM

LT

line,

whe

reth

eM

Rda

tash

ows

ade

crea

se.T

here

lativ

ely

high

PV

valu

eat

the

3cm

line

isno

trel

ated

toth

ein

flow

jetb

utis

due

toth

evo

rtex

inth

elo

wer

part

ofth

eve

ntric

le.T

his

can

bese

enby

look

ing

atth

eve

loci

tyfie

ldat

the

time

Page 71: MR · 2002. 2. 20. · Adeler A TV Erhver vsf or skerpr ojekt EF 698 IMM-PHD-2001-86 ISSN 0909-3192 ISBN 87-88306-13-5 c 2001 by Pernille Thorup Adeler Printed by IMM, DTU Bookbinder

122

Sim

ulat

ing

path

olog

ical

hear

tcon

ditio

ns

+4

+3

+2

+1

ML

T

-2

-26

ms

PV

ÑÒÓ

+26

ms

+52

ms

+78

ms

1.04

7s1.

073

s1.

099

s1.

125s

1.15

1s

0.2

0.4

0.6

0.8

0.2

0.4

0.6

0.8

0.2

0.4

0.6

0.8

0.2

0.4

0.6

0.8

0.2

0.4

0.6

0.8

0.2

0.4

0.6

0.8

0.2

0.4

0.6

0.8

0.2

0.4

0.6

0.8

0.2

0.4

0.6

0.8

0.2

0.4

0.6

0.8

0.2

0.4

0.6

0.8

0.2

0.4

0.6

0.8

0.2

0.4

0.6

0.8

0.2

0.4

0.6

0.8

0.2

0.4

0.6

0.8

0.2

0.4

0.6

0.8

0.2

0.4

0.6

0.8

0.2

0.4

0.6

0.8

0.2

0.4

0.6

0.8

0.2

0.4

0.6

0.8

0.2

0.4

0.6

0.8

0.2

0.4

0.6

0.8

0.2

0.4

0.6

0.8

0.2

0.4

0.6

0.8

0.2

0.4

0.6

0.8

0.2

0.4

0.6

0.8

0.2

0.4

0.6

0.8

0.2

0.4

0.6

0.8

0.2

0.4

0.6

0.8

0.2

0.4

0.6

0.8

Fig

ure

6.21

:V

eloc

itypr

ofile

sof

abso

lute

velo

city

(m/s

)alo

ngsi

xlin

esat

five

times

from

asi

mul

atio

nwhe

reve

ntric

ular

rela

xatio

nis

slow

.If

the

velo

city

profi

leis

plot

ted

atth

etim

eof

PV

ata

line,

PV

ism

arke

dby

a

Ô .of

PV

atth

eM

LT

line

show

nin

Fig

ure6

.25.

Bec

ause

ofth

isvo

rtex

we

shou

ldno

tpu

ttoo

muc

hem

phas

ison

the

velo

city

inde

xesf

rom

the

3an

d4

cmlin

es,s

ince

they

are

notr

elat

edto

the

inflo

wje

tbut

rath

erto

the

vort

ex.

We

only

see

asm

allc

hang

ein

VI

inth

epr

esen

tsim

ulat

ion

com

pare

dto

asi

mul

atio

nof

ahe

alth

ype

rson

.How

ever

,F

igur

e6.

23sh

ows

that

the

velo

city

inde

xV

Iis

gene

rally

high

erin

the

sim

ulat

ion

than

seen

inM

Rm

easu

rem

ents

ofhe

alth

yper

sons

.We

have

nom

easu

redd

ata

ofV

Iin

patie

ntsw

itha

glob

ally

redu

cedf

unct

ioni

ngof

the

vent

ricle

toco

mpa

rew

ith.

Fig

ure

6.24

ofT

Dsh

ows

that

atlin

es1

and

2cm

dow

nstr

eam

ofth

eM

LT

line

TD

issu

bsta

ntia

llyhi

gher

com

pare

dto

asi

mul

atio

nof

ahe

alth

yper

son.

At

the

3an

d4

cmlin

esT

Dis

noth

ighe

ror

only

mod

erat

elyh

ighe

r.T

Dat

the

3an

d4

cmlin

esis

noto

btai

nedf

orth

ein

flow

jet,

asde

scrib

edab

ove,

butr

athe

r

6.4

Sim

ulat

ions

ofpa

thol

ogic

alhe

artc

ondi

tions

123

-2

01

23

4Distance

from

MLT

[cm]

0.2

0.4

0.6

0.81

PV[m/s]

MR

healthy

Healthy

Ventr.

slow

Fig

ure

6.22

:Pea

kvel

ocity

(PV

)att

hesi

xlin

esfr

omM

Rm

easu

rem

entso

fhe

alth

yper

sons

(

Õ ),an

dfr

oma

sim

-ul

atio

nof

ahe

alth

ype

rson

(

& )an

da

sim

ulat

ion

whe

reth

eve

ntric

ular

re-

laxa

tion

issl

ow(

- ).

-2

01

23

4Distance

from

MLT

[cm]

0.2

0.4

0.6

0.81

1.2

1.4

1.6

VI

MR

healthy

Healthy

Ventr.

slow

Fig

ure6

.23:

Vel

ocity

inde

x(V

I)at

the

six

lines

from

MR

mea

sure

men

tsof

heal

thyp

erso

ns(

Õ ),an

dfr

oma

sim

-ul

atio

nof

ahe

alth

ype

rson

(

& )an

da

sim

ulat

ion

whe

reth

eve

ntric

ular

re-

laxa

tion

issl

ow(

- ).

-2

01

23

4Distance

from

MLT

[cm]

-500

50

100

TD[ms]

MR

healthy

Healthy

Ventr.

slow

Fig

ure

6.24

:Tim

ede

lay(

TD

)at

the

six

lines

from

MR

mea

sure

men

tsofh

ealth

ype

rson

s(

Õ ),an

dfro

ma

sim

ulat

iono

fahe

alth

yper

son(

& )and

asi

mul

atio

nwhe

reth

eve

ntric

ular

rela

xatio

nis

slow

(

- ).

Page 72: MR · 2002. 2. 20. · Adeler A TV Erhver vsf or skerpr ojekt EF 698 IMM-PHD-2001-86 ISSN 0909-3192 ISBN 87-88306-13-5 c 2001 by Pernille Thorup Adeler Printed by IMM, DTU Bookbinder

124

Sim

ulat

ing

path

olog

ical

hear

tcon

ditio

ns

from

the

vort

exin

the

vent

ricle

.If

the

vort

exw

asno

tpre

sent

we

wou

ldex

pect

that

TD

wou

ldbe

muc

hhi

gher

atlo

wer

lines

.Stu

gaar

deta

l.(1

994b

)mea

sure

sth

eap

ical

time

dela

yin

dogs

,bot

hin

heal

thy

dogs

and

whe

nbe

ta-b

lock

adeis

indu

ced.

Acc

ordi

ngto

Kim

(200

1)in

duct

iono

fbet

a-bl

ocka

deaf

fect

sthe

vent

ricle

glob

ally

,so

we

can

uset

his

for

com

paris

onw

ithou

rpre

sent

sim

ulat

ion.

Stu

gaar

det

al.(

1994

b)fin

dth

atth

em

eanv

alue

ofth

eap

ical

time

dela

yfo

rhe

alth

ydog

sis

21m

s,an

dit

incr

ease

sto80

ms

whe

nbe

ta-b

lock

adeis

indu

ced.

Thu

sth

esu

bsta

ntia

llyin

crea

sedT

Din

ours

imul

atio

ncom

pare

swel

lwith

mea

sure

men

ts.

Ifw

eco

mpa

reth

eve

loci

tyfie

ldat

the

time

ofpe

akve

loci

tyat

the

mitr

alle

aflet

tips

(Fig

ure

6.25

)with

the

velo

city

field

from

ahe

alth

yhum

an(F

igur

e6.

19)w

eca

nse

etha

tthe

inflo

wje

tis

nota

sst

rong

.It

hasl

ower

velo

citie

sand

does

not

reac

has

deep

lyin

toth

eve

ntric

leas

for

ahe

alth

yhum

an.B

oth

ofth

esefi

ndin

gsar

eid

entic

alto

the

findi

ngs

ofth

eve

loci

typr

ofile

san

din

dexe

sab

ove

and

are

sign

sofp

oord

iast

olic

fillin

g.F

igur

e6.

26sh

ows

the

time

varia

tion

ofth

epr

essu

redi

ffer

ence

betw

eent

heat

rium

and

vent

ricle

durin

gdi

asto

lefr

omth

esi

mul

atio

n.B

yco

mpa

ringt

hefig

ure

with

the

sam

efro

ma

sim

ulat

ion

ofa

heal

thy

pers

on(F

igur

e6.

20)w

ese

eth

atth

epe

akpr

essu

redi

ffer

ence

durin

gea

rlyfil

ling

isre

duce

d.In

ahe

alth

yhum

anit

isap

prox

imat

ely2

mm

Hg,

whi

leit

isap

prox

imat

ely1

.2m

mH

gin

the

pres

ent

sim

ulat

ion,

i.e.a

40%

redu

ctio

n.S

tuga

arde

tal.

(199

4b)fi

nda

peak

pres

sure

diff

eren

cebe

twee

natr

ium

and

vent

ricle

of3.

9m

mH

g(m

ean

valu

e)in

heal

thy

dogs

,whi

leit

falls

to3.

4m

mH

gdu

ring

indu

ctio

nof

beta

-blo

ckad

e,thi

sis

a13

%

Time

1.073

Fig

ure

6.25

:V

eloc

ityfie

ldat

the

time

ofpe

akve

loci

tyat

the

ML

Tlin

efr

oma

sim

ulat

ionw

here

the

vent

ricul

arre

laxa

tioni

ssl

ow.

6.4

Sim

ulat

ions

ofpa

thol

ogic

alhe

artc

ondi

tions

125

11.2

1.4

1.6

1.8

t[s]

-101234

pressure[mmHg]

Fig

ure

6.26

:Tim

eva

riatio

nof

pres

sure

diff

eren

ce(m

mH

g)be

twee

natr

ium

and

vent

ricle

from

asi

mul

atio

nwhe

reth

eve

ntric

ular

rela

xatio

nis

slow

.

redu

ctio

n.Le

mm

onan

dY

ogan

atha

n(20

00a)

have

mad

ean

inve

stig

atio

nof

vent

ricul

ardy

sfun

ctio

nusi

nga

3Dm

odel

ofth

ele

ftat

rium

and

vent

ricle

base

don

the

im-

mer

sedb

ound

arym

etho

d(Le

mm

onan

dY

ogan

atha

n,200

0b).

The

irm

odel

have

been

foun

dto

bein

agre

emen

twith

clin

ical

lyob

serve

ddi

asto

licflo

wco

nditi

ons

(Lem

mon

and

Yog

anat

han,2

000b

),bu

tthe

intr

aven

tric

ular

flow

patte

rnha

snot

been

com

pare

dinde

tailw

ithe.

g.M

Rda

ta.

Lem

mon

and

Yog

anat

han(2

000a

)exa

min

ethe

bloo

dve

loci

tyin

the

vent

ricu-

lari

nflow

trac

t,th

atis

,fro

mth

em

itral

annu

lusa

nd3.

5cm

into

the

vent

ricle

.One

ofth

eirs

imul

atio

ncas

esis

sim

ilart

oou

rpre

sent

sim

ulat

ion:

dela

yedv

entr

icul

arre

laxa

tion.

The

yco

mpa

reth

eirs

imul

atio

nwith

asi

mul

atio

nwhe

reth

ere

laxa

tion

isno

rmal

.The

yfin

dth

atth

epe

akve

loci

tyis

decr

ease

dinth

edi

seas

edca

se:th

epe

akve

loci

tyat

the

mitr

alrin

gin

the

norm

alca

seis

appr

oxim

atel

y0.7

4cm

/san

dit

decr

ease

stoap

prox

imat

ely0

.68

cm/s

inth

edi

seas

edca

se.B

oth

ofth

esev

alue

sar

ehi

gher

than

ours

imila

rres

ults

and

high

erth

anth

eva

lue

from

the

MR

data

,bu

twith

inth

est

anda

rdde

viat

ion

ofth

is.

Lem

mon

and

Yog

anat

han(

2000

a)fin

dth

atth

epe

akve

loci

typr

ogre

sses

slow

erin

toth

eve

ntric

le.

Sum

mar

izin

gour

resu

lts,w

efin

dth

ata

slow

erre

laxa

tiono

fthe

entir

eve

ntri-

cle

resu

ltsin

gene

rally

low

erpe

akve

loci

tiesi

nth

eve

ntric

lean

da

dela

yedfi

lling

.It

can

beex

plai

ned

bya

redu

cedp

ress

ured

iffer

ence

betw

eent

heat

rium

and

the

Page 73: MR · 2002. 2. 20. · Adeler A TV Erhver vsf or skerpr ojekt EF 698 IMM-PHD-2001-86 ISSN 0909-3192 ISBN 87-88306-13-5 c 2001 by Pernille Thorup Adeler Printed by IMM, DTU Bookbinder

126

Sim

ulat

ing

path

olog

ical

hear

tcon

ditio

ns

vent

ricle

.The

low

erpe

akve

loci

tiesa

ndde

laye

dfilli

ngis

sim

ilart

oth

esi

mul

atio

nre

sults

ofLe

mm

onan

dY

ogan

atha

n(200

0a),w

hous

ea3D

mod

elof

the

left

side

ofth

ehe

art.

The

incr

ease

dtim

ede

lay

and

redu

cedp

ress

ured

iffer

ence

isin

ac-

cord

ance

with

the

findi

ngso

fStu

gaar

deta

l.(1

994b

),w

hom

easu

redth

ech

ange

sin

dogs

durin

gin

duct

ion

ofbe

ta-b

lock

ade,w

hich

affe

ctst

heve

ntric

legl

obal

ly.

6.4.

2S

low

rela

xatio

nof

apic

alre

gion

The

seco

ndsc

enar

iois

asi

mul

atio

nw

here

the

rela

xatio

nof

the

apic

alre

gion

(reg

ion

3in

Fig

ure

6.7)

issl

owed

.Thi

sco

rres

pond

stom

odel

ling

ahe

artw

here

the

apic

alre

gion

isis

chem

ic.S

tein

eeta

l.(1

999)

mea

sure

s

Ü inthe

apic

alre

gion

inhe

alth

ydog

sand

indo

gsw

ithac

utei

sche

mic

failu

re.A

cute

isch

emic

failu

reis

obta

ined

byin

duce

dcor

onar

ymic

roem

boliz

atio

n.S

tein

eeta

l.(1

999)

mea

sure

sa

Ü ã.àä

inth

eap

ical

regi

onin

the

isch

emic

hear

tof4

9

* 6m

s(m

ean

* SD

).T

husw

ech

oose

tole

tthe

rela

xatio

nrat

eco

nsta

nt

Þ ß be% !!(Ø) in

the

apic

alre

gion

,w

hile

itis

still

% +,(Ø) in

the

rest

ofth

eve

ntric

leas

for

ahe

alth

yhum

an.T

hele

ngth

ofa

hear

tcyc

leis

still

0.90

9s.

Fig

ure

6.27

show

sth

eve

loci

typr

ofile

sal

ong

the

six

tran

sver

selin

esat

five

times

:25

ms

befo

reP

Vat

the

mitr

alle

aflet

tips,

atth

etim

eof

PV

atth

em

itral

leafl

ettip

s,an

d25

,50

and

76m

saf

tert

hetim

eof

PV

atth

em

itral

leafl

ettip

s.T

heve

loci

typr

ofile

sar

eno

tver

ydi

ffer

entf

rom

the

ones

inth

esi

mul

atio

nof

ahe

alth

yper

soni

nF

igur

e6.

15.

Fig

ures

6.28

–6.3

0sho

wth

epe

akve

loci

tyP

V,th

eve

loci

tyin

dex

VI,

and

the

time

dela

yT

D,

resp

ectiv

ely.

Inea

chof

thes

eth

ree

figur

esth

eco

rres

pond

ing

data

from

MR

mea

sure

men

tsof

heal

thy

pers

onsa

ndA

MI

patie

ntsa

ndfr

oma

sim

ulat

iono

fahe

alth

yper

sona

rein

clud

ed.T

heda

tafr

omth

eM

Rm

easu

rem

ents

isid

entic

alto

that

ofF

igur

es6.

2–6.

4,w

hile

the

data

from

asi

mul

atio

nofa

heal

thy

pers

onis

iden

tical

toth

atof

Fig

ures

6.16

–6.1

8.F

igur

e6.

28sh

ows

that

PV

isno

tver

ydi

ffer

entin

the

pres

ents

imul

atio

ncom

-pa

red

toa

sim

ulat

ion

ofa

heal

thy

pers

on.O

nly

atth

e3

cmlin

edo

we

see

aco

nsid

erab

lyhig

herP

V.T

his

is,a

ssee

nin

the

prev

ious

sim

ulat

ion,

rela

tedt

oth

evo

rtex

pres

entin

the

vent

ricle

,as

can

bese

enby

look

ing

atth

eve

loci

tyfie

ldat

the

time

ofP

Vat

the

ML

Tlin

ein

Fig

ure

6.31

.The

chan

gein

PV

betw

eena

sim

-ul

atio

nof

ahe

alth

yper

sona

ndth

epr

esen

tsim

ulat

ion

isno

tthe

sam

eas

seen

inM

Rm

easu

rem

entsb

etw

eenh

ealth

yper

sons

and

AM

Ipa

tient

s.In

the

MR

mea

-su

rem

entsP

Vde

crea

sesat

the

3an

d4

cmlin

es,a

ndin

the

sim

ulat

ionw

eac

tual

lyse

ean

incr

ease

(aga

inbe

caus

eoft

hevo

rtex

).T

hesa

mep

atte

rnis

seen

forV

Iin

Fig

ure6

.29.

VI

isth

esa

mef

rom

the

pres

ent

sim

ulat

iona

ndth

esi

mul

atio

nofa

heal

thyp

erso

n,ex

cept

atth

e3

and

4cm

lines

.

6.4

Sim

ulat

ions

ofpa

thol

ogic

alhe

artc

ondi

tions

127

+4

+3

+2

+1

ML

T

-2

-25

ms

PV

ÑÒÓ

+25

ms

+50

ms

+76

ms

0.98

5s1.

010

s1.

035s

1.06

0s1.

086

s

0.2

0.4

0.6

0.8

0.2

0.4

0.6

0.8

0.2

0.4

0.6

0.8

0.2

0.4

0.6

0.8

0.2

0.4

0.6

0.8

0.2

0.4

0.6

0.8

0.2

0.4

0.6

0.8

0.2

0.4

0.6

0.8

0.2

0.4

0.6

0.8

0.2

0.4

0.6

0.8

0.2

0.4

0.6

0.8

0.2

0.4

0.6

0.8

0.2

0.4

0.6

0.8

0.2

0.4

0.6

0.8

0.2

0.4

0.6

0.8

0.2

0.4

0.6

0.8

0.2

0.4

0.6

0.8

0.2

0.4

0.6

0.8

0.2

0.4

0.6

0.8

0.2

0.4

0.6

0.8

0.2

0.4

0.6

0.8

0.2

0.4

0.6

0.8

0.2

0.4

0.6

0.8

0.2

0.4

0.6

0.8

0.2

0.4

0.6

0.8

0.2

0.4

0.6

0.8

0.2

0.4

0.6

0.8

0.2

0.4

0.6

0.8

0.2

0.4

0.6

0.8

0.2

0.4

0.6

0.8

Fig

ure

6.27

:V

eloc

itypr

ofile

sof

abso

lute

velo

city

(m/s

)alo

ngsi

xlin

esat

five

times

from

asi

mul

atio

nwhe

reth

eap

ical

rela

xatio

nis

slow

.If

the

velo

city

profi

leis

plot

ted

atth

etim

eof

PV

ata

line,

PV

ism

arke

dby

a

Ô .H

ere,

VI

ishi

gher

inth

epr

esen

tsim

ulat

ion.

MR

mea

sure

men

tsofh

ealth

yper

sons

and

AM

Ipa

tient

ssho

wth

atV

Ish

ould

decr

ease

inan

AM

Ipa

tient

satt

he3

and

4lin

esan

dot

herw

iseb

eun

chan

ged.

Fig

ure

6.30

show

sth

atT

Dis

high

erin

the

pres

ents

imul

atio

ntha

nse

enin

the

sim

ulat

ion

ofa

heal

thy

pers

on,e

xcep

tatt

he2

cmlin

ew

here

itis

low

er.

The

MR

data

also

show

sth

atT

Din

crea

sesin

anA

MI

patie

ntco

mpa

redt

oa

heal

thy

pers

on,b

uton

lyat

the

3an

d4

cmlin

es.B

ecau

seof

the

vort

exin

the

sim

ulat

ions

we

shou

ldno

tput

too

muc

hem

phas

ison

the

resu

ltsfr

omth

e3

and

4cm

lines

,so

we

mus

tcon

clud

etha

tTD

does

nots

how

sign

ifica

ntch

ange

sinth

epr

esen

tsi

mul

atio

ncom

pare

dto

the

sim

ulat

iono

fahe

alth

yper

son.

The

plot

ofth

eve

loci

tyfie

ldat

the

time

ofpe

akve

loci

tyat

the

mitr

alle

aflet

tips

(Fig

ure

6.31

)is

very

sim

ilar

toth

eve

loci

tyfie

ldse

enfo

ra

heal

thyh

uman

Page 74: MR · 2002. 2. 20. · Adeler A TV Erhver vsf or skerpr ojekt EF 698 IMM-PHD-2001-86 ISSN 0909-3192 ISBN 87-88306-13-5 c 2001 by Pernille Thorup Adeler Printed by IMM, DTU Bookbinder

128

Sim

ulat

ing

path

olog

ical

hear

tcon

ditio

ns

-2

01

23

4Distance

from

MLT

[cm]

0.2

0.4

0.6

0.81

PV[m/s]

MR

healthy

MR

AMI

Healthy

Apex

slow

Fig

ure

6.28

:Pea

kvel

ocity

(PV

)att

hesi

xlin

esfr

omM

Rm

easu

rem

entso

fhe

alth

yper

sons

(

Õ )an

dA

MI

patie

nts

(

Ö ),an

dfro

ma

sim

ulat

iono

fahe

alth

ype

rson

(

& )an

da

sim

ulat

ionw

here

the

apic

alre

laxa

tioni

ssl

ow(

- ).

-2

01

23

4Distance

from

MLT

[cm]

0.2

0.4

0.6

0.81

1.2

1.4

1.6

VI

MR

healthy

MR

AMI

Healthy

Apex

slow

Fig

ure6

.29:

Vel

ocity

inde

x(V

I)at

the

six

lines

from

MR

mea

sure

men

tsof

heal

thyp

erso

ns(

Õ )an

dA

MI

patie

nts

(

Ö ),an

dfro

ma

sim

ulat

iono

fahe

alth

ype

rson

(

& )an

da

sim

ulat

ionw

here

the

apic

alre

laxa

tioni

ssl

ow(

- ).

-2

01

23

4Distance

from

MLT

[cm]

-500

50

100

TD[ms]

MR

healthy

MR

AMI

Healthy

Apex

slow

Fig

ure

6.30

:Tim

ede

lay(

TD

)at

the

six

lines

from

MR

mea

sure

men

tsofh

ealth

ype

rson

s(

Õ )an

dA

MI

patie

nts(

Ö ),an

dfr

oma

sim

ulat

iono

fahe

alth

yper

son(

& )an

da

sim

ulat

ionw

here

the

apic

alre

laxa

tioni

ssl

ow(

- ).

6.4

Sim

ulat

ions

ofpa

thol

ogic

alhe

artc

ondi

tions

129

Time

1.010

Fig

ure

6.31

:V

eloc

ityfie

ldat

the

time

ofpe

akve

loci

tyat

the

ML

Tlin

efr

oma

sim

ulat

ion

whe

reth

eap

ical

rela

xatio

nis

slow

.

11.2

1.4

1.6

1.8

t[s]

-101234

pressure[mmHg] Fig

ure6

.32:

Tim

eva

riatio

nofp

ress

ure

diff

eren

ce(m

mH

g)be

twee

nat

rium

and

vent

ricle

from

asi

mul

atio

nw

here

the

apic

alre

laxa

tioni

ssl

ow.

(Fig

ure

6.19

),w

hich

agre

esw

ithth

ere

sults

abov

e:th

epr

esen

tsim

ulat

ion

isno

tve

rydi

ffer

entf

rom

the

sim

ulat

iono

fahe

alth

yhum

anpr

esen

tedin

Sec

tion6

.3.3

.T

his

isfu

rthe

rsup

port

edby

the

plot

ofth

epr

essu

redi

ffer

ence

betw

eena

triu

man

dve

ntric

lesh

own

inF

igur

e6.

32.

The

peak

pres

sure

diff

eren

ceis

som

ewha

tlo

wer

than

inth

esi

mul

atio

nof

ahe

alth

yhum

an(F

igur

e6.

20),

itha

sdec

reas

edap

prox

imat

ely1

5%.B

utth

isis

noti

nag

reem

entw

ithw

hatS

tuga

arde

tal.

(199

4b)

foun

dfo

rdo

gsw

ithac

ute

isch

emic

failu

re,w

here

the

peak

pres

sure

diff

eren

cede

crea

seda

ppro

xim

atel

y59%

.In

sum

mar

y,w

efin

dth

atth

esi

mul

atio

nof

asl

owre

laxa

tion

ofth

eap

ical

regi

onis

not

very

diff

eren

tcom

pare

dto

asi

mul

atio

nof

ahe

alth

ype

rson

,an

obse

rvatio

nw

hich

hold

sfo

rbo

thve

loci

tyan

dpr

essu

redi

ffer

ence

data

.T

hese

sim

ulat

ionr

esul

tsar

eno

tin

agre

emen

twith

mea

sure

men

tson

hum

ansa

nddo

gs,

whe

resu

bsta

ntia

lchan

gesa

rese

enin

AM

Ipa

tient

scom

pare

dto

heal

thyp

erso

ns.

6.4.

3A

pica

lreg

ion

inac

tive

The

third

scen

ario

we

inve

stig

atei

sth

eca

seof

anin

activ

e(o

rpas

sive)

apic

alre

-gi

on.T

his

mea

nsth

atth

ere

gion

neith

erco

ntra

ctsn

orre

laxe

s.It

issi

mpl

ypa

ssive

Page 75: MR · 2002. 2. 20. · Adeler A TV Erhver vsf or skerpr ojekt EF 698 IMM-PHD-2001-86 ISSN 0909-3192 ISBN 87-88306-13-5 c 2001 by Pernille Thorup Adeler Printed by IMM, DTU Bookbinder

130

Sim

ulat

ing

path

olog

ical

hear

tcon

ditio

ns

tissu

efol

low

ing

the

mot

ion

ofth

ebl

ood.

