MRI at a Glance

Catherine Westbrook, Senior Lecturer and Course Leader, Faculty of Medical Science, Anglia Ruskin University, UK.

• Preface viiAcknowledgements viiiHow to use your textbook ixAbout the companion website xi1 Magnetism and electromagnetism 22 Atomic structure 43 Alignment 64 Precession 85 Resonance and signal generation 106 Contrast mechanisms 127 Relaxation mechanisms 148 T1 Recovery 169 T2 decay 1810 T1 weighting 2011 T2 weighting 2212 PD weighting 2413 Conventional spin echo 2614 Fast or turbo spin echo – how it works 2815 Fast or turbo spin echo – how it is used 3016 Inversion recovery 3217 Gradient echo – how it works 3418 Gradient echo – how it is used 3619 The steady state 3820 Coherent gradient echo 4021 Incoherent gradient echo 4222 Steady-state free precession 4423 Balanced gradient echo 4624 Ultrafast sequences 4825 Diffusion and perfusion imaging 5026 Functional imaging techniques 5227 Gradient functions 5428 Slice selection 5629 Phase encoding 5830 Frequency encoding 6031 K space – what is it? 6232 K space – how is it filled? 6433 K space and image quality 6634 Data acquisition – frequency 6835 Data acquisition – phase 7036 Data acquisition – scan time 7237 K space traversal and pulse sequences 7438 Alternative K space filling techniques 7639 Signal to noise ratio 7840 Contrast to noise ratio 8041 Spatial resolution 8242 Chemical shift artefacts 8443 Phase mismapping 8644 Aliasing 8845 Other artefacts 9046 Flow phenomena 9247 Time-of-flight MR angiography 9448 Phase contrast MR angiography 9649 Contrast-enhanced MR angiography 9850 Contrast agents 10051 Magnets 10252 Radiofrequency coils 10453 Gradients and other hardware 10654 MR safety – bio-effects 10855 MR safety – projectiles 110Appendix 1a: The results of optimizing image quality 112Appendix 1b: Parameters and their associated trade-offs 113Appendix 2: Artefacts and their remedies 114Appendix 3: Main manufacturers’ acronyms 115Glossary 116Index 121