F. Schmitt . M. K. Stehling . R. Turner

Echo-Planar Imaging

Springer Berlin Heidelberg New York Barcelona Budapest Hong Kong London Milan Paris Santa Clara Singapore Tokyo

F. Schmitt· M. K. Stehling· R. Turner

Echo-Planar Imaging Theory, Technique and Application

Foreword by Sir Peter Mansfield, FRS

With Contributions by

P. A. Bandettini, R. Bowtell, R. Bruning, M. S. Cohen, A. J. S. de Crespigny, J. C. Duerk, D. A. Feinberg, D. N. Firmin, H. Fischer, J. Hennig, W. Irnich, B. Kiefer, K. Kwong, R. Ladebeck, C. H. Meyer, M. F. Muller, B. Poncelet, P. V. Prasad, P. Reimer, B. R. Rosen, F. Schmitt, B. Siewert, O. P. Simonetti, M. K. Stehling, R. Turner, S. Warach, P. A. Wielopolski, and E. C. Wong

With 386 Figures and 18 Tables

i Springer

Franz Schmitt Siemens Medical Systems Department MRG HenkestraBe 127 91052 Erlangen, Germany

Michael K. Stehling, PhD, MD Heinrich-Heine-StraBe 4 63303 Dreieich, Germany

Robert Turner, PhD Wellcome Department of Cognitive Neurology Institute of Neurology, University College London 12 Queen Square London WCIN 3BG, UK

The cover illustrations were kindly provided by Dr. Alistair Howseman (Well come Department of Cognitive Neurology, London), Dr. Betina Siewert and Dr. Stephen Warach (Beth Israel Hospital, Boston), and Dr. Piotr Wielopolski (Dr. Daniel Den Hoed Kliniek, Rotterdam, Holland).

Library of Congress Cataloging-in-Publication Data

Echo-planar imaging: theory, technique, and application I [edited by] F. Schmitt, M.K. Stehling, R. Turner; with contributions by P.A. Bandettini ... let al.]. p. cm. Includes bibliographical references and index.

ISBN-13: 978-3-642-80445-8 DOl: 10.1 007/978-3-642-80443-4

e-ISBN-13: 978-3-642-80443-4

1. Magnetic resonance imaging. 1. Schmitt, F. (Franz), 1953-. II. Stehling, M. K. (Michael K.), 1961-. III. Turner, R. (Robert), 1944-. IV. Bandettini, P. A. (Peter A.) [DNLM: 1. Echo-Planar Imaging. WN 185E18 1998] RC78.7.N83E24 1998 616.07'548-dc21

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© Springer-Verlag Berlin Heidelberg 1998 Softcover reprint of the hardcover I st edition 1998 The use of general descriptive names, registered names, trademarks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use.

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Production: ProEdit GmbH, 69126 Heidelberg, Germany Cover design: Erich Kirchner, 69126 Heidelberg, Germany Typesetting: Hagedorn Kommunikation, 68519 Viernheim, Germany

SPIN 10104822 21/3135-5 4 3 2 1 0 - Printed on acid-free paper

Preface

"Dost thou love life? Then do not squander time, for that's the stuff life is made oj':

