This edition first published 2019
© 2019 John Wiley & Sons Ltd
Edition History
Blackwell Science (1e, 1993, 2e, 1998); Blackwell Publishing Ltd (3e, 2005, 4e 2011).
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Library of Congress Cataloging-in-Publication Data
Names: Westbrook, Catherine, author. | Talbot, John (Writer on magnetic
resonance imaging), author.
Title: MRI in practice / by Catherine Westbrook, John Talbot.
Description: Fifth edition. | Hoboken, NJ : Wiley, 2018. | Includes
bibliographical references and index. |
Identifiers: LCCN 2018009382 (print) | LCCN 2018010644 (ebook) | ISBN
9781119391999 (pdf) | ISBN 9781119392002 (epub) | ISBN 9781119391968
(pbk.)
Subjects: | MESH: Magnetic Resonance Imaging–methods | Magnetic Resonance
Imaging–instrumentation
Classification: LCC RC78.7.N83 (ebook) | LCC RC78.7.N83 (print) | NLM WN 185
| DDC 616.07/548–dc23
LC record available at https://lccn.loc.gov/2018009382
Cover image: Courtesy of John Talbot
Cover design by Wiley
The MRI in Practice brand continues to grow from strength to strength. The fourth edition of MRI in Practice is an international best-seller and is translated into several languages. At the time of writing, the accompanying MRI in Practice course is 26 years old. We have delivered the course to more than 10 000 people in over 20 countries and have a large and growing MRI in Practice online community. Our readers and course delegates include a variety of professionals such as radiographers, technologists, radiologists, radiotherapists, veterinary practitioners, nuclear medicine technologists, radiography students, postgraduate students, medical students, physicists, and engineers.
The unique selling point of MRI in Practice has always been its user-friendly approach to physics. Difficult concepts are explained as simply as possible and supported by clear diagrams, images, and animations. Clinical practitioners are not usually interested in pages of math and just want to know how it essentially “all works.” We believe that MRI in Practice is so popular because it speaks your language without being oversimplistic.
This fifth edition has had a significant overhaul and specifically plays to the strengths of the MRI in Practice brand. We have created a synergy between the book and the course so that they are best able to support your learning. We purposefully focus on physics in this edition and on essential concepts. It is important to get the fundamentals right, as they underpin more specialist areas of practice. There are completely new chapters on MRI equipment and safety, and substantially revised and expanded chapters on gradient-echo pulse sequences, k-space, artifacts, and angiography. The very popular learning tips and analogies from previous editions are expanded and revised. There is also a new glossary, lots of new diagrams and images, and suggestions for further reading for those who wish to delve deeper into physics. The accompanying website includes new questions and additional animations. We also include some equations in this edition, but don’t worry: they are there only for those who like equations, and we explain what they mean in a user-friendly style.
However, probably the most significant change in this edition is the inclusion of scan tips. Throughout the book, your attention is drawn to how theory applies to practice. Scan tips are specifically used to alert you to what is going on “behind the scenes” when you select a parameter in the scan protocol. We hope this helps you make the connection between theory and practice. Physics in isolation is of little value to the clinical practitioner. What is important is how this knowledge is applied. We stand by the MRI in Practice philosophy that physics does not have to be difficult, and we hope that our readers, old and new, find these changes helpful. Richard Feynman, who is considered one of the finest physics teachers of all time, was renowned for his ability to transfer his deep understanding of physics to the page with clarity and a minimum of fuss. He believed that it is unnecessary to make physics more complicated than it need be. Our aspiration is that the fifth edition of MRI in Practice emulates his way of thinking.
We hope that the many fans of MRI in Practice around the world continue to enjoy and learn from it. A big thank you for your continued support and happy reading!
Catherine Westbrook
John Talbot
November 2017
United Kingdom
Many thanks to all my loved ones for their continued support, especially Maggie Barbieri (my mother, whose brain scans feature many times in all the editions of this book and in the MRI in Practice course for the last 26 years. She must have the most viewed brain in the world!), Francesca Bellavista, Amabel Grant, Adam, Ben and Maddie Westbrook.
Catherine Westbrook
I’d like to thank my family Dannie, Joey, and Harry for bringing coffee, biscuits, and occasionally gin and tonic. I would also like to take the opportunity to acknowledge the work of a great MRI pioneer, Prof. Sir Peter Mansfield, who died this year. Prof. Mansfield’s team created the first human NMR image in 1976, and he kindly shared all of his most important research papers with me when I first started writing about this amazing field.
