During the last two decades, new developments in functional MRI (magnetic resonance imaging) have made it possible to detect changes in the brain over time, as opposed to the "snapshot" produced by conventional MRI. Essentials of Functional MRI breaks down the technical challenges for physicians, researchers, and technologists who use functional MRI but may not be experts in the necessary math and physics. The author describes the theory and practical details of functional MRI (fMRI) methodology, including how to acquire and analyze images, and a wide range of examples demonstrate how fMRI has been used thus far. The author provides the essential information to study, understand, use, and teach the practical aspects of fMRI for those people who are most likely to extend its use into clinical practice.
Table of Contents
Basic Anatomy of an MRI System
Representing Images with Numbers and Vice Versa
Recurring Math Concepts: Representing Data as Sums of Meaningful Components
Source of the MR Signal and Its Properties
Origins of the MR Signal.
The Equilibrium State—Magnetization in Tissues Behavior of the Magnetization When Not at Equilibrium. Pushing the Magnetization Away from Equilibrium—The RF Pulse Detecting the MR Signal. Relaxation Back to Equilibrium Observing the Effects of Relaxation
The Fundamental Building Blocks of MRI Methods: Spin Echoes and Gradient Echoes
The Need for Echoes
Steady-State Methods and Stimulated Echoes.
Signal Weighting and Contrast
Magnetization Transfer Contrast
Creating an Image from the Magnetic Resonance Signal
Spatially Selective Radio-Frequency Pulses
Encoding Spatial Information into the MR Signal to Create an Image
Constructing an Image from k-Space
Signal Strength, Imaging Speed, and Spatial Resolution—You Cannot Have It All Fast Imaging Methods Parallel Imaging Causes of Image Artifacts and Distortion
Principles and Practice of Functional MRI
How MRI Becomes Functional MRI
Contrast Mechanisms: Linking the MR Signal and Neural Function
General BOLD fMRI Methods
Specific Examples of fMRI Applications—Setting the Acquisition Parameters Alternative Contrast Mechanisms
Functional MRI Study Design
Basic Principles of fMRI Study Design
Choice of Stimulation Method or Task
Choice of the fMRI Study Design
Order and Timing of Presentation of Tasks or Stimuli
Timing of Tasks or Stimuli, Duration, Sampling Rate.
Summary of Factors Influencing fMRI Study Design
Functional MRI Data Analysis
fMRI Analysis Software.
Data Analysis Methods
Statistical Threshold, and Correction for Multiple Comparisons
Interpretation of fMRI Results—What Do They Really Mean?
Clinical Applications of Functional MRI
Examples of Current Clinical Applications of fMRI.
Examples of Forthcoming Clinical Applications
Patrick. W. Stroman, Ph.D., is now an associate professor Queen’s University in Ontario, Canada. He holds a Canada research chair in imaging physics, and leads a research program that focuses on the development of spinal fMRI as a tool for clinical assessments and spinal cord research.
"A comprehensive book, combining a strong theoretical background with profound practical hints for the use of fMRI in medical research.... represents a major step forward."
—Massimo Filippi, M.D., Department of Neurology, Scientific Institute HSR, Italy
"I find the book packed with information. It will be useful for both a clinical audience and MR technologists."
—W. Einar Mencl, Ph.D., Director of Neuroimaging Research, Haskins Laboratories and Yale University, New Haven, Connecticut