Benjamin Franklin

This book describes the technical principles and applications of echo-planar imaging (EPI) which, as much as any other technique, has shaped the develop­ment of modern magnetic resonance imaging (MRI). The principle of EPI, namely, the acquisition of multiple nuclear magnetic resonance echoes from a single spin excitation, has made it possible to shorten the previously time-con­suming MRI data acquisition from minutes to much less than a second. Interest­ingly, EPI is one of the oldest MRI techniques, conceived in 1976 by Sir Peter Mansfield only 4 years after the initial description of the principles of MRI. One of the inventors of MRI himself, Mansfield realized that fast data acquisition would be paramount in bringing medical applications of MRI to full fruition. The technological challenges in implementing EPI, however, were formidable. Until the end of the 1980s few people believed that EPI would be clinically useful, since its complexity was far greater than that of "conventional" MRI methods. Many fundamental improvements in hardware, such as high performance gradi­ent coil systems, magnetic screening of gradient and RF coils, improved gradient amplifiers, as well as more sophisticated and faster image formation algorithms, had to be developed to make EPI work, In turn, these technological improve­ments laid the foundation for most modern MRI techniques. Fast spin-echo (FSE) imaging, which is ubiquitously used in modern MRI, snap-shot FSE, used for abdominal and cardiac imaging, BOLD (blood oxygen level dependent) and diffusion techniques, used in neurofunctional and stroke' research, as well as fast gradient echo techniques employed for 3D musculoskeletal imaging and gadolinium-enhanced MR-angiography have all profited directly or indirectly from EPI.

The idea to write this book first emerged during the final year of my PhD studies at the University of Nottingham in 1989 when I realized the profound impact EPI would have on the further development of MRI. Two years later, while working at the Siemens MR - research and development laboratory, Franz Schmitt enthusiastically supported my idea and, 1 year later, after we had both moved to Boston's Beth Israel Hospital to join Siemen's EPI prototype project headed by Robert Edelman, we signed the contract with Springer to get the book underway. Some time later Robert Turner joined us and provided crucial support in guiding the project through a difficult phase of its genesis. The book

VI Preface

in its final form, however, would not exist without the enormous enthusiasm and discipline and the skills of Franz Schmitt in leading all the contributors to the finish line.

Our book endeavors to provide the first comprehensive treatment of the physics and technology of EPI and its applications in research and medicine. The editors were fortunate to have obtained the support of many pioneers and international experts in the field of EPI and related subjects whose contributions to this book give profound insights into the current development of EPI and its applications. Since the book is aimed at both scientists and medical doctors, it covers the range from profound mathematical treatments to illustrative medical examples, both of which can be studied independently.

On behalf of my coauthors Franz Schmitt and Robert Turner I would like to express gratitude to everybody who has contributed to this book, including the many unnamed supporters.

Dreieich London Erlangen April 1998

Michael K. Stehling Robert Turner Franz Schmitt

Foreword

Some 23 years have passed since the idea of echo-planar imaging was conceived. In its original form it was called "Multi-planar Image Formation using NMR Spin-Echoes", but as time evolved it seemed necessary to follow the then current vogue of using catchy acronyms to encapsulate the technique. The nomenclature became reduced to echo-planar imaging (EPI), which is now the accepted term for this high-speed, one-shot imaging modality.

I well remember a symposium of experts convened at the University of Not­tingham in 1977. I was asked to speak on a topic and chose to unveil the EPI method. The audience of about 20-25 people included Richard Ernst, Paul Lau­terbur and others, and I recollect the look of disbelief and incredulity that greeted my presentation. There were no questions and it was as if I had never spoken. To put things in perspective, one has to remember that imaging times were typically of the order of 1 h and there was I proposing a method which would produce images in milliseconds. The response was not entirely surprising.

A lot of water has passed under the bridge from those heady and exciting days until today. From conception, EPI took a year or two before implementation of the crudest kind, and following those early IS-ms images there was a long strug­gle to raise funds and convince people by example that EPI could eventually work and compete in clinical imaging. Countless numbers of students, postdocs and visitors passed through Nottingham and made their contribution to the develop­ment of EPI, but it was not until a superconductive magnet had been acquired in the late 1970s, and not without the enthusiasm and dedication of a group of people at Nottingham and two of my former students, Ian Pykett and Richard Rzedzian, who went to the United States to set up their own company to make EPI machines, that the topic took off in a way which convinced far-sighted radi­ologists that there was something to the method. Once clinical interest was aroused, the various major companies in MRI took an interest in the technique and with that came final acceptance of the method.

