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8/3/2019 Radiology-in-Neurosurgery .

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Radiologyin

Neurosurgery

An Introduc tion

The LSU-Shreveport Department o f Neurosurgery

Presenting Authors: Neurosurgery Residents & Faculty


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Why know imaging?

Every physic ian must be a b le to verba lly communic a te, inbasic terms, wha t is on d ifferent rad iographic stud ies.

Rad iolog y rep orts c an take severa l hours to forma llyappea r c ritic a l pa tient d ec isions must b e ma de before

that time.


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Descriptions

Identify Patient name

Date of study

Spec ific type of study

Abnormal findings with loc ation

Important norma l find ings with loc ation

Differentia l d iag nosis


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Description

Identify Patient name

Date of study

Spec ific type of study

Abnorma l findings withlocation

Important normal find ingswith loc ation

Differential d iagnosis


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Imaging Studies: Types

Plain X-Ray

CT Scan

Myelogram (Plain &CT)

MRI

Angiogram (X-ray &MRA)

PET Sc an


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Plain X-Rays

Skull Films

Normal: Observe shape, suture lines

Abnormal

Lytic Lesions -- Multiple myeloma, metastatic

disease

Frac tures usually following trauma


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Normal Skull Films

AP Skull X-ray La tera l Skull X-ray

** Skull X-rays a re ra rely used in neurosurgery, with advent of CT Sc an


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Multip le Myeloma


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Spine X-rays

Cervic a l Sp ine most d iffic ult & imp ortant! Ask: Is this an adequa te film? (MUST see C7-T1 junc tion)

Ask: Are the three lines approp ria te?

Ask: Is there soft tissue swelling (a llowed 7 mm @ C3 & 21 mm a t C7)

Ask: Any frac tures otherwise?

Ask: Is the c liva l-C1 line smoo th?

Thorac ic & Lumba r frac tures Transverse proc ess and c om pression/ burst frac tures mo re often seen

Divide sp ine into 3 columns 2 or mo re c olumn injury genera llysuggests instability


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Normal C-Spine Films

Facets

Spinous

Process

AP view


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Normal C-Spine Films(continued)

Lateral view


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Normal C-Spine Films(continued)

Open-Mouth Odontoid View:To detec t stability of C1 frac tures & Dens

Dens

Overhang

Of lateralmasses


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Flexion-Extension C-Spine X-rays:

Is there Instability?


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What is wrong with this x-ray?

Answer: Cannot visua lize the C7-T1 junc tion


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CT Sc an

Computed Axia l Tomog raphy A collec tion of superimp osed X-rays

CALCIFIED STRUCTURES (e .g. bone, ACUTE c a lc ium in BLOODappear WHITE, or hyp erdense)

Isc hemic Stroke does NOT show on CT until 12-24 hours a fter ithas oc c urred it appears DARK (or hypodense) then

Slic es a re taken a t p lane p ara llel to anterior skull base floor

A CT sc an is the most frequently ordered study in Neurosurgery -- # 1 reason: To Rule Out BLEED


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CT Sc an

Bone Window Soft Tissue Window


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Intrac rania l Hemorrhage

Intrac rania l hemorrhage c an be c lassifiedac c ord ing to the spac e oc c upied by the b lood :

Ep idura l Hemorrhage

Subd ura l Hemorrhage

Subarac hnoid Hemorrhage

Intrap arenchyma l Hemorrhage

Intraventric ula r Hemorrhag e


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Intrac ranial Hemorrhage: Types


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Epidural Hemorrhage

Between skull and dura , limited byperiostea l layer so stops a t sutures of skulland thus b ic onvex (lens) shaped

Due to midd le meningeal artery tear,often assoc ia ted with skull frac ture

Pa tients can have c onc ussion a t injury,then a luc id interval when theyreawake from the concussion, and thensuddenly worsen due to blood

compressing brain

Trea tment is usua lly emergent surgery(unless extremely sma ll)


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Subdural Hemorrhage

Oc c ur in the 4 A s: Alc oholic s, Antic oa gulant-trea ted , Age d , and Abuse vic tims (shakenba by syndrome