Itco

rres

pond

stoa

myo

card

ialin

farc

-tio

n,w

here

part

ofth

ehe

artw

alld

ies

due

toa

bloc

kage

ofth

eco

rona

ryar

terie

san

dsu

bseq

uent

lyloo

sesi

tsab

ility

toco

ntra

ctan

dre

lax.

Whe

nw

esi

mul

atea

nin

activ

ere

gion

ofth

ehe

artw

alli

n2D

itco

rres

pond

stoa

who

lecr

osss

ectio

nof

the

hear

tbei

ngin

activ

ein

3D.T

hus,

this

type

ofsi

mul

atio

nis

only

reas

onab

lew

hent

hein

activ

ere

gion

islo

cate

datt

heap

ex.C

hoos

inga

nyot

herr

egio

nin

a2D

mod

elw

ould

notb

eve

rym

eani

ngfu

l.W

esi

mul

ate

apa

ssive

regi

onby

letti

ngit

bede

fined

sim

ilarly

toth

eva

lve

tissu

e,i.e

.by

notl

ettin

git

have

any

mus

clep

rope

rty.

We

doth

ison

lyfo

rth

elin

ksal

ong

the

hear

twal

lin

the

apex

regi

on,i

.e.n

otfo

rth

ecr

ossl

inks

inth

ere

gion

.W

ere

duce

the

size

ofth

eap

ical

regi

onbe

caus

ethe

mod

elca

nnot

with

stan

dthe

pres

sure

insy

stol

ewhe

nth

een

tire

apic

alre

gion

isin

activ

e.A

sa

cons

eque

nce

ofth

ehi

ghpr

essu

re,th

ew

alls

leak

and

bloo

dle

aves

the

vent

ricle

thro

ugh

the

vent

ricul

arw

all.

Eve

nw

hen

we

redu

ceth

esi

zeof

the

inac

tive

regi

onw

eha

veto

incr

ease

the

num

bero

fbou

ndar

ypoi

ntst

ow

ithst

andt

hesy

stol

icpr

essu

re.

Dur

ing

dias

tole

the

hear

tbou

ndar

ycon

figur

atio

nfro

mth

esi

mul

atio

nwith

anin

activ

eap

ical

regi

on(le

ftsi

depl

otin

Fig

ure

6.33

)is

notv

ery

diff

eren

tfro

mth

eco

nfigu

ratio

nfor

ahe

alth

yper

son(

Fig

ure

6.19

),th

eve

ntric

lebe

ing

slig

htly

larg

er.B

utw

hen

syst

oles

etsi

nit

iscl

eart

hatt

heap

ical

part

isin

activ

e:it

bulg

esou

tand

hang

slik

ea

ballo

onfil

led

with

wat

erbe

low

the

cont

ract

edup

perp

arto

fth

eve

ntric

le.T

herig

htsi

depl

otin

Fig

ure

6.33

show

sth

eve

loci

tyfie

ldan

dhe

art

Time

1.035

Time

1.666

Fig

ure6

.33:

Vel

ocity

field

andh

eartb

ound

arya

tthe

time

ofpe

akve

loci

tyat

ML

Tlin

e(le

ft)an

ddu

ring

syst

ole(

right

)fr

oma

sim

ulat

ion

whe

reth

eap

ical

regi

onis

inac

tive.

6.4

Sim

ulat

ions

ofpa

thol

ogic

alhe

artc

ondi

tions

131

+4

+3

+2

+1

ML

T

-2

-25

ms

PV

ÑÒÓ

+25

ms

+51

ms

+76

ms

1.01

0s1.

035

s1.

060

s1.

086s

1.11

1s

0.2

0.4

0.6

0.8

0.2

0.4

0.6

0.8

0.2

0.4

0.6

0.8

0.2

0.4

0.6

0.8

0.2

0.4

0.6

0.8

0.2

0.4

0.6

0.8

0.2

0.4

0.6

0.8

0.2

0.4

0.6

0.8

0.2

0.4

0.6

0.8

0.2

0.4

0.6

0.8

0.2

0.4

0.6

0.8

0.2

0.4

0.6

0.8

0.2

0.4

0.6

0.8

0.2

0.4

0.6

0.8

0.2

0.4

0.6

0.8

0.2

0.4

0.6

0.8

0.2

0.4

0.6

0.8

0.2

0.4

0.6

0.8

0.2

0.4

0.6

0.8

0.2

0.4

0.6

0.8

0.2

0.4

0.6

0.8

0.2

0.4

0.6

0.8

0.2

0.4

0.6

0.8

0.2

0.4

0.6

0.8

0.2

0.4

0.6

0.8

0.2

0.4

0.6

0.8

0.2

0.4

0.6

0.8

0.2

0.4

0.6

0.8

0.2

0.4

0.6

0.8

0.2

0.4

0.6

0.8

Fig

ure

6.34

:V

eloc

itypr

ofile

sof

abso

lute

velo

city

(m/s

)alo

ngsi

xlin

esat

five

times

from

asi

mul

atio

nwhe

reth

eap

ical

regi

onis

inac

tive.

Ifth

eve

loci

typr

ofile

ispl

otte

dat

the

time

ofP

Vat

alin

e,P

Vis

mar

ked

bya

Ô .bo

unda

ryat

æ ò$

$$ s,w

here

the

larg

eve

ntric

leis

clea

rlyse

en.C

ompa

reth

ispl

otw

ithth

eve

loci

tyfie

ldin

the

last

fram

e(a

t

æ ò/ $ s)

inF

igur

e4.

2.T

hetw

opl

ots

are

atth

esa

met

ime

rela

tive

toth

ele

ngth

ofa

hear

tcyc

le.

Fig

ure

6.34

show

sth

eve

loci

typr

ofile

sal

ong

the

six

tran

sver

selin

esin

the

vent

ricle

atfiv

etim

es:

25m

sbe

fore

PV

atth

em

itral

leafl

ettip

s,at

the

time

ofP

Vat

the

mitr

alle

aflet

tips,

and

25,5

1an

d76

ms

afte

rthe

time

ofP

Vat

the

mitr

alle

aflet

tips.

Com

parin

gthe

velo

city

profi

les

with

thos

eobt

aine

dfor

ahe

alth

yhum

an(F

igur

e6.

15)w

ese

esev

eral

chan

ges.

The

profi

les

are

gene

rally

low

er,w

ider

and

mor

esk

ewed

.T

hela

tterc

anal

sobe

seen

from

the

plot

ofth

eve

loci

tyfie

ldat

the

time

ofpe

akve

loci

tyat

the

mitr

alle

aflet

tips

inF

igur

e6.

33.

Ifw

eco

mpa

reth

isto

the

velo

city

field

for

the

heal

thyh

uman

(Fig

ure

6.19

)we

see

that

the

dire

ctio

nof

the

inflo

wje

tis

mor

eto

war

dth

ean

terio

rwal

lin

the

Page 76: MR · 2002. 2. 20. · Adeler A TV Erhver vsf or skerpr ojekt EF 698 IMM-PHD-2001-86 ISSN 0909-3192 ISBN 87-88306-13-5 c 2001 by Pernille Thorup Adeler Printed by IMM, DTU Bookbinder

132

Sim

ulat

ing

path

olog

ical

hear

tcon

ditio

ns

-2

01

23

4Distance

from

MLT

[cm]

0.2

0.4

0.6

0.81

PV[m/s]

MR

healthy

MR

AMI

Healthy

Apex

inact.

Fig

ure

6.35

:Pea

kvel

ocity

(PV

)att

hesi

xlin

esfr

omM

Rm

easu

rem

entso

fhe

alth

yper

sons

(

Õ )an

dA

MI

patie

nts

(

Ö ),an

dfro

ma

sim

ulat

iono

fahe

alth

ype

rson

(

& )an

da

sim

ulat

ionw

here

the

apic

alre

gion

isin

activ

e(

- ).

-2

01

23

4Distance

from

MLT

[cm]

0.2

0.4

0.6

0.81

1.2

1.4

1.6

VI

MR

healthy

MR

AMI

Healthy

Apex

inact.

Fig

ure6

.36:

Vel

ocity

inde

x(V

I)at

the

six

lines

from

MR

mea

sure

men

tsof

heal

thyp

erso

ns(

Õ )an

dA

MI

patie

nts

(

Ö ),an

dfro

ma

sim

ulat

iono

fahe

alth

ype

rson

(

& )an

da

sim

ulat

ionw

here

the

apic

alre

gion

isin

activ

e(

- ).

-2

01

23

4Distance

from

MLT

[cm]

-500

50

100

TD[ms]

MR

healthy

MR

AMI

Healthy

Apex

inact.

Fig

ure

6.37

:Tim

ede

lay(

TD

)at

the

six

lines

from

MR

mea

sure

men

tsofh

ealth

ype

rson

s(

Õ )an

dA

MI

patie

nts(

Ö ),an

dfr

oma

sim

ulat

iono

fahe

alth

yper

son(

& )an

da

sim

ulat

ionw

here

the

apic

alre

gion

isin

activ

e(

- ).

6.4

Sim

ulat

ions

ofpa

thol

ogic

alhe

artc

ondi

tions

133

pres

ents

imul

atio

n.F

urth

erm

ore,t

hesh

apeo

fthe

profi

lesi

nF

igur

e6.

34ar

emor

etr

iang

ular

than

for

ahe

alth

yper

son.

Fig

ures

6.35

–6.3

7sho

wth

epe

akve

loci

tyP

V,th

eve

loci

tyin

dex

VI,

and

the

time

dela

yT

D,

resp

ectiv

ely.

Inea

chof

thes

eth

ree

figur

esth

eco

rres

pond

ing

data

from

MR

mea

sure

men

tsof

heal

thy

pers

onsa

ndA

MI

patie

ntsa

ndfr

oma

sim

ulat

iono

fahe

alth

yper

sona

rein

clud

ed.T

heda

tafr

omth

eM

Rm

easu

rem

ents

isid

entic

alto

that

ofF

igur

es6.

2–6.

4,w

hile

the

data

from

asi

mul

atio

nofa

heal

thy

pers

onis

iden

tical

toth

atof

Fig

ures

6.16

–6.1

8.F

igur

e6.

35sh

ows

that

dow

nstr

eam

ofth

eM

LT

line

PV

islo

wer

atth

e3

and

4cm

lines

com

pare

dto

the

sim

ulat

ion

ofa

heal

thyp

erso

n.T

his

isin

cont

rast

tow

hatw

esa

win

the

prev

ious

scen

ario(

with

asl

owre

laxa

tiono

fthe

apic

alre

gion

),he

reP

Vw

ashi

gher

atth

osel

ines

.In

the

pres

ents

imul

atio

nP

Vis

low

erde

spite

the

vort

expr

esen

tinth

eve

ntric

le,s

ow

ebe

lieve

that

we

can

trus

tthe

sere

sults

mor

e.T

hech

ange

inth

eva

riatio

nof

PV

with

the

dist

ance

from

the

ML

Tlin

eis

very

sim

ilari

nsi

mul

atio

nsan

dM

Rm

easu

rem

ents

:PV

isge

nera

llylo

wer

ina

dise

ased

hear

t,but

mos

tlyat

the

3an

d4

cmlin

es.

We

find

the

sam

egoo

dagr

eem

entbe

twee

nsim

ulat

ions

andM

Rm

easu

rem

ents

whe

nw

elo

okat

VI

inF

igur

e6.

36.V

Iis

low

erat

the

4cm

line

ina

dise

ased

hear

t(b

oth

from

sim

ulat

ions

andM

Rda

ta)th

anin

ahe

alth

yhea

rt,o

ther

wis

eitd

oesn

otch

ange

muc

h.It

shou

ldbe

note

d,ho

wev

er,t

hati

nM

Rm

easu

rem

entsV

Iis

also

low

erat

the

3cm

line

inan

AM

Ipa

tient

than

ina

heal

thyp

erso

nF

igur

e6.

37sh

ows

that

TD

ishi

gher

inth

epr

esen

tsim

ulat

iont

han

inth

esi

m-

ulat

ion

ofa

heal

thyp

erso

n,es

peci

ally

for

the

-2an

d4

cmlin

es.T

his

isin

reas

on-

able

agre

emen

twith

the

MR

mea

sure

men

ts.Her

e,T

Dis

high

erat

the

3an

d4

cmlin

esfo

rA

MI

patie

ntsc

ompa

redt

ohe

alth

yper

sons

,oth

erw

isei

tis

unch

ange

d.T

Dfr

omth

epr

esen

tsim

ulat

ion

isev

eryw

here

with

inth

est

anda

rdde

viat

ion

ofth

eM

Rre

sults

.Am

uch

high

erT

Dat

the

line

clos

estto

the

apex

isin

good

agre

e-m

entw

ithth

efin

ding

sof

Stu

gaar

deta

l.(1

994b

).T

hey

mea

sure

the

time

dela

yin

heal

thyd

ogsa

nddo

gsw

ithac

utei

sche

mic

failu

rean

dfin

dth

atth

etim

ede

lay

incr

ease

sapp

roxi

mat

elyb

ya

fact

orof

5(f

rom

20m

sto

101

ms)

.T

hesi

mul

atio

nre

sults

can

part

lybe

expl

aine

dby

the

pres

sure

diff

eren

cebe

-tw

een

atriu

man

dve

ntric

le,w

hich

ispl

otte

din

Fig

ure

6.38

.The

figur

esh

ows

asm

allp

ositi

vepr

essu

redi

ffer

ence

first

,and

then

,del

ayed

com

pare

dto

ahe

alth

yhu

man

(Fig

ure

6.20

),a

larg

erpo

sitiv

epr

essu

repe

akoc

curs

.The

peak

pres

sure

diff

eren

ceis

larg

erth

anfo

rth

ehe

alth

yhum

an.T

hela

tero

ccur

renc

eoft

hepe

akpr

essu

redi

ffer

ence

expl

ains

why

TD

incr

ease

s,but

sinc

eth

epe

akis

larg

erth

anfo

ra

heal

thyp

erso

nit

does

note

xpla

inw

hyP

Van

dV

Iar

elo

wer

atth

e4

cmlin

e.T

hela

rger

peak

pres

sured

iffer

ence

inth

epr

esen

tsim

ulat

ionc

ompa

redto

the

sim

-ul

atio

nof

ahe

alth

yper

soni

sno

tin

agre

emen

twith

the

findi

ngso

fStu

gaar

deta

l.

Page 77: MR · 2002. 2. 20. · Adeler A TV Erhver vsf or skerpr ojekt EF 698 IMM-PHD-2001-86 ISSN 0909-3192 ISBN 87-88306-13-5 c 2001 by Pernille Thorup Adeler Printed by IMM, DTU Bookbinder

134

Sim

ulat

ing

path

olog

ical

hear

tcon

ditio

ns

11.2

1.4

1.6

1.8

t[s]

-101234

pressure[mmHg]

Fig

ure

6.38

:Tim

eva

riatio

nof

pres

sure

diff

eren

ce(m

mH

g)be

twee

natr

ium

and

vent

ricle

from

asi

mul

atio

nwhe

reth

eap

ical

regi

onis

inac

tive.

(199

4b).

The

yfin

dth

atth

epe

akpr

essu

rede

crea

sesw

ithap

prox

imat

ely5

8%in

dogs

durin

gac

utei

sche

mic

failu

reco

mpa

redt

ohe

alth

ydog

s.T

hesi

mul

atio

nof

anin

activ

eap

ical

regi

onco

mpa

resr

easo

nabl

ywel

lw

ithM

Rm

easu

rem

entso

fAM

Ipa

tient

s.W

ese

ethe

sam

echa

nges

inth

eve

loci

typr

o-fil

esan

din

dexe

sfou

ndby

Hou

lind

etal

.(20

01)i

nM

Rm

easu

rem

entso

fhea

lthy

pers

onsa

ndA

MI

patie

nts.

The

shap

esof

the

velo

city

profi

lesa

rem

ore

tria

ngul

arin

adi

seas

edhe

art,

and

PV

and

VI

are

low

erne

arth

eap

exw

hile

TD

ishi

gher

near

the

apex

.T

heva

riatio

nof

the

pres

sure

diff

eren

cebe

twee

nthe

atriu

man

dth

eve

ntric

leex

plai

nsth

ehi

gher

TD

valu

ebu

tnot

the

low

erva

lues

ofP

Van

dV

I.F

urth

erm

ore,t

hepe

akpr

essu

rediff

eren

ceis

noti

nag

reem

entw

ithm

easu

rem

ents

.

6.5

Con

clus

ions

We

have

impl

emen

teda

grad

uala

ctiv

atio

nof

the

hear

tmus

clei

nth

em

odel

and

com

pare

dasi

mul

atio

nw

ithth

egr

adua

lact

ivat

ion

with

the

refe

renc

esim

ulat

ion

from

Cha

pter

4.T

heco

mpa

rison

show

edth

atth

em

odel

isve

ryse

nsitiv

eto

the

ac-

tivat

ion

time

ofth

epa

pilla

rym

uscl

e,be

caus

ethe

latte

rinfl

uenc

esth

eco

ntra

ctio

npa

ttern

ofth

eve

ntric

ular

wal

land

the

mov

emen

toft

hem

itral

valv

e.T

here

sults

from

asi

mul

atio

nw

here

we

adju

sted

the

activ

atio

ntim

eof

the

papi

llary

mus

cle

6.5

Con

clus

ions

135

and

the

prop

agat

ionv

eloc

ityin

the

vent

ricle

show

edth

atth

egr

adua

lact

ivat

ion

does

noti

ntro

duce

maj

ordi

ffer

ence

sinth

eflo

wpa

ttern

.The

bigg

estd

iffer

ence

isse

enat

the

aort

icou

tflow

asa

dela

yedo

peni

ng/c

losi

ngof

the

aort

icsi

nkan

da

low

erpe

akou

tflow

rate

.We

choo

seno

tto

use

the

grad

uala

ctiv

atio

nbe

caus

eitin

trod

uces

only

smal

lcha

nges

,and

beca

useo

fth

ese

nsitiv

ityto

the

activ

atio

nof

the

papi

llary

mus

cle.

We

also

impl

emen

teda

regi

onal

activ

atio

n,w

here

itis

poss

ible

tode

fine

the

para

met

ersd

eter

min

ingt

heac

tivat

ion

func

tion

inde

pend

ently

for

5re

gion

sin

the

vent

ricul

arw

all.

Thi

sw

asou

rbas

isfo

rco

nduc

tingi

nves

tigat

ions

ofth

em

echa

-ni

smso

fthe

early

dias

tolic

fillin

gph

ase.

We

sim

ulat

eda

heal

thyh

uman

and

com

pare

dthe

resu

ltsw

ithM

Rm

easu

re-

men

ts.T

heve

loci

typr

ofile

alon

gsi

xtr

ansv

erse

lines

inth

eve

ntric

lean

dth

eve

-lo

city

inde

xesd

eriv

edfr

omth

epr

ofile

sco

mpa

rere

ason

ablyw

ellw

ithM

Rm

ea-

sure

men

ts.T

hepr

essu

redi

ffer

ence

betw

eena

triu

man

dve

ntric

le,w

hich

driv

esth

ebl

ood

into

the

vent

ricle

,als

oco

mpa

redw

ellw

ithm

easu

rem

ents

.W

eha

vein

vest

igat

edth

ree

scen

ario

swhi

chre

flect

the

mec

hani

smso

fea

rlydi

asto

licfil

ling:

slow

rela

xatio

nof

the

vent

ricle

,slo

wre

laxa

tion

ofth

eap

ical

regi

on,a

ndan

inac

tive

apic

alre

gion

.We

hypo

thes

ized

that

dias

tolic

dysf

unct

ion

coul

dbe

mod

elle

dby

alo

wer

rela

xatio

nrat

e

Þ"ß (corr

espo

ndin

gtoa

high

er

Ü inm

easu

rem

ents

)orsi

mpl

yby

letti

nga

regi

onof

the

hear

twal

lbe

inac

tive.

Inth

efir

stsc

enar

iowe

saw

low

erpe

akve

loci

tiesa

nda

dela

yedfi

lling

,an

dthi

sco

uld

beex

plai

ned

bya

redu

cedp

ress

ured

iffer

ence

betw

eent

heat

rium

and

the

vent

ricle

.T

hese

resu

ltsw

ere

inag

reem

entw

ithth

em

easu

rem

entso

fS

tuga

ard

etal

.(19

94b)

,who

inve

stig

ated

dogs

durin

gin

duct

ion

ofbe

ta-b

lock

ade,w

hich

affe

cts

the

vent

ricle

glob

ally

.T

hus

itis

poss

ible

tosi

mul

ateg

loba

lisc

hem

iain

the

vent

ricle

byde

crea

sing

Þuß .T

hese

cond

scen

ario

reve

aled

that

the

sim

ulat

ion

resu

ltsdo

notc

hang

ever

ym

uch

whe

non

ere

gion

rela

xes

slow

erth

anth

eot

herr

egio

ns.

The

sesi

mul

atio

nre

sults

are

noti

nag

reem

entw

ithm

easu

rem

entso

nbo

thhu

man

and

dogs

,whe

resu

bsta

ntia

lchan

gesa

rese

en.T

husd

ecre

asin

g

Þuß regio

nally

does

nots

imul

atea

loca

lisc

hem

icsi

tuat

ion.

The

resu

ltsof

the

third

scen

ario

whe

reth

eap

ical

regi

onis

inac

tive

com

pare

dw

ellw

ithM

Rm

easu

rem

entso

fAM

Ipa

tient

s.B

oth

velo

city

profi

lesa

ndve

loci

tyin

dexe

ssho

wed

the

sam

echa

ngeb

etw

eena

heal

thya

nda

dise

ased

hear

t(AM

I)as

seen

inM

Rda

ta.H

owev

er,t

hese

chan

gesc

ould

only

part

lybe

expl

aine

dby

the

pres

sured

iffer

ence

betw

eena

triu

man

dven

tric

lese

enin

the

sim

ulat

ion.

The

peak

pres

sure

diff

eren

cew

as,fu

rthe

rmor

e,no

tin

agre

emen

twith

mea

sure

men

ts.Thu

sle

tting

the

apic

alre

gion

bein

activ

ese

emst

obe

are

ason

ablew

ayof

mod

ellin

gA

MI.

Page 78: MR · 2002. 2. 20. · Adeler A TV Erhver vsf or skerpr ojekt EF 698 IMM-PHD-2001-86 ISSN 0909-3192 ISBN 87-88306-13-5 c 2001 by Pernille Thorup Adeler Printed by IMM, DTU Bookbinder

136

Sim

ulat

ing

path

olog

ical

hear

tcon

ditio

ns

We

conc

lude

that

the

mod

elca

nbe

used

tost

udyc

erta

inm

echa

nism

sinvo

lved

inth

eea

rlydi

asto

licfil

ling

phas

e.T

hem

odel

canc

aptu

rem

echa

nism

sthat

chan

geth

ere

laxa

tionp

atte

rndr

astic

ally,

buts

mal

lerc

hang

esin

the

rela

xatio

npat

tern

dono

tcha

nget

hem

odel

resu

lts.W

eha

vesh

own

that

itis

poss

ible

tom

odel

agl

obal

dias

tolic

dysf

unct

ionb

ych

angi

ngth

ere

laxa

tionr

ate

Þ ß .Buti

nth

eca

seof

anis

chem

icap

ical

regi

on(a

loca

ldys

func

tioni

ngre

gion

),w

eco

uld

notm

odel

itby

chan

ging

Þ ß ,butw

ew

ere

able

tosi

mul

atea

nin

farc

tion

byle

tting

the

regi

onbe

inac

tive,

even

thou

ghth

edr

ivin

gpr

essu

redi

ffer

ence

was

noti

nag

reem

entw

ithm

easu

rem

ents

.

Cha

pter

7

The

3Dhe

artm

odel

Orig

inal

lyit

was

hope

dtha

tthe

2Dm

odel

coul

dbe

used

asa

prel

imin

aryt

estin

gto

olfo

rex

perim

ents

even

tual

lyto

beca

rrie

dout

inth

e3D

hear

tmod

el.H

owev

er,

ittu

rned

outt

hatt

he3D

mod

elw

asco

mpu

tatio

nally

too

dem

andi

ngan

ddi

dno

tm

atch

MR

mea

sure

men

tswel

leno

ught

obe

used

for

expe

rimen

tsan

din

vest

iga-

tions

ofth

ety

pepr

esen

tedin

Cha

pter

6fo

rth

e2D

mod

el.

Thi

sch

apte

rdes

crib

esbr

iefly

the

3Dhe

artm

odel

and

pres

entsa

com

paris

onof

the

outp

utfr

oma

sim

ulat

ionw

ithM

Rda

ta.T

heco

mpu

tatio

nalde

man

doft

he3D

mod

elis

also

pres

ente

d.

7.1

Des

crip

tion

ofth

em

odel

The

prin

cipl

esof

the

3Dm

odel

are

sim

ilart

oth

oseo

fthe

2Dm

odel

.The

hear

tisim

mer

sedi

na

cube

fille

dw

itha

fluid

ofth

esa

med

ensi

tyan

dvi

scos

ityas

bloo

d.T

hehe

artb

ound

ary(

mus

cula

rwal

land

the

valv

ele

aflet

s)ar

etr

eate

dasm

assl

ess

one-

dim

ensi

onalb

ound

arie

stota

llyim

mer

sedi

nflu

id(b

lood

)with

the

pote

ntia

lof

exer

ting

forc

eson

the

fluid

.In-

and

outfl

owto

the

hear

tism

odel

ledb

yso

urce

san

dsi

nks

and

the

mod

elin

clud

esan

exte

riors

ink/

sour

ceto

mak

ero

omfo

rth

eva

riatio

nin

tota

lhea

rtvo

lum

edu

ring

ahe

artb

eat.

The

maj

ordi

ffer

ence

betw

eent

he2D

and

3Dm

odel

sis

that

the

3Dm

odel

isof

the

full

hear

t(al

lfou

rhea

rtch

ambe

rsand

the

near

bygr

eatv

esse

ls),w

hile

the

2Dm

odel

isof

the

left

side

only

.F

urth

erm

ore,

som

ecom

puta

tiona

ldiff

eren

ces

exis

tand

thes

eare

desc

ribed

inth

efo

llow

ing.

Page 79: MR · 2002. 2. 20. · Adeler A TV Erhver vsf or skerpr ojekt EF 698 IMM-PHD-2001-86 ISSN 0909-3192 ISBN 87-88306-13-5 c 2001 by Pernille Thorup Adeler Printed by IMM, DTU Bookbinder

138

The

3Dhe

artm

odel

7.1.

