Author: Christopher M. Collins
Publisher: Morgan & Claypool Publishers
Release Date: 2016-03-01
In the past few decades, Magnetic Resonance Imaging (MRI) has become an indispensable tool in modern medicine, with MRI systems now available at every major hospital in the developed world. But for all its utility and prevalence, it is much less commonly understood and less readily explained than other common medical imaging techniques. Unlike optical, ultrasonic, X-ray (including CT), and nuclear medicine-based imaging, MRI does not rely primarily on simple transmission and/or reflection of energy, and the highest achievable resolution in MRI is orders of magnitude smaller that the smallest wavelength involved. In this book, MRI will be explained with emphasis on the magnetic fields required, their generation, their concomitant electric fields, the various interactions of all these fields with the subject being imaged, and the implications of these interactions to image quality and patient safety. Classical electromagnetics will be used to describe aspects from the fundamental phenomenon of nuclear precession through signal detection and MRI safety. Simple explanations and Illustrations combined with pertinent equations are designed to help the reader rapidly gain a fundamental understanding and an appreciation of this technology as it is used today, as well as ongoing advances that will increase its value in the future. Numerous references are included to facilitate further study with an emphasis on areas most directly related to electromagnetics.
Author: Jianming Jin
Release Date: 2018-02-06
This book presents a comprehensive treatment of electromagnetic analysis and design of three critical devices for an MRI system - the magnet, gradient coils, and radiofrequency (RF) coils. Electromagnetic Analysis and Design in Magnetic Resonance Imaging is unique in its detailed examination of the analysis and design of the hardware for an MRI system. It takes an engineering perspective to serve the many scientists and engineers in this rapidly expanding field. Chapters present: an introduction to MRI basic concepts of electromagnetics, including Helmholtz and Maxwell coils, inductance calculation, and magnetic fields produced by special cylindrical and spherical surface currents principles for the analysis and design of gradient coils, including discrete wires and the target field method analysis of RF coils based on the equivalent lumped-circuit model as well as an analysis based on the integral equation formulation survey of special purpose RF coils analytical and numerical methods for the analysis of electromagnetic fields in biological objects With the continued, active development of MRI instrumentation, Electromagnetic Analysis and Design in Magnetic Resonance Imaging presents an excellent, logically organized text - an indispensable resource for engineers, physicists, and graduate students working in the field of MRI.
Author: Pierre-Marie Robitaille
Publisher: Springer Science & Business Media
Release Date: 2007-12-31
The foundation for understanding the function and dynamics of biological systems is not only knowledge of their structure, but the new methodologies and applications used to determine that structure. This volume in Biological Magnetic Resonance emphasizes the methods that involve Ultra High Field Magnetic Resonance Imaging. It will interest researchers working in the field of imaging.
Author: Victor D. Köchli
Release Date: 2013-03-09
Wie funktioniert eigentlich MRI? Diese Frage wird so oft gestellt, daß wir uns entschlossen haben, unser Modell von der Funktionsweise dieser faszinierenden und zukunftsweisenden Methode zusammen zufassen. Modell, notabene, denn in Tat und Wahrheit sind die physikali schen und technischen Hintergründe viel komplizierter, als wir sie hier darstellen. Aber dieses Skript richtet sich auch nicht an Physiker innen und Physiker, sondern an all diejenigen, die sich für MRI inter essieren, regelmäßig damit zu tun haben oder einfach sonst genauer wissen möchten, was hinter MRI steckt, also z. B. an Ärztinnen und Ärzte, MTRAs, Studentinnen und Studenten. Das Ziel ist deshalb nicht eine fundierte und exakte Abhandlung aller physikalischen Zusam menhänge und Formeln, sondern eine (hoffentlich) verständliche Einführung in die Prinzipien der MR-Bildgebung. Insbesondere werden (hoffentlich!) alle wichtigen Begriffe behan delt, die auch in der klinischen Anwendung von Bedeutung sind, und es wird versucht, die zugrundeliegenden physikalischen Vorgänge verständlich zu machen. Es geht also trotz allem nicht ohne ein bi߭ chen Physik! Wir danken allen, die uns bei der Verbesserung dieses Skripts mit Rat und Kritik geholfen haben. Besonderer Dank gebührt an dieser Stelle Herrn Constantin von Weymarn, der bei der Überarbeitung des Skripts geholfen und die physikalischen Grundlagen abgesichert hat. Außerdem danken wir Herrn Johannes Fröhlich von der Firma Guerbet AG für seine zahlreichen konstruktiven Anregungen. Wir sind auch in Zukunft froh um jede Kritik, die es uns ermöglicht, diese Ein führung zu verbessern, damit sie ihr Ziel erreichen kann.
Author: Stewart C. Bushong
Publisher: Elsevier Health Sciences
Release Date: 2003-01-01
Dette er en grundlæggende lærebog om konventionel MRI samt billedteknik. Den begynder med et overblik over elektricitet og magnetisme, herefter gives en dybtgående forklaring på hvordan MRI fungerer og her diskuteres de seneste metoder i radiografisk billedtagning, patientsikkerhed m.v.
ABSTRACT: The effect of electromagnetic field on cardiovascular system in the literature is defined in ambiguous way. The aim of this study was to evaluate the effect of electromagnetic field on the heart rate variability (HRV) during the examination with magnetic resonance. Forty-two patients underwent Holter ECG heart monitoring for 30 minutes twice: immediately before and after the examination with magnetic resonance imaging (MRI). HRV was analysed by assessing a few selected time and spectral parameters. Is has been shown that standard deviation of NN intervals (SDNN) and very low frequency rates increased, whereas the low frequency:high frequency parameter significantly decreased following the MRI examination. These results show that MRI may affect the HRV most likely by changing the sympathetic-parasympathetic balance.
Author: Anatoly Legtchenko
Publisher: John Wiley & Sons
Release Date: 2013-12-04
Genre: Technology & Engineering
This book presents the basics of the non-invasive geophysical method for groundwater investigation, called Magnetic Resonance Sounding (MRS) or Surface Nuclear Magnetic Resonance (SNMR), and its practical application to the problems of groundwater localization and aquifer characterization. The method is based on the nuclear magnetic resonance (NMR) phenomenon and is selectively sensitive to groundwater. The main aims of the author are to teach the reader the basic principles of the method as well as to formulate consistent approximate models, leading to reasonably simple inverse problems. Containing an extensive bibliography, numerous practical and numerical examples as well as a detailed presentation of the nuts and bolts of the method based on the long-term experience of SNMR development and practical use, this book is useful for students, scientists and professional engineers working in the field of hydrogeophysics and hydrogeology. Contents 1. SNMR Imaging for Groundwater. 2. The Basics of NMR. 3. Forward Modeling. 4. Inversion. 5. Link Between SNMR and Aquifer Parameters.
Author: Mushabbar A. Syed
Publisher: Springer Science & Business Media
Release Date: 2012-12-19
This textbook is alone in focusing on the subject of cardiac magnetic resonance (CMR) imaging in pediatric and adult patients with congenital heart disease. The topic of congenital heart disease imaging is usually relegated to a single chapter in most general CMR texts. The expanding scope of CHD warrants a text dedicated to covering CHD and CMR imaging in detail. Our proposed book aims to be a comprehensive and authoritative text on this subject. This book is be a multi-authored, illustrated text that includes supplementary access to a number of clinical videos. Authors have been selected from imaging experts in the most medically advanced areas of the world, heavily weighted by experts in the US and Europe to produce the quintessential reference in this topic.
Author: Robert Kraus Jr.
Publisher: Oxford University Press
Release Date: 2014-02-26
This book is designed to introduce the reader to the field of NMR/MRI at very low magnetic fields, from milli-Tesla to micro-Tesla, the ultra-low field (ULF) regime. The book is focused on applications to imaging the human brain, and hardware methods primarily based upon pre-polarization methods and SQUID-based detection. The goal of the text is to provide insight and tools for the reader to better understand what applications are best served by ULF NMR/MRI approaches. A discussion of the hardware challenges, such as shielding, operation of SQUID sensors in a dynamic field environment, and pulsed magnetic field generation are presented. One goal of the text is to provide the reader a framework of understanding the approaches to estimation and mitigation of low signal-to-noise and long imaging time, which are the main challenges. Special attention is paid to the combination of MEG and ULF MRI, and the benefits and challenges presented by trying to accomplish both with the same hardware. The book discusses the origin of unique relaxation contrast at ULF, and special considerations for image artifacts and how to correct them (i.e. concomitant gradients, ghost artifacts). A general discussion of MRI, with special consideration to the challenges of imaging at ULF and unique opportunities in pulse sequences, is presented. The book also presents an overview of some of the primary applications of ULF NMR/MRI being pursued.
Author: Martin C. Powell
Release Date: 2013-10-22
Magnetic Resonance Imaging in Obstetrics and Gynecology focuses on the potential of magnetic resonance imaging (MRI) as a major imaging modality in the management of malignant diseases in the pelvis. This text is organized into two parts encompassing 11 chapters that provide images obtained by MRI in obstetrics and gynecology. Part one deals with the distinctive features of the normal uterus and vagina and those with carcinoma. It also presents the images of the benign disease and carcinomous ovary. Part 2 considers images of the maternal anatomy, placenta, fetus, and the gestational trophoblastic neoplasia. This book is of great value to obstetricians, gynecologists, and MRI technicians.
Author: Jay Newman
Publisher: Springer Science & Business Media
Release Date: 2008-10-09
Each chapter has three types of learning aides for students: open-ended questions, multiple-choice questions, and quantitative problems. There is an average of about 50 per chapter. There are also a number of worked examples in the chapters, averaging over 5 per chapter, and almost 600 photos and line drawings.