窥知

Multidetector CT in Neuroimaging.pdf MULTIDETECTOR CT IN NEUROIMAGING Evelyn M Teasdale • Susan Aitken CLINICAL PUBLISHING An Atlas and Practical Guide Teasdale • A itken C L IN IC A L P U B L ISH IN G An Atlas and Practical Guide MULTIDETECTOR CT IN NEUROIMAGING Multidetector CT continues to find new applications in an ever increasing range of specialties, and this new volume provides a superbly illustrated introduction to using MDCT when examining the central nervous system. Beginning with an overview of the capabilities of the technique, the authors then review each of the principal anatomical regions in turn, detailing appropriate protocols for obtaining satisfactory images, and illustrating normal anatomy and normal variants before presenting a comprehensive selection of common pathological findings, with notes on how these images may be recorded to best advantage. Special sections are dedicated to CT angiography, particularly in the assessment of stroke, trauma and other emergencies, and to skull base imaging, now an indispensable tool for planning complex surgical approaches. Other titles in this series: Ischemic Stroke: an Atlas of Diagnosis and Treatment IE Silverman, MM Rymer ISBN 978 1 84692 017 2 Hemorrhagic Stroke: an Atlas of Diagnosis and Treatment IE Silverman, MM Rymer ISBN 978 1 84692 039 4 Website: www.clinicalpublishing.co.uk ISBN: 978 1 904392 68 2 9 781904 392682 ISBN 978-1-904392-68-2 M U LT ID E T E C T O R C T IN N E U R O IM A G IN G MDCT cover repro_hl.qxd 6/7/09 11:51 Page 1 An Atlas and Practical Guide MULTIDETECTOR CT IN NEUROIMAGING Evelyn M Teasdale BSc MBChB MRCP FRCR Consultant Neuroradiologist Department of Clinical Neuroradiology Institute of Neurological Sciences South Glasgow University Hospital, Southern General Hospital Glasgow, UK Susan Aitken DCR(R)(T), BA Superintendent for CT Department of Clinical Neuroradiology Institute of Neurological Sciences South Glasgow University Hospital, Southern General Hospital Glasgow, UK CLINICAL PUBLISHING OXFORD MDCT final_hl.qxd:Dementia final.qxd 26/6/09 11:40 Page iii Clinical Publishing an imprint of Atlas Medical Publishing Ltd Oxford Centre for Innovation Mill Street Oxford OX2 0JX UK Tel: +44 1865 811116 Fax: +44 1865 251550 Email: info@clinicalpublishing.co.uk Web: www.clinicalpublishing.co.uk Distributed in USA and Canada by: Clinical Publishing 30 Amberwood Parkway Ashland OH 44805 USA Tel: 800-247-6553 (toll free within US and Canada) Fax: 419-281-6883 Email: order@bookmasters.com Distributed in UK and Rest of World by: Marston Book Services Ltd PO Box 269 Abingdon Oxon OX14 4YN UK Tel: +44 1235 465500 Fax: +44 1235 465555 Email: trade.orders@marston.co.uk © Atlas Medical Publishing Ltd 2009 First published 2009 All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, without the prior permission in writing of Clinical Publishing or Atlas Medical Publishing Ltd. Although every effort has been made to ensure that all owners of copyright material have been acknowledged in this publication, we would be glad to acknowledge in subsequent reprints or editions any omissions brought to our attention. A catalogue record of this book is available from the British Library ISBN-13 978 1 904392 68 2 ISBN e-book 978 1 84692 596 2 The publisher makes no representation, express or implied, that the dosages in this book are correct. Readers must therefore always check the product information and clinical procedures with the most up-to-date published product information and data sheets provided by the manufacturers and the most recent codes of conduct and safety regulations. The authors and the publisher do not accept any liability for any errors in the text or for the misuse or misapplication of material in this work. Printed by Henry Ling Ltd, Dorchester, Dorset, UK MDCT final_hl.qxd:Dementia final.qxd 26/6/09 11:40 Page iv Contents Preface vi General note vii Image display vii Contributor vii Bibliography viii Abbreviations viii 1 Routine noncontrast brain imaging 1 2 Contrast enhanced brain imaging 11 3 Orbital pathology 27 4 Visual failure 35 5 Pituitary imaging 45 6 Cranial nerve palsies 3–6 53 7 Intracranial imaging in stroke: ischaemic 61 8 Vascular imaging in ischaemic stroke and TIA 69 9 Acute haemorrhagic stroke 81 10 Variations in arterial anatomy 93 11 Venous pathology and variations in venous anatomy 101 12 Cranial nerve palsies 7–12 113 13 Spinal imaging 121 Concluding comments 139 Index 141 MDCT final_hl.qxd:Dementia final.qxd 26/6/09 11:40 Page v vi Preface Multidetector computed tomography (MDCT) offers new and exciting opportunities for imaging patients suspected of afflictions of the nervous system. Achievement of this benefit requires an understanding of its full potential in displaying the features of the spectrum of relevant diseases. It also depends upon employing an approach that ensures that it is applied to best effect by tailoring the technique of examination to the patient's clinical problem. We hope that this account, distilling the conceptual and technical lessons gained from our extensive experience of MDCT, will provide practical guidance to radiologists, whether general or specialist, and their team of radiographers/technicians that will enable them to take full advantage of the opportunities offered by MDCT in brain and spine imaging. This will enrich their practice and expand the benefits they can bring to their patients. The advantages of MDCT include its ability for routine sub-millimetre scanning of large areas at acceptable radiation doses. The enhanced postprocessing techniques and the rapidity and ease with which they can be obtained mean that they can be applied with no limitation on throughput or reporting times. Although magnetic resonance imaging (MRI), with its ability to differentiate soft tissues has many applications, computed tomography (CT) remains the appropriate first-line investigation for most patients with an acute cerebral event and for those who still cannot undergo MR for one reason or another (approximately 1 patient in 5). MDCT has many technical benefits over single-slice CT but when a small area is to be covered, e.g. the orbit and the cavernous sinus, a single slice scanner is acceptable and a 4- slice MDCT can be almost as effective as a 64-slice CT. In contrast, when a large area is to be covered, a scanner with 16 or more detectors is optimal and single slice imaging precluded by technical limitations and the radiation dose it would give. MDCT provides new opportunities to improve the standard of routine brain examinations and to expand CT techniques into new areas. The techniques we describe can be adapted to any MDCT system for any similar clinical situation In most radiology textbooks a systematic approach is followed. The appearances of specific pathologies, e.g tumours, trauma, and degenerative disease, are classified, described and inclusively illustrated. In practice, most patients present with a combination of symptoms and signs which must be investigated in order that pathology can be either excluded or identified and managed. This book adopts such a problem-based approach and is intended to be a supplement to the standard disease-based texts. Our approach is based on the concept that the information from the clinical referral can be used to define a tailored MDCT technique which will optimize the likelihood of correctly identifying or excluding causative pathology. The commonly held belief that a single CT brain protocol is appropriate in all situations is no longer realistic, appropriate, or tenable. The illustrations are intended to convey how the CT techniques applied affected diagnosis or management in a range of common clinical scenarios. They show how MDCT can be used in a routine service role in a way that maximizes its potential, and how knowledge of that potential enables its use to be extended to unexpected applications. The illustrations are not inteded to be a comprehensive catalogue of abnormalities, but to convey why such images should be obtained and how to get the most from them. Protocols are given in detail so that radiographers or technicians, with the MDCT final_hl.qxd:Dementia final.qxd 26/6/09 11:40 Page vi ...