1E

quat

ions

ofm

otio

n

The

gove

rnin

geq

uatio

nsof

mot

ion

are

01 232 æ 3 4 3

5ò ó476 84î 39

(7.1

)

4 3 ò:ì<; ûæí

(7.2

)

9ì<; ûæí ò

=?>ìA@ ûB ûûæí C

ì ; óDì @ ûB û ûæíí ñ @ñ Bñ

(7.3

)

2D

2 æìA@ ûB ûûæíò3ìDìA@ ûB û ûæí ûæí

(7.4

a)

ò= 3ì ; ûæí Cì<; óDì @ ûB û ûæíí ñ ;

(7.4

b)

E òF1GHGIGIG2

D2

GHGIGIGJ@ ûB û ûæ

5

(7.5

)

K ò2D% 2

2D% 2

(7.6

)

>ò2 2 ì E Kí

(7.7

)

The

3DE

uler

ian

varia

bles

are

the

velo

city

3ì ; ûæí ,

the

pres

sure

6ì<; ûæí ,

the

forc

e

9ì<; ûæí ñ ; a

ndth

ede

nsity

dist

ribut

ion

ofth

eso

urce

sand

sink

s

:ì<; ûæí ,

whe

re

; den

otes

posi

tion

insp

ace,

ñ ; isth

evo

lum

eel

emen

t,and

æ istim

e.T

heLa

gran

gian

varia

bles

are

the

fiber

poin

tpos

ition

DìA@ ûB û ûæí ,

the

fiber

tens

ion

EìA@ ûB û ûæíñ @ñ B ,

the

unit

tang

entto

the

fiber

s

Kì @ ûB û ûæí

and

the

resu

ltant

fiber

forc

e>ìA@ ûB ûûæí

ñ @ñ Bñ .

9 and>

are

corr

espo

ndin

gforc

ede

nsiti

es.H

ere@ ,

B

and

are

curv

iline

arco

ordi

nate

scho

seni

nsu

cha

way

that

ì @ ûBí

labe

lsa

part

ic-

ular

fiber

and

ì @ ûB ûí la

bels

apa

rtic

ular

mat

eria

lpoi

nt.T

heeq

uatio

ns,as

writ

ten

here

,des

crib

eath

ree-

dim

ensi

onals

yste

mof

fiber

sasi

sap

prop

riate

for

the

thic

khe

artw

all.

Ava

lve

leafl

etis

afib

er-r

einf

orce

dsur

face

and

can

bede

scrib

edby

drop

ping

one

ofth

ein

dice

s@ or

B .E

quat

ion(

7.1)

isth

eth

ree-

dim

ensi

onalN

avie

r-S

toke

sequ

atio

nand

equa

tion

(7.2

)is

the

cont

inui

tyeq

uatio

n,th

e3D

vers

ions

ofeq

uatio

ns(3

.1)a

nd(3

.2),

re-

spec

tivel

yfo

rth

e2D

case

.Pes

kin

and

McQ

ueen

have

not,

toou

rkn

owle

dge,

publ

ishe

dade

scrip

tiono

fthe

dens

itydi

strib

utio

n

: in3D

,but

sinc

esou

rces

and

sink

sare

hand

ledi

dent

ical

lyin

the

2Dan

d3D

mod

els,

the

dens

itydi

strib

utio

nin

the

3Dm

odel

will

beof

the

sam

efor

mas

inth

e2D

mod

el(s

eeeq

uatio

n(3.

8)).

The

only

diff

eren

ceis

that

the

sum

mat

ioni

sov

erth

eto

taln

umbe

rofs

ourc

esan

dsi

nksi

nth

e3D

mod

el.

7.1

Des

crip

tion

ofth

em

odel

139

Rec

ently

McQ

ueen

and

Pes

kin

(200

0)in

trod

uced

the

new

form

ofth

em

o-m

entu

meq

uatio

ndis

cuss

edin

Sec

tion4

.6,w

hich

take

sint

oac

coun

tthe

diff

eren

tfo

rmof

the

cont

inui

tyeq

uatio

nand

cons

eque

ntlyt

hedi

ffer

entf

orm

ofth

em

o-m

entu

meq

uatio

n,w

hen

dist

ribut

edso

urce

sand

sink

sare

incl

uded

.How

ever

,thi

sit

isno

tinc

lude

din

the

vers

iono

fthe

3Dco

dew

ew

ork

with

.E

quat

ions

(7.3

)and

(7.4

b)ar

eth

ein

tera

ctio

nequ

atio

nsth

atco

nnec

tEul

eria

nan

dLa

gran

gian

quan

titie

s,an

alog

ousto

equa

tions

(3.3

)and

(3.4

)in

the

2Dca

se.

Her

eCì ; óDìA@ ûB û ûæíí is

the

thre

e-di

men

sion

alDira

cde

ltafu

nctio

n.E

quat

ions

(7.6

)–(7

.7)a

reth

efib

ereq

uatio

nsth

atar

eus

edto

dete

rmin

ethe

Lagr

angi

anfib

erfo

rce

dens

ity

>

from

the

fiber

confi

gura

tion

D attim

e

æ .In

equa

tion(

7.5)

, 2D% 2 is

the

fiber

stra

inan

d

F isthe

stre

ss-s

trai

nrela

tion

ofth

efib

ers.

Not

eth

eex

plic

ittim

ede

pend

encei

n

F ,whi

chal

low

sth

ehe

artto

cont

ract

and

rela

x.

Bou

ndar

yfo

rces

Inth

e3D

case

the

hear

tmus

clei

sno

trep

rese

nted

byth

e3

elem

entm

odel

de-

scrib

edin

Sec

tion3

.3.5

for

the

2Dm

odel

,nor

isth

epa

ssive

tissu

emod

elle

dby

linea

rspr

ings

.Inth

e3D

mod

elth

ete

nsio

n

E ina

shor

tfibe

rseg

men

tisgi

ven

bya

non-

linea

rrel

atio

nsh

ip

E òLNM<O MAPQ å1 R óR å R å5î RSRå

RTRå

whe

re

R isth

ele

ngth

ofth

efib

erse

gmen

t,Rå isth

ere

stin

gle

ngth

ofth

ese

g-m

enta

nd

Q å isthe

stiff

ness

.In

the

case

ofac

tive,

cont

ract

ilehe

artm

uscl

eRå

and

Q å aretim

ede

pend

ent,w

hile

they

are

cons

tant

for

pass

ivetis

sue.

Inth

eor

ig-

inal

2Dm

odel

the

entir

eat

rium

cont

ract

ssim

ulta

neou

sly,a

nd,a

ftera

dela

y,th

een

tire

vent

ricle

cont

ract

ssim

ulta

neou

sly,th

isis

also

the

case

inth

e3D

mod

el.

The

prop

agat

iono

fthe

activ

atio

nw

ave

intr

oduc

edin

the

2Dm

odel

inC

hapt

er6

coul

dea

sily

bein

trod

uced

in3D

byde

finin

gth

etim

ede

pend

ence

of

R å and

Q å

diff

eren

tlyfo

rdi

ffer

entp

arts

ofth

ehe

art.

Sou

rces

and

sink

s

The

3Dm

odel

incl

udes

allt

hene

arby

grea

tves

selso

fthe

hear

t:th

eao

rta,

the

pul-

mon

arya

rter

y,th

efo

urpu

lmon

aryv

eins

and

the

supe

riora

ndin

ferio

rven

acav

a.A

llth

eve

ssel

shav

ebl

ind

ends

,but

are

equi

pped

with

eith

era

sour

ce(p

ulm

onar

y

Page 80: MR · 2002. 2. 20. · Adeler A TV Erhver vsf or skerpr ojekt EF 698 IMM-PHD-2001-86 ISSN 0909-3192 ISBN 87-88306-13-5 c 2001 by Pernille Thorup Adeler Printed by IMM, DTU Bookbinder

140

The

3Dhe

artm

odel

vein

san

dve

naca

va)

ora

sink

(aor

taan

dpu

lmon

arya

rter

y).

Fur

ther

mor

e,an

exte

riors

ourc

e/si

nkal

low

sfo

rvo

lum

ech

ange

sast

hehe

artfi

llsan

dej

ects

.A

sin

the

orig

inal

2Dm

odel

the

rela

tion

betw

eenfl

owan

dpr

essu

refo

ral

lso

urce

sand

sink

sis

chos

ento

bea

linea

rres

ista

ncem

odel

pum

ping

agai

nsta

cons

tant

pres

sure

rese

rvoir,

seeS

ectio

n3.2

.1fo

ra

desc

riptio

noft

helin

earr

esis

-ta

ncem

odel

ofth

eat

rials

ourc

ein

the

2Dm

odel

.

7.1.

2C

ompu

tatio

nalm

etho

d

The

num

eric

alm

etho

duse

din

the

3Dm

odel

isdi

ffer

entf

rom

the

one

inth

e2D

mod

el.

Itis

base

don

the

follo

win

gdi

scre

tizat

iono

fth

eeq

uatio

nsof

mot

ion.

Tim

eis

divi

ded

into

inte

rval

sof

leng

th

æ .T

heflu

ideq

uatio

nsar

edi

scre

tized

ona

regu

larc

ubic

latti

cein

the

phys

ical

spac

eof

the

varia

ble;

òìAU ) ûU î ûU'í ,

and

the

fiber

equa

tions

are

disc

retiz

edon

are

ctan

gula

rlatti

cein

the

spac

eoft

heLa

gran

gian

para

met

ers@ ,

B , .T

hem

eshw

idth

sof

thes

elat

tices

are

V òU )ò

U îò U' an

d

@ ,

B ,

,res

pect

ively

.O

nth

eflu

idla

ttice

the

forw

ard,

back

ward

and

cent

rald

ivid

eddi

ffer

ence

oper

-at

orsa

rede

note

d

Wï ,

W Ø and

Wå ,res

pect

ively

.Asu

bscr

ipt

Ý ò û" û+ in

dica

tes

the

dire

ctio

nin

whi

chth

edi

ffer

ence

isap

plie

d.

Xå isus

edfo

rth

eve

ctor

diff

er-

ence

oper

ator

ì Xå ) ûXå î ûXå 'í ,w

hich

corr

espo

ndsto

4 .O

nth

eLa

gran

gian

fiber

latti

ceth

ece

ntra

ldiff

eren

ceop

erat

orin

the

fiber

di-

rect

ion

isde

note

d

W ç andde

fined

by

ì W çYíìAíòì YìA % "í óYì ó%"íí%

The

disc

retiz

edeq

uatio

nsar

e

0Z 3êï) ó3ê æ'\[ ] ^)_ê ]W` ]3êa ò ó

Xå 6êï) 8

'\[ ] ^)Wï ]WØ ]3êï) 9ê

(7.8

)

Xå 3êï)ò:ê

(7.9

)

9ê ì ;í ò[ b éß éç>ê ìA@ûB û

í Cdcì ;óDê ì @ ûB ûíí@ B

(7.1

0)

Dêï)ìA@ ûB ûí òDê ì @ ûB ûíæ[ e3êï)ì<;í Cdcì ; óDê ì @ ûB ûííV' (7

.11)

7.1

Des

crip

tion

ofth

em

odel

141

Eê òFì W çDê J@ûB û

í

(7.1

2)

Kê òW çDê W ç

(7.1

3)

>êòW çì EêKêí

(7.1

4)

Inth

esee

quat

ions

_ê ]W` ] re

fers

toup

win

ddi

ffer

enci

ng:t

hefo

rwar

ddi

ffer

-en

ceis

used

ifth

eco

nvec

tionv

eloc

ity

_ê isne

gativ

ean

dth

eba

ckwa

rddi

ffer

ence

ifth

eco

nvec

tionv

eloc

ityis

posi

tive.

The

nota

tion

f b éß éçre

fers

toa

sum

over

the

fiber

latti

ce,w

hile

f e ref

erst

oa

sum

over

the

fluid

latti

ce.F

inal

ly,t

heno

tatio

n

C c

refe

rsto

anap

prox

imat

iono

fthe

thre

e-di

men

sion

alDira

cde

ltafu

nctio

n.T

he

C c

func

tion

used

inth

e3D

mod

elis

C cì<;íò V'C c

g U ) Vh C cg U î Vh C cg U ' Vh

whe

re

Cdcì BíòLNMAMAMAMAO MAMAMAMAP+ ó

" Bi jB ój Bî

,

û B k

! ó" B ói ó/" B ój Bî

,

û k B k"

û

" k B

The

com

puta

tiona

lmet

hod

proc

eeds

asfo

llow

s.G

iven

the

fiber

confi

gura

-tio

nDê ìA@ ûB ûí an

dth

eflu

idve

loci

ty

3êì ;í ev

alua

teth

efib

erfo

rces

>ê ìA@ûB û

í

thro

ught

hesu

cces

sive

useo

fequ

atio

ns(7

.12)

,(7.

13)a

nd(7

.14)

.The

nap

ply

the

fiber

forc

esto

the

com

puta

tiona

llatti

ceof

the

fluid

usin

geq

uatio

n(7.

10).

The

nup

date

the

fluid

velo

city

byso

lvin

gth

esy

stem

ofeq

uatio

ns(7

.8)a

nd(7

.9)f

or

ì 3êï) û6êï) í .

Thi

sis

done

byFo

urie

rtra

nsfo

rmin

gthe

equa

tions

,sol

ving

for

the

Four

iert

rans

form

sof

3 and6 ,

and

then

appl

ying

the

inve

rseF

ourie

rtra

nsfo

r-m

atio

n.T

hede

tails

ofth

isis

expl

aine

din

Pes

kina

ndM

cQue

en(1

996)

.Fin

ally

,in

terp

olat

ethe

new

velo

city

field

and

mov

eth

efib

ers

usin

geq

uatio

n(7.

11),

and

the

time

step

isco

mpl

ete.

Thi

sne

wco

mpu

tatio

nalm

etho

dre

mov

esth

ene

edto

scal

eal

lle

ngth

sand

time

bya

fact

or

l asdo

nein

the

2Dm

odel

.Thu

s,in

the

3Dm

odel

the

visc

os-

ity(a

ndco

nseq

uent

lythe

Rey

nold

snu

mbe

r)is

kept

atits

phys

iolo

gica

llyco

r-re

ctva

lue.

Pes

kina

ndM

cQue

enha

veim

prov

edth

eco

mpu

tatio

nalm

etho

deve

nm

ore

rece

ntly

byre

duci

ngth

enu

mer

ical

visc

osity

thro

ugh

the

intr

oduc

tion

ofa

(for

mal

ly)

seco

ndor

dera

ccur

atem

etho

d(M

cQue

enan

dP

eski

n,20

00;L

aian

dP

eski

n,20

00).

Page 81: MR · 2002. 2. 20. · Adeler A TV Erhver vsf or skerpr ojekt EF 698 IMM-PHD-2001-86 ISSN 0909-3192 ISBN 87-88306-13-5 c 2001 by Pernille Thorup Adeler Printed by IMM, DTU Bookbinder

142

The

3Dhe

artm

odel

7.1.

3In

itial

geom

etry

The

initi

alge

omet

ryof

the

hear

tinth

e3D

mod

elis

muc

hm

ore

real

istic

than

inth

e2D

mod

el.I

tis

base

don

the

wor

kby

Tho

mas

(195

7),w

hoga

vea

deta

iled

desc

riptio

nof

the

fiber

layo

utof

mus

cle

fiber

sin

the

vent

ricle

sof

mam

mal

ian

hear

tsan

don

the

wor

kby

Str

eete

reta

l.(1

969;

1978

)who

mad

emea

sure

men

tsof

the

dist

ribut

ion

offib

eran

gles

inth

ele

ftve

ntric

ular

wal

l.P

eski

nand

McQ

ueen

cons

truc

tsthe

initi

alla

yout

offib

ers(

asbe

stas

poss

ible

)tom

imic

the

fiber

layo

utde

scrib

edin

Tho

mas

(195

7)an

dS

tree

tere

tal.

(196

9;19

78).

The

deta

ilsof

the

initi

alhe

artg

eom

etry

are

desc

ribed

inP

eski

nand

McQ

ueen

(199

6).T

hein

itial

layo

utof

the

hear

tcon

sist

ofm

ore

than

4000

fiber

san

dap

prox

imat

ely6

0000

0bo

unda

rypo

ints

.F

igur

e7.

1sh

ows

the

initi

alge

omet

ryof

the

hear

t.F

rom

the

figur

eit

isse

en

vein

sP

ulm

onar

y

Aor

ta

Left

atriu

m

Left

vent

ricle

Rig

ht

Pul

mon

ary

arte

ry

vent

ricle

Fig

ure

7.1:

Initi

alge

omet

ryof

the

3Dhe

art,t

herig

htat

rium

and

the

infe

riora

ndsu

perio

rven

acav

aca

nnot

bese

en.

7.2

Res

ults

143

Mitr

alva

lve

Rig

htLe

ftve

ntric

le

Left

atriu

m

Aor

ta

Aor

ticva

lve

Pul

mon

ary

vein

s

vent

ricle

Fig

ure

7.2:

Cut

-aw

ayvi

ewof

the

initi

alfib

erco

nfigu

ratio

n.

that

the

initi

alge

omet

ryis

still

sim

plifi

edco

mpa

redt

oa

real

istic

shap

eof

the

hear

t,but

the

geom

etry

chan

gesq

uick

lyto

am

ore

real

istic

shap

ewhe

nth

em

odel

isru

n.F

rom

Fig

ure

7.1

itis

diffi

cult

tose

ethe

inte

rioro

fth

ehe

art,

buti

nF

ig-

ure

7.2

acu

t-aw

ayvi

ewof

the

initi

alge

omet

ryis

show

n.H

ere,

the

mitr

alan

dao

rtic

valv

esca

nbe

seen

,asw

ella

sthe

initi

alco

nesh

apeo

fthe

left

vent

ricle

.T

hehe

artin

the

3Dm

odel

isal

sote

ther

edto

fixed

poin

ts,in

aw

aysi

mila

rto

that

desc

ribed

for

the

2Dm

odel

inS

ectio

n3.3

.7.I

nth

e3D

mod

elth

efix

poin

tsar

elo

cate

dal

ong

the

initi

alpo

sitio

nsof

the

outfl

owve

ssel

sof

the

hear

t.T

hete

ther

ings

inth

e2D

and

3Dm

odel

swer

ein

trod

uced

inde

pend

ently.

7.2

Res

ults

Asi

mul

atio

nw

ithth

e3D

mod

elst

arts

indi

asto

le,ju

stas

the

2Dm

odel

,but

inth

e3D

mod

elno

neof

the

fiber

sar

eun

dert

ensi

onat

initi

altim

e(t

heir

rest

ing

Page 82: MR · 2002. 2. 20. · Adeler A TV Erhver vsf or skerpr ojekt EF 698 IMM-PHD-2001-86 ISSN 0909-3192 ISBN 87-88306-13-5 c 2001 by Pernille Thorup Adeler Printed by IMM, DTU Bookbinder

144

The

3Dhe

artm

odel

leng

thsa

reeq

ualt

oth

eir

initi

alle

ngth

s).

Thu

sth

ein

itial

setu

pis

even

mor

eun

real

istic

than

inth

e2D

mod

el.A

sa

cons

eque

nceof

this

,the

mod

elst

arts

with

alo

ngfil

ling

phas

e(it

last

sfor

3/4

ofa

hear

tcyc

le),

then

atria

lsys

tole

sets

inan

dth

esi

mul

atio

nco

mpu

teso

nehe

artb

eat.

The

tota

lsim

ulat

ion

time

isth

us1.

75he

artb

eats

.The

long

fillin

gin

the

begi

nnin

gof

asi

mul

atio

nis

driv

ensi

mpl

yby

the

flow

ofbl

ood

ente

ringf

rom

the

sour

cesin

the

atria

,bec

ause

neith

erst

iffne

sses

norr

estin

glen

gths

(whi

chde

term

iner

elax

atio

nand

cont

ract

ion)

ofth

eco

ntra

ctile

fiber

scha

ngeu

ntil

the

onse

tofa

tria

lsys

tole

.W

epe

rfor

med

one

sim

ulat

ionw

ithth

e3D

mod

elw

here

the

para

met

ersd

eter

-m

inin

gth

etim

eco

urse

inth

em

odel

(ons

etan

ddu

ratio

ntim

esof

vent

ricul

aran

dat

rials

ysto

le)a

reid

entic

alto

the

para

met

ersin

ourr

efer

ence

sim

ulat

ionw

ithth

e2D

mod

el(s

eeS

ectio

n3.3

.6).

We

chos

ethe

sepa

ram

eter

sto(h

opef

ully

)be

able

tom

atch

the

sim

ulat

ionr

esul

tsw

ithth

eM

Rda

tase

twe

com

pare

dthe

2Dm

odel

with

(see

Cha

pter

5).

We

did

notc

hang

eany

othe

rpar

amet

erva

lues

inth

em

odel

,so

the

rem

aini

ngva

lues

are

thus

aspu

blis

hedb

yP

eski

nand

McQ

ueen

(see

e.g.

Pes

kina

ndM

c-Q

ueen

,199

6;P

eski

nand

McQ

ueen

,199

4).T

his

mea

nsth

atth

eco

mpu

tatio

nsar

epe

rfor

med

ona

128

m 128

m 128

grid

with

3276

8tim

est

epsp

erhe

artb

eat,g

ivin

ga

tota

lof5

7344

time

step

scor

resp

ondi

ngto

1.75

hear

tbea

ts.

Sim

ulat

ions

with

the

3Dm

odel

are

com

puta

tiona

llyve

ryde

man

ding

.The

sim

ulat

ionp

rese

nted

here

take

sapp

roxi

mat

ely5

80cp

uho

urso

na

Cra

yC

90an

dus

es51

2M

Bof

mem

ory.

The

impl

emen

tatio

nof

the

code

one.

g.th

eC

ray

isde

scrib

edin

McQ

ueen

and

Pes

kin(

1997

).F

rom

this

pape

ritis

also

seen

that

the

com

puta

tiona

llyde

man

ding

part

sare

the

inte

grat

ion

ofth

eN

avie

r-S

toke

seq

ua-

tions

and

the

inte

ract

ions

betw

eenfl

uid

and

fiber

latti

ces.

Fur

ther

mor

e,du

ring

asi

mul

atio

nm

any

outp

utfil

esar

epr

oduc

edan

dsu

bseq

uent

lythe

post

proc

essi

ngis

also

com

puta

tiona

llyve

ryde

man

ding

.In

Fig

ure

7.3

the

flow

thro

ugh

the

mitr

alan

dao

rtic

valv

esdu

ring

the

sim

u-la

tion

issh

own.

The

flow

thro

ugh

the

aort

icva

lve

look

sas

expe

cted

:zer

oflo

wun

tilth

eon

seto

fsy

stol

e,th

ena

larg

efo

rwar

dpe

ak,f

ollo

wed

bya

smal

lbac

k-w

ard

peak

atth

etim

eof

clos

ureo

fthe

valv

e,an

dfin

ally

zero

flow

.For

the

mitr

alva

lve

flow

ther

eis

ape

akat

the

time

ofat

rials

ysto

le,a

sex

pect

ed,b

utth

isis

follo

wed

bya

long

perio

dof

time

with

back

flow

(neg

ativ

eflo

w),

until

the

onse

tof

the

next

dias

tolic

phas

e,w

hen

afo

rwar

dpe

ak(t

heE

peak

)is

seen

.The

long

perio

dof

back

flow

isno

texp

ecte

dbut

mig

htbe

caus

edby

the

mitr

alva

lves

bein

gcl

osed

and

bulg

ing

into

the

left

atriu

m,i.

e.th

eba

ckwa

rdflo

wm

aybe

bloo

dflo

w-

ing

tow

ard

the

mitr

alle

aflet

sfro

mth

eve

ntric

le.W

ew

ould

have

expe

cted

ala

rger

back

flow

atth

etim

eof

the

clos

ureo

fth

em

itral

valv

e,as

seen

inth

e2D

mod

el.

Thi

sha

sbee

nsee

nin

othe

rsim

ulat

ions

with

the

3Dm

odel

.The

last

peak

inth

e

7.2

Res

ults

145

0.25

0.5

0.75

11.25

1.5

t[s]

0

100

200

300

400

flow[cm^3/s]

Fig

ure7

.3:F

low

time

profi

leof

the

flow

(cm

' /s)t

hrou

ghth

em

itral

valv

e(d

ashe

d)an

dth

roug

hthe

aort

icva

lve

(sol

id).

Ver

tical

dash

edlin

ein

dica

test

hetim

eof

the

long

fillin

gph

ase(

æ ò /"

s).

mitr

alflo

wpr

ofile

corr

espo

ndsto

the

Epe

ak,a

ndth

issh

ould

have

been

larg

erth

anth

efir

stpe

akin

the

flow

profi

le.

Fig

ure

7.4

show

sth

etim

eve

loci

typr

ofile

for

the

abso

lute

cent

reve

loci

tyat

the

aort

icva

lve.

Com

pare

dto

the

velo

city

profi

lefr

omM

Rda

ta(F

igur

e5.

5)w

ese

eth

atth

epe

akve

loci

tyis

muc

hla

rger

inth

e3D

mod

el,4

60cm

/sin

the

3Dm

odel

and

90cm

/sin

MR

data

.T

hese

cond

peak

inth

esi

mul

atio

npr

ofile

isca

used

byba

ckflo

wat

the

time

ofcl

osur

eoft

heva

lve.

Thu

sthe

time

inte

rval

the

valv

eis

open

isap

prox

imat

ely2

50m

s,w

hich

isle

ssth

anse

enin

the

MR

data

(app

roxi

mat

ely3

65m

s).

Fig

ure

7.5

show

sth

etim

eve

loci

typr

ofile

for

the

abso

lute

cent

reve

loci

tyat

the

mitr

alva

lve.

Thi

sis

mor

edi

fficu

ltto

judg

eth

anth

eao

rtic

velo

city

profi

lebe

caus

eitis

notc

lear

whi

chpe

aksa

rere

late

dto

forw

ard

flow

and

whi

char

ere

late

dto

back

ward

flow

.B

utth

efir

stpe

akaf

tert

heve

rtic

allin

em

ustb

eca

used

byat

rials

ysto

le,a

ndw

eex

pect

the

follo

win

gpe

akto

bere

late

dto

back

flow

byth

etim

eof

clos

ureo

fthe

mitr

alva

lve.

