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.
Wie schon die beiden vorherigen Auflagen, führt dieses Buch kurz und prägnant in die Physik und Funktionsweise der Magnetresonanztomographie ein. Insbesondere werden alle wichtigen Begriffe, die in der Klinik von Bedeutung sind und die zugrundeliegenden physikalischen Vorgänge verständlich gemacht. Entsprechend liegt der Schwerpunkt auf einem klar strukturierten Aufbau. Alle Kapitel wurden überarbeitet und auf den neuesten Stand des Wissens gebracht. Neu sind die Kapitel "Determinanten des Signal-zu-Rausch-Verhältnisses" und "Sicherheit und Risiken". Der zunehmenden Bedeutung des MRI in der nichtinvasiven Gefässdiagnostik wird mit einem speziellen Kapitel Rechnung getragen. Die Kapitel über MR-Sequenzen wurden neu gegliedert, um der Entwicklung zu immer schnelleren Sequenzen gerecht zu werden. Das Buch richtet sich in erster Linie an Ärzte, MTRAs und Studenten, die sich mit den Grundlagen der MR-Bildgebung vertraut machen wollen.
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: 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: Stewart C Bushong
Publisher: Elsevier Health Sciences
Release Date: 2014-07-28
Magnetic Resonance Imaging: Physical and Biological Principles, 4th Edition offers comprehensive, well-illustrated coverage on this specialized subject at a level that does not require an extensive background in math and physics. It covers the fundamentals and principles of conventional MRI along with the latest fast imaging techniques and their applications. Beginning with an overview of the fundamentals of electricity and magnetism (Part 1), Parts 2 and 3 present an in-depth explanation of how MRI works. The latest imaging methods are presented in Parts 4 and 5, and the final section (Part 6) covers personnel and patient safety and administration issues. This book is perfect for student radiographers and practicing technologists preparing to take the MRI advanced certification exam offered by the American Registry of Radiologic Technologists (ARRT). ""I would recommend it to anyone starting their MRI training and anyone trying to teach MRI to others."" Reviewed by RAD Magazine, June 2015Challenge questions at the end of each chapter help you assess your comprehension.Chapter outlines and objectives assist you in following the hierarchy of material in the text."Penguin" boxes highlight key points in the book to