John Talbot
Generic | Siemens | GE | Philips | Hitachi | Toshiba |
Pulse sequences | |||||
Conventional spin-echo (SE) | SE | SE | SE | SE | SE |
Turbo spin-echo (TSE) | TSE | FSE | TSE | FSE | FSE |
Single-shot TSE (SS-TSE) | HASTE | SS-FSE | SS-TSE | SS-FSE | FASE |
TSE (with restoration pulse) | RESTORE | FRFSE | DRIVE | driven equilibrium FSE | T2 Puls FSE |
Inversion recovery (IR) | IR | IR/MPIR | IR | IR | IR |
Fast inversion recovery | TIR | Fast IR | IR-TSE | IR | IR |
Short tau IR (STIR) | STIR | STIR | STIR | STIR | fast STIR |
Fluid-attenuated IR (FLAIR) | turbo dark fluid | FLAIR | FLAIR | FLAIR | fast FLAIR |
Gradient-echo (GRE) | GRE | GRE | FFE | GE | field echo |
Coherent gradient-echo | FISP | GRASS | FFE | rephased SARGE | SSFP |
Incoherent gradient-echo | FLASH | SPGR | T1 FFE | spoiled SARGE | fast FE |
Reverse-echo gradient-echo | PSIF | SSFP | T2 FFE | time-reversed SARGE | — |
Balanced gradient-echo | true FISP | FIESTA | BFFE | balanced SARGE | true SSFP |
Echo-planar imaging (EPI) | EPI | EPI | EPI | EPI | EPI |
Double-echo steady state | DESS | — | — | — | — |
Balanced dual excitation | CISS | FIESTA-C | — | phase balanced SARGE | — |
Multi-echo-data-image-combination | MEDIC | MERGE | MFFE | — | — |
Fast gradient-echo | turbo FLASH | fast GRE, fast SPGR | TFE | RGE | Fast FE |
Hybrid sequence | TGSE | — | GRASE | — | Hybrid EPI |
Contrast parameters | |||||
Repetition time (TR) | TR | TR | TR | TR | TR |
Time to echo (TE) | TE | TE | TE | TE | TE |
Time from inversion (TI) | TI | TI | TI | TI | TI |
Flip angle | flip angle | flip angle | flip angle | flip angle | Flip angle |
Number of echoes (in TSE) | turbo factor | ETL | turbo factor | shot factor | ETL |
b factor/value | b factor | b factor | b factor | b factor | b factor |
Geometry parameters | |||||
Field of view (FOV) | FOV (mm) | FOV (cm) | FOV (mm) | FOV (mm) | FOV (mm) |
Rectangular FOV | FOV phase | PFOV | rectangular FOV | rectangular FOV | rectangular FOV |
Slice gap | distance factor | gap | gap | slice interval | gap |
Data acquisition parameters | |||||
Averages | average | NEX | NSA | NSA | NSA |
Bandwidth | bandwidth (Hz/pixel) | receive bandwidth (KHz) | fat water shift (pixel) | bandwidth (KHz) | bandwidth (KHz) |
Variable bandwidth | optimized bandwidth | variable bandwidth | optimized bandwidth | variable bandwidth | matched bandwidth |
Partial averaging | half Fourier | fractional NEX | half scan | half scan | AFI |
Partial echo | asymmetric echo | partial echo | partial echo | half echo | matched bandwidth |
Parallel imaging (image based) | mSENSE | ASSET | SENSE | RAPID | SPEEDER |
Parallel imaging (k-space based) | GRAPPA | ARC | — | — | — |
Artifact reduction techniques | |||||
Radial k-space filling | BLADE | PROPELLOR | multiVane | RADAR | JET |
Gradient moment rephasing | GMR/flow comp | flow comp | flow comp/FLAG | GR | FC |
Presaturation | pre SAT | Sat | REST | Pre SAT | Pre SAT |
Moving sat pulse | travel SAT | walking SAT | travel REST | Sequential pre SAT | BFAST |
Fat saturation | fat SAT | chem SAT | SPIR | Fat Sat | MSOFT |
Out-of-phase imaging | DIXON | IDEAL | ProSET | Water excitation | PASTA |
Respiratory compensation | respiratory gated | respiratory compensation | PEAR | MAR | respiratory gated |
Antialiasing (frequency) | oversampling | antialiasing | frequency oversampling | frequency oversampling | frequency wrap suppression |
Antialiasing (phase) | phase oversampling | no phase wrap | fold-over suppression | antiwrap | phase wrap suppression |
Special techniques | |||||