By

com

parin

gthe

time

cour

sein

Fig

ure7

.3w

ithth

isfig

ure,

we

belie

veth

atth

ela

stpe

akse

enm

ustb

eth

eE

peak

,whi

chhe

reis

appr

oxim

atel

y25

cm/s

.In

the

MR

data

the

Epe

akis

appr

oxim

atel

y65

cm/s

(Fig

ure

5.4)

.Eve

nif

the

high

estp

eaks

een(

appr

oxim

atel

y43

cm/s

)was

caus

edby

max

imum

forw

ard

flow

,thi

sis

less

than

the

65cm

/sse

enin

the

MR

data

.The

low

peak

velo

city

coul

dbe

caus

edby

ask

ewed

inflo

w,

but

othe

rdat

afr

omth

e

Page 83: MR · 2002. 2. 20. · Adeler A TV Erhver vsf or skerpr ojekt EF 698 IMM-PHD-2001-86 ISSN 0909-3192 ISBN 87-88306-13-5 c 2001 by Pernille Thorup Adeler Printed by IMM, DTU Bookbinder

146

The

3Dhe

artm

odel

0.25

0.5

0.75

11.25

1.5

t[s]

100

200

300

400

velocity[cm/s]

Fig

ure

7.4:

Vel

ocity

time

profi

lefo

rth

eab

solu

tece

ntre

velo

city

(cm

/s)a

tthe

aort

icva

lve.

Ver

tical

dash

edlin

ein

dica

test

hetim

eof

the

long

fillin

gph

ase(

æ ò

/" s)

.

0.25

0.5

0.75

11.25

1.5

t[s]

10

20

30

40

velocity[cm/s]

Fig

ure

7.5:

Vel

ocity

time

profi

lefo

rth

eab

solu

tece

ntre

velo

city

(cm

/s)a

tthe

mitr

alva

lve.

Ver

tical

dash

edlin

ein

dica

test

hetim

eof

the

long

fillin

gph

ase(

æ ò

/" s)

.

7.2

Res

ults

147

sim

ulat

iond

oesn

otsu

ppor

tthis

.T

hepr

essu

rein

the

mod

elis

notr

ealis

tic.E

spec

ially

the

pres

sure

inth

eve

n-tr

icle

sis

fart

oohi

gh,w

here

am

axim

umpr

essu

reab

ove

1200

mm

Hg

isre

ache

d.T

his

isa

gene

ralp

robl

emw

ithth

e3D

mod

elth

atha

snot

yetb

eens

olve

d.E

ven

thou

ghth

ehe

arti

ste

ther

ed,it

isdi

fficu

ltto

exam

ine

the

flow

patte

rnin

side

the

hear

tbec

ause

ofth

em

ovem

ento

fth

ehe

art.

Thu

sit

isdi

fficu

ltto

see

the

vort

expa

ttern

inth

ele

ftve

ntric

le.

But

inF

igur

e14

.12

inP

eski

nan

dM

cQue

en(1

996)

the

flow

durin

gea

rlydi

asto

licfil

ling

isde

pict

edby

stre

aklin

es,

i.e.t

raje

ctor

ieso

fpa

rtic

lesi

mm

erse

din

the

flow

.T

hefig

ure

isre

prod

uced

inF

igur

e7.

6.H

ere

we

clea

rlyse

eavo

rtex

ring

form

ing

belo

wth

em

itral

ring.

Thi

sis

also

seen

inF

igur

e1in

McQ

ueen

andP

eski

n(20

00),

whi

chw

eha

vere

prod

uced

Fig

ure

7.6:

Cut

-aw

ayvi

ewof

the

hear

tdur

ing

early

vent

ricul

ardi

-as

tole

.Not

eth

erin

gvo

rtex

visi

ble

inth

ele

ftve

ntric

lebe

low

the

mi-

tral

valv

e.F

rom

Pes

kin

and

Mc-

Que

en(1

996)

.

Fig

ure7

.7:S

ectio

nthr

ough

the

left

vent

ri-cl

esh

owin

gst

ream

lines

ofve

ntric

ular

fill-

ing.

Apa

irof

vort

ices

(cro

ss-s

ectio

nof

avo

rtex

ring)

hasb

eens

hedf

rom

the

mitr

alle

aflet

san

dha

sm

igra

ted

dow

nwar

dsto

-w

ards

the

apex

ofth

ele

ftve

ntric

le.F

rom

McQ

ueen

and

Pes

kin(

2000

).

Page 84: MR · 2002. 2. 20. · Adeler A TV Erhver vsf or skerpr ojekt EF 698 IMM-PHD-2001-86 ISSN 0909-3192 ISBN 87-88306-13-5 c 2001 by Pernille Thorup Adeler Printed by IMM, DTU Bookbinder

148

The

3Dhe

artm

odel

inF

igur

e7.

7.In

this

figur

eth

eflo

wis

show

nas

stre

amlin

es,w

hich

are

com

pute

dby

choo

sing

atim

eof

inte

rest

,fixi

ngth

eve

loci

tyfie

ldat

that

give

ntim

e,an

dco

mpu

tinga

ndpl

ottin

gw

hatt

hetr

ajec

torie

sofp

artic

lesw

ould

beif

the

part

icle

sw

ere

tom

ove

inth

at(t

ime-

inde

pend

ent)v

eloc

ityfie

ld.B

oth

ofth

efig

ures

clea

rlysh

owth

efo

rmat

ion

ofa

vort

exrin

gbe

low

the

mitr

alva

lve,

and

whe

ncu

tting

thro

ught

herin

gw

ese

eapa

irof

vort

ices

,sim

ilart

ow

hatw

ese

ein

the

2Dm

odel

,se

eFig

ure

5.1.

7.3

Dis

cuss

ion

The

resu

ltspr

esen

tedin

this

chap

ters

how

that

the

3Dm

odel

hast

obe

adju

sted

and

impr

oved

befo

rea

reas

onab

lecom

paris

onw

ithM

Rda

taca

nbe

obta

ined

.Thi

sis

nota

surp

rise,

sinc

eit

took

alo

ngtim

eto

find

ago

odpa

ram

eter

setti

ngin

the

2Dm

odel

,and

the

3Dm

odel

isev

enm

ore

com

plex

.B

utit

was

hope

dtha

tbec

ause

the

3Dm

odel

was

base

don

are

alis

tic,h

uman

hear

tthe

resu

ltsw

ould

have

been

reas

onab

lewith

outt

oom

any

para

met

erch

ange

s.Pa

ram

eter

sdet

erm

inin

gthe

time

cour

se,th

eco

ntra

ctio

nand

rela

xatio

noft

hefib

ers,

the

pre-

and

afte

rload

and

poss

ibly

the

geom

etry

ofth

eva

lves

have

tobe

adju

sted

toim

prov

eth

eco

mpa

rison

betw

eenm

odel

and

MR

data

.But

sim

ula-

tions

with

the

3Dm

odel

are

com

puta

tiona

llyve

ryde

man

ding

,als

oin

the

post

proc

essi

ngst

ep.T

hus

itis

notr

ealis

ticto

achi

eve

abe

tterp

aram

eter

setti

ngfo

rth

em

odel

with

ina

reas

onab

letim

epe

riod.

Eve

nif

the

com

paris

onw

ithon

esp

ecifi

cM

Rda

tase

tis

notg

ood,

we

can

still

obta

inva

luab

lein

sigh

tsin

toth

eflo

wpa

ttern

,par

ticul

arly

inth

ele

ftve

ntric

le,

from

the

3Dm

odel

.Bec

ause

the

mod

elis

3Dan

dthe

geom

etry

ofth

ele

ftve

ntric

leis

very

real

istic

we

can

uset

hem

odel

toex

amin

ethe

vort

expa

ttern

durin

gfil

ling.

Fro

mth

ere

sults

repr

oduc

edhe

re,w

ese

etha

tavo

rtex

ring

form

sdu

ring

dias

tole

and

acu

t-aw

ayvi

ewof

this

show

sa

vort

expa

ir,ex

actly

asse

enin

the

2Dm

odel

.T

his

supp

orts

the

idea

ofth

evo

rtex

patte

rnbe

ing

a3D

phen

omen

onas

indi

cate

dby

the

MR

data

inC

hapt

er5.

Cha

pter

8

Con

clus

ions

and

sugg

estio

ns

The

purp

oseo

fth

isP

h.D

.pro

ject

hasb

eent

oac

hiev

ea

bette

rund

erst

andi

ngof

the

hem

odyn

amic

sof

the

hear

tusi

nga

com

puta

tiona

lmod

elan

dM

Rda

ta.W

eha

vepr

esen

teda

2Dco

mpu

tatio

nalm

odel

ofth

ebl

ood

flow

inth

ele

ftsi

deof

the

hum

anhe

art,

whi

chw

asco

nstr

ucte

dby

intr

oduc

ing

mod

ifica

tions

and

impr

ove-

men

tsto

Pes

kin

and

McQ

ueen

’s2D

hear

tmod

eldi

men

sion

edto

ado

g’s

hear

t.T

hese

mod

ifica

tions

and

impr

ovem

ents

wer

eba

sedo

nph

ysio

logi

calk

now

ledg

ean

dco

mpa

rison

swith

MR

data

onhu

man

s.

8.1

Sum

mar

yof

conc

lusi

ons

We

com

pare

dout

putf

rom

our2

Dm

odel

with

anM

Rve

loci

tyda

tase

t.In

par-

ticul

ar,

we

exam

ined

the

intr

aven

tric

ular

velo

city

field

san

dth

eve

loci

tytim

escu

rves

over

the

mitr

alrin

gan

dac

ross

the

aort

icou

tflow

trac

t.W

efo

und

reas

on-

able

agre

emen

tbetw

eent

hege

nera

lflow

patte

rnfr

omth

esi

mul

atio

nand

the

MR

data

:aw

ide

inflo

wje

tdur

ing

fillin

g,th

efo

rmat

ion

ofan

ante

riorv

orte

x,an

da

wid

eou

tflow

jetd

urin

gej

ectio

n.H

owev

er,t

here

wer

ediff

eren

cesin

the

deta

ilsof

the

two

flow

patte

rns,p

artic

ular

lyin

the

vort

exfo

rmat

ions

.Inth

esi

mul

atio

nsth

evo

rtic

esw

ere

mor

edi

stin

ctan

dth

eve

loci

tyin

the

vort

ices

was

high

er.

Fur

ther

-m

ore,

we

saw

thre

evo

rtic

esin

the

sim

ulat

ion

buto

nly

two

inth

eM

Rda

ta.T

heth

irdvo

rtex

inth

esi

mul

atio

nis

prob

ably

unph

ysio

logi

cal,a

ndit

wou

ldim

prov

eth

em

odel

cons

ider

ablyi

fit

coul

dbe

rem

oved

.T

hetim

eco

urse

ofdi

asto

lean

dsy

stol

ein

the

sim

ulat

ion

was

fairl

ygo

od:

the

timin

gof

atria

lsys

tole

and

the

onse

tof

vent

ricul

arsy

stol

ewer

ese

trea

son-

ably

wel

l,bu

tthe

dura

tion

ofsy

stol

ecou

ldbe

furt

heri

mpr

oved

byex

tend

ing

it.

Page 85: MR · 2002. 2. 20. · Adeler A TV Erhver vsf or skerpr ojekt EF 698 IMM-PHD-2001-86 ISSN 0909-3192 ISBN 87-88306-13-5 c 2001 by Pernille Thorup Adeler Printed by IMM, DTU Bookbinder

150

Con

clus

ions

and

sugg

estio

ns

The

velo

city

time

profi

les

atth

em

itral

ring

and

aort

ictr

actf

rom

the

sim

ulat

ion

mat

ched

reas

onab

lywel

lwith

MR

data

.The

timin

gof

the

profi

lesw

asve

rygo

od,

whi

leth

esh

apes

and

max

imum

valu

esdi

ffer

edso

mew

hat.

The

conn

ectio

nbet

wee

nthe

sim

ulat

ionr

esul

tsan

dthe

para

met

ersin

the

mod

elis

very

com

plex

,and

we

belie

veth

atim

prov

emen

tscan

beac

hiev

edby

furt

herp

a-ra

met

erad

just

men

ts.H

owev

er,t

here

ason

ablec

ompa

rison

with

MR

data

just

ifies

usin

gth

em

odel

for

inve

stig

atio

nsof

the

hem

odyn

amic

soft

hehe

art.

We

impl

emen

teda

grad

uala

ctiv

atio

nof

the

hear

tmus

cle,

i.e.p

ropa

gatio

nof

the

activ

atio

nac

ross

the

hear

twal

lwith

agi

ven

velo

city

,whi

chre

sem

bles

the

activ

atio

nof

the

hear

tmus

clei

nth

eno

rmal

hear

t.We

foun

dth

atth

isdi

dno

taffe

ctth

esi

mul

atio

nre

sults

muc

h,an

dth

ere

sults

wer

eve

ryse

nsitiv

eto

the

activ

atio

nof

the

papi

llary

mus

cle.

We

perf

orm

edan

inve

stig

atio

nof

cert

ain

mec

hani

smsa

ffect

ing

the

dias

tolic

func

tioni

ngof

the

hear

tby

exam

inin

gth

eflo

wpa

ttern

durin

gea

rlyfil

ling.

We

foun

dre

ason

ablea

gree

men

tbetw

eens

imul

atio

nres

ults

andM

Rda

tafo

rahe

alth

yhu

man

.Inpa

rtic

ular

,the

pres

sure

diff

eren

ceth

atdr

ives

the

fillin

gof

the

vent

ricle

was

inag

reem

entw

ithcl

inic

alda

ta.

We

wer

eno

tabl

eto

sim

ulat

ethe

chan

gess

eenc

linic

ally

inth

eflo

wpa

ttern

ina

loca

lisc

hem

icco

nditi

onby

letti

ngth

eap

ical

regi

onre

lax

mor

esl

owly

than

the

rest

ofth

eve

ntric

le.H

owev

er,w

esu

cces

sful

lysim

ulat

eda

glob

alis

chem

icve

ntric

leby

letti

ngth

een

tirev

entr

icle

rela

xmor

eslo

wly

than

inth

ehe

alth

yhea

rt.

We

foun

dlo

wer

peak

velo

citie

sand

dela

yedfi

lling

inth

issi

tuat

ionc

ompa

redw

itha

sim

ulat

iono

fahe

alth

yhum

an.T

hese

chan

gesa

resi

mila

rto

mea

sure

ddat

aon

heal

thy

dogs

and

dogs

ina

glob

alis

chem

icco

nditi

on.

Fur

ther

mor

e,w

ew

ere

able

tosi

mul

atea

cute

myo

card

ialin

farc

tion(

AM

I)by

letti

ngth

eap

ical

regi

onbe

inac

tive.

Her

eth

eve

loci

tyda

tafr

omth

esi

mul

atio

nm

atch

edth

oseo

btai

nedb

yM

Rm

easu

rem

entsin

AM

Ipa

tient

s.H

owev

er,t

hedr

ivin

gpr

essu

rediff

eren

cew

asno

tin

good

agre

emen

twith

clin

ical

data

.W

eha

vesh

own

that

oura

nato

mic

allys

impl

e2D

mod

elis

able

toca

ptur

esom

eof

the

chan

gess

eend

urin

gpa

thol

ogic

alhe

artc

ondi

tions

.The

mod

elca

nbe

used

tost

udy

mec

hani

smsth

atin

trod

ucem

ajor

diff

eren

cesin

the

flow

patte

rn,w

hile

sim

ulat

ions

ofle

ssse

vere

cond

ition

sdo

nota

ltert

heflo

wpa

ttern

com

pare

dwith

the

flow

patte

rnfr

oma

sim

ulat

iono

fahe

alth

yper

son.

We

have

pres

ente

dPes

kina

ndM

cQue

en’s

3Dm

odel

ofth

een

tire

hear

tand

brie

flyco

mpa

redi

tsre

sults

with

anM

Rve

loci

tyda

tase

t.T

his

show

edth

atth

em

odel

hast

obe

furt

heri

mpr

oved

befo

rea

reas

onab

leagr

eem

entca

nbe

obta

ined

.In

part

icul

ar,t

heflo

wan

dve

loci

tyov

erth

em

itral

ring

isno

tin

agre

emen

t.Fur

-th

erm

ore,

sinc

eth

e3D

mod

elis

com

puta

tiona

llyve

ryde

man

ding

itis

notv

ery

usef

ulas

ato

olfo

rhe

mod

ynam

icinv

estig

atio

nsof

the

hear

t.H

owev

er,f

rom

the

8.2

Sug

gest

ions

for

futu

rew

ork

151

sim

ulat

ion

resu

ltsw

est

illga

inin

sigh

tint

oth

e3D

natu

reof

the

flow

patte

rnin

-si

deth

ehe

art.

The

resu

ltssh

owa

clea

rvor

tex

ring

form

ing

belo

wth

em

itral

ring

durin

gfil

ling.

8.2

Sug

gest

ions

for

futu

rew

ork

Sug

gest

ions

for

futu

rew

ork

can

bedi

vide

din

two

part

s:fu

ture

wor

kw

ithth

em

odel

pres

ente

dinth

isth

esis

and

futu

rew

ork

with

hear

tsim

ulat

ions

inge

nera

l.W

ebe

lieve

that

the

2Dm

odel

pres

ente

dinth

isth

esis

cans

tillb

eof

impo

rtan

cein

unde

rsta

ndin

gthe

hem

odyn

amic

soft

hehe

artif

itslim

itatio

nsar

ekep

tinm

ind.

The

follo

win

gsc

enar

iosc

ould

besi

mul

ated

and

inve

stig

ated

inth

e2D

mod

el:

Ô Diast

olic

func

tioni

ng.T

hein

vest

igat

ions

pres

ente

dinth

isth

esis

coul

dbe

exte

nded

e.g.

bysi

mul

atin

ginc

reas

edst

iffne

ssin

part

ofth

eve

ntric

ular

wal

ldu

eto

anin

farc

tion.

Ô Hyper

trop

hicc

ardi

omyo

path

y(HC

M).

Thi

sco

nditi

ons,

whi

chis

char

acte

r-iz

edby

incr

ease

dgro

wth

ofth

ele

ftve

ntric

ular

wal

l,ca

nbe

sim

ulat

edin

the

mod

elby

rais

ing

the

stiff

ness

es

Q .à ,

Q çà and

Q å inthe

mus

cula

rmod

el(s

eeS

ectio

n3.3

.5).

Ô Mitral

valv

est

enos

is.T

his

narr

owin

gof

the

mitr

alva

lve

can

besi

mu-

late

dby

intr

oduc

ingo

neor

seve

ralc

ross

links

betw

eent

hetw

om

itral

valv

ele

aflet

s.Ô Mitr

alva

lve

regu

rgita

tion.

Thi

sis

back

flow

ofbl

ood

from

the

vent

ricle

toth

eat

rium

due

tom

itral

valv

ein

suffi

cien

cyan

dca

nbe

sim

ulat

edby

intr

o-du

cing

bend

ingr

esis

tanc

einth

em

itral

leafl

ets,

whi

chw

ould

caus

ethe

mno

tto

clos

e.B

endi

ngre

sist

ance

can

bein

trod

uced

byth

epr

oced

ured

escr

ibed

inP

eski

nand

McQ

ueen

(198

0)on

mod

ellin

gpr

osth

etic

hear

tval

ves.

The

resu

ltspr

esen

tedin

this

thes

issu

ppor

tthe

idea

ofco

mpu

tatio

nalm

odel

sas

ato

olfo

run

ders

tand

ingth

ehe

mod

ynam

icso

fth

ehe

art.

How

ever

,si

nce

the

intr

aven

tric

ular

flow

patte

rnis

thre

edi

men

sion

al,fu

ture

wor

ksh

ould

even

tual

lybe

perf

orm

edw

itha

3Dm

odel

.W

ebe

lieve

that

this

wou

ldno

tha

veto

bea

com

puta

tiona

llyde

man

ding

mod

elof

the

entir

ehe

art,

like

the

mod

elof

Pes

kin

and

McQ

ueen

.Ins

tead

,asi

mpl

er3D

mod

elof

the

left

side

ofth

ehe

artw

ould

been

ough

tom

eett

hede

man

dsof

ahe

mod

ynam

ictoo

l.T

hew

ork

pres

ente

dhe

reha

ssho

wn

that

an(a

nato

mic

ally

)sim

ple2

Dm

odel

can,

with

inlim

its,p

redi

ct

Page 86: MR · 2002. 2. 20. · Adeler A TV Erhver vsf or skerpr ojekt EF 698 IMM-PHD-2001-86 ISSN 0909-3192 ISBN 87-88306-13-5 c 2001 by Pernille Thorup Adeler Printed by IMM, DTU Bookbinder

152

Con

clus

ions

and

sugg

estio

ns

phys

iolo

gica

llyco

rrec

tflow

patte

rns.

Thu

sasi

mpl

e3D

mod

elsh

ould

also

beab

leto

doth

isan

dev

enbe

tter.

Suc

ha3D

mod

elsh

ould

beev

alua

teda

ndva

lidat

edin

deta

ilby

com

paris

onw

ithM

Rve

loci

tyda

ta.O

ncet

his

isdo

ne,th

em

odel

coul

dbe

used

for

inve

stig

atio

nssi

mila

rto

thos

epr

esen

tedin

this

thes

isan

dto

thos

esu

gges

teda

bove

for

futu

rew

ork

with

the

2Dm

odel

.

App

endi

xA

Mag

netic

reso

nanc

eimag

ing

Thi

sap

pend

ixpr

ovid

esan

intr

oduc

tion

tom

agne

ticre

sona

nceim

agin

g(M

RI)

.It

prov

ides

the

read

erw

itha

know

ledg

eon

how

the

MR

Ida

taus

edin

the

thes

isis

reco

rded

.Itde

scrib

esth

eba

sics

ofM

RI:

spin

ofnu

clei

,exc

itatio

n,re

laxa

tion

and

puls

eseq

uenc

esuse

din

MR

scan

ning

.Ital

sode

scrib

esth

eim

agin

gpr

oces

s:ho

wM

RI

iscr

eate

d,ch

oice

ofsc

anar

ea,s

patia

lenc

odin

gand

imag

ing

sequ

ence

sin

MR

I.F

inal

ly,v

eloc

itym

easu

rem

entsw

ithM

RI

usin

gve

loci

tyen

codi

ngis

de-

scrib

ed.T

hem

ain

sour

cefo

rth

isap

pend

ixis

Phi

lips

(n.d

.).

A.1

Bas

icso

fMR

I

The

prin

cipl

eof

MR

scan

ning

isba

sedo

nth

em

agne

ticpr

oper

tieso

fnuc

leiw

ithan

unev

enat

omic

mas

sor

atom

icnu

mbe

r,e.g

.

) n .S

uch

nucl

eipo

sses

sang

ular

mom

entu

man

dhav

ea

char

acte

ristic

spin

quan

tum

num

berg

reat

erth

anze

ro.T

hesp

inin

duce

sam

agne

ticfie

ldw

ithan

axis

coin

cide

ntw

ithth

eax

isof

spin

,and

with

am

agni

tude

and

dire

ctio

nre

pres

ente

dby

the

mag

netic

dipo

lem

omen

t,or

dipo

leve

ctor

,8 ,se

eFig

ure

A.1

.N

orm

ally

,the

dipo

leve

ctor

ofa

nucl

eusi

sor

dere

dran

dom

ly.B

ut,w

hen

anex

tern

alm

agne

ticfie

ldis

appl

iedt

hedi

pole

vect

oris

alig

nedi

npa

ralle

lora

ntip

ar-

alle

ldire

ctio

nw

ithth

eap

plie

dfiel

d.In

the

pres

ence

ofan

exte

rnal

mag

netic

field

the

dipo

leve

ctor

ofth

enu

cleu

sexp

erie

nces

ato

rque

,whi

chca

uses

itto

rota

te(o

rpr

eces

s)ar

ound

the

axis

ofth

eex

tern

alfie

ldw

itha

cert

ain

freq

uenc

y.T

his

phen

omen

onis

calle

dLa

rmor

prec

essi

on,se

eFig

ure

A.2

.T

hera

teof

prec

essi

onde

pend

supo

nth

eph

ysic

alch

arac

teris

ticso

fth

enu

-cl

eusa

ndth

est

reng

th,

o å ,ofth

em

agne

ticfie

ld.T

his

isex

pres

sedin

the

Larm

or

Page 87: MR · 2002. 2. 20. · Adeler A TV Erhver vsf or skerpr ojekt EF 698 IMM-PHD-2001-86 ISSN 0909-3192 ISBN 87-88306-13-5 c 2001 by Pernille Thorup Adeler Printed by IMM, DTU Bookbinder

154

Mag

netic

reso

nanc

eimag

ing

µ

Fig

ureA

.1:A

spin

ning

nucl

eusw

ithits

dipo

leve

ctor

8 whe

nno

exte

rnal

mag

-ne

ticfie

ldis

appl

ied.

The

spin

axis

co-

inci

desw

ithth

edi

pole

vect

or.

B0

B0

Fig

ure

A.2

:P

rece

ssio

nof

the

dipo

leve

ctor

ofa

spin

ning

nucl

eusa

bout

anex

tern

alm

agne

ticfie

ld

o å .eq

uatio

n

p òlo å û

whe

re

p isth

eLa

rmor

freq

uenc

y,

l isth

egy

rom

agne

ticra

tiosp

ecifi

cto

the

nu-

cleu

sand

o å isthe

stre

ngth

ofth

eex

tern

alm

agne

ticfie

ld.

Sin

ce

l issp

ecifi

cto

each

nucl

eust

heLa

rmor

freq

uenc

yis

ther

ebya

lso

spec

ifict

oea

chnu

cleu

s.e.

g.fo

rth

ehy

drog

ennu

cleu

s,

) n ,th

eLa

rmor

freq

uenc

yis

42.5

759a

tan

exte

rnal

mag

netic

field

of1

T(S

chla

ikje

rand

Kol

enda

,199

7).

Larm

orpr

eces

sion

isa

reso

nanc

ephe

nom

enon

.Ifa

syst

emha

sana

tura

lreso

nanc

e,ene

rgy

can

bem

ost

effic

ient

lytr

ansf

erre

dto

the

syst

emat

this

freq

uenc

y.In

MR

imag

ing

itis

mai

nly

the

) n

nucl

eus(

the

prot

on)t

hati

sco

nsid

ered

.W

eth

eref

orel

imit

ours

elve

sto

this

case

inth

efo

llow

ing.

Con

side

ringa

colle

ctio

nof

prot

onsi

na

volu

me

inth

eab

senc

eofa

nex

tern

alm

agne

ticfie

ld.