Between dura and arac hnoid of brain, follows c ontour of brain so c resc ent shaped

Due to co rtic al bridg ing vein tear as hemog lob in broken down, blood c hanges c olor on CTsc an, and c an be easily missed (see suba c ute sc an above)

Usually patients with Subd ura l hema toma have WORSE brain injury than Ep idura l hemato ma

Sma ll size b leed s can be spo ntaneously absorbed by the b od y, but if midline shift is present,need surgica l eva c uation

Acute Subacute Chronic


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Subarac hnoid Hemorrhage

Subarachno id hemorrhage is genera llyfea thery in appea ranc e on CT sc an, as it smixed in with c erebrosp ina l fluid

The MOST COMMON c ause o f suba rac hnoidhemorrha ge is TRAUMA; the 2nd and 3rd most

common causes are aneurysms andarteriovenousmalformations

No intervention is genera lly performed forsuba rac hnoid hemorrhag e a lone

However, subarachno id hemorrhage cancause hydrocephalus (due to obstruction ofCSF flow) or vasospasm (due to ?b loodproducts irritating a vessel) in a delayedfashion


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Intraparenchymal Hemorrhage Called c ontusions in trauma bruising of the brain

Coup (direc t injury of brain from impac t) or c ontre-c oup (injury due to b ra in hitting skull on opposite side a sskull dec elera tes but b ra in doesnt) usuallytemporal/frontal

Can develop extreme a mount of edema or blossom, so

must fo llow c losely with repea t CT sc ans

Can be c aused b y hypertensive hemorrhage inc harac teristic loc a tions (basa l gang lia , thalamus, pons,c ereb ellum) or a rteriovenous ma lforma tions

In older pa tients (>60) c an be caused by c erebralamyloid angiopa thy, usually in a lob ar loc a tion

Surgic al evac uation if exc essive ma ss effec t,avoidance of important brain structures to access

surg ic a lly, and meaningful surviva l possib le


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Intraventricular Hemorrhage

Usually due to extensionof intraparenc hyma lb leed (most commonly

from hypertension)

Treatment depends onwhether hyd roc ep halusdevelop s then pa tient

ma y needventriculostomyplacement


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Skull Frac tures

Assoc ia ted w ith

pneumoc ephaly (air in head ) ra rely c an deve lop tensionpneumocephalus

Only signific ant if op en to a ir,

cosmetic a lly d isfiguring (grea tertha n full thicknessd isp lac em ent), or assoc ia ted

with a ir sinus (fo r risk of infec tion)

or underlying b leed (ep idura lhematoma)

Trea tment ONLY for c osmesis orprevention of infec tion (if op en

to a ir or to an a ir sinus)


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Hydrocephalus

CT c ut

showingportion ofventricular

c a theter, inenlarged

ventricularsystem

Tem pora l

Horns ofthe la tera lventricles,

not norma llyseen on CT sc ans,

a re p rominenthere.

Norma l CSF flow is from latera lventric les to third v., viaaqued uc t to fourth v., thenthrough foramina of Ma gend ieand Lusc hka to suba rac hnoidspac e, then absorp tion via

arac hnoid granula tions into thesuperior sag itta l sinus

Any obstruct ion of this pathwayc an c ause hyd roc ephalus

Treatment is temporarily byd iverting sp ina l fluid viaventric ulostomy c atheter;permanently, a shunt (e.g.

ventric ulop eritonea l, or VPshunt).


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CT Spine

Axial CT showingfrac ture o f ped icle

and lam ina Sagittal CT rec onstruc tions showingsignificant body frac ture and subluxation


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MRI

Gives BEST p ic ture o f bra in, in grea test deta il

Only handic ap s a re that it takes longer to do thanCT sc an (30 min. for MRI vs. 5 min. for CT), andCANNOT visua lize ACUTE b lood as well as CT c an

Good for studying b ra in tumors, multip le sc lerosis,or othe r lesions in b ra in whic h a re sometimesd iffic ult to find with CT sc an


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MRI

Basic images:

T1 Weighted Ima ge Bette r for looking a t bra in struc ture in de ta il

CSF is blac k

Ca n g ive CONTRAST injec tion to visua lize b lood vessels (andhenc e tumors whic h ENHANCE with c ontrast injec tion)

T2 Weighted ima ge Bette r for looking a t fluid (CSF is WHITE) bec ause of this, ed ema

(e.g. a round a bra in tumor or c ontusion) shows up well on T2

A Bright lesion on MRI is c a lled hyperintense on MRI ; a Darklesion is hyp o-intense NOT hyperdense or hypodense as isdesc ribed for CT


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MRI Brain:The Basic Study Types

T1 w/ o c ontrast T1 w/ c ontrast T2 (contrast never g iven)


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MRI: Views in d ifferent p lanes

http://www.strokecenter.org/pat/diagnosis/mri.htm


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Compare the detail:CT (left) vs. MRI T1 (right)


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Compare the detail:CT (left) vs. MRI T2 (right)


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Spine MRI: Sagitta l Herniated Disc with stenosis

T1 T2


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Spine MRI: Axia l Herniated Disc c ausing canal

stenosis

T2 Normal canal T2 Herniated d isc c ausing c analEncroachment & nerve roo timpingement


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Angiography

Three Types: Conventiona l X-ray Ang iog raphy enter femora l

a rtery a t g roin, advance c a theter to internalc arotid and verteb ra l a rteries, and injec t d ye tovisualize vessels using X-ray

MR Angiog raphy Does not req uire any injec tionof contrast, least inva sive, c an see a ll but themore deta iled struc tures (>3mm resolution foraneurysms)

CT Ang iography Req uires intravenous c ontrastdye injec tion, used to rec onstruc t and visua lizethe vasc ula ture


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Basic Study

Must inc lude a ll four vessels

2 interna l ca rotid a rteries and 2 verteb ra l a rteries

Done in multip le views with d ifferent angles AP/ La tera l/ Ob lique views

Options for TREATMENT during ang iography inc lude:

Emboliza tion (injec ting g lue into arteriovenous malformations)

Mec hanic a lly d islod g ing thrombus

Injec ting TPA for stroke Performing b a lloon ang iop lasty

Coiling o f aneurysms


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Conventional Angiography:Aneurysm

An ab norma l ba llooning or expa nsion of the int ima andadventitia of the vessel, whic h is missing the tunic amed ia / smooth musc le layer.

Aneurysms a lmost a lways oc c ur a t the b ifurc a tion of vessels.


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Conventional Angiography:Arteriovenous Malformation (AVM)

An abnorma l tangle o f vessels, w ith ea rly filling of thevenous c irc ula tion (at the time c ap illa ries would norma llyfill) ind ic a tes shunting of the b lood from the a rtery to thevein via the nidus or tang le o f vessels.


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Conventional Angiography:AV Fistula

A d irec t shunting of b lood from arteries to veins without anelabora te nidus as for an arteriovenous ma lformation visua lized by early filling of the venous system on d yeinjection.


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PET Sc an

Princ ip le

Tests meta bolism by ind ic a tinguptake o f rad iolabeled glucose.

During spec ific ac tions, certa inparts of the b ra in show inc reasedac tivity on PET (see figure)

Utility of PET sc ans

In d ifferentia ting rad ia tion-rela tednec rosis (whic h does not up ta ke

g lucose a nd so a ppea rs c old )vs. a metabolic a lly ac tive b ra intumor (which up takes high leve lsof g lucose, so is hot or da rk onPET sc ans.


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Sample c ases:

How would you manage...


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20 YO WM in MVA

Intub ated a ndsedated

GCS 3 in the field

Head CT as here

What do you see &What would you do? Case 1


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56 YO AA M w h/ o HTN

Co llapsed a t home

Found to have some

c onfusion and L d rift Letha rg ic in ER, thensta rted to have a seizureand wa s intuba ted

Just waking up from

para lytic / sed ation whenyou see p a tient


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References

http :/ / www.c hm.bris.ac .uk/ webprojec ts2002/ wrigglesworth/b ra inimaging.htm


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The End

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