Revised by R. Edward Hendrick, PhD, FACR, under the auspices of:

(the former) Commission on Neuroradiology and Magnetic Resonance
William G. Bradley, Jr., MD, PhD, FACR, Chair

Committee on Research and Technology Assessment – Body MR

Steven E. Harms, MD, FACR, Co-Chair
Jeffrey J. Brown, MD, FACR
Andrew L. Deutsch, MD
Charles B. Higgins, MD
Narinder Kumar, PhD
Donald G. Mitchell, MD

Copyright © 2005 American College of Radiology

All rights reserved. This book protected by copyright. No part of it may be duplicated or reproduced in any manner without written permission from the American College of Radiology.

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Introduction to the Fifth Edition

The field of biomedical magnetic resonance imaging and spectroscopy has continued to prosper and mature in the ten years since the fourth edition of this glossary was published. The terminology applied to MR imaging and spectroscopy is also evolving. In this fifth edition of the Glossary of MR Terms, we have introduced new terms, revised or expanded some of the existing definitions, and deleted some outmoded terms. We have attempted to avoid the inclusion of proprietary terms. The goal of this expanded glossary is to contribute to the scientific and educational development of MR imaging and spectroscopy by fostering clear communication. It is our goal that this newly revised glossary be made as widely available as possible.

I thank Dr. Bill Bradley and Dr. Steve Harms for marshalling this project through to fruition. Special thanks also go to Dr. Don Mitchell for a careful review of new MR Glossary terms and to Ms. Rebecca Lewis at the ACR for her steadfast administrative support of this project.

Original Introduction

This glossary of conventional NMR-related terms, along with the accompanying table of basic quantities in electricity and magnetism, are offered by the American College of Radiology for the use of physicians, medical physicists, and manufacturers. For physicians and physicists, being familiar with this glossary will aid in reading scientific papers and manufacturers' product descriptions; it is also hoped that potential authors will use the suggested definitions and conventions as standards in writing papers of their own. For manufacturers, the glossary provides a standard set of terms and symbol and display conventions to use in product descriptions and display design. Although technically accurate, no effort has been made to formalize the definitions. Only those concepts most directly related to medical NMR have been included. Important related areas, such as digital data processing, have been purposely omitted. In order to simplify the notation, the use of subscripts and Greek letters has been minimized (it may be clearer to use some symbols in subscripted forms when writing equations).

This glossary has been produced under the auspices of the American College of Radiology's Subcommittee on NMR Nomenclature and Phantom Development under the chairmanship of Leon Axel, PhD, MD

Commission on NMR

Thomas F. Meaney, MD, Chairman
Stanley Baum, MD
Thomas F. Budinger, MD, PhD
Richard H. Greenspan, MD
A. Everette James, Jr., MSc, JD, MD
Alexander R. Margulis, MD
Juan M. Taveras, MD
James E. Youker, MD

Committee on MR Imaging Technology and Equipment

Alexander R. Margulis, MD, Chairman
Leon Axel, PhD, MD
S. Morry Blumenfeld, PhD
Lawrence E. Crooks, PhD
Waldo S. Hinshaw, PhD
Leon Kaufman, PhD
James A. Nelson, MD

Subcommittee on MR Nomenclature and Phantom Development

Leon Axel, PhD, MD, Chairman
Lawrence E. Crooks, PhD
Andre Luiten, PhD
Manfred Pfeiler, PhD
John F. Schenck, MD, PhD
Stephen R. Thomas, PhD