The

indi

vidu

aldi

pole

vect

orsa

reor

dere

dran

dom

lyan

dth

usth

ene

tmag

netic

mom

ent,

q å ,iszer

o.In

the

follo

win

gw

ere

fert

oth

ene

tmag

netic

mom

enta

sth

em

agne

tizat

ionv

ecto

r.W

hen

anex

tern

alm

agne

ticfie

ld

o å isap-

plie

dth

edi

pole

vect

orsw

illte

ndto

alig

npa

ralle

lor

antip

aral

lelto

the

appl

ied

field

.T

here

isa

slig

htex

cess

favo

urin

gth

epa

ralle

ldire

ctio

n(t

helo

wen

ergy

stat

e),a

ndth

usth

em

agne

tizat

ionv

ecto

r

q å isnon

-zer

oand

isor

ient

edin

the

dire

ctio

nof

the

appl

ied

mag

netic

field

.T

here

isno

tran

sver

seco

mpo

nent

sinc

eth

ein

divi

dual

prec

essi

ngpr

oton

sare

rand

omly

orie

nted

with

resp

ectto

the

phas

eof

thei

rpre

cess

iona

lmot

ion.

A.1

Bas

icso

fMR

I15

5

We

now

intr

oduc

eaco

ordi

nate

syst

emw

here

the

r ó axis

ispa

ralle

ltoth

edi

-re

ctio

nof

the

exte

rnal

mag

netic

field

o å .Weca

nth

enth

ink

ofth

em

agne

tizat

ion

vect

oras

havi

ngtw

oco

mpo

nent

s:

q äs in

the

tran

sver

sepl

ane

and

qut inth

elo

ngitu

dina

lpla

ne.I

nth

eeq

uilib

rium

stat

ewe

have

q tòq å

and

q äsò .

Inth

isst

atet

hem

agne

tizat

ionv

ecto

ris

stat

ican

ddo

esno

tind

ucea

curr

ent,i

.e.w

eca

nnot

obta

inan

ysi

gnal

from

the

volu

me

unde

robs

erva

tion.

Inor

dert

oob

tain

asi

gnal

,the

spin

shav

eto

bepe

rtur

beda

ndle

ave

the

equi

libriu

mst

ate.

A.1

.1E

xcita

tion

The

equi

libriu

mst

atec

anbe

left

byex

posi

ngth

esp

insy

stem

toa

radi

ofr

eque

ncy

(RF

)pu

lse

inth

efo

rmof

atim

eva

ryin

gm

agne

ticfie

ld

o ) .

o ) ism

ade

tobe

perp

endi

cula

rtoth

est

atic

field

o å and

varie

swith

the

Larm

orfr

eque

ncy.

The

o ) fiel

d,w

hich

istu

rned

onon

lyfo

ra

shor

tper

iod

oftim

e,is

prod

uced

bya

coil

with

itsax

isin

the

Uv ópl

ane.

The

stat

icfie

ldis

typi

cally

ofth

eor

dero

f0.

1-1.

5T,

whi

leth

eex

cita

tion

field

isof

the

orde

rof1

mT.

The

effe

ctof

appl

ying

the

o ) fiel

dis

that

the

mag

netiz

atio

nvec

tora

lso

pre-

cess

esab

outth

isse

cond

field

and

rota

tesa

way

from

the

vert

ical

dire

ctio

nto

war

dth

e

Uv ópl

ane.

The

o å field

still

affe

cts

the

mag

netiz

atio

nvec

tora

ndm

akes

itpr

eces

sabo

utth

e

r ó axis

,so

the

tota

leffe

ctis

that

,whi

leth

eR

Fpu

lse

istu

rned

on,t

hem

agne

tizat

ionv

ecto

rper

form

sasp

iralli

ngm

otio

non

asp

here

assk

etch

edin

Fig

ure

A.3

.W

hen

obse

rvin

gthe

situ

atio

nin

aco

ordi

nate

syst

em

ì Uw ûvw ûrí th

atro

tate

sab

outth

e

r ó axis

with

the

Larm

orfr

eque

ncy,

the

effe

ctof

appl

ying

o ) isse

enas

sim

ply

flipp

ing

the

mag

netiz

atio

nvec

tort

owar

dth

eUw vw ó pla

ne.T

hele

ngth

ofth

em

agne

tizat

ionv

ecto

rispr

actic

ally

cons

tant

durin

gth

esh

ortp

erio

dof

time

the

RF

0x

0 y

0

z

0

z

z

y

x

Fig

ure

A.3

:S

pira

lling

mot

ion

ofth

em

agne

tizat

ionv

ecto

rdur

ing

anR

Fpu

lse.

Page 88: MR · 2002. 2. 20. · Adeler A TV Erhver vsf or skerpr ojekt EF 698 IMM-PHD-2001-86 ISSN 0909-3192 ISBN 87-88306-13-5 c 2001 by Pernille Thorup Adeler Printed by IMM, DTU Bookbinder

156

Mag

netic

reso

nanc

eimag

ing

puls

eis

on.T

hefin

alfli

pan

gle

x can

beca

lcul

ated

by

x òlo )æ ,w

here

l isth

egy

rom

agne

ticra

tioan

d

æ isth

edu

ratio

nof

the

RF

puls

e.T

hus

the

final

posi

tion

ofth

em

agne

tizat

ionv

ecto

rin

spac

eafte

rthe

RF

puls

eis

turn

edof

fde

pend

son

the

mag

nitu

deof

the

o ) field

and

the

dura

tiono

fthe

RF

puls

e.A

ftere

xcita

tion

the

mag

netiz

atio

nvec

tor’s

prec

essi

onin

duce

sacu

rren

tcal

led

the

MR

sign

al.T

heco

ilpr

oduc

ingt

he

o ) fiel

dca

nal

sobe

used

tosa

mpl

ethi

ssi

gnal

.Whe

nsa

mpl

inga

nM

Rsi

gnal

only

the

com

pone

ntin

the

Uv ó

plan

eca

nbe

dete

cted

.Thu

sth

em

axim

umM

Rsi

gnal

isob

tain

edat

afli

pan

gle

of

yz .In

MR

Ity

pica

llytw

oex

cita

tions

are

inte

rest

ing:

the

yz (

% " )an

dth

e

,z (

)pu

lses

.The

nam

esre

fert

oth

efli

pan

gleo

fthe

mag

netiz

atio

nwhe

nth

eR

Fpu

lse

istu

rned

off.

Thu

sthe

180

z puls

eis

anin

vers

iono

fthe

mag

netiz

atio

nvec

tor.

A.1

.2R

elax

atio

n

Afte

rex

cita

tion

the

nucl

eire

turn

toth

eeq

uilib

rium

stat

e.T

his

proc

essis

calle

dre

laxa

tiona

ndbe

gins

atth

ete

rmin

atio

nof

the

RF

puls

e.D

urin

gre

laxa

tionb

oth

the

long

itudi

nal(

qt )and

the

tran

sver

se(

q äs )co

mpo

nent

sretu

rnto

thei

requ

i-lib

rium

valu

es.T

helo

ngitu

dina

land

tran

sver

sere

laxa

tions

are

mut

ually

inde

pen-

dent

.In

Fig

ure

A.4

the

time

varia

tion

ofth

ele

ngth

ofth

elo

ngitu

dina

land

tran

s-ve

rsec

ompo

nent

sof

the

mag

netiz

atio

nvec

tord

urin

gre

laxa

tion

issh

own.

The

mag

netiz

atio

nvec

torr

etur

nsto

itseq

uilib

rium

valu

ein

anex

pone

ntia

lfash

iona

sin

dica

tedi

nF

igur

eA

.4.

The

long

itudi

nalr

elax

atio

n(of

ten

refe

rred

toas

spin

-latti

cere

laxa

tion)

isre

-la

tedt

oho

wfa

stth

enu

clei

emit

ener

gyth

roug

hint

erac

tionb

etw

eent

hesp

insa

ndth

ela

ttice

.In

MR

Ith

ela

ttice

isth

em

agne

tican

dth

erm

alen

viro

nmen

toft

henu

-cl

ei.T

hetim

eva

riatio

noft

helo

ngitu

dina

lmag

netiz

atio

nvec

tord

urin

gre

laxa

tion

isgi

ven

by

q tòq å| ó×ØÙÚ 7~ ch

arac

teriz

edby

the

time

cons

tant

E ) ,see

the

top

pane

lofF

igur

eA.4

.In

biol

ogic

altis

sue

E ) rang

esfr

omab

out5

0m

illis

econ

dsto

afe

wse

cond

s.T

rans

vers

erel

axat

ion(

orsp

in-s

pinr

elax

atio

n)is

rela

tedt

oth

ein

tera

ctio

nof

indi

vidu

alsp

ins

caus

ingl

ocal

varia

tions

inth

est

atic

mag

netic

field

o å .The

seva

riatio

nsle

adto

fluct

uatio

nsin

the

prec

essi

onalf

requ

ency

ofth

ein

divi

dual

nu-

clei

.T

his

resu

ltsin

agr

adua

land

rand

omde

phas

ingo

fth

esp

insa

ndhe

ncei

na

deca

yin

the

mag

nitu

deof

the

tran

sver

seco

mpo

nent

ofth

em

agne

tizat

ionv

ec-

tor.

Fig

ure

A.5

show

sth

ede

phas

ingo

fsp

ins

afte

ran

90

z RF

puls

e.T

hetim

eva

riatio

nof

the

tran

sver

sem

agne

tizat

ionv

ecto

rdur

ing

rela

xatio

nis

give

nby

q äsòq å×ØÙÚ

,w

here

E î isthe

tran

sver

sere

laxa

tion

time

cons

tant

.

E î isal

way

ssm

alle

rthan

E ) andi

sty

pica

llyin

the

rang

eofa

few

mill

isec

onds

toa

few

seco

ndsin

biol

ogic

altis

sue.

A.1

Bas

icso

fMR

I15

7

M M0

Mz

T 1tim

e

M M0

Mxy

T 2tim

e

Fig

ureA

.4:T

hetim

eva

riatio

noft

hele

ngth

ofth

em

agne

tizat

ionv

ecto

rdur

ing

re-

laxa

tion.

Top:

long

itudi

nalr

elax

atio

n;bo

ttom

:tra

nsve

rser

elax

atio

n.R

elax

atio

nco

nsta

nts

E ) and

E î aresh

own.

yy

xx

Fig

ure

A.5

:D

epha

sing

ofsp

insa

ftera

90

z puls

e.Le

ft:im

med

iate

lyaf

tert

heR

Fpu

lse;

right

:so

met

ime

afte

rthe

RF

puls

e,w

hen

the

spin

sare

outo

fph

asea

ndth

em

agne

tizat

ionv

ecto

rhas

deca

yed.

Page 89: MR · 2002. 2. 20. · Adeler A TV Erhver vsf or skerpr ojekt EF 698 IMM-PHD-2001-86 ISSN 0909-3192 ISBN 87-88306-13-5 c 2001 by Pernille Thorup Adeler Printed by IMM, DTU Bookbinder

158

Mag

netic

reso

nanc

eimag

ing

1

2de

cay

T*

time

2Tde

cay

FID

Fig

ure

A.6

:T

ime

varia

tion

ofth

eF

IDw

ithth

e

Eù î and

E î decay

show

n.

The

rela

xatio

ntim

eco

nsta

ntsd

epen

don

the

fact

that

diff

eren

ttis

sues

have

diff

eren

tcou

rses

ofre

laxa

tion.

The

sedi

ffer

ence

sare

the

basi

sfor

the

MR

Isc

an-

ning

. The

tran

sver

seco

mpo

nent

q äs ind

uces

acu

rren

t(a

sign

al)w

hich

isca

lled

the

Fre

eInd

uctio

nD

ecay

(FID

).T

heco

ilus

edto

crea

teth

e

o ) field

(with

itsax

isin

the

Uv ó

plan

e)ca

nal

sobe

used

tosa

mpl

ethe

sign

alin

the

Uv ó

plan

eafte

rthe

exci

tatio

npu

lse

iste

rmin

ated

.Inth

esa

mpl

ing,

ampl

itude

,freq

uenc

y,ph

asea

ndde

caya

rede

tect

ed.T

heam

plitu

deof

the

MR

sign

alde

cays

expo

nent

ially

with

atim

eco

nsta

nt

Eù î ,due

tobo

thsp

in-s

pin(

tran

sver

se)re

laxa

tiona

ndm

agne

ticfie

ldin

hom

ogen

eitie

s.

Eù î issm

alle

rtha

n

E î .Figur

eA

.6sh

ows

the

time

varia

tion

ofth

eF

IDw

ithbo

thth

e

Eù î andth

e

E î decay

ssho

wn.

A.1

.3P

ulse

sequ

ence

s

Itis

impo

rtan

tto

bear

inm

ind

that

the

MR

sign

alde

pend

son

both

E ) and

E î ,bu

tit

ispo

ssib

le,th

roug

hthe

useo

fpul

sese

quen

ces,to

obta

inan

MR

sign

alth

atde

pend

sprim

arily

onei

ther

E ) or

E î .A

puls

eseq

uenc

eisa

seto

fRF

puls

esus

edin

conj

unct

ionw

itha

sign

alsa

m-

plin

g.T

here

are

seve

ralp

ulse

sequ

ence

savai

labl

e.T

hein

divi

dual

sequ

ence

sare

char

acte

rized

bygi

ving

anM

Rsi

gnal

who

sein

tens

ityde

pend

sprim

arily

onei

ther

E ) or

E î .This

isca

lled

a

E ) or

E î weigh

tedM

Rsi

gnal

.For

aE ) w

eigh

teds

igna

lth

esa

tura

tionr

ecov

ery

orin

vers

ionr

ecov

ery

sequ

ence

sarea

vaila

ble,

and

fora

E î

A.1

Bas

icso

fMR

I15

9

wei

ghte

dsig

nalth

esp

inec

hose

quen

ceis

avai

labl

e.In

this

sect

iont

hesp

inec

hose

quen

cesw

illbe

pres

ente

dasa

nex

ampl

eofa

puls

eseq

uenc

e.

Spi

nec

ho

The

FID

sign

alfo

llow

sa

Eù î decay

caus

edby

both

spin

-spi

nrel

axat

ion(

E î decay

)an

dby

mag

netic

field

inho

mog

enei

ties,s

eeF

igur

eA.6

.Thu

sthe

FID

sign

alal

one

cann

otbe

used

tom

easu

retr

ue

E î relaxa

tion.

How

ever

,spi

n-sp

inre

laxa

tioni

sa

rand

oman

dirr

ever

sibl

epr

oces

s,w

hile

field

inho

mog

enei

tiesa

rest

atic

and

can

beac

coun

tedf

or,

and

this

isex

ploi

ted

inth

esp

inec

hopu

lse

sequ

ence

.Thi

sse

quen

ceai

ms

atel

imin

atin

gth

ein

fluen

ceof

the

field

inho

mog

enei

ties,l

eavi

ngon

lyth

etr

ue

E î relaxa

tion.

The

sequ

ence

star

tsw

itha

90z R

Fpu

lse

that

flips

the

mag

netiz

atio

nvec

tor

into

the

Uv ó

plan

e.Im

med

iate

lyaf

ter,

the

rela

xatio

npro

cess

sets

in:

the

tran

s-ve

rse

com

pone

nt

q äs de

cays

follo

win

gth

e

Eù î deca

y.T

heef

fect

ofth

est

atic

mag

netic

field

inho

mog

enei

tiesca

uses

the

indi

vidu

alsp

inst

opr

eces

sout

ofph

ase

(dep

hase

),see

Fig

ure

A.7

b–c.

At

æ ò%" (T

Eis

the

echo

time)

a18

0

z puls

eis

appl

ied.

Thi

spu

lse

inve

rts

all

the

spin

s,w

hich

isse

enas

am

irror

ing

inth

e

Uv ó

plan

e,se

eFig

ure

A.7

c–d.

Afte

rth

ispu

lse,

the

field

inho

mog

enei

tiess

tilli

n-

o

puls

e

t = T

E18

0

t = T

E

t = T

E/2−

t = T

E/2+

0 <

t <

TE

/2

TE

/2 <

t <

TE

f)

b) e)

c) d)

t = 0

a)

Fig

ure

A.7

:T

hesp

inec

hose

quen

ce:de

phas

ingo

fspi

nsdu

eto

the

field

inho

mo-

gene

ities

and

the

elim

inat

ion

ofth

eef

fect

ofth

eseb

ya

180

z puls

e.

Page 90: MR · 2002. 2. 20. · Adeler A TV Erhver vsf or skerpr ojekt EF 698 IMM-PHD-2001-86 ISSN 0909-3192 ISBN 87-88306-13-5 c 2001 by Pernille Thorup Adeler Printed by IMM, DTU Bookbinder

160

Mag

netic

reso

nanc

eimag

ing

fluen

ceth

esp

ins,

butn

owit

caus

esth

emto

reph

aseb

ecau

seof

the

inve

rsio

n,se

eF

igur

eA

.7d–

f.A

ttim

e

æ ò th

esp

insa

reon

ceag

ain

inph

asea

ndth

eM

Rsi

gnal

can

besa

mpl

ed.T

heec

hosi

gnal

(MR

sign

alat

æ ò )

has

asm

alle

ram

plitu

deth

anth

esi

gnal

at

æ ò

,due

toth

esp

in-s

pinr

elax

atio

n.T

hesp

in-s

pin

rela

xatio

nis

nota

ffect

edby

the

inve

rsio

npu

lse

beca

useit

isra

ndom

and

irre-

vers

ible

.The

sign

alde

cayf

rom

æ ò

to

æ ò is

then

am

easu

reof

the

true

E î

rela

xatio

n.If

subs

eque

nt180

z puls

esar

eap

plie

d,at

æ ò% " û+% " û!% " û

and

the

sign

alsa

mpl

edat

E ò û" û+ û th

esa

mpl

edsi

gnal

will

con-

tinue

tode

caya

ccor

ding

toth

etr

ue

E î relaxa

tion

and

the

E î relaxa

tionc

anbe

dete

rmin

edw

ithhi

gher

accu

racy.

Fig

ure

A.8

show

sth

etim

eva

riatio

nof

the

sig-

nala

mpl

itude

durin

ga

spin

echo

sequ

ence

.A

part

icul

arvo

lum

ebe

ing

scan

nedis

ofte

nco

mpo

sedo

fse

vera

ltis

sues

and

the

sam

pled

MR

sign

alis

asu

mof

the

sign

alsf

rom

the

indi

vidu

altis

sues

.Eac

htis

sueh

asdi

ffer

entr

elax

atio

ntim

eco

nsta

ntsa

ndth

isis

expl

oite

din

the

puls

ese-

quen

ces,e

.g.i

nth

ech

oice

ofT

Ein

the

spin

echo

sequ

ence

.The

optim

alT

Eis

atim

eva

lue

such

that

the

diff

eren

cebe

twee

nthe

sign

alam

plitu

deso

fth

ein

di-

vidu

altis

sues

isla

rge.

Sig

nals

ampl

inga

tthe

optim

altim

ere

sults

inan

imag

e

1

1/2T

E3/

2TE

2Tde

cay

2de

cay

T*

FID

time

2TE

TE

Fig

ure

A.8

:T

ime

varia

tion

ofth

eM

Rsi

gnal

ampl

itude

durin

ga

spin

echo

se-

quen

ces.

180

z puls

esar

eap

plie

d,at

æ ò% " û+% " û!% " û a

ndth

esi

gnal

issa

mpl

edat

E ò û" û+ û .

A.2

Imag

ing

met

hods

161

M

M

time

tissu

e w

ith lo

w T

cont

rast

2

tissu

e w

ith h

igh

T 2

xy

optim

al T

E

Fig

ure

A.9

:T

rans

vers

erel

axat

ionc

urve

for

two

tissu

esw

ithdi

ffer

ent

E î values

.In

asp

inec

hose

quen

ceth

eop

timal

echo

time

isat

æ.Ù whe

reth

edi

ffer

ence

betw

eens

igna

lam

plitu

desis

larg

e.

whe

reth

ere

isa

larg

eco

ntra

stbe

twee

nthe

indi

vidu

altis

sues

whe

nth

esi

gnal

istr

ansf

orm

edin

toan

imag

e(se

eSec

tionA

.2).

Fig

ure

A.9

show

sth

etr

ansv

erse

re-

laxa

tionc

urve

sfor

two

diff

eren

ttiss

ues(

with

diff

eren

t

E î values

)with

the

optim

alT

Ein

dica

ted.

A.2

Imag

ing

met

hods

The

situ

atio

nde

scrib

edin

the

prev

ious

sect

ion

isth

atw

here

the

entir

evo

lum

eun

dero

bser

vatio

nis

exci

ted.

Sin

ceth

esa

mpl

edM

Rsi

gnal

isa

resu

ltoft

here

lax-

atio

npr

oces

sinth

een

tire

volu

me,

itco

ntai

nsno

spat

ialin

form

atio

n.In

orde

rto

cons

truc

tan

MR

imag

ethe

sign

alha

sto

besp

atia

llyen

code

d.T

hesp

atia

lenc

od-

ing

isac

hiev

edus

ing

the

fact

that

the

Larm

orfr

eque

ncy

depe

ndso

nth

em

agne

ticfie

ldst

reng

th.I

fth

em

agne

ticfie

ldva

riesw

ithpo

sitio

nin

aco

ntro

lled

way

,the

reso

nanc

efreq

uenc

yof

the

indi

vidu

alsp

insv

arie

sacc

ordi

ngly.

Thu

sspi

nsca

nbe

pick

edou

tand

exci

ted

byth

eirp

ositi

onin

spac

e.In

anM

Rsc

anne

rthre

eset

sofc

oils

are

pres

ent,t

hem

ain

coils

,whi

chcr

eate

the

stat

icm

agne

ticfie

ld

o å ,thehi

ghfr

eque

ncy

coils

,whi

chem

itth

eR

Fpu

lses

ands

ampl

ethe

MR

sign

al,a

ndfin

ally

the

grad

ient

coils

,whi

char

euse

dto

cont

rol

the

spat

ialv

aria

tion

ofth

em

agne

ticfie

ld.

The

grad

ient

coils

crea

tea

mag

netic

Page 91: MR · 2002. 2. 20. · Adeler A TV Erhver vsf or skerpr ojekt EF 698 IMM-PHD-2001-86 ISSN 0909-3192 ISBN 87-88306-13-5 c 2001 by Pernille Thorup Adeler Printed by IMM, DTU Bookbinder

162

Mag

netic

reso

nanc

eimag

ing

field

whi

chis

para

llelto

the

mai

nfie

ld

o å .Ifw

eas

sum

e,as

prev

ious

ly,t

hatt

hem

ain

field

ispa

ralle

ltoth

e

r ó axis

we

have

o tòo å äUsv tr

whe

re

ä ,

s and

t are

mag

netic

field

grad

ient

sinth

eU ó

,v ó

and

r ó direc

tions

,re

spec

tivel

y.T

hegr

adie

ntfie

ldis

wea

kcom

pare

dto

the

stat

icm

agne

ticfie

ld,b

e-in

gty

pica

llyin

the

rang

e1–1

0mT

/m(A

nder

sen,

1997

).T

heth

reeg

radi

entfi

elds

are

ofte

nre

ferr

edto

asth

esl

ice

sele

ctio

ngra

dien

t,the

read

-out

orfr

eque

ncy

en-

codi

nggr

adie

nt,a

ndth

eph

asee

ncod

ingg

radi

ent,b

ecau

seof

thei

rfun

ctio

nsin

anM

RI

sequ

ence

.

A.2

.1S

lice

sele

ctio

ngra

dien

t

Ifa

grad

ient

istu

rned

onw

hile

the

volu

me

isbe

ing

expo

sedt

oan

RF

puls

econ

-ta

inin

ga

give

nra

nge

offr

eque

ncie

s,on

lyth

esl

ice

whi

chco

ntai

nssp

inw

itha

Larm

orfr

eque

ncy

that

mat

ches

the

freq

uenc

iesin

the

puls

ewill

beex

cite

d.T

heth

ickn

esso

fa

slic

eis

dete

rmin

edby

the

band

wid

thof

the

RF

puls

e(i.

e.th

era

ngeo

ffr

eque

ncie

sinth

epu

lse)

.The

slic

ese

lect

iong

radi

entfi

eld

ispe

r-pe

ndic

ular

toth

esl

ice

dire

ctio

nan

dca

nbe

chos

enin

any

give

ndi

rect

ion.

The

MR

imag

eis

cons

truc

tedb

ya

Four

iera

naly

siso

fth

esa

mpl

edM

Rsi

gnal

.E.g

.if

we

use

asl

ice

sele

ctio

ngra

dien

tpar

alle

lto

the

r ó axis

inco

mbi

natio

nwith

asp

inec

hose

quen

ceof

puls

es,th

eFo

urie

rtra

nsfo

rmof

the

MR

sign

alw

illbe

apr

ojec

tiono

fa

E î weigh

teds

igna

lfrom

the

entir

ese

lect

edsl

ice

onto

the

r ó axis

.B

utth

erei

sno

spat

ialre

solu

tiono

fthe

sele

cted

slic

e.T

heFo

urie

rcon

nect

ionb

etw

eenM

Rim

agea

ndR

Fpu

lses

(thr

ough

the

sam

-pl

edsi

gnal

)infl

uenc

esth

ech

oice

ofR

Fpu

lse.

Whe

na

shar

pre

ctan

gula

rslic

e

tran

sfor

mF

ourie

r

Fig

ure

A.1

0:A

sinc

wav

epu

lsea

ndits

Four

iert

rans

form

:the

step

func

tion.

The

sinc

wav

eis

ade

cayi

ngsi

new

ave:

ì æí ò ì æí%ì æí

A.2

Imag

ing

met

hods

163

profi

leis

need

edth

eR

Fpu

lse

shou

ldbe

ade

cayi

ngsi

ncw

ave,

sinc

eth

esi

ncw

ave

and

the

step

func

tion

are

each

othe

rsFo

urie

rtra

nsfo

rms,

seeF

igur

eA

.10.

The

mag

netic

field

influ

enci

ngth

esp

ins

insi

deth

ese

lect

edsl

ice

will

vary

slig

htly

beca

useo

fth

egr

adie

nt.T

hefr

eque

ncy

ofth

ein

divi

dual

spin

swill

then

vary

acco

rdin

gly,

and

thus

they

will

deph

ase.

Toac

hiev

eth

em

axim

alsi

gnal

the

spin

sare

reph

ased

byap

plyi

nga

mag

netic

field

grad

ient

with

the

oppo

site

pola

rity

ofth

esl

ice

sele

ctio

ngra

dien

t.Thi

sis

calle

da

reph

asin

ggra

dien

t.W

ithth

esl

ice

sele

ctio

ngr

adie

nt,a

part

icul

arsl

ice

tobe

exci

ted

has

been

pick

edou

tbut

noin

form

atio

non

how

that

slic

eis

spat

ially

reso

lved

isob

tain

ed.

