Overview and Course Content

An Introduction to MRI Physics and Analysis

Michael Jay Schillaci, PhDMonday, January 28th, 2008

Course Content

Course Textbooks

We will focus on the Physics of fMRI

Applications in Social Psychology

Course ContentDay : Date Title – Topics Assignment

1 : January 28th Course Overview – Scope of course, Safety and Ethics Ch 1-2

2 : February 4th MRI Basics – MRI Physics Ch 3; Lab 2

3 : February 11th Image Formation Ch 4; Lab 4

4 : February 18th Contrast Mechanisms Ch 5; Lab 5

5 : February 25th Origin of the BOLD Signal Ch 6-9; Lab 7

6 : March 3rd Experimental Design Ch 11

: March 10th No Class Spring Break –

7 : March 17th Student Presentations Paper 1 Due

8 : March 24th Standard Statistical Techniques Ch 10,12; Lab 8

9 : March 31st Advanced Statistical Methods Lab 9, 10

10 : April 7th Standard MRI Analysis – Using FSL to Analyze fMRI Data Lab 11,12

12 : April 14th Advanced MRI Analysis – Using Matlab and SPM Lab 13

13 : April 21st Meta Analysis of fMRI Data Handout

14 : April 28th Student Presentations - Last Day of Classes Paper 2 Due

15 : May 1 Final Examination Period Final Project Due

MRI History

Scope of fMRI Experiments

fMRI is a Measurement Technique…

BRAIBRAINN

BEHAVIBEHAVIOROR

Measurement TechniquesfMRI, PET, EEG

Manipulation Techniques

Lesions, TMS, Stimulation

Timeline of MR Imaging

1920 1930 1940 1950 1960 1970 1980 1990 2000

1924 - Pauli suggests that nuclear particles

may have angular momentum (spin).

1937 – Rabi measures magnetic moment of

nucleus. Coins “magnetic resonance”.

1944 – Rabi wins Nobel prize in

Physics.

1946 – Purcell shows that matter absorbs energy at a resonant

frequency.

1946 – Bloch demonstrates that nuclear precession can be

measured in detector coils.

1952 – Purcell and Bloch share Nobel prize in Physics.

1972 – Damadian patents idea for large

NMR scanner to detect malignant

tissue.

1959 – Singer measures blood flow

using NMR (in mice).

1973 – Lauterbur publishes method for

generating images using NMR gradients.

1973 – Mansfield independently

publishes gradient approach to MR.

1975 – Ernst develops 2D-Fourier transform for MR.

NMR becomes MRI

MRI scanners become clinically

prevalent.

1990 – Ogawa and colleagues create functional images using endogenous, blood-oxygenation

contrast.

1985 – Insurance reimbursements for MRI exams begin.

M R I f

Early Human MR Images (Damadian)

Mink5 Image – Damadian (1977)

Blood-Oxygenation-Level

Dependent contrast

Key Concepts

Contrast Spatial Resolution Temporal Resolution Functional Resolution

Spatial Resolution: Examples

~8mm~8mm22 ~4mm~4mm22 ~2mm~2mm22

~1.5mm~1.5mm22 ~1mm~1mm22

Contrast: Functional

Contrast-to-noise is critical for fMRI: How effectively can we decide whether a given brain region has property X or property

Y?

Spatial Resolution: Voxels

Voxel: A small rectangular prism that is the basic sampling unit of fMRI. Typical anatomical voxel: (1.5mm)3. Typical functional voxel: (4mm)3.

Temporal Resolution

Determining factors Sampling rate, usually repetition time (TR) Dependent variable, usually BOLD response

BOLD response is sluggish, taking 2-3 seconds to rise above baseline and 4-6 seconds to peak

Experimental design

Most FMRI studies have temporal resolution on the order of a few seconds With specialized designs and data acquisition, this can be improved

to ~100ms

Students: Please sit with your project group in the first set of

rows.

Auditors: Please sit in the back.

FMRI : Ethics

Topics in Ethics

Safety issuesTesting of subject groups (IRB)

Privacy: HIPAA Incidental findings

PUBLIC LAW 104-191

AUG. 21, 1996

HEALTH INSURANCE PORTABILITY AND ACCOUNTABILITY ACT OF 1996

Public Law 104-191104th Congress

An Act

To amend the Internal Revenue Code of 1986 to improve portability and continuity of health insurance coverage in the group and individual markets, to combat waste, fraud, and abuse in health insurance and health care delivery, to

promote the use of medical savings accounts, to improve access to long-term care services and coverage, to simplify the administration of health insurance,

and for other purposes.

Be it enacted by the Senate and House of Representatives of the United States of America in Congress assembled,

What is Private Health Information?(for a research study) Name of participant Insurance, medical records Medical history, current conditions Group assignments (e.g., Alzheimer’s) Brain data?