ABSTRACT
FDA Food and drug administration FE Frequency encoding FFE Fast eld echo FFT Fast Fourier transform FID Free induction decay FISP Fast imaging with steady-state precession FLAIR Fluid-attenuated inversion recovery FLASH Fast low-angle shot fMRI Functional MRI FOV Field of view FSE Fast spin echo FT Fourier transform GRE Gradient echo GMN Gradient moment nulling g-factor Geometry factor GRAPPA Generalized auto-calibrating partially par-
allel acquisition GRE Gradient-recalled echo IF Intermediate frequency IR Inversion recovery MIP Maximum intensity projection MR Magnetic resonance
3.7.4.1 Partial Fourier Imaging ........................................................................................................................ 106 3.7.4.2 Parallel Imaging .................................................................................................................................... 107
3.7.5 Real-Time and Dynamic Imaging ....................................................................................................................... 107 3.8 Advanced Techniques in MRI ......................................................................................................................................... 108
3.8.1 Tissue Suppression Methods ................................................................................................................................ 108 3.8.2 MR Angiography ................................................................................................................................................. 109 3.8.3 Diffusion MRI ......................................................................................................................................................110 3.8.4 Magnetization Transfer .........................................................................................................................................110 3.8.5 Magnetic Resonance Spectroscopy ......................................................................................................................111 3.8.6 High-Field Imaging ..............................................................................................................................................112
3.9 Image Artifacts .................................................................................................................................................................112 3.9.1 Motion Artifacts ...................................................................................................................................................112 3.9.2 Ringing Artifact....................................................................................................................................................113 3.9.3 Partial Volume Artifact ........................................................................................................................................113 3.9.4 Aliasing Artifact ...................................................................................................................................................114 3.9.5 Off-Resonance Artifact ........................................................................................................................................114
3.10 Scanner Hardware ............................................................................................................................................................114 3.10.1 Main Magnet.........................................................................................................................................................115 3.10.2 RF Coils ................................................................................................................................................................116 3.10.3 Gradient Coils .......................................................................................................................................................116 3.10.4 MRI Receiver ........................................................................................................................................................117
3.11 MRI Safety .......................................................................................................................................................................117 3.11.1 Field Strength and Magnetic Projectiles ...............................................................................................................117 3.11.2 Medical Devices and Implants .............................................................................................................................118 3.11.3 Nerve Stimulation .................................................................................................................................................118 3.11.4 Local Heating and Burns ......................................................................................................................................118 3.11.5 Power Deposition ..................................................................................................................................................118 3.11.6 Acoustic Noise ......................................................................................................................................................118 3.11.7 Claustrophobia ......................................................................................................................................................118
3.12 Summary and Key Points .................................................................................................................................................119 3.12.1 Summary ..............................................................................................................................................................119 3.12.2 Key Points .............................................................................................................................................................119
Bibliography ............................................................................................................................................................................. 120