Volume TSE variable flip angle | SPACE | CUBE | VISTA | — | — |
Volume gradient-echo | VIBE | LAVA-XV | THRIVE | TIGRE | — |
Dynamic MRA | TWIST | TRICKS-SV | keyhole (4d Trak) | — | — |
Noncontrast MRA gradient-echo | NATIVE – true FISP | inhance inflow IR | B-TRANCE | VASC ASL | TIME-SLIP |
Noncontrast MRA spin- echo | NATIVE-SPACE | — | TRANCE | VASC FSE | FBI |
Susceptibility weighting | SWI | SWAN | Venous BOLD | — | — |
High-resolution breast imaging | VIEWS | VIBRANT-XV | BLISS | — | RADIANCE |
Diffusion-weighted imaging | DWI | DWI | DWI | DWI | DWI |
Diffusion tensor imaging | DTI | DTI | diffusion tensor imaging | — | DTI |
Body diffusion imaging | REVEAL | — | DWIBS | — | body vision |
S | spin quantum number | |
N+ | number of spins in the high-energy population (Boltzmann) | |
N− | number of spins in the low-energy population (Boltzmann) | |
ΔE | energy difference between high- and low-energy populations (Boltzmann) | J |
k | Boltzmann’s constant | J/K |
T | temperature of the tissue | K |
ω0 | precessional or Larmor frequency | MHz |
γ | gyromagnetic ratio | MHz/T |
B0 | external magnetic field strength | T |
E | energy of a photon | J |
h | Planck’s constant | J/s |
θ | flip angle | ° |
ω1 | precessional frequency of B1 | μT |
B1 | magnetic field associated with the RF excitation pulse | mT |
τ | duration of the RF excitation pulse | ms |
ϵ | emf | V |
N | number of turns in a coil | |
dΦ | changing magnetic flux in a single loop | V/s |
dt | changing time | s |
Mzt | amount of longitudinal magnetization at time t | |
Mz | full longitudinal magnetization | |
Mxyt | amount of transverse magnetization at time t | |
Mxy | full transverse magnetization | |
SI | signal intensity in a tissue | |
ΔB0 | variation in magnetic field | ppm |
G | gradient amplitude | mT/m |
δ | gradient duration | ms |
Δ | time between two gradient pulses | ms |
b | b value or b factor | s/mm2 |
ST | scan time | s |
ES | echo spacing in turbo spin-echo (TSE) | ms |
t | time from inversion (TI) | ms |
Ernst | Ernst angle | ° |
TEeff | effective TE | ms |
TEact | TE set at the console | ms |
Bp | magnetic field strength at a point along the gradient | T |
Slt | slice thickness | mm |
TBW | transmit bandwidth | KHz |
ωsampling | digital sampling frequency | KHz |
ΔTs | sampling interval | ms |
ωNyquist | Nyquist frequency | KHz |
RBW | receive bandwidth | KHz |
Ws | sampling window | ms |
M(f) | frequency matrix | |
M(p) | phase matrix | |
Ns | number of slice locations | |
G(p) | max amplitude of the phase encoding gradient | mT/m |
φ | incremental step between each k-space line | |
G(f) | amplitude of the frequency encoding gradient | mT/m |
FOV(f) | frequency FOV | cm |
σ | standard deviation of background signal or noise | |
Sp | separation between ghosts due to motion p | pixels |
Tm | period of motion of something moving in the patient | ms |
Re | Reynolds number | |
d | density of blood | g/cm3 |
v | velocity of flow | cm/s |
m | diameter of a vessel | cm |
vis | viscosity of blood | g/cm s |
fp | perceived frequency | KHz |
ft | actual frequency | KHz |
ωcsf | chemical shift frequency difference between fat and water | Hz |
Cs | chemical shift (3.5 ppm or 3.5 × 10−6) | ppm |
CSp | pixel shift | mm |
H0 | magnetic intensity | A/m |
q | charge of a particle | C |
F | Lorentz force (total emf on a charged particle) | V |
E | electric field vector | |
B | magnetic field vector |
This book is accompanied by a companion website:
www.wiley.com/go/westbrook/mriinpractice
The website includes: