Computed Tomography Hariqbal Singh, Sushil Kachewar
INDEX
×
Chapter Notes

Save Clear


1Jaypee Gold Standard Mini Atlas Series® COMPUTED TOMOGRAPHY
2“University is a nursery of Scientific Research and Mental Education”. “Pride in one's profession is demanded, but not professional conceit, snobbery or academic arrogance, all of which grow from false egoism”.
From the inaugural address of Wilhelm Conrad Röentgen, on being appointed by the University of Würzburg as the Director of Physical Institute in 1894, a year before his discovery of X-rays.
3Jaypee Gold Standard Mini Atlas Series® COMPUTED TOMOGRAPHY
Hariqbal Singh MD DMRD Professor and Head Department of Radiology Smt Kashibai Navale Medical College Pune, Maharashtra, India Sushil Kachewar MD DNB Assistant Professor Department of Radiology Smt Kashibai Navale Medical College Pune, Maharashtra, India
4Published by
Jitendar P Vij
Jaypee Brothers Medical Publishers (P) Ltd
Corporate Office
4838/24 Ansari Road, Daryaganj, New Delhi - 110002, India, Phone: +91-11-43574357
Fax: +91-11-43574314
Registered Office
B-3 EMCA House, 23/23B Ansari Road, Daryaganj, New Delhi - 110 002, India
Phones: +91-11-23272143, +91-11-23272703, +91-11-23282021
+91-11-23245672, Rel: +91-11-32558559, Fax: +91-11-23276490, +91-11-23245683
Offices in India
Overseas Offices
Jaypee Gold Standard Mini Atlas Series®: Computed Tomography
© 2010, Jaypee Brothers Medical Publishers (P) Ltd
All rights reserved. No part of this publication should be reproduced, stored in a retrieval system, or transmitted in any form or by any means: electronic, mechanical, photocopying, recording, or otherwise, without the prior written permission of the authors and the publisher.
This book has been published in good faith that the material provided by authors is original. Every effort is made to ensure accuracy of material, but the publisher, printer and authors will not be held responsible for any inadvertent error (s). In case of any dispute, all legal matters are to be settled under Delhi jurisdiction only.
First Edition: 2010
9789350250532
Typeset at JPBMP typesetting unit
Printed at Ajanta Offset
5To Prof Maruti Nivrutti Navale an ardent educationalist and Founder President Sinhgad Technical Education Society Pune, Maharashtra, India6
7Preface
The advent of Computed Tomography (CT scan) has revolutionized the field of medicine. The CT images in this book provide a peep into a wide range of pathology. With these images in mind, it will help the residents, radiologists and the practitioners to interpret the possible diagnosis during their routine practice. It is important to correlate the images to the clinical data to arrive at a probable diagnosis.
The book is meant for radiology residents, radiologists, general practitioners, other specialists, CT technical staff and those who have a special interest in CT imaging. It is meant for medical colleges, institutional and departmental libraries and for stand-alone CT establishments.
Hariqbal Singh
Sushil Kachewar8
9Acknowledgments
We express our gratitude to Professor Arvind V Bhore, Dean, Smt Kashibai Navale Medical College, Pune, Maharashtra, India for his kind permission in this endeavor.
We profusely thank the consultants Dr Shrinivas Desai, Mumbai; Sanjay Jain, Mumbai, Maharashtra; Abhijit Pawar, Pune, Maharashtra; Anubhav Khandelwal, Gurgaon, Haryana; Col RA George, Pune, Maharashtra; Rajul Rastogi, Moradabad, Uttar Pradesh; Ravi Varma, Mumbai; Sachin Patil, Pune; Santosh Konde, Pune; Sushant Bhadane, Nashik and Priscilla Joshi, Pune. They have contributed a large number of cases to the Mini Atlas.
Our special thanks to the CT Scan Technicians—Rahul More, Demello Thomas, Musmade Bala, Raghvendra of the CT unit for their untiring help in retrieving data.
We thank Manjusha Chikale nursing sister and CT receptionist and Snehal Nikalje, Sunanda Jangalagi, Sachin Babar and Anna Bansode for their clerical help.
We are grateful to God and mankind who have allowed us to have this wonderful experience.10
13Introduction
CT was invented in 1972 by British Engineer, Sir Godfrey Newbold Hounsfield in Hayes, United Kingdom at EMI Central Research Laboratories using X-rays. EMI Laboratories is best known today for its music and recording business. About the same time South Africa-born American Physicist, Allan McLeod Cormack of Tufts University, Massachusetts, USA independently invented a similar process, and both shared the 1979 Nobel Prize.
The first clinical CT scan was installed in 1974. The initial systems were dedicated only to head scanning due to small gantry, but soon this was overcome and whole body CT systems with larger gantry became available in 1976.
 
CT SCAN
Basic principle is to obtain a tomogram having thickness in millimeters of the region of interest using pencil beam X-radiation. The radiation transmitted through the patient is counted by scintillation detector. This information when fed in the computer is analyzed by mathematical algorithms and reconstructed as a tomographic image so as to provide an insight into the structure being studied.
14
 
DEVELOPMENTS IN CT TECHNOLOGY
 
Conventional Axial CT
Generation of CT scan
Motion of X-ray tube Detector system
Stationary detectors
X-ray beam type
First
Translate-Rotate
Two detectors
Pencil beam
Second
Translate-Rotate
Multiple detectors up to 30
Narrow fan beam (10°)
Third
Rotate-Rotate
Multiple detectors up to 750
Wide fan beam (50°)
Fourth
Rotate-Fixed
Ring of 1500-4500
Fan beam
 
Spiral/Helical CT
Spiral CT uses the conventional technology in conjunction with slip ring technology, which simultaneously provides high voltage for X-ray tube, low voltage for control unit and transmits digital data from detector array. Slip ring is a circular instrument with sliding bushes that enables the gantry to rotate continuously while the patient table moves into the gantry simultaneously, thus three dimensional volume rendered image can be obtained. The advantages over the conventional scanner are the reduced scan time, reduced radiation exposure and reduced contrast requirement with superior information.
15
 
Electron Beam CT (EBCT)
In EBCT, both the X-ray source and the detectors are stationary. High energy focused electron beam is magnetically steered on the tungsten target to emit X-rays which pass through the subject on to the detectors and image is acquired. EBCT is particularly used for faster imaging in cardiac studies.
 
Multislice/Multidetector CT (MDCT)
Spiral CT uses single row of detectors, resulting in a single slice per gantry rotation. Multislice CT, multiple detector arrays are used resulting in multiple slices per gantry rotation. In addition, fan beam geometry of spiral CT is replaced by cone beam geometry. The major advantages over spiral CT are improved spatial and temporal resolution, reduced image noise, faster and longer anatomic coverage and increased concentration of intravenous contrast.
 
Dual Source CT
Two X-ray sources are used as against single X-ray source in multislice CT scanner for faster imaging especially for structure like heart.
The enduring continuity of research in CT imaging, aims to provide superior resolution, reduced noise, faster imaging, minimize radiations and minimize the use of contrast medium.