MRI Made Easy for Beginners

Chapter 1. Basic Principles 1
Longitudinal Magnetization 2
Transverse Magnetization 3
MR Signal 4
Localization of the Signal 5
Chapter 2. T1, T2 Relaxations and Image Weighting 8
Longitudinal Relaxation 8
Transverse Relaxation 9
T1 10
T2 11
T2* (T2 star) 11
TR and TE 12
TI 13
T1 Weighted Image 13
T2 Weighted Image 14
Proton Density (PD) Image 16
Chapter 3. K-Space and Scanning Parameters 17
K-Space 17
Parameters of Scanning 18
Image Quality Determinants 20
Chapter 4. Magnetic Resonance Instrumentation 22
Magnetism 22
Magnetic Field Strength 23
Magnets 24
Gradients 29
Radiofrequency Coils 30
Computers and Accessories 32
Chapter 5. Sequences I: Basic Principles and
Classification 33
Classification 34
Spin Echo (SE) Pulse Sequence 34
Gradient Echo (GRE) Sequence 37
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xviii MRI Made Easy (for Beginners)
Inversion Recovery (IR) Sequence 40
Echo Planar Imaging (EPI) 44
Chapter 6. Sequences II: Accessory Techniques 47
Fat Suppression 47
Parallel Imaging 52
Respiratory Compensation Techniques 53
Gradient Moment Rephasing (GMR) 53
Magnetization Transfer 55
Keyhole Imaging 56
Saturation Band 56
Chapter 7. Sequences III: When to Use What Sequences 58
T1- Weighted Sequences 58
T2-Weighted Sequences 61
T2* Weighted Sequences 70
Cartilage Sensitive Sequences 70
Chapter 8. Magnetic Resonance Imaging Artifacts 73
Ghosts/Motion Artifacts 73
Aliasing/ Wraparound 75
Chemical Shift Related Artifacts 76
Truncation Artifact 78
Magnetic Susceptibility Artifact 78
Straight Lines and Zipper Artifacts 80
Shading Artifacts 81
Cross Excitation and Cross Talk 82
Parallel Imaging Artifact 84
Chapter 9. Magnetic Resonance Safety 85
MR Bioeffects 85
Safety Related Issues 86
Chapter 10. Magnetic Resonance Contrast Media 91
Classification of MR Contrast Media 91
Mechanism of MR Contrast Enhancement 92
Gadolinium 93
Nephrogenic Systemic Fibrosis (NSF) 96
Other MR Contrast Agents 97
Oral Contrast Agents 98
Role of Contrast in MRI 98
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Contents xix
Chapter 11. Principles of Interpretation: Neuroimaging 102
Normal signal intensity 102
Sequence Selection 103
Chapter 12. Principles of Interpretation: Body Imaging 115
Sequences 115
Section 2
Chapter 13. 3-Tesla MRI 125
Physics Differences 125
Artifacts 126
Safety Issues 126
Clinical Applications 128
Chapter 14. Magnetic Resonance Angiography 129
Types of MRA 129
Noncontrast MRA Techniques 131
Contrast Enhanced MRA (CEMRA) 136
Chapter 15. Magnetic Resonance Diffusion 137
What is Diffusion? 137
How do we Acquire Diffusion Weighted Images? 138
Clinical Applications of DWI 140
Diffusion Tensor Imaging 146
Chapter 16. Magnetic Resonance Perfusion 148
Principles 148
Technique of MR Perfusion with Exogenous Contrast Agent 149
Clinical Applications 150
Arterial Spin Labeling (ASL) 155
Chapter 17. Magnetic Resonance Spectroscopy 158
Basic Principles 158
Localization Techniques in MRS 160
Steps in MRS Acquisition 161
Metabolites of 1H MRS 164
Clinical Uses of MRS 167
Chapter 18. Cardiac Magnetic Resonance Imaging 172
ECG Gating 172
Imaging Sequences 172
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xx MRI Made Easy (for Beginners)
Imaging Planes 173
Clinical Applications of CMRI 176
Chapter 19. Magnetic Resonance
Cholangiopancreatography 183
Principles 183
Sequences used in MRCP 183
MRCP Protocol and Technique 185
Clinical Applications of MRCP 186
Chapter 20. Miscellaneous Neuroimaging
MR Techniques 190
fMRI : Functional MRI 190
Susceptibility Weighted Imaging 192
Cerebrospinal Fluid Flow Study 192
Chapter 21. Miscellaneous Body Imaging
MR Techniques 196
Magnetic Resonance Enterography 196
MR Urography 198
Iron Overload Imaging 199
Magnetic Resonance Elastography 201
Magnetic Resonance Arthrography 201
Index 203–208