The many aspects of this developmental process are encapsulated in the differ­ent chapters of this book, which also include EPI variants such as spiral scan EPI. The three authors are themselves pioneers in the subsequent development of EPI and especially its application, in the clinical radiological sense, the func­tional imaging research sense and the industrial sense. Two of the authors, I am proud to say, are ex-Nottingham researchers.

The editors of this book have, in my view, succeeded in producing a fine balance between the basics of EPI, the hardware aspects, safety issues and the clinical and radiological application.

VIII Foreword

This book, which is long overdue, certainly has my imprimatur. Aspects of EPI have been mentioned in other texts and in other reviews, but this is the first major book dedicated entirely to EPI and its hybrid variants. I have found the book generally very informative and stimulating. It is a book that will be of considerable value to MRI experts as well as to new students in the topic. Its appearance signals the corning of age of EPI.

Nottingham, April 1998 Peter Mansfield

Contents

1. The Historical Development of Echo-Planar Magnetic Resonance Imaging R. Turner, F. Schmitt, and M. K. Stehling

2. Theory of Echo-Planar Imaging M.S. Cohen

3. Echo-Planar Imaging Hardware R. Bowtell and F. Schmitt

1

11

31

4. Echo-Planar Imaging Pulse Sequences . . . . . . . . . . . . . . . . . . . .. 65

P. A. Wielopolski, F. Schmitt, and M. K. Stehling

S. Echo-Planar Image Reconstruction ....................... 141

F. Schmitt and P. A. Wielopolski

6. Echo-Planar Imaging Image Artifacts ..................... 179

H. Fischer and R. Ladebeck

7. Physiological Side Effects of Fast Gradient Switching .......... 201

F. Schmitt, W. Irnich, and H. Fischer

8. Echo-Planar Imaging Angiography ....................... 253

P. A. Wielopolski, O. P. Simonetti, and J. c. Duerk

9. Diffusion Imaging with Echo-Planar Imaging ................ 311

R. Turner

10. Echo-Planar Imaging of the Abdomen. . . . . . . . . . . . . . . . . . . .. 325

P. Reimer and R. Ladebeck

11. Abdominal Diffusion Imaging Using Echo-Planar Imaging ....... 371

M. F. Muller and P. V. Prasad

12. Echo-Planar Imaging of the Heart ....................... 389

D. N. Firmin and B. Poncelet

x Contents

13. Perfusion Imaging with Echo-Planar Imaging 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 419

Mo Ko Stehling, Ro Bruning, and Bo Ro Rosen

14. Clinical Applications of Neuroimaging Using Echo-Planar Imaging 0 0 465

Bo Siewert and So Warach

15. Echo-Planar Magnetic Resonance Imaging of Human Brain Activation 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 493

Po Ao Bandettini and Eo C. Wong

16. Research Issues Using Echo-Planar Imaging for Functional Brain Imaging 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 531

Ko Kwong

17. Echo-Planar Imaging on Small-Bore Systems 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 545

Ao Jo So de Crespigny

18. Echo-Planar Imaging-Hybrids: Single Shot RARE 0 0 0 0 0 0 0 0 0 0 0 0 0 0 567

Jo Hennig

19. Echo-Planar Imaging-Hybrids: Turbo Spin-Echo Imaging 0 0 0 0 0 0 0 0 0 583

Bo Kiefer

20. Echo-Planar Imaging-Hybrids: Gradient and Spin-Echo (GRASE) Imaging 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 605

Do Ao Feinberg

21. Spiral Echo-Planar Imaging 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 633

CoHo Meyer

Subject Index 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 659

List of Contributors

Bandettini, Peter A., PhD Biophysics Research Institute Medical College of Wisconsin 8701 W. Watertown Plank Rd. Milwaukee, WI 53226, USA

Bowtell, Richard, PhD Magnetic Resonance Centre Department of Physics, Science Park University of Nottingham Nottingham, NG7 2RD, UK

Bruning, Roland, MD Magnetic Resonance Imaging Unit Clinic for Diagnostic Radiology Klinikum GroBhadern Marchioninistr. 15 81377 Munchen, Germany

