BME 595 - Medical Imaging Applications Part 2: INTRODUCTION TO MRI Lecture 3 Multi-Dimensional Imaging Feb. 28, 2005

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BME 595 - Medical Imaging ApplicationsPart 2
INTRODUCTION TO MRILecture 3 Multi-Dimensional
ImagingFeb. 28, 2005

• James D. Christensen, Ph.D.
• IU School of Medicine
• Department of RadiologyResearch II building,
  E002C
• jadchris_at_iupui.edu317-274-3815

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References
Online resources for introductory review of MRI
physics
Robert Coxs book chapters online
http//afni.nimh.nih.gov/afni/edu/ See
Background Information on MRI section Mark
Cohens intro Basic MR Physics slides http//porkp
ie.loni.ucla.edu/BMD_HTML/SharedCode/MiscShared.ht
ml Douglas Nolls Primer on MRI and Functional
MRI http//www.bme.umich.edu/dnoll/primer2.pdf J
oseph Hornaks Web Tutorial, The Basics of
MRI http//www.cis.rit.edu/htbooks/mri/mri-main.ht
m
Book covering Multi-Dimensional MRI
E. Mark Haacke, et al. Magnetic Resonance
Imaging Physical Principles and Sequence Design,
1999.
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Phase-Encoding
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2D Gradient-Echo Pulse Sequence (a)
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2D Gradient-Echo Pulse Sequence (b)
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2D Gradient-Echo K-Space
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Multi-Slice 2D Pulse Sequence
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Multi-Slice 2D Slice Excitation
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2D Echo-Planar Imaging (EPI)
Pulse Sequence K-Space Trajectory
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3D Gradient-Echo Pulse Sequence
Phase Spoiling (RF or gradients) causes
Incoherence in transverse magnetization
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Fast-Imaging(Steady-State Incoherent pulse
sequence)
For a train of RF pulses repeated every TR seconds
The steady-state equilibrium magnetization is
where
The transverse magnetization following the nth RF
pulse is
The Steady-State Incoherent signal intensity is
proportional to M
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Flip Angle (?), TR T1 in Fast Imaging
where
Steady-State Incoherent (SSI) signal intensity
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Flip Angle (?), TR T1 in Fast Imaging
where
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Steady-State Coherence Pulse Sequence
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Steady-State Coherence Pulse Sequence
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Chemical-Shift Imaging (CSI)
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Chemical-Shift Imaging (CSI)
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Chemical-Shift Imaging (CSI)
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Chemical-Shift Imaging (CSI)
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Homework
Problem 1