Prelims

MRI Made Easy^® (for Beginners)

Third Edition

Govind B Chavhan MBBS MD DNB DABR Staff Pediatric Radiologist The Hospital for Sick Children Professor of Radiology University of Toronto Ontario, Canada

Jaypee Brothers Medical Publishers (P) Ltd

Headquarters

EMCA House

23/23-B, Ansari Road, Daryaganj

New Delhi 110 002, India

Landline: +91-11-23272143, +91-11-23272703

+91-11-23282021, +91-11-23245672

E-mail: jaypee@jaypeebrothers.com

Corporate Office

Jaypee Brothers Medical Publishers (P) Ltd.

4838/24, Ansari Road, Daryaganj

New Delhi 110 002, India

Phone: +91-11-43574357

Fax: +91-11-43574314

E-mail: jaypee@jaypeebrothers.com

Overseas Office

JP Medical Ltd.

83, Victoria Street, London

SW1H 0HW (UK)

Phone: +44-20 3170 8910

Fax: +44(0)20 3008 6180

E-mail: info@jpmedpub.com

Website: www.jaypeebrothers.com

Website: www.jaypeedigital.com

The views and opinions expressed in this book are solely those of the original contributor(s)/author(s) and do not necessarily represent those of editor(s) or publisher of the book.

All rights reserved by the author. No part of this publication may be reproduced, stored or transmitted in any form or by any means, electronic, mechanical, photocopying, recording or otherwise, without the prior permission in writing of the publishers.

All brand names and product names used in this book are trade names, service marks, trademarks or registered trademarks of their respective owners. The publisher is not associated with any product or vendor mentioned in this book.

Medical knowledge and practice change constantly. This book is designed to provide accurate, authoritative information about the subject matter in question. However, readers are advised to check the most current information available on procedures included and check information from the manufacturer of each product to be administered, to verify the recommended dose, formula, method and duration of administration, adverse effects and contraindications. It is the responsibility of the practitioner to take all appropriate safety precautions. Neither the publisher nor the author(s)/editor(s) assume any liability for any injury and/or damage to persons or property arising from or related to use of material in this book.

This book is sold on the understanding that the publisher is not engaged in providing professional medical services. If such advice or services are required, the services of a competent medical professional should be sought.

Every effort has been made where necessary to contact holders of copyright to obtain permission to reproduce copyright material. If any have been inadvertently overlooked, the publisher will be pleased to make the necessary arrangements at the first opportunity. The CD/DVD-ROM (if any) provided in the sealed envelope with this book is complimentary and free of cost. It is Not meant for sale.

Inquiries for bulk sales may be solicited at: jaypee@jaypeebrothers.com

MRI Made Easy^® (for Beginners) / Govind B Chavhan

First Edition: 2006

Third Edition: 2022

9789354655593

Printed at:

Ravi Sir (Professor Ravi Ramakantan)

The teacher par excellence

unchallengeable Radiologist

“Niswarth Karmayogi” relentlessly working toward

the benefit of thousands of poor patients

the great igniter of minds

this is for you

Preface to the Third Edition

Similar to other fields in medicine, MRI is ever advancing field. Many new techniques have been added in clinical practice since second edition. MRI is rapidly moving from qualitative to quantitative techniques regularly applied in patient management. Nephrogenic systemic fibrosis suddenly surfaced and changed the practice of contrast administration. As NSF cases became rare, concerns over gadolinium deposition in various body tissues started emerging. This little book has become a staple for radiology students and trainees beginning to learn MRI, selling over 1,000 copies yearly in the last decade. Third edition is an attempt to update this book with new advances and knowledge in the field.

The third edition of MRI Made Easy remains superficial overview of the subject explaining the basic fundamentals in simple language. This work is done keeping in mind needs of the person beginning to learn MR, especially radiology residents. As before, in attempt to simplify the subject, many complex things have been purposely omitted. This book is by no means complete source of the subject. This should serve as an appetizer for further reading of this interesting subject.

The book is still divided into two sections. First section deals with basic principles, instrumentation of MR system, sequences, and artifacts. Many new sequences and modifications are added in the chapters on sequences. The chapter on contrast media has up to date discussion on current issues. Also discussed in the section I are basic principles of MR interpretations with addition of a new chapter on normal signal intensity on MRI. Section II is on higher applications of MRI and has many new chapters covering new and upcoming MRI techniques including quantitative techniques.

Best Wishes and Happy Reading!

Govind B Chavhan

Preface to the First Edition

Radiology is the fastest advancing branch of medical sciences. It is moving from evaluation of anatomy to physiology, structural to functional, morphological to tissue diagnosis and biochemical information. MR takes the lead in this rapid march of advancement of radiology. No other modality has developed so much as MR in the last 20 years. MR has emerged as strong modality, which gives final answer in many conditions in all body systems.

This short introductory book is the superficial overview of the subject explaining the basic fundamentals. This work is done keeping in mind needs of the person beginning to learn MR, especially radiology residents. In attempt to simplify the subject, many complex things have purposely been omitted. This book is by no means complete source of the subject. This should serve as an appetizer for further reading of this interesting subject.

This book is divided into two sections. First section deals with basic principles, instrumentation of MR system, sequences and artifacts. Also discussed are few basic principles of MR interpretations. Section two has some advances and higher applications of MR. Following are few things to remember while reading this book:

Start reading from the first chapter and go in sequence for better understanding.
Protons, nuclei and spins are used synonymously; so do not get confused by them. They are one and the same.
For quick reference to the sequence, list of the common sequences with their long forms is given in the beginning.

Govind B Chavhan

Acknowledgments

High-quality radiology work done by my idols Dr Bhavin Jankharia and Dr Meher Ursekar inspired me to write MRI Made Easy. Their work and teaching still inspire me. I am grateful to them for their continued support and love. Most of the images of the first edition are retained in this third edition. These images are courtesy of Jankharia Imaging, Mumbai, Maharashtra, India.

I was fortunate to have excellent teachers and guides at every step of my carrier. It started with Professor Ravi Ramakantan in King Edward Memorial (KEM) Hospital, University of Mumbai who instilled ability, confidence and values for patient care. Dr Malini Nadkarni introduced me to pediatric imaging. MRI learning was with Dr Jankharia and Dr Ursekar in Mumbai. This was followed by support and guidance from Dr Manohar Shroff and Dr Paul Babyn in Toronto. I am ever grateful to Dr Babyn for mentoring me in the exciting field of pediatric body MRI.

Thank you to my all colleagues in the department at The Hospital for Sick Children, Toronto. I am fortunate to be working with such brilliant minds and nice human beings. Thank you to constant flow of trainees including residents and fellows to our department. Learning from them and teaching them is one of the greatest joys of my life.

Thank you to my friends Drs Pradeep Krishnan, Kushaljit Singh Sodhi and Giles Santyr for providing some images of their valuable work in the field for this book.

I take this opportunity to thank all the readers who commented, criticized, and made suggestions on Amazon website. My sincere and heartfelt thank you to those who reached me directly by email and pointed out some mistakes in the second edition. This has helped to improve the third edition.

My sincere thanks to Shri Jitendar P Vij (Group Chairman), Mr Ankit Vij (Managing Director), Mr MS Mani (Group President) of M/s Jaypee Brothers Medical Publishers (P) Ltd, New Delhi, India, for publishing the book. Special thank you to Dr Richa Saxena (Associate Director-Professional Publishing), Ms Pooja Bhandari (Production Head), Ms Nedup Denka Bhutia (Development Editor), of M/s Jaypee Brothers Medical Publishers (P) Ltd, New Delhi, India.

Last but not the least, pillars of my existence, creativity, and joy—my family, my wife Barakha and my sons Yash and Raj. Thank you for your love and bearing with me.

Few Commonly Used Short Forms

ADC	:	Analog to Digital Converter
CEMRA	:	Contrast Enhanced Magnetic Resonance Angiography
FOV	:	Field of View
FT	:	Fourier Transformation
GMR	:	Gradient Moment Rephasing
GMN	:	Gradient Moment Nulling
GRE	:	Gradient Echo
IR	:	Inversion Recovery
LM	:	Longitudinal Magnetization
MTC	:	Magnetization Transfer Contrast
NEX	:	Number of Excitation (Averages of Acquisition)
NMV	:	Net Magnetization Vector
PD	:	Proton Density
RF	:	Radiofrequency
SAR	:	Specific Absorption Rate
SE	:	Spin Echo
SNR	:	Signal to Noise ratio
TE	:	Time to Echo
TI	:	Time to Invert (Inversion Time)
TM	:	Transverse Magnetization
TR	:	Time to Repeat
VENC	:	Velocity Encoding

Summary of Sequences

	SEQUENCES	SIEMENS*	GE *	PHILIPS*
1.	Spin Echo Sequences
	Conventional SE (90–180° RF pulses)	SE	SE	SE
	Double SE (90° followed by two 180° RF pulses)	PD/T2	PD/T2	PD/T2
	Multi-SE (90° followed by multiple 180° RF pulses)	Turbo SE	Fast SE	Turbo SE
	Multi-SE with flip-back 90° pulse	RESTORE	FRFSE	DRIVE
	Single-shot Multi-SE (Multi-SE with half k-space filling)	HASTE	Single Shot FSE	Ultrafast SE
	3D versions of T2-weighted Fast spin-echo sequence	SPACE	CUBE	VISTA
	Fast spin-echo with radial k-space filling	BLADE	PROPELLER	MultiVane
2.	Gradient Echo Sequences
	A. Incoherent spoiled TM	FLASH	SPGR	T1-FFE
	3D versions	3D FLASH VIBE	LAVA FAME	THRIVE
	3D versions with radial/stack of star k-space filling	Star VIBE	LAVA Star	3D VANE
	B. Coherent/Rephased TM
	Post-excitation refocused (FID sampled)	FISP	GRASS	FFE
	Pre-excitation refocused (Spin echo sampled)	PSIF	SSFP	T2-FFE
	Fully refocused (both FID and spin echo sampled)	True FISP	FIESTA	Balanced FFE
3.	Inversion Recovery Sequences Short TI (80–150 ms), e.g., STIR Medium TI (200–1,200 ms), e.g., MPRAGE Long TI (1,500–2,500 ms), e.g., FLAIR
4.	Hybrid Combination of SE and GRE	TGSE	GRASE	GRASE
5.	EPI Single shot Multishot-segmented
* Vendor nomenclatures for sequences are taken from References:1. Nitz WR. MR Imaging: Acronyms and clinical applications. Eur Radiol. 1999;9(5):979-97.2. Brown MA, Semelka RC. MR Imaging Abbreviations, Definitions, and Descriptions: a review. Radiology. 1999;213(3):647-62.3. MRIQuestions.com accessed on January 1, 2021.
(EPI: echo planar imaging; FAME: fast acquisition with multiphase enhanced fast 3D GRE; FLASH: fast low-angle shot; FFE: fast field echo; FISP: fast imaging with steady-state precession; GRASS: gradient-recalled acquisition in the steady state; LAVA: liver acquisition with volume acquisition; SPGR: spoiled gradient-recalled; SSFP: steady-state free precession; THRIVE: T1-weighted high-resolution isotropic volume examination; VIBE: volumetric interpolated breath-hold examination)

Chapter Notes