Cohen, Mark S., PhD Brain Mapping Division School of Medicine University of California Los Angeles RNRC 3256, 710 Westwood Plaza Los Angeles, CA 90024, USA

de Crespigny, Alexander, J. S., PhD Department of Radiology Stanford University Medical Center Lucas MRS Building Stanford, CA 94305-5488, USA

Duerk, Jeffrey C., PhD Department of Radiology University Hospitals 11100 Euclid Avenue Cleveland, OH 44106, USA

XII

Feinberg, David A., PhD, MD Neuro Radiology Section Mallinckrodt Institute 510 South Kingshighway Blvd. St. Louis, MO 63110, USA

Firmin, David N., PhD Royal Brompton Hospital Magnetic Resonance Unit Sydney Street London SW3 6NP, UK

Fischer, Hubertus, PhD Siemens Medical Systems Department MRO Henkestr. 127 91052 Erlangen, Germany

Hennig, Jiirgen, MD Department of Diagnostic Radiology Radiological University Hospital Albert Ludwigs University of Freiburg Hugstetter Str. 55 79106 Freiburg, Germany

Irnich, Werner, Professor Dr. Dipl.-Ing. Institute of Medical Technics University of GieBen Aulweg 123 35392 GieBen, Germany

Kiefer, Berthold, PhD Siemens Medical Systems Department MRIS Henkestr. 127 91052 Erlangen, Germany

Kwong, Kenneth, PhD Massachusetts General Hospital NMR Center Building 149, 13th Street Charlestown, MA 02129, USA

Ladebeck, Ralph, Dipl.-Phys. Siemens Medical Systems Department MRIS Henkestr. 127 91052 Erlangen, Germany

List of Contributors

List of Contributors

Meyer, Craig H., PhD Information Systems Laboratory Department of Electrical Engineering Stanford University 120 Durand Street Stanford, CA 94305, USA

Muller, Markus, F., MD Department of Diagnostic Radiology Inselspital, University of Berne Freiburgstrasse 4 3010 Bern, Switzerland

Poncelet, Brigitte, MD Department of Radiology NMR Center Massachusetts General Hospital Building 149, 13th Street Charlestown, MA 02129, USA

Prasad, Pottumarthi Vara, PhD Department of Radiology Beth Israel Hospital 330 Brookline Avenue, AN-242 Boston, MA 02215, USA

Reimer, Peter, MD Institute of Clinical Radiology Westfalische Wilhelms University Albert-Schweitzer-Str. 33 48129 Munster, Germany

Rosen, Bruce R., PhD, MD MRI Massachusetts General Hosfital 2nd Floor, Building 149, 13t Street Charlestown, MA 02129, USA

Schmitt, Franz Siemens Medical Systems Department MRG Henkestr. 127 91052 Erlangen, Germany

Siewert, Betina, MD 915 Tenth Street Hermosa Beach, CA 90254, USA

XIII

XIV

Simonetti, Orlando P., PhD Siemens Medical Systems MR Research & Development 448 East Ontario, Suite 700 Chicago, IL 60611, USA

Stehling, Michael K., PhD, MD Heinrich-Heine-Str. 4 63303 Dreieich, Germany

Turner, Rohert, PhD Wellcome Department of Cognitive Neurology Institute of Neurology University College London 12 Queen Square London WCIN 3BG, UK

Warach, Steve, PhD, MD Department of Neurology Beth Israel Hospital Harvard Medical School 330 Brookline Avenue Boston, MA 02215, USA

Wielopolski, Piotr A., PhD Department of Radiology University Hospital Rotterdam P.O. Box 5201 Rotterdam 3008 AE, The Netherlands

Wong, Eric C., PhD, MD Departments of Radiology and Psychiatry University of San Diego MRI 410 Dickinson Street San Diego, CA 92103-8749, USA

List of Contributors