Biomedical Engineering P l a c i d i MRI: Essentials for Innovative Technologies describes novel methods to improve magnetic resonance imaging (MRI) beyond its current limitations. It proposes smart encoding methods and acquisition sequences to deal with frequency displacement due to residual static magnetic field inhomogeneity, motion, and undersampling. Requiring few or no hardware modifications, these speculative methods offer building blocks that can be combined and refined to overcome barriers to more advanced MRI applications, such as real-time imaging and open systems. After a concise review of basic mathematical tools and the physics of MRI, the book describes the severe artifacts produced by conventional MRI techniques. It first tackles magnetic field inhomogeneities, outlining conventional solutions as well as a completely different approach based on time-varying gradients and temporal frequency variation coding (acceleration). The book then proposes two innovative acquisition methods for reducing acquisition time, motion, and undersampling artifacts: adaptive acquisition and compressed sensing. The concluding chapter lays out the author’s predictions for the future of MRI. For some of the proposed solutions, this is the first time the reported results have been published. Where experimental data is preliminary or unavailable, the book presents only numerical solutions. Offering insight into emerging MRI techniques, this book provides readers with specialized knowledge to help them design better acquisition sequences and select appropriate correction methods. Giuseppe Placidi K11872 ISBN 978-1-4398-4040-5 90000 9 781439 840405 K11872_COVER_final.indd 1 3/23/12 3:48 PM MRI Essentials for Innovative Technologies K11872_FM.indd 1 3/28/12 5:41 PM TThhiiss ppaaggee iinntteennttiioonnaallllyy lleefftt bbllaannkk Giuseppe Placidi K11872_FM.indd 3 3/28/12 5:42 PM CRC Press Taylor & Francis Group 6000 Broken Sound Parkway NW, Suite 300 Boca Raton, FL 33487-2742 © 2012 by Taylor & Francis Group, LLC CRC Press is an imprint of Taylor & Francis Group, an Informa business No claim to original U.S. Government works Version Date: 20120320 International Standard Book Number-13: 978-1-4398-4062-7 (eBook - PDF) This book contains information obtained from authentic and highly regarded sources. Reasonable efforts have been made to publish reliable data and information, but the author and publisher cannot assume responsibility for the validity of all materials or the consequences of their use. The authors and publishers have attempted to trace the copyright holders of all material reproduced in this publication and apologize to copyright holders if permission to publish in this form has not been obtained. If any copyright material has not been acknowledged please write and let us know so we may rectify in any future reprint. Except as permitted under U.S. Copyright Law, no part of this book may be reprinted, reproduced, transmitted, or utilized in any form by any electronic, mechanical, or other means, now known or hereafter invented, including photocopying, microfilming, and recording, or in any information stor- age or retrieval system, without written permission from the publishers. For permission to photocopy or use material electronically from this work, please access www.copy- right.com (http://www.copyright.com/) or contact the Copyright Clearance Center, Inc. (CCC), 222 Rosewood Drive, Danvers, MA 01923, 978-750-8400. CCC is a not-for-profit organization that pro- vides licenses and registration for a variety of users. For organizations that have been granted a pho- tocopy license by the CCC, a separate system of payment has been arranged. Trademark Notice: Product or corporate names may be trademarks or registered trademarks, and are used only for identification and explanation without intent to infringe. Visit the Taylor & Francis Web site at http://www.taylorandfrancis.com and the CRC Press Web site at http://www.crcpress.com i ii iii iv v To my family The author’s proceeds from the sale of this book will be entirely donated to Bambin Gesu` Children’s Hospital in Rome.