A.2

.2P

hase

enco

ding

grad

ient

Afte

rthe

slic

ese

lect

iona

ndre

phas

ingg

radi

ents

have

been

appl

ieda

long

with

the

RF

puls

eall

spin

sin

the

sele

cted

slic

epr

eces

satt

hesa

mef

requ

ency

andi

nph

ase.

Ifa

seco

ndgr

adie

nt,th

eph

asee

ncod

ingg

radi

ent,i

sth

entu

rned

on,e

.g.i

nth

e

v ó

dire

ctio

n,th

ere

sona

ncefr

eque

ncy

ofth

esp

insc

hang

esal

ong

thev ó

axis

and

the

rate

ofpr

eces

sion

chan

gesa

ccor

ding

ly.W

hen

the

phas

eenc

odin

ggra

dien

tisth

entu

rned

off,

the

spin

sonc

eaga

inpr

eces

satt

hesa

mef

requ

ency

,but

now

thei

rph

ases

are

nolo

nger

the

sam

e.T

hein

divi

dual

spin

shav

ea

phas

etha

tdep

ends

onth

eirp

ositi

onal

ong

thev ó

axis

.

A.2

.3R

ead-

outg

radi

ent

Ifa

third

grad

ient

,the

read

-out

orfr

eque

ncy

grad

ient

e.g.

inth

e

U ó dire

ctio

n,is

appl

ied

whi

leth

eM

Rsi

gnal

isbe

ing

sam

pled

,the

freq

uenc

yof

the

emitt

edsi

gnal

varie

sacc

ordi

ngto

itspo

sitio

nal

ong

the

U ó axi

s.T

hesi

gnal

ata

spec

ific

freq

uenc

yal

ongt

he

U ó axi

sis

asu

mof

alls

pins

ina

row

alon

gthev

ó axis

(whe

reth

erei

sa

phas

evar

iatio

n).

The

sign

alis

sam

pled

at

ä

poin

tsin

the

read

-out

(or

U ó )di

rect

ion.

The

mea

sure

men

tisre

peat

ed

s times

ford

iffer

entv

alue

soft

heph

asee

ncod

ing(v ó

)gr

adie

nt,th

usge

nera

tinga

mat

rixof

äm s s

igna

lpoi

nts.

Per

form

inga

2DFo

urie

rtra

nsfo

rmof

the

mat

rixyi

elds

a2D

spec

trum

who

sein

tens

ityis

ava

lue

ofth

esi

gnal

dist

ribut

ion

inth

eim

agin

gsl

ice.

The

typi

calfi

nalM

Rim

age

isa

grey

-sca

lere

pres

enta

tiono

fth

esp

ectr

um.F

igur

eA

.11

show

san

MR

spec

trum

and

itsco

rres

pond

ingg

rey

scal

eim

age.

The

imag

emat

rixde

term

ines

the

num

bero

fpix

els

inth

eM

Rim

age,

and

the

colo

urof

each

pixe

lrep

rese

ntsth

ein

tens

ityof

the

MR

sign

alfr

omth

eco

rres

pond

-in

gvo

lum

eel

emen

t,orv

oxel

.The

volu

me

ofa

voxe

lis

dete

rmin

edby

the

mat

rixsi

zedi

vide

dby

the

field

ofvi

ew(a

ctua

lsiz

eof

imag

ein

mm

)mul

tiplie

dby

the

Page 92: MR · 2002. 2. 20. · Adeler A TV Erhver vsf or skerpr ojekt EF 698 IMM-PHD-2001-86 ISSN 0909-3192 ISBN 87-88306-13-5 c 2001 by Pernille Thorup Adeler Printed by IMM, DTU Bookbinder

164

Mag

netic

reso

nanc

eimag

ing

Fig

ure

A.1

1:M

Rsp

ectr

uman

dco

rres

pond

ingg

rey

scal

eim

age.

slic

eth

ickn

ess.

The

MR

sign

alfr

oma

voxe

lis

the

aver

ageo

fthe

sign

alfr

omal

lth

enu

clei

inth

atvo

xel.

The

abov

epr

oced

uref

orob

tain

ing

anM

RI

isju

stan

exam

ple,

and

alte

rna-

tive

proc

edur

esar

eav

aila

ble.

An

MR

Ico

uld

e.g.

also

beob

tain

edas

avo

lum

eim

age/

3Dim

age.

Ina

volu

me

imag

eth

een

tire

volu

me

isex

cite

d(i.

e.no

slic

ese

lect

iond

urin

gex

cita

tion)

and

toob

tain

asl

ice

sele

ctio

nase

cond

phas

eenc

od-

ing

grad

ient

isap

plie

d.T

head

vant

ages

ofth

ism

etho

dis

that

nois

eis

redu

ced,

slic

eth

ickn

essc

anbe

redu

ced,

and

spat

ialre

solu

tioni

nal

lthr

eedi

rect

ions

canb

eid

entic

al,i.

e.is

otro

picv

oxel

s.

A.2

.4Im

agin

gse

quen

ces

The

proc

esso

fcr

eatin

gan

MR

Iis

done

onth

eba

siso

fan

imag

ing

sequ

ence

s.Im

agin

gse

quen

cesde

scrib

ethe

RF

puls

es,th

eap

plic

atio

nof

grad

ient

field

san

dth

etim

ing

ofM

Rsi

gnal

aqui

sitio

n.T

hus

anim

agin

gse

quen

ceis

anex

tend

edpu

lse

sequ

ence

s,whi

chw

asde

scrib

edin

Sec

tion

A.1

.3.

An

imag

ing

sequ

ence

typi

cally

cons

ists

ofth

ree

part

s:sp

inpr

epar

atio

n,si

gnal

prod

uctio

nan

dim

age

gene

ratio

n.W

here

imag

egen

erat

ions

impl

yis

Four

iert

rans

form

atio

noft

heM

Rsi

gnal

.

Spi

npr

epar

atio

n

Insp

inpr

epar

atio

nRF

prep

ulse

sor

mag

netic

field

grad

ient

sare

empl

oyed

toch

ange

the

char

acte

ristic

soft

heM

Rsi

gnal

.Spi

npr

epar

atio

ncan

cons

isto

fpre

-pu

lses

(e.g

.an

inve

rsio

npul

se)o

rit

can

besa

tura

tiono

fpa

rtof

the

volu

me,

sat-

A.2

Imag

ing

met

hods

165

urat

ion

bein

ga

long

term

exci

tatio

n.T

here

sult

isth

atth

em

agne

tizat

ionv

ecto

rap

proa

chesz

eroa

nddu

ring

the

follo

win

gex

cita

tion

puls

eonl

yth

evo

lum

eout

side

the

satu

rate

dpar

tis

exci

ted

(And

erse

n,19

97).

Thr

ough

the

use

ofan

inve

rsio

npr

epul

sein

the

spin

echo

sequ

ence

itis

poss

ible

toge

nera

teim

ages

that

are

E )

wei

ghte

dand

not

E î weigh

teda

sast

anda

rdsp

inec

hose

quen

ce.

Sig

nalp

rodu

ctio

n

Sig

nalp

rodu

ctio

ncon

sist

sofg

ener

atin

gthe

MR

sign

alan

den

codi

ngit

with

spa-

tial

info

rmat

ion.

Thi

sca

nbe

done

inth

ree

way

s:F

ID,

spin

echo

and

grad

ient

echo

.A

FID

gene

rate

dsig

nali

sa

sam

plin

gof

the

FID

sign

al.

Thi

sgi

ves

anim

agew

here

imag

eint

ensi

tyis

prop

ortio

nalto

the

nete

quili

briu

mm

agne

tizat

ion

vect

or.

The

spin

echo

gene

rate

dsig

nalis

aco

mbi

natio

nof

the

spin

echo

puls

ese

quen

cede

scrib

edin

Sec

tionA

.1.3

and

the

the

MR

Ipr

oced

ured

escr

ibed

inS

ec-

tions

A.2

.1-A

.2.3

.T

hepu

lse

sequ

ence

isre

peat

ed

s tim

esto

obta

inth

efu

llsp

atia

linfo

rmat

ion.

The

time

betw

eens

ucce

ssive

exci

tatio

npu

lses

isca

lled

the

repe

titio

ntim

eT

R.T

hust

hefu

llsc

antim

eis

sm TR

.The

grad

ient

echo

gene

r-at

edsi

gnal

isba

sedo

na

com

bina

tiono

fthe

grad

ient

echo

sequ

ence

and

the

MR

Ipr

oced

ured

escr

ibed

abov

e(S

ectio

nsA

.2.1

-A.2

.3).

The

grad

ient

echo

sequ

ence

isde

scrib

edin

the

follo

win

gse

ctio

n.

Gra

dien

tech

ose

quen

ce

Inth

egr

adie

ntec

hose

quen

cea

mag

netic

field

grad

ient

isus

edto

crea

tean

echo

,as

oppo

sedt

oth

eus

eofa

180

z puls

ein

the

spin

echo

sequ

ence

.In

the

grad

ient

echo

sequ

ence

agr

adie

ntis

appl

ied

inth

ere

ad-o

utdi

rect

ion,

e.g.

the

U ó dire

ctio

n,fo

ra

limite

dtim

edi

rect

lyaf

tert

heex

cita

tion

puls

e.T

his

mak

esth

esp

inpr

eces

satd

iffer

entr

ates

alon

gth

ere

ad-o

utdi

rect

ion,

resu

lting

ina

deph

asin

gofs

pins

.The

grad

ient

isth

enre

vers

ed,w

hich

caus

essp

into

reph

ase

and

crea

tean

echo

.F

igur

eA

.12

sket

ches

the

grad

ient

echo

sequ

ence

.An

exci

tatio

npu

lse

with

flip

angl

e

Ý isapp

lied

atth

esa

met

imes

asth

esl

ice

sele

ctio

ngra

dien

tin

the

r ó direc

tion.

Imm

edia

tely

follo

win

gth

esl

ice

sele

ctio

ngra

dien

tisth

ere

phas

ing

grad

ient

inth

esl

ice

sele

ctio

ndire

ctio

n,se

eSec

tionA

.2.1

.The

nth

eph

asee

ncod

-in

ggr

adie

ntis

turn

edon

(inth

isca

sein

thev ó

dire

ctio

n)at

the

sam

etim

eas

the

echo

grad

ient

inth

ere

ad-o

utdi

rect

ion

(U ó dire

ctio

n).T

heec

hogr

adie

ntco

nsis

tsof

two

part

swith

reve

rsed

pola

rity

(asd

escr

ibed

abov

e).A

fter

the

echo

grad

ient

the

echo

iscr

eate

dand

the

sign

alis

sam

pled

inth

ere

ad-o

utdi

rect

ion

atth

esa

me

time

asth

ere

ad-o

utgr

adie

ntis

appl

ied.

Thi

sse

quen

ceis

repe

ated

s times

with

diff

eren

tval

ueso

fthe

phas

eenc

odin

ggra

dien

t.Thi

sis

illus

trat

edin

the

figur

eby

Page 93: MR · 2002. 2. 20. · Adeler A TV Erhver vsf or skerpr ojekt EF 698 IMM-PHD-2001-86 ISSN 0909-3192 ISBN 87-88306-13-5 c 2001 by Pernille Thorup Adeler Printed by IMM, DTU Bookbinder

166

Mag

netic

reso

nanc

eimag

ing

Gy

Gx

Gz

αpu

lse

αpu

lse

echo

grad

ient

echo

grad

ient

TR

Sig

nal

RF

slic

ese

lect

ion

reph

asin

g

phas

een

codi

ng

grad

ient

read

−ou

t

TE

Fig

ure

A.1

2:T

hegr

adie

ntec

hose

quen

ce.

seve

rall

ines

draw

nat

the

phas

eenc

odin

ggra

dien

t.T

heec

hotim

e,T

E,a

ndth

ere

petit

iont

ime,

TR

,are

indi

cate

d.T

head

vant

ages

ofth

egr

adie

ntec

hose

quen

ce,co

mpa

redt

oth

esp

inec

hose

quen

ce,ar

eth

epo

ssib

ility

ofsm

alle

rpul

sefli

pan

gles

,sho

rter

echo

times

and

shor

terr

epet

ition

times

,yie

ldin

ga

muc

hsh

orte

rtota

lim

agin

gtim

e.In

the

spin

echo

sequ

ence

the

repe

titio

ntim

eha

sto

belo

ngto

assu

reth

atth

elo

ngitu

dina

lrel

axat

ioni

sco

mpl

eteb

efor

ethe

next

exci

tatio

npu

lsei

sap

plie

d.If

the

long

itudi

nalr

elax

atio

nis

notc

ompl

etet

heef

fect

ive

mag

netiz

atio

nvec

tor

flipp

edin

toth

e

Uv ó

plan

eis

smal

ler.

Afte

rse

vera

lexc

itatio

nsth

em

agne

tiza-

tion

vect

orde

cays

tow

ard

zero

and

the

volu

me

beco

mes

satu

rate

d(re

fert

oS

ec-

A.2

Imag

ing

met

hods

167

tion

A.2

.4ab

ove)

.T

here

petit

ion

time

coul

dbe

redu

cedb

yus

ing

anex

cita

tion

puls

ewith

asm

alle

rflip

angl

etha

n90

z (e.g

.15-

45

z ),m

akin

gth

etim

eto

rest

ore

long

itudi

nalr

elax

atio

nsm

alle

r.B

utev

enin

the

case

ofa

puls

ew

itha

low

flip

angl

ea

larg

epa

rtof

the

netm

agne

tizat

ionis

inth

elo

ngitu

dina

ldire

ctio

n.W

itha

180

z inve

rsio

npul

seth

isw

ould

also

affe

ctth

elo

ngitu

dina

lmag

netiz

atio

nand

noto

nly

the

tran

sver

sem

agne

tizat

ion.

Inth

egr

adie

ntec

hose

quen

ceit

ispo

ssib

leto

use

puls

esw

ithsh

orte

rflip

angl

esbe

caus

ethe

echo

iscr

eate

dby

agr

adie

ntra

ther

than

anin

vers

ion

puls

e.Lo

wer

flip

angl

esle

adto

shor

terr

ecov

ery

time

ofth

elo

ngitu

dina

lmag

netiz

atio

n(p

rior

toth

ene

xtex

cita

tion

puls

e).

Thi

ssh

orte

nsth

eT

Ran

dth

ereb

ythe

tota

lim

agin

gtim

e.T

his

isth

epr

imar

yar

gum

entfo

rus

ing

agr

adie

ntec

hose

quen

cera

ther

than

asp

inec

hose

quen

ce.

A.2

.5M

otio

nar

tifac

ts

Mot

ion

resu

ltsin

ghos

tingo

rbl

urrin

gof

the

MR

imag

e.In

the

pres

entc

ontex

tm

otio

nus

ually

mea

nspa

tient

mov

emen

ts,re

spira

tory

orca

rdia

cmot

ion

orm

otio

ndu

eto

swal

low

ing.

Dep

endi

ngon

the

type

ofM

Rim

ageb

eing

reco

rded

diff

eren

tm

otio

nsar

eun

wan

ted.

E.g

.if

the

brai

nis

bein

gm

appe

dcar

diac

orre

spira

tory

mot

ion

isno

tapr

oble

m.

Sin

ceth

isth

esis

isco

ncer

nedw

ithca

rdia

cMR

Iw

ede

scrib

ethe

proc

edur

esfo

rel

imin

atin

gth

eef

fect

ofpa

tient

mov

emen

ts,a

sw

ell

asca

rdia

cand

resp

irato

rym

otio

n.

Sig

nala

vera

ging

:B

ecau

seof

the

rand

omna

ture

ofpa

tient

mov

emen

tthe

effe

ctca

nbe

redu

cedb

yav

erag

ingt

heM

Rsi

gnal

over

seve

rals

ampl

ings

.The

draw

back

isth

atth

eto

tali

mag

ing

time

isin

crea

sed.

Car

diac

trig

gerin

g:T

heef

fect

ofca

rdia

cmot

ion

can

beel

imin

ated

byco

uplin

gth

eaq

uisi

tiont

oa

trig

gers

igna

l,in

the

card

iacc

aset

heE

CG

(ele

ctro

card

io-

gram

)sig

nal.

The

hear

tcyc

leis

assu

med

perio

dica

ndby

trig

gerin

gon

e.g.

the

Rpe

akof

the

EC

G,a

quis

ition

isdo

neat

the

sam

etim

ein

the

hear

tcyc

leev

ery

time

and

the

effe

ctof

card

iacm

otio

nis

min

imiz

ed.T

hedr

awba

ckis

that

tota

lim

agin

gtim

eis

subs

tant

ially

incr

ease

d.

Res

pira

tory

trig

gerin

g:T

his

issi

mila

rto

card

iact

rigge

ringe

xcep

ttha

ther

ethe

trig

gerin

gis

rela

tedt

oa

sign

alin

dica

ting

expi

ratio

n.

Res

pira

tory

gatin

g:A

quis

ition

isdo

new

hile

the

resp

irato

rym

otio

nis

min

imal

.T

his

isan

effe

ctiv

epr

oced

ureb

utin

crea

sesth

eto

tali

mag

ing

time

subs

tan-

tially

.

Page 94: MR · 2002. 2. 20. · Adeler A TV Erhver vsf or skerpr ojekt EF 698 IMM-PHD-2001-86 ISSN 0909-3192 ISBN 87-88306-13-5 c 2001 by Pernille Thorup Adeler Printed by IMM, DTU Bookbinder

168

Mag

netic

reso

nanc

eimag

ing

Bre

ath

hold

:In

ash

orta

quis

ition

sequ

ence

the

aqui

sitio

ncan

bedo

new

hile

the

patie

ntho

lds

his/

herb

reat

h,th

ereb

yelim

inat

ing

the

effe

ctof

resp

irato

rym

otio

n.

A.3

Vel

ocity

mea

sure

men

ts

All

the

MR

imag

esde

scrib

edpr

evio

usly

are

grey

scal

eim

ages

ofth

ein

tens

ityof

the

MR

sign

al.

The

yar

eof

ten

refe

rred

toas

mag

nitu

deor

mod

ulus

imag

es.I

tis

also

poss

ible

toob

tain

info

rmat

ion

onth

eve

loci

tyof

the

tissu

e(e.

g.bl

ood)

inea

chvo

xeli

nan

MR

I.T

heph

aseo

fspi

nsin

bloo

dar

ealte

redb

yth

ebl

ood

flow

,aph

enom

enon

calle

da

phas

eshi

ft.T

his

can

beex

ploi

ted

ina

phas

evel

ocity

map

whe

reth

eph

aseo

fth

esp

insa

reco

rrel

ated

toth

eve

loci

tyof

the

mov

ing

spin

s.W

hen

am

ovin

gsp

inis

subj

ecte

dto

abi

pola

rgra

dien

tthe

spin

hasa

phas

eat

the

term

inat

iono

fth

egr

adie

ntw

hich

ispr

opor

tiona

ltoth

eve

loci

tyof

the

spin

.T

his

isop

pose

dto

ast

atic

spin

,whi

chha

sno

netp

hase

atth

ete

rmin

atio

nof

abi

pola

rgra

dien

t.S

oby

appl

ying

abi

pola

rgra

dien

tinan

imag

ese

quen

ceit

ispo

ssib

leto

reco

rdth

eve

loci

tyof

the

bloo

din

each

voxe

l.T

hebi

pola

rgra

dien

tca

nbe

appl

ied

inan

ych

osen

dire

ctio

n,or

inal

lthr

eesp

atia

ldire

ctio

nsto

obta

inth

reed

imen

sion

alve

loci

tyin

form

atio

n.A

phas

eshi

ftca

nha

veot

herc

ause

stha

nflo

wve

loci

ty,

e.g.

mag

netic

field

inho

mog

enei

ties.T

hus

itis

nece

ssar

ytore

cord

aflo

w-c

ompe

nsat

edba

ckgr

ound

imag

e.T

hrou

ghth

eus

eof

flow

-com

pens

ated

grad

ient

sit

ispo

ssib

leto

reco

rda

phas

eimag

e,w

here

phas

eeffe

ctss

tem

only

from

unw

ante

ddev

iatio

ns.T

his

flow

-co

mpe

nsat

edim

agec

anth

enbe

subt

ract

edfr

omth

eph

asev

eloc

itym

ap,le

avin

ga

phas

eim

agew

hich

isth

ere

sulto

nly

offlo

wve

loci

typh

ases

hifts

.P

hase

velo

city

map

ping

requ

ireso

btai

ning

seve

ralim

ages

pers

lice:

onei

mag

epe

rvel

ocity

com

pone

ntan

don

eve

loci

ty-c

ompe

nsat

edim

age.

Thu

sit

incr

ease

sth

eto

tals

can

time.

Fig

ure

A.1

3sh

ows

thre

eim

ages

from

ave

loci

tyen

code

dca

rdia

cMR

I:th

em

odul

usim

age,

the

velo

city

imag

e(w

ithve

loci

tyve

ctor

sfro

mth

ein

-pla

neco

mpo

nent

s)and

the

velo

city

imag

esu

perim

pose

don

the

mod

ulus

imag

e.T

heve

loci

tyim

agei

sof

limite

dva

lue

onits

own,

buti

tis

very

usef

ulw

hen

itis

supe

rimpo

sedo

nth

em

odul

usim

age.

Thi

sco

mbi

natio

nis

ave

ryst

rong

imag

ing

tech

niqu

ewhe

ne.

g.th

eca

rdia

cfun

ctio

nis

eval

uate

d.

A.3

Vel

ocity

mea

sure

men

ts16

9

Fig

ure

A.1

3:Im

ages

from

aca

rdia

cM

RI

with

velo

city

enco

ding

.To

p:th

em

odul

usim

age,

mid

dle:

the

velo

city

imag

ew

ithin

-pla

neve

loci

tyco

mpo

nent

ssh

own

asve

ctor

s,bo

ttom

:vel

ocity

imag

esup

erim

pose

don

mod

ulus

imag

e.T

hean

atom

yoft

hehe

arts

eeno

nth

eM

RI

isex

plai

nedi

nF

igur

e6.

5.

Page 95: MR · 2002. 2. 20. · Adeler A TV Erhver vsf or skerpr ojekt EF 698 IMM-PHD-2001-86 ISSN 0909-3192 ISBN 87-88306-13-5 c 2001 by Pernille Thorup Adeler Printed by IMM, DTU Bookbinder

Bib

liogr

aph

y

Ade

ler,

P.T.

and

Jaco

bsen

,J.M

.(20

01).

Blo

odflo

win

the

hear

t,in

J.T.

Otte

sen,

M.S

.Olu

fsen

and

J.La

rsen

(eds

),A

pp

lied

Ma

the

ma

tica

lMo

de

lsin

Hu

ma

nP

hys

iolog

y,to

bepu

blis

hedb

yS

IAM

,cha

pter

3.

And

erse

n,O

.T.(

1997

).B

illed

dann

else

med

NM

R(in

Dan

ish)

,Me

dic

insk

Ele

k-tr

on

ik(in

Da

nis

h),

Inst

itutf

orIn

form

atio

nste

knol

ogi,T

echn

ical

Uni

vers

ityof

Den

mar

k,ch

apte

r11.

Bey

er,R

.P.(

1992

).A

com

puta

tiona

lmod

elof

the

coch

leau

sing

the

imm

erse

dbo

unda

rym

etho

d,J.

Co

mp

ut.P

hys

.98(

1):1

45–1

62.

Bey

er,R

.P.a

ndLe

Veq

ue,R

.J.(

1992

).A

naly

siso

faon

e-di

men

sion

almod

elfo

rth

eim

mer

sedb

ound

arym

etho

d,S

IAM

J.N

um

er.A

na

l.29

(2):

332–

364.

Bor

gers

,C.a

ndP

eski

n,C

.S.(

1987

).A

lagr

angi

anfr

actio

nals

tepm

etho

dfor

the

inco

mpr

essi

bleN

avie

r-S

toke

seq

uatio

nson

ape

riodi

cdo

mai

n.,J

.Co

mp

ut.

Ph

ys.7

0(2)

:397

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.

Cap

pello

,A.,

Gnu

di,G

.an

dLa

mbe

rti,

C.

(199

5).

Iden

tifica

tion

ofth

eth

ree-

elem

entw

indk

esse

lmod

elin

corp

orat

inga

pres

sure

-dep

ende

ntcom

plia

nce,

An

na

lso

fBio

me

dic

alE

ng

ine

erin

g23(

2):1

64–1

77.

Cho

rin,A

.J.

(196

8).N

umer

ical

solu

tion

ofth

eN

avie

r-S

toke

seq

uatio

ns,M

ath

.C

om

p.2

2:74

5–76

2.

Cho

rin,

A.

J.(1

969)

.O

nth

eco

nver

genc

eof

disc

rete

appr

oxim

atio

nsto

the

Nav

ier-

Sto

kese

quat

ions

,Ma

th.C

om

p.2

3:34

1–35

3.

Dav

is,P

.(19

95).

The

arto

fthe

hear

tval

ve,S

IAM

New

s28

(5):

1an

d13

.

Des

popo

ulos

,A.

and

Silb

erna

gl,S

.(19

91).

Co

lor

Atla

so

fPh

ysio

logy,

4th

edn,

Thi

eme,

Stu

ttgar

t.

Page 96: MR · 2002. 2. 20. · Adeler A TV Erhver vsf or skerpr ojekt EF 698 IMM-PHD-2001-86 ISSN 0909-3192 ISBN 87-88306-13-5 c 2001 by Pernille Thorup Adeler Printed by IMM, DTU Bookbinder

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Bib

liogr

aph

y

Din

g,T.

and

Sch

oeph

oers

ter

,R.T

.(19

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Eva

luat

ion

ofgl

obal

left

vent

ricul

arfu

nctio

nba

sedo

nsi

mul

ated

flow

dyna

mic

scom

pute

dfro

mre

gion

alw

all

mot

ion,

AS

ME

,Bio

en

gin

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rin

gDiv

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n(P

ub

lica

tion

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g,Y

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iom

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an

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Me

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nic

alP

rop

ert

ieso

fLiv

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Tiss

ue

s,2n

ded

n,S

prin

ger-V

erla

g,N

ewY

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Gan

ong,

W.

F.(1

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.R

evie

wo

fM

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ica

lPh

ysio

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16th

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Pre

ntic

e-H

all

Inte

rnat

iona

l,Lon

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Geo

rgia

dis,

J.G

.,W

ang,

M.

and

Pasi

poul

arid

es,A

.(1

992)

.Com

puta

tiona

lfluid

dyna

mic

sof

left

vent

ricul

arej

ectio

n,A

nn

als

of

Bio

me

dic

alE

ng

ine

erin

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7.

Gon

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z,E.a

ndS

choe

phoe

rste

r,R

.T.(

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sim

ulat

iono

fthr

ee-d

imen

sion

alsy

stol

icflo

wdy

nam

icsi

na

sphe

rical

vent

ricle

:E

ffect

sof

abno

rmal

wal

lm

otio

n,A

nn

als

ofB

iom

ed

ica

lEn

gin

ee

rin

g24:

48–5

7.

Gre

enbe

rg,S

.,M

cQue

en,D

.M.a

ndP

eski

n,C

.S.(

1987

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hree

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ensi

onalfl

uid

dyna

mic

sin

atw

o-di

men

sion

alam

ount

ofce

ntra

lmem

ory,

inA

.J.

Cho

rinan

dA

.J.

Maj

da(e

ds),

Wa

veM

otio

n:

Th

eo

ry,M

od

elli

ng

an

dC

om

pu

tatio

n.

Pro

cee

din

gso

faC

on

fere

nce

inH

on

oro

fth

e6

0th

Birth

da

yo

fPe

terD

.La

x.,

Spr

inge

r-Ver

lag,

New

Yor

k,pp

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146.

Gro

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ndD

ijk,

P.v.

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7).D

esig

noffl

owad

just

ableg

radi

entw

avef

orm

s,in

J.T.

E.d

.Kle

ef(e

d.),

So

cie

tyo

fM

agn

etic

Re

son

an

cein

Me

dic

ine,

6th

an

nu

alm

ee

ting,

p.86

8.

Guy

ton,

A.

C.(

1991

).Te

xtb

oo

kofM

ed

ica

lPh

ysio

logy,

8th

edn,

W.B

.Sau

nder

sC

ompa

ny,P

hila

delp

hia,

US

A.

Hou

lind,

K.

(200

1a).

Priv

ate

com

mun

icat

ion.

Hou

lind,

K.

(200

1b).

Ea

rly

dia

sto

licle

ftve

ntr

icu

larb

loo

dflo

wp

atte

rns.

Ass

e-

me

nts

by

mag

ne

ticre

son

an

ceve

loci

tym

ap

pin

g.,P

hDth

esis

,Dep

t.of

Car

-di

otho

raci

cand

Vas

cula

rSur

gery

T,A

arhu

sUni

vers

ityH

ospi

tal.

Hou

lind,

K.,

Ped

erse

n,E.M

.,O

yre,

S.,

Kim

,W

.Y

.,W

alke

r,P.

G.,

Ege

blad

,H.

and

Yog

anat

han,A

.P.

(199

4).L

eftv

entr

icul

arbl

ood

flow

patte

rnsa

sses

sed

bym

agne

ticre

sona

ncev

eloc

itym

appi

ngin

patie

ntsw

ithis

chem

iche

artd

is-

ease

,Am

.J.o

fNo

nin

vas.

Ca

rdio

l.8:

317–

325.

Bib

liogr

aph

y17

3

Hou

lind,

K.,

Sch

roed

er,A

.P.

,E

gebl

ad,H

.an

dP

eder

sen,E

.M.

(199

9).

Age

-de

pend

entch

ange

sin

spat

iala

ndte

mpo

ralb

lood

velo

city

dist

ribut

ion

ofea

rlyle

ftve

ntric

ular

fillin

g,M

agn

etic

Re

son

an

ceIm

agin

g17

(6):

859–

868.

Hou

lind,

K.,

Sch

roed

er,A

.P.

,Stø

dkild

e-Jø

rgens

en,H

.,Pa

ulse

n,P.

K.,

Ege

blad

,H

.an

dP

eder

sen,E

.M

.(2

001)

.In

trav

entr

icul

ardi

sper

sion

and

tem

pora

lde

layo

fea

rlyle

ftve

ntric

ular

fillin

gaf

tera

cute

myo

card

ialin

farc

tion.

Ass

-es

men

tby

mag

netic

reso

nanc

evel

ocity

map

ping

,inH

oulin

d(2

001b

).

Jaco

bsen

,J.M

.(1

999)

.P

eski

n’s2D

mod

elof

ase

ctio

nof

the

left

side

ofth

ehe

art:

Des

crip

tion,

Inve

stig

atio

nand

Mod

ifica

tion.

Unp

ublis

hedr

epor

t.

Jaco

bsen

,J.M

.,A

dele

r,P.

T.,

Kim

,W

.Y

.,H

oulin

d,K

.,P

eder

sen,E

.M

.an

dLa

rsen

,J.(

2001

).E

valu

atio

nofa

2Dm

odel

ofth

ele

ftsi

deof

ahu

man

hear

tag

ains

tmag

netic

reso

nanc

evel

ocity

map

ping

,Ca

rdio

vasc

ula

rEn

gin

ee

rin

g1(

2):5

9–76

.

Jako

bsen

,B.

and

Nis

s,K

.(2

000)

.B

ehan

dlin

gaf

impu

lsve

dki

lder

ogdr

æn

iC

.S.P

eski

ns2D

-hje

rtem

odel(

inD

anis

h),T

ech

nic

alR

ep

ort

,Te

kstN

r3

88,

Ros

kild

eUni

vers

ity.

Jone

s,T.

N.a

ndM

etax

as,D

.N.(

1998

).Pa

tient

-spe

cific

anal

ysis

ofle

ftve

ntric

-ul

arbl

ood

flow

,in

W.

M.

Wel

ls,A

.C

olch

este

rand

S.D

elp

(eds

),M

ed

ica

lIm

age

Co

mp

utin

gan

dC

om

pu

er-A

ssis

tedI

nte

rve

ntio

n–M

ICC

AI’

98

.Pro

-ce

ed

ing

s.,V

ol.1

498o

fLe

ctu

reN

ote

sin

Co

mp

ute

rSci

en

ce,S

prin

gerV

erla

g,pp

.156

–166

.

Kim

,W

.Y.,

Wal

ker,

P.G

.,P

eder

sen,E

.M.,

Pou

lsen

,J.K

.,O

yre,

S.,

Hou

lind,

K.

andY

ogan

atha

n,A.P

.(19

95).

Left

vent

ricul

arbl

ood

flow

patte

rnsin

norm

alsu

bjec

ts:A

quan

titat

ivean

alys

isby

thre

e-di

men

sion

almag

netic

reso

nanc

eve

loci

tym

appi

ng,J

.Am

.Co

ll.C

ard

iol.

26(1

):22

4–23

8.

Kim

,Y.H

.(20

01).

Priv

ate

com

mun

icat

ion.

Lai,

M.-

C.a

ndP

eski

n,C

.S.(

2000

).A

nim

mer

sedb

ound

arym

etho

dwith

form

alse

cond

orde

racc

urac

yan

dre

duce

dnum

eric

alvi

scos

ity,

J.C

om

pu

t.P

hys

.16

0:70

5–71

9.

Lem

mon

,J.D

.an

dY

ogan

atha

n,A.

P.(1

998)

.T

hree

-dim

ensi

onalc

ardi

acm

od-

els

with

fluid

-str

uctu

rein

tera

ctio

n:A

pplic

atio

nof

the

imm

erse

dbou

ndar

ym

etho

datp

hysi

olog

icR

eyno

lds

num

bers

,AS

ME

,Bio

en

gin

ee

rin

gDiv

isio

n(P

ub

lica

tion

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74.

Page 97: MR · 2002. 2. 20. · Adeler A TV Erhver vsf or skerpr ojekt EF 698 IMM-PHD-2001-86 ISSN 0909-3192 ISBN 87-88306-13-5 c 2001 by Pernille Thorup Adeler Printed by IMM, DTU Bookbinder

174

Bib

liogr

aph

y

Lem

mon

,J.D

.and

Yog

anat

han,A

.P.

(200

0a).

Com

puta

tiona

lmod

elin

gof

left

hear

tdia

stol

icfu

nctio

n:E

xam

inat

iono

fven

tric

ular

dysf

unct

ion,

Jou

rna

lof

Bio

me

cha

nic

alE

ng

ine

erin

g122

(4):

297–

303.

Lem

mon

,J.D

.and

Yog

anat

han,A

.P.(

2000

b).T

hree

-dim

ensi

onalc

ompu

tatio

nal

mod

elof

left

hear

tdia

stol

icfu

nctio

nw

ithflu

id-s

truc

ture

inte

ract

ion,

Jou

rna

lo

fBio

me

cha

nic

alE

ng

ine

erin

g122

(2):

109–

117.

May

o,A

.A

.an

dP

eski

n,C

.S.(

1993

).A

nim

plic

itnu

mer

ical

met

hodf

orflu

iddy

nam

icsp

robl

emsw

ithim

mer

sede

last

icbo

unda

ries,i

nA

.Y

.C

heer

and

C.P

.van

Dam

(eds

),Flu

idD

yna

mic

sin

Bio

log

y,V

ol.1

41,A

mer

ican

Mat

h-em

atic

alS

ocie

ty,P

rovi

denc

e,R

hode

Isla

nd,p

p.26

1–27

7.

McC

rack

en,M

.F.

and

Pes

kin,

C.

S.(

1980

).A

vort

exm

etho

dfo

rbl

ood

flow

thro

ughh

eart

valv

es,J

.Co

mp

ut.P

hys

.35:

183–

205.

McQ

ueen

,D.

M.

and

Pes

kin,

C.S

.(19

83).

Com

pute

r-ass

iste

ddes

igno

fpi

vot-

ing

disc

pros

thet

icm

itral

valv

es,J

ou

rna

lof

Th

ora

cic

an

dC

ard

iova

scu

lar

Su

rge

ry86

:126

–135

.

McQ

ueen

,D.M

.and

Pes

kin,

C.S

.(19

85).

Com

pute

r-ass

iste

ddes

igno

gbu

tterfl

ybi

leafl

etva

lves

for

the

mitr

alpo

sitio

n,S

can

d.J

.T

ho

r.C

ard

iova

sc.S

urg

.19

(2):

139–

148.

McQ

ueen

,D.

M.

and

Pes

kin,

C.S

.(19

89).

Ath

ree-

dim

ensi

onalc

ompu

tatio

nal

met

hodf

orbl

ood

flow

inth

ehe

art.I

I.C

ontr

actil

eFib

ers,

J.C

om

pu

t.Ph

ys.

89:2

89–2

97.

McQ

ueen

,D.

M.

and

Pes

kin,

C.S

.(19

97).

Sha

red-

mem

oryp

aral

lelv

ecto

rim

-pl

emen

tatio

nof

the

imm

erse

dbo

unda

rym

etho

dfo

rth

eco

mpu

tatio

nof

bloo

dflo

win

the

beat

ing

mam

mal

ianh

eart

,Jo

urn

alo

fS

up

erco

mp

utin

g11

(3):

213–

236.

McQ

ueen

,D.

M.

and

Pes

kin,

C.S

.(20

00).

Hea

rtsi

mul

atio

nby

anim

mer

sed

boun

dary

met

hodw

ithfo

rmal

seco

nd-o

rdera

ccur

acy

andr

educ

ednu

mer

ical

visc

osity

,P

roce

ed

ing

sof

ICTA

M2

00

0,K

luw

erA

cade

mic

Pub

lishe

rs.T

oap

pear.

McQ

ueen

,D.M

.,P

eski

n,C

.S.a

ndY

ellin

,E.E

.(19

82).

Flu

iddy

nam

icso

fth

em

itral

valv

e:P

hysi

olog

ical

aspe

ctso

fam

athe

mat

icalm

odel

,Am

.J.P

hys

iol.

242:

H10

95–H

1110

.

Bib

liogr

aph

y17

5

Mei

sner

,J.S

.,M

cQue

en,D

.M.,

Ishi

da,Y

.,V

ette

r,H

.O.,

Bor

tolo

tti,U

.,S

trom

,J.

A.,

Fra

ter,

R.W

.M

.,P

eski

n,C

.S.a

ndY

ellin

,E

.L.

(198

5).

Effe

cts

oftim

ing

ofat

rials

ysto

leon

LVfil

ling

and

mitr

alva

lve

clos

ure:

com

pute

rand

dog

stud

ies,

Am

.J.P

hys

iol.2

49:H

604–

H61

9.

Net

ter,F

.H.(

1991

).H

ea

rt,V

ol.5

ofT

heC

iba

Co

llect

iono

fMe

dic

alIl

lust

ratio

ns,

CIB

A.

Nis

hiha

ra,K

.,M

ikam

i,T.

,Ta

kats

uji,

H.,

Ono

zuka

,H.,

Sai

to,N

.,Y

amad

a,S

.,U

rasa

wa,

K.

and

Kita

bata

ke,A

.(2

000)

.Use

fuln

esso

fea

rlydi

asto

licflo

wpr

opag

atio

nvel

ocity

mea

sure

dby

colo

rM-m

ode

Dop

pler

tech

niqu

efor

the

asse

smen

tofle

ftve

ntric

ular

dias

tolic

func

tion

inpa

tient

swith

hype

rtro

phic

card

iom

yopa

thy,J

.Am

.So

c.E

cho

card

iog

r.13

:801

–808

.

Noo

rder

graa

f,A

.(1

978)

.C

ircu

lato

ryS

yste

mD

yna

mic

s,A

cade

mic

Pre

ss,S

anD

iego

.

Oht

e,N

.,N

arita

,H.,

Has

him

oto,

T.,

Hay

ano,

J.,A

kita

,S

.and

Kur

okaw

a,K

.(1

999)

.Dif

fere

ntia

tiono

fab

norm

alre

laxa

tionp

atte

rnw

ithag

ing

from

ab-

norm

alre

laxa

tion

patte

rnw

ithco

rona

ryar

tery

dise

asei

ntr

ansm

itral

flow

with

the

use

oftis

sue

Dop

pler

imag

ing

ofth

em

itral

annu

lus,

J.A

m.S

oc.

Ech

oca

rdio

gr.

12:6

29–6

35.

Olu

fsen

,M.,

Ade

ler,

P.T.

,Dan

iels

en,M

.an

dLa

rsen

,J.(

2001

).C

ardi

ovas

cula

ran

dpu

lmon

aryp

hysi

olog

yand

anat

omy,i

nJ.

T.O

ttese

n,M

.S.O

lufs

enan

dJ.

Lars

en(e

ds),

Ap

plie

dM

ath

em

atic

alM

od

els

inH

um

an

Ph

ysio

logy,

tobe

publ

ishe

dby

SIA

M,c

hapt

er2.

Park

,J.,

Met

axas

,D.

N.

and

Axe

l,L.

(199

6).

Ana

lysi

sof

left

vent

ricul

arw

all

mot

ion

base

don

volu

met

ricde

form

able

mod

elsa

ndm

risp

amm

,Me

dic

al

Imag

eA

na

lysi

s1(1

):53

–71.

Pes

kin,

C.S

.(19

72a)

.F

low

Patte

rns

aro

un

dH

ea

rtVa

lve

s,P

hDth

esis

,Alb

ert

Ein

stei

nCol

lege

ofM

edic

ine.

Pes

kin,

C.S

.(19

72b)

.Flo

wpa

ttern

saro

undh

eart

valv

es:A

num

eric

alm

etho

d,J.

Co

mp

ut.P

hys

.10:

252–

271.

Pes

kin,

C.S

.(19

75).

Mat

hem

atic

alas

pect

sofh

eart

phys

iolo

gy,C

oura

ntIn

stitu

teof

Mat

hem

atic

alS

cien

ces,N

ewY

ork

Uni

vers

ity,L

ectu

reN

otes

.

Pes

kin,

C.S

.(19

77).

Num

eric

alan

alys

isof

bloo

dflo

win

the

hear

t,J.

Co

mp

ut.

Ph

ys.2

5:22

0–25

2.

Page 98: MR · 2002. 2. 20. · Adeler A TV Erhver vsf or skerpr ojekt EF 698 IMM-PHD-2001-86 ISSN 0909-3192 ISBN 87-88306-13-5 c 2001 by Pernille Thorup Adeler Printed by IMM, DTU Bookbinder

176

Bib

liogr

aph

y

Pes

kin,

C.S

.(19

81).

Mat

hem

atic

alas

pect

sofp

hysi

olog

y,in

F.C

.Hop

pens

tead

t(e

d.),

Ma

the

ma

tica

lAsp

ect

sofP

hys

iolog

y.L

ect

ure

sin

Ap

plie

dM

ath

em

at-

ics,

Vol.

19,

Am

eric

anM

athe

mat

ical

Soc

iety,

Pro

vide

nce,

Rho

deIs

land

,pp

.69–

93.

Pes

kin,

C.S

.(19

89).

Fib

erar

chite

ctur

eoft

hele

ftve

ntric

ular

wal

l:A

nas

ympt

otic

anal

ysis

,Co

mm

un

.Pu

reA

pp

l.M

ath

.XLI

I:7

9–11

3.

Pes

kin,

C.S

.(19

98).

Inco

mpr

essi

blefl

uid

dyna

mic

swith

dist

ribut

edso

urce

sand

sink

s.U

npub

lishe

dnot

e.

Pes

kin,

C.S

.(20

01).

Priv

ate

com

mun

icat

ion.

Pes

kin,

C.S

.and

McQ

ueen

,D.M

.(1

980)

.Mod

elin

gpr

osth

etic

hear

tval

vesf

ornu

mer

ical

anal

ysiso

fblo

odflo

win

the

hear

t,J.C

om

pu

t.Ph

ys.3

7:11

3–13

2.

Pes

kin,

C.S

.and

McQ

ueen

,D.M

.(1

989)

.AT

hree

-Dim

ensi

onalc

ompu

tatio

nal

met

hodf

orbl

ood

flow

inth

ehe

art,J

.Co

mp

ut.P

hys

.81:

372–

405.

Pes

kin,

C.S

.and

McQ

ueen

,D.M

.(1

992)

.Car

diac

fluid

dyna

mic

s,C

ritic

alR

e-

view

sin

Bio

me

dic

alE

ng

ine

erin

g20(

5,6)

:451

–459

.

Pes

kin,

C.S

.and

McQ

ueen

,D.M

.(19

93a)

.Car

diac

fluid

dyna

mic

s,in

T.C

.Pilk

-in

gton

etal

.(ed

.),H

igh

-pe

rfo

rma

nce

Co

mp

utin

gin

Bio

me

dic

alR

ese

arch

,C

RC

Pre

ss.

Pes

kin,

C.S

.and

McQ

ueen

,D.M

.(19

93b)

.Com

puta

tiona

lbiofl

uid

dyna

mic

s,in

A.

Y.C

heer

and

C.P

.van

Dam

(eds

),F

luid

Dyn

am

icsi

nB

iolo

gy,

Vol

.141

,A

mer

ican

Mat

hem

atic

alS

ocie

ty,P

rovi

denc

e,R

hode

Isla

nd,p

p.16

1–18

6.

Pes

kin,

C.S

.and

McQ

ueen

,D.M

.(1

994)

.M

echa

nica

lequ

ilibr

ium

dete

rmin

esth

efr

acta

lfibe

rar

chite

ctur

eof

aort

iche

artv

alve

leafl

ets,

Am

.J.

Ph

ysio

l.26

6:H

319–

H32

8.

Pes

kin,

C.S

.and

McQ

ueen

,D.

M.

(199

5).

Age

nera

lmet

hodf

orth

eco

mpu

ter

sim

ulat

ion

ofbi

olog

ical

syst

emsi

nter

actin

gwith

fluid

s,in

C.P

.E

lling

ton

andT

.J.P

edley

(eds

),Bio

log

ica

lFlu

idD

yna

mic

s:P

roce

ed

ing

sofa

me

etin

gh

eld

att

he

Un

ive

rsity

ofL

ee

ds,

UK

,4

-8Ju

ly1

99

4,V

ol.4

9of

Sym

po

siao

fth

eS

oci

ety

for

Exp

erim

en

talB

iolo

gy,

Cam

brid

ge,U

K,p

p.26

5–27

6.

Pes

kin,

C.S

.and

McQ

ueen

,D.

M.

(199

6).

Flu

iddy

nam

icso

fth

ehe

arta

ndits

valv

es,in

H.O

thm

er,F

.R.A

dler

,M.

A.

Lew

isan

dJ.

C.D

allo

n(e

ds),

Ca

seS

tud

iesin

Ma

the

ma

tica

lMo

de

ling

-E

colo

gy,

Ph

ysio

logy,

an

dC

ell

Bio

log

y,P

rent

ice-

Hal

l,Inc

.,E

nglew

ood

Clif

fs,N

ewJe

rsey,

chap

ter1

4,pp

.309

–337

.

Bib

liogr

aph

y17

7

Pes

kin,

C.

S.a

ndP

rintz

,B.

F.(1

993)

.Im

prov

edvo

lum

eco

nser

vatio

nin

the

com

puta

tiono

fflow

sw

ithim

mer

sedb

ound

arie

s,J.C

om

pu

t.Ph

ys.1

05:3

3–46

.

Phi

lips

(n.d

.).B

asi

cPrin

cip

leso

fMR

Imag

ing,

Phi

lips

Med

ical

Sys

tem

.

Rid

eout

,V.(

1991

).M

ath

em

atic

ala

nd

Co

mp

ute

rMo

de

ling

ofP

hys

iolog

ica

lSys

-te

ms,

Pre

ntic

eHal

l,B

ioph

ysic

sand

Bio

engi

neer

ingS

erie

s.

Sab

er,N

.R

.,G

osm

an,A

.D

.,W

ood,

N.

B.,

Kiln

er,

P.J.

,Cha

rrie

r,C

.L.

and

Firm

in,

D.

N.

(200

1).

Com

puta

tiona

lflow

mod

elin

gof

the

left

vent

ricle

base

don

invi

voM

RI

data

:Ini

tial

expe

rienc

e,A

nn

als

of

Bim

ed

ica

lEn

gi-

ne

erin

g29(

4):2

75–2

83.

Sch

laik

jer,M

.and

Kol

enda

,T.(

1997

).M

RI,

den

grun

dlgg

ende

teor

i(in

Dan

ish)

,S

tud

en

trep

ort,

Tech

nica

lUni

vers

ityof

Den

mar

k.U

npub

lishe

d.

Sch

oeph

oers

ter

,R.T

.,S

ilva,

C.L

.an

dR

ay,G

.(19

93).

Fin

itean

alyt

icm

odel

for

left

vent

ricul

arsy

stol

icflo

wdy

nam

ics,

Jou

rna

lofE

ng

ine

erin

gMe

cha

nic

s11

9(4)

:733

–747

.

Sch

oeph

oers

ter

,R.T

.,S

ilva,

C.L

.an

dR

ay,

G.(

1994

).E

valu

atio

nof

left

ven-

tric

ular

func

tion

base

don

sim

ulat

edsy

stol

icflo

wdy

nam

icsc

ompu

tedf

rom

regi

onal

wal

lmot

ion,

J.B

iom

ech

an

ics2

7(2)

:125

–136

.

Sch

roed

er,A

.P.(

1999

).M

agn

etic

reso

na

nce

imag

ing

for

the

stu

dyo

fle

ftve

ntr

ic-

ula

rre

mo

de

linga

fte

racu

tem

yoca

rdia

lin

farc

tion,

PhD

thes

is,D

epar

tmen

tof

Car

diol

ogy,

Ske

jby

Hos

pita

l,Uni

vers

ityof

Aar

hus.

St.

Goa

r,F.

G.,

Mas

uyam

a,T.,

Ald

erm

an,E

.L.a

ndP

opp,

R.L

.(19

91).

Left

ven-

tric

ular

dias

tolic

dysf

unct

ioni

nen

d-st

aged

ilate

dca

rdio

myo

path

y:Sim

ulta

-ne

ousD

oppl

erec

hoca

rdio

grap

hyand

hem

odyn

amice

valu

atio

n,J.

Am

.So

c.E

cho

card

iog

r.4:

349–

360.

Ste

ine,

K.,

Stu

gaar

d,M

.an

dS

mis

eth,

O.(

1999

).M

echn

ism

sof

reta

rded

apic

alfil

ling

inac

utei

sche

mic

left

vent

ricul

arfa

ilure

,Cir

cula

tion

99:2

048–

2054

.

Sto

ckie

,J.M

.an

dW

etto

n,B

.T.

R.(

1995

).S

tabi

lity

anal

ysis

for

the

imm

erse

dfib

erpr

oble

m,S

IAM

J.A

pp

l.M

ath

.55(

6):1

577–

1591

.

Str

eete

r,Jr

.,D

.D

.,P

ower

s,W

.E

.,R

oss,

M.

A.

and

Torr

ent-

Gua

sp,F.

(197

8).

Thr

ee-d

imen

sion

alfibe

rorie

ntat

ioni

nth

em

amm

alia

nlef

tven

tric

lew

all,

inJ.

Baa

n,A

.N

oord

ergr

aafa

ndJ.

Rai

nes(

eds)

,Ca

rdio

vasc

ula

rSys

tem

Dy-

na

mic

s,M

ITP

ress

,Cam

brid

ge,M

A,

pp.7

3–84

.

Page 99: MR · 2002. 2. 20. · Adeler A TV Erhver vsf or skerpr ojekt EF 698 IMM-PHD-2001-86 ISSN 0909-3192 ISBN 87-88306-13-5 c 2001 by Pernille Thorup Adeler Printed by IMM, DTU Bookbinder

178

Bib

liogr

aph

y

Str

eete

r,Jr

.,D

.D

.,S

potn

iz,H

.M

.,Pa

tel,

D.

P.,

Ros

s,Jr

.,J.

and

Son

nenb

lick,

E.H

.(1

969)

.F

iber

orie

ntat

ioni

nth

eca

nine

left

vent

ricle

durin

gdi

asto

lean

dsy

stol

e,C

irc.

Re

s.24

:339

–347

.

Stu

gaar

d,M

.,B

roda

hl,U

.,To

rp,H

.an

dIh

len,

H.

(199

4a).

Abn

orm

aliti

esof

left

vent

ricul

arfil

ling

inpa

tient

swith

coro

nary

arte

rydi

seas

e:as

sesm

entby

colo

urM

-mod

eD

oppl

erte

chni

que,

Eu

rop

ea

nHe

art

Jou

rna

l15:

318–

327.

Stu

gaar

d,M

.,R

isoe

,C.,

Ihle

n,H

.an

dS

mis

eth,

O.

(199

4b).

Intr

acav

itary

fill-

ing

patte

rnin

the

faili

ngle

ftve

ntric

leas

sese

dby

colo

rM

-mod

eD

oppl

erec

hoca

rdio

grap

hy,J.

Am

.Co

ll.C

ard

iol.

24:6

63–6

70.

Stu

gaar

d,M

.,S

mis

eth,

O.

A.,

Ris

oe,

C.

and

Ihle

n,H

.(1

993)

.In

trav

entr

ic-

ular

early

dias

tolic

fillin

gdu

ring

acut

em

yoca

rdia

linfa

rctio

n,C

ircu

latio

n88

:270

5–27

13.

Tayl

or,T

.W.,

Oki

no,H

.and

Yam

aguc

hi,T

.(19

93).

The

effe

ctso

fsup

raval

vula

rao

rtic

sten

osiso

nre

alis

ticth

ree-

dim

ensi

onalle

ftve

ntric

ular

bloo

dej

ectio

n,B

iorh

eo

log

y30

(5–6

):42

9–43

4.

Tayl

or,

T.W

.,S

uga,

H.,

Got

o,Y

.,O

kino

,H.

and

Yam

aguc

hi,T

.(1

996)

.T

heef

fect

sof

card

iaci

nfar

ctio

non

real

istic

thre

e-di

men

sion

allef

tve

ntric

ular

bloo

dej

ectio

n,J.

Bio

me

ch.E

ng.

118(

1):1

06–1

10.

Tayl

or,T

.W.a

ndY

amag

uchi

,T.(

1995

a).F

low

patte

rnsin

thre

e-di

men

sion

alleft

vent

ricul

arsy

stol

ican

ddi

asto

licflo

ws

dete

rmin

edfr

omco

mpu

tatio

nalflu

iddy

nam

ics,

Bio

rhe

olo

gy

32(1

):61

–71.

Tayl

or,

T.W

.an

dY

amag

uchi

,T.

(199

5b).

Rea

listic

thre

e-di

men

sion

allef

tve

n-tr

icul

arej

ectio

ndet

erm

ined

from

com

puta

tiona

lfluid

dyna

mic

s,M

ed

.En

g.P

hys

.17(

8):6

02–6

08.

Tho

mas

,C.E

.(19

57).

The

mus

cula

rarc

hite

ctur

eoft

heve

ntric

leso

fhog

and

dog

hear

ts,T

he

Am

erica

nJo

urn

alo

fAn

ato

my1

01:1

7–57

.

Tho

rup,

P.(1

997)

.He

mo

dyn

am

icMo

de

llin

go

fth

eH

ea

rt,M

aste

r’sth

esis

,Dep

t.of

Hyd

rody

nam

icsa

ndW

ater

Res

ourc

es(I

SVA

),Te

chni

calU

nive

rsity

ofD

enm

ark(

DT

U).

Tort

ora,

G.J

.(19

99).

Prin

cip

les

ofH

um

an

An

ato

my,

8th

edn,

Add

ison

Wes

leyLo

ngm

an,In

c.,M

enlo

Park

,Cal

iforn

ia.

Bib

liogr

aph

y17

9

Tu,

C.a

ndP

eski

n,C

.S.(

1992

).S

tabi

lity

and

inst

abili

tyin

the

com

puta

tiono

fflo

ws

with

mov

ing

imm

erse

dbou

ndar

ies:

Aco

mpa

rison

ofth

ree

met

hods

,S

IAM

J.S

ci.S

tat.C

om

pu

t.13(

6):1

462–

1376

.

Ves

ier,

C.

C.

and

Yog

anat

han,

A.

P.(1

992)

.A

com

pute

rmet

hod

for

sim

ula-

tion

ofca

rdio

vasc

ular

flow

field

s:va

lidat

ion

ofap

proa

ch,J.

Co

mp

ut.P

hys

.99

(2):

271–

287.

Wal

ker,

P.G

.,C

rann

ey,G

.B.,

Grim

es,R

.Y.,

Del

ator

e,J.

,Rec

tenw

ald,

J.,P

ohos

t,G

.M.

and

Yog

anat

han,A

.P.

(199

6).

Thr

ee-d

imen

sion

alrec

onst

ruct

iono

fth

eflo

win

ahu

man

left

hear

tby

usin

gm

agne

ticre

sona

ncep

hase

velo

city

enco

ding

,An

na

lso

fBio

me

dic

alE

ng

ine

erin

g24(

1):1

39–1

47.

Wal

ker,

P.G

.,C

rann

ey,G

.B.,

Sch

eide

gger

,M.

B.,

Was

eles

ki,G

.,P

ohos

t,G.M

.an

dY

ogan

atha

n,A.

P.(1

993)

.Sem

i-aut

omat

edm

etho

dfor

nois

ered

uctio

nan

dba

ckgr

ound

phas

eerr

orre

duct

iono

fM

Rph

asev

eloc

ityda

ta,J

.Mag

n.

Re

son

.Imag

ing

3:52

1–53

0.

Wei

ss,J

.L.,

Fre

derik

sen,J

.W.a

ndW

eisf

eldt

,M.L

.(19

76).

Hem

odyn

amicd

eter

-m

inan

tsof

the

time-

coru

seof

fall

inca

nine

left

vent

ricul

arpr

essu

re,Jo

urn

al

ofC

linic

alI

nve

stig

atio

n58:

751–

760.

Yam

amot

o,K

.,M

asuy

ama,

T.,

Tano

uchi

,J.,

Nai

to,

J.,

Man

o,T.

,K

ondo

,H.,

Nag

ano,

R.,

Mas

atsu

guan

dK

amad

a,T.

(199

5).I

ntra

vent

ricul

ardi

sper

sion

ofea

rlydi

asto

licfil

ling:

Ane

wm

arke

rofl

eftv

entr

icul

ardi

asto

licdy

sfun

c-tio

n,A

m.H

ea

rt.J

.129

:291

–299

.

Yel

lin,E

.L.,

Pes

kin,

C.S

.,Y

oran

,C.,

Koe

nigs

berg,

M.,

Mat

sum

oto,

M.,

Lani

ado,

S.,

McQ

ueen

,D.M

.,S

hore

,D.a

ndF

rate

r,R.W

.M.(

1981

).M

echa

nism

sof

mitr

alva

lve

mot

ion

durin

gdi

asto

le,A

m.J

.Ph

ysio

l.241

(3):

H38

9–H

400.

Yog

anat

han,A

.P.

,Lem

mon

,J.D

.,K

im,

Y.

H.,

Levi

ne,R

.A.

and

Ves

ier,

C.C

.(1

995)

.Ath

ree-

dim

ensi

onalc

ompu

terin

vest

igat

iono

fint

rave

ntric

ular

fluid

dyna

mic

s:E

xam

inat

ioni

nto

the

initi

atio

nof

syst

olic

ante

riorm

otio

nof

the

mitr

alva

lve

leafl

ets,

J.B

iom

ech

.En

g.11

7:94

–102

.

Yog

anat

han,

A.

P.,

Lem

mon

,J.D

.,K

im,

Y.

H.,

Wal

ker,

P.G

.,Le

vine

,R

.A

.an

dV

esie

r,C

.C

.(1

994)

.A

com

puta

tiona

lstu

dyof

ath

in-w

alle

dth

ree-

dim

ensi

onal

left

vent

ricle

durin

gea

rlysy

stol

e,J.

Bio

me

ch.E

ng.

116:

307–

314.

Page 100: MR · 2002. 2. 20. · Adeler A TV Erhver vsf or skerpr ojekt EF 698 IMM-PHD-2001-86 ISSN 0909-3192 ISBN 87-88306-13-5 c 2001 by Pernille Thorup Adeler Printed by IMM, DTU Bookbinder

Ph.

D.t

hese

sfro

mIM

M1.

Lars

en,R

asm

us.(

1994

).E

stim

atio

nofv

isu

alm

otio

nin

imag

ese

qu

en

ces.

xiv

+14

3pp

.

2.R

ygar

d,Je

nsM

ober

g.(1

994)

.De

sig

nan

do

ptim

iza

tiono

fflex

ible

ma

nu

-fa

ctu

rin

gsy

ste

ms.x

iii+

232

pp.

3.La

ssen

,Nie

lsC

hris

tian

Krie

ger.

(199

4).

Au

tom

ate

dde

term

ina

tiono

fcr

ysta

lorie

nta

tion

sfro

me

lect

ron

ba

cksc

atte

rin

gpa

tte

rns.

xv+

136

pp.

4.M

elga

ard,

Hen

rik.

(199

4).I

de

ntifi

catio

no

fph

ysic

alm

od

els

.xvi

i+24

6pp

.

5.W

ang,

Chu

nyan

.(1

994)

.Sto

cha

stic

diff

ere

ntia

leq

ua

tion

san

da

bio

log

i-ca

lsys

tem

.xxii

+15

3pp

.

6.N

iels

en,A

llan

Aas

bjer

g.(1

994)

.A

na

lysi

sof

reg

ula

rly

an

dirre

gu

larly

sam

ple

dsp

atia

l,mu

ltiva

ria

te,a

nd

mu

lti-t

em

po

rald

ata

.xxi

v+

213

pp.

7.E

rsbø

ll,A

nnet

teK

jær.

(199

4).O

nth

esp

atia

lan

dte

mp

ora

lco

rre

latio

ns

inex

pe

rim

en

tatio

nwith

agricu

ltura

lap

plic

atio

ns.

xviii

+34

5pp

.

8.M

ølle

r,D

orte

.(1

994)

.Me

tho

dsf

or

an

aly

sisa

nd

de

sig

nofh

ete

roge

ne

ou

ste

leco

mm

un

ica

tionn

etw

ork

s.V

olum

e1-

2,xx

xviii

+28

2pp

.,28

3-56

9pp.

9.Je

nsen

,Jen

sChr

istia

n.(1

995)

.Te

ore

tiske

oge

ksp

erim

en

telled

yna

mis

keu

nd

ers

øge

lse

rafj

ern

ba

ne

køretø

jer.v

iii+

174

pp.

10.

Kuh

lman

n,Li

onel

.(1

995)

.O

na

uto

ma

ticvi

sua

lin

spe

ctio

nofre

flect

ive

surf

ace

s.V

olum

e1,

xviii

+22

0pp

.,(V

olum

e2,

vi+

54pp

.,fo

rtro

lig).

11.

Laza

rides

,Nik

olao

s.(1

995)

.No

nlin

ea

rity

insu

pe

rcon

du

ctiv

itya

nd

Jose

ph

-so

nJu

nct

ion

s.iv

+15

4pp

.

12.

Ros

tgaa

rd,M

orte

n.(1

995)

.M

od

elli

ng,

est

ima

tiona

nd

con

trol

of

fast

sam

ple

ddyn

am

ica

lsys

tem

s.xiv

+34

8pp

.

13.

Sch

ultz

,Net

te.

(199

5).S

egm

en

tatio

nan

dcl

ass

ifica

tiono

fbio

log

ica

lob

-je

cts.

xiv

+19

4pp

.

14.

Jørg

ense

n,M

icha

elF

inn.

(199

5).N

on

line

arH

am

ilto

nia

nsy

ste

ms.x

iv+

120

pp.

Page 101: MR · 2002. 2. 20. · Adeler A TV Erhver vsf or skerpr ojekt EF 698 IMM-PHD-2001-86 ISSN 0909-3192 ISBN 87-88306-13-5 c 2001 by Pernille Thorup Adeler Printed by IMM, DTU Bookbinder

15.

Bal

le,S

usan

neM

.(1

995)

.Dis

trib

ute

d-m

em

orym

atr

ixco

mp

uta

tion

s.iii

+10

1pp

.

16.

Koh

l,N

ikla

s.(1

995)

.E

xact

me

tho

dsf

or

time

con

stra

ine

dro

utin

ga

nd

rela

teds

che

du

lingp

rob

lem

s.xv

iii+

234

pp.

17.

Rog

on,T

hom

as.(

1995

).Po

rou

sme

dia

:An

aly

sis,

reco

nst

ruct

iona

nd

pe

r-co

latio

n.x

iv+

165

pp.

18.

And

erse

n,A

llan

The

odor

.(19

95).

Mo

de

llin

go

fpa

cke

ttra

ffic

with

ma

trix

an

aly

ticm

eth

od

s.xv

i+24

2pp

.

19.

Hes

thav

en,J

an.(

1995

).N

um

erica

lstu

die

sofu

nst

ea

dyc

oh

ere

nts

tru

ctu

res

an

dtr

an

spo

rtin

two

-dim

en

sio

na

lflow

s.R

isø

-R-8

35(E

N)2

03pp

.

20.

Sliv

sgaa

rd,E

vaC

harlo

tte.

(l995

).O

nth

ein

tera

ctio

nb

etw

ee

nwh

ee

lsan

dra

ilsin

railw

ay

dyn

am

ics.

viii

+19

6pp

.

21.

Har

teliu

s,K

arst

en.

(199

6).A

na

lysi

sofi

rreg

ula

rly

dis

trib

ute

dp

oin

ts.x

vi+

260

pp.

22.

Han

sen,

Anc

aD

anie

la.

(199

6).

Pre

dic

tive

con

trol

an

did

en

tifica

tion

-A

pp

lica

tion

sto

ste

erin

gdyn

am

ics.

xviii

+30

7pp

.

23.

Sad

egh,

Pay

man

.(19

96).

Exp

erim

en

tde

sig

nan

do

ptim

iza

tioni

nco

mp

lexsy

ste

ms.x

iv+

162

pp.

24.

Ska

nds,

Ulri

k.(1

996)

.Qu

an

tita

tivem

eth

od

sfo

rth

ea

na

lysi

sofe

lect

ron

mic

rosc

op

eim

age

s.xv

i+19

8pp

.

25.

Bro

-Nie

lsen

,Mor

ten.

(199

6).

Me

dic

ali

mag

ere

gis

tratio

na

nd

surg

ery

sim

ula

tion

.xxv

ii+

274

pp.

26.

Ben

dtse

n,C

laus

.(19

96).

Para

lleln

um

erica

lalg

orith

msf

orth

eso

lutio

no

fsy

ste

mso

ford

ina

ryd

iffe

ren

tiale

qu

atio

ns.

viii

+79

pp.

27.

Laur

itsen

,M

orte

nB

ach.

(199

7).

De

lta-d

om

ain

pre

dic

tive

con

trol

an

did

en

tifica

tionf

or

con

trol.

xxii

+29

2pp

.

28.

Bis

chof

f,S

vend

.(19

97).

Mo

de

llin

gco

llid

ing

-pu

lsem

od

e-lo

cked

sem

ico

n-

du

cto

rla

sers

.xxi

i+21

7pp

.

29.

Arn

bjer

g-N

iels

en,K

arst

en.

(199

7).S

tatis

tica

lan

aly

siso

furb

an

hyd

rol-

ogy

with

spe

cia

lem

ph

asi

son

rain

fall

mo

de

llin

g.In

stitu

tfor

Milj

øte

knik

,D

TU

.xiv

+16

1pp

.

30.

Jaco

bsen

,Jud

ithL.

(199

7).

Dyn

am

icm

od

elli

ng

of

pro

cess

esin

rive

rsa

ffect

edb

yp

reci

pita

tion

run

off.

xix

+21

3pp

.

31.

Som

mer

,H

elle

lgaa

rd.

(199

7).V

aria

bili

tyin

mic

rob

iolo

gic

ald

egra

-d

atio

nex

pe

rim

en

ts-A

na

lysi

san

dca

sest

ud

y.xi

v+

211

pp.

32.

Ma,

Xin

.(1

997)

.Ad

ap

tivee

xtre

mu

mco

ntro

lan

dw

ind

turb

ine

con

trol.

xix

+29

3pp

.

33.

Ras

mus

sen,

Kim

Ørs

kov.

(199

7).N

on

line

ara

nd

sto

cha

stic

dyn

am

icso

fco

he

ren

tstr

uct

ure

s.x

+21

5pp

.

34.

Han

sen,

Lars

Hen

rik.

(199

7).

Sto

cha

stic

mo

de

llin

go

fce

ntra

lh

ea

ting

syst

em

s.xxi

i+30

1pp

.

35.

Jørg

ense

n,C

laus

.(1

997)

.Driftso

ptim

erin

gpa

kra

ftva

rme

syst

em

er

.29

0pp

.

36.

Sta

unin

g,O

le.(

1997

).A

uto

ma

ticva

lida

tion

ofn

um

erica

lso

lutio

ns.

viii

+11

6pp

.

37.

Ped

erse

n,M

orte

nW

ith.

(199

7).

Op

timiz

atio

no

fre

curre

ntn

eu

ral

ne

t-w

ork

sfo

rtim

ese

rie

smo

de

ling.

x+

322

pp.

38.

Tho

rsen

,Run

e.(1

997)

.Re

sto

ratio

no

fha

nd

fun

ctio

nin

tetra

ple

gic

su

sin

gm

yoe

lect

rica

llyco

ntro

lled

fun

ctio

na

lele

ctrica

lstim

ula

tion

oft

he

con

trol-

ling

mu

scle.

x+

154

pp.+

App

endi

x.

39.

Ros

holm

,And

ers.

(199

7).S

tatis

tica

lme

tho

dsf

or

seg

me

nta

tiona

nd

cla

s-si

fica

tion

ofi

mag

es.

xvi+

183

pp.

40.

Pet

erse

n,K

imT

ilgaa

rd.

(199

7).E

stim

atio

nofs

pe

ech

qu

alit

yin

tele

com

-m

un

ica

tions

yste

ms.x

+25

9pp

.

41.

Jens

en,C

arst

enN

ords

trø

m.(

1997

).N

on

line

ars

yste

msw

ithd

iscr

ete

an

dco

ntin

uo

use

lem

en

ts.19

5pp

.

42.

Han

sen,

Pet

erS

.K.(

1997

).S

ign

als

ub

spa

cem

eth

od

sfor

spe

ech

en

ha

nce

-m

en

t.x

+22

6pp

.

43.

Nie

lsen

,Ole

ller.

(199

8).W

ave

lets

insc

ien

tificc

om

pu

ting.

xiv

+23

2pp

.

44.

Kje

ms,

Ulri

k.(1

998)

.B

aye

sia

nsig

na

lpro

cess

inga

nd

inte

rpre

tatio

no

fb

rain

sca

ns.

iv+

129

pp.

Page 102: MR · 2002. 2. 20. · Adeler A TV Erhver vsf or skerpr ojekt EF 698 IMM-PHD-2001-86 ISSN 0909-3192 ISBN 87-88306-13-5 c 2001 by Pernille Thorup Adeler Printed by IMM, DTU Bookbinder

45.

Han

sen,

Mic

hael

Pile

gaar

d.(1

998)

.Me

tah

eu

rist

icsfo

rm

ulti

ple

ob

ject

ive

com

bin

ato

ria

lop

timiz

atio

n.x

+16

3pp

.

46.

Riis

,Sø

ren

Kam

aric

.(1

998)

.Hid

de

nm

ark

ovm

od

els

an

dn

eu

raln

etw

ork

sfo

rsp

ee

chre

cog

niti

on

.x+

223

pp.

47.

rch,

Nie

lsJa

cob

San

d.(1

998)

.Am

ulti

varia

tea

pp

roa

chto

fun

ctio

na

ln

eu

rom

od

elin

g.xv

i+14

7pp

.

48.

Fry

dend

al,I

b.(

1998

.)Q

ua

lity

insp

ect

iono

fsu

ga

rbe

ets

usi

ng

visi

on

.iv

+97

pp.+

app.

49.

Lund

in,

Lars

Kris

tian.

(199

8).

Para

llel

com

pu

tatio

nof

rota

ting

flow

s.vi

ii+

106

pp.

50.

Bor

ges,

Ped

ro.(

1998

).M

ulti

crite

ria

pla

nn

ing

an

do

ptim

iza

tion

.-H

eu

ris-

tica

pp

roa

che

s.xi

v+

219

pp.

51.

Nie

lsen

,Jak

obB

irked

al.

(199

8).

New

dev

elo

pm

en

tsin

the

the

ory

of

wh

ee

l/ra

ilco

nta

ctm

ech

an

ics.

xviii

+22

3pp

.

52.

Fog

,Tor

ben.

(199

8).C

on

diti

on

mo

nito

rin

ga

nd

fau

ltd

iag

no

sisi

nm

arin

ed

iese

len

gin

es.

xii+

178

pp.

53.

Knu

dsen

,Ole

.(19

98).

Ind

ust

ria

lvis

ion

.xii

+12

9pp

.

54.

And

erse

n,Je

nsS

trod

l.(1

998)

.Sta

tistic

ala

na

lysi

sofb

iote

sts.

-A

pp

lied

toco

mp

lexp

ollu

ted

sam

ple

s.xx

+20

7pp

.

55.

Phi

lipse

n,P

eter

Als

hede

.(19

98).

Re

con

stru

ctio

nan

dre

sto

ratio

no

fPE

Tim

age

s.vi

+13

2pp

.

56.

Th

yges

en,U

ffeH

øgs

bro.

(199

8).R

obu

stp

erf

orm

an

cea

nd

dis

sip

atio

nof

sto

cha

stic

con

trols

yste

ms.1

85pp

.

57.

Hin

tz-M

adse

n,M

ads.

(199

8).A

pro

ba

bili

stic

fra

mew

ork

forc

lass

ifica

tion

ofd

erm

ato

sco

pici

mag

es.

xi+

153

pp.

58.

Sch

ram

m-N

iels

en,K

arin

a.(1

998)

.E

nvir

on

me

nta

lre

fere

nce

ma

teria

lsm

eth

od

san

dca

sest

ud

ies.

xxvi

+26

1pp

.

59.

Sky

ggeb

jerg

,Ole

.(1

999)

.Acq

uis

itio

na

nd

an

aly

siso

fco

mp

lexd

yna

mic

intr

a-a

nd

inte

rce

llula

rsig

na

ling

eve

nts

.83

pp.

60.

Jens

en,K

are

Jean

.(1

999)

.S

ign

alp

roce

ssin

gfo

rd

istr

ibu

tion

ne

two

rkm

on

itorin

g.xv

+19

9pp

.

61.

Fol

m-H

anse

n,Jø

rgen

.(19

99).

On

chro

ma

tica

nd

geo

me

tric

alc

alib

ratio

n.

xiv

+23

8pp

.

62.

Lars

en,J

espe

r.(19

99).

Para

lleliz

atio

no

fth

eve

hic

lero

utin

gp

rob

lem

with

time

win

do

ws.

xx+

266

pp.

63.

Cla

usen

,Car

lB

alsl

ev.

(199

9).

Sp

atia

lso

lito

nsin

qu

asi

-ph

ase

ma

tch

ed

stru

ktu

res.

vi+

(fler

epa

g.)

64.

Kvi

st,

Trin

e.(1

999)

.Sta

tistic

alm

od

elli

ngo

ffish

sto

cks.

xiv

+17

3pp

.

65.

And

rese

n,P

erR

øns

holt.

(199

9).S

urf

ace

-bo

un

de

dgro

wth

mo

de

linga

p-

plie

dto

hu

ma

nma

nd

ible

s.xx

ii+

125

pp.

66.

rens

en,P

erS

ette

rgre

n.(1

999)

.Sp

atia

ldis

trib

utio

nm

ap

sfo

rb

en

thic

com

mu

niti

es.

67.

And

erse

n,H

elle

.(19

99).

Sta

tistic

alm

od

els

for

sta

nd

ard

ize

dto

xici

tyst

ud

-ie

s.vi

ii+

(fler

epa

g.)

68.

And

erse

n,La

rsN

onbo

e.(1

999)

.Sig

na

lpro

cess

ingi

nth

ed

olp

hin

son

ar

syst

em

.xii

+21

4pp

.

69.

Bec

hman

n,H

enrik

.(1

999)

.Mo

de

llin

go

fwa

stew

ate

rsys

tem

s.xvi

ii+

161

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70.

Nie

lsen

,Hen

rikA

albo

rg.(

1999

).Pa

ram

etr

ica

nd

no

n-p

ara

me

tric

syst

em

mo

de

llin

g.xv

iii+

209

pp.

71.

Gra

mk

ow,C

laus

.(19

99).

2D

an

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Do

bje

ctm

ea

surem

en

tfor

con

trola

nd

qu

alit

ya

ssu

ran

cein

the

ind

ust

ry.

xxvi

+23

6pp

.

72.

Nie

lsen

,Jan

Nyg

aard

.(1

999)

.Sto

cha

stic

mo

de

llin

go

fdyn

am

icsy

ste

ms.

xvi+

225

pp.

73.

Lars

en,A

llan.

(200

0).T

he

dyn

am

icve

hic

lero

utin

gp

rob

lem

.xvi

+18

5pp

.

74.

Hal

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r,S

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n.(2

000)

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stic

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rop

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ina

nis

otro

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gen

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usm

ate

ria

ls.x

iv+

133

pp.

Page 103: MR · 2002. 2. 20. · Adeler A TV Erhver vsf or skerpr ojekt EF 698 IMM-PHD-2001-86 ISSN 0909-3192 ISBN 87-88306-13-5 c 2001 by Pernille Thorup Adeler Printed by IMM, DTU Bookbinder

75.

Lars

en,

The

isLe

th.

(200

0).

Ph

osp

ho

rusd

iffu

sio

nin

floa

tzo

ne

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on

crys

talg

row

th.v

iii+

119

pp.

76.

Dirs

cher

l,K

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(200

0).O

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icro

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sw

ithp

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46pp

.

77.

Fis

ker,

Run

e.(2

000)

.M

aki

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de

form

ab

lete

mp

late

mo

de

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pe

ratio

na

l.xx

+21

7pp

.

78.

Hul

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g,T

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.(20

00).T

op

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mp

uta

tion

allin

ea

rop

timiz

atio

n.

xiv

+18

0pp

.

79.

And

erse

n,K

laus

Kaa

e.(2

000)

.Sto

cha

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ne

rgy

syst

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s.xi

v+

191

pp.

80.

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.(2

001)

.Mo

de

llin

ga

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mo

nito

rin

gin

inje

ctio

nm

old

ing.

xvi+

132

pp.

81.

Sch

jødt

-Erik

sen,

Jens

.(2

001)

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rre

stin

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sein

inh

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ne

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sa

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ultr

afa

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err

me

dia

.

82.

Ben

nets

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Chr

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n.(2

000)

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um

erica

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ula

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live

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xi+

205

pp+

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83.

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.(20

01).

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pro

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nce.xi

+10

4pp

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dix.

84.

Nie

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,Tor

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con

trol

inn

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-lin

ea

rsto

cha

stic

syst

em

s.xvi

ii+

242

pp.

85.

Oje

lund

,H

enrik

.(2

001)

.M

ulti

varia

teca

libra

tion

of

che

mic

als

en

sors.

xviii

+18

4pp

.

86.

Ade

ler,

Per

nille

Tho

rup.

(200

1).H

em

od

yna

mics

imu

latio

no

fth

eh

ea

rtu

sin

ga

2D

mo

de

lan

dM

Rd

ata

.xv

+17

9pp

.