[eBook Code] Rad Tech's Guide to MRI (eBook Code, 2nd)

1. Hardware Overview 1

Instrumentation: Magnets 1

Instrumentation: RF Subsystem 6

Instrumentation: Gradient Subsystem 8

2. Fundamental Principles 11

Electromagnetism: Faraday’s Law of Induction 11

Magnetism 12

Behavior of Hydrogen in a Magnetic Field 14

3. Production of Magnetic Resonance Signal 19

4. Relaxation and Tissue Characteristics 23

T2-Relaxation 23

T1-Relaxation 24

Proton Density 24

T2* (Pronounced “T2 star”) 25

5. Data Acquisition and Image Formation 27

Pulse Sequences 27

Image Contrast Control 30

Image Formation 42

Data Acquisition 43

Scan Time 50

Controlling Image Quality with FSE 57

6. Magnetic Resonance Image Quality 61

Spatial Resolution 61

Signal-to-Noise Ratio (SNR) 63

7. Artifacts 75

Chemical Shift (Water and Fat in Different Voxels) 75

Chemical Shift (Water and Fat in the Same Voxel) 77

Magnetic Susceptibility 79

Motion and Flow 81

Spatial Presaturation 82

Gradient Moment Nulling (Flow Compensation) 84

Compensation for Respiration 84

Cardiac Compensation 86

Aperiodic Motion 88

Aliasing 89

Gibbs and Truncation Artifact 91

Radio-Frequency Artifacts 92

Gradient Malfunctions 93

Image Shading 93

Inadequate System Tuning 94

Reconstruction Artifacts 94

8. Flow Imaging 97

Flow Patterns 97

Magnetic Resonance Angiography (Non Contrast) 98

Reduction of Flow Artifacts 102

Signal Loss in MRA 102

Two-Dimensional and Three-Dimensional Time-of-Flight 103

Signal Loss with Two-Dimensional TOF 104

Three-Dimensional TOF 106

Signal Loss with Three-Dimensional TOF 108

PC Techniques 109

Contrast Enhanced MRA (CE-MRA) 113

9. Diffusion and Perfusion Imaging 117

Diffusion-Weighted Imaging (DWI) 117

10. Gadolinium-Based Contrast Agents 125

Characteristics, Composition and Structure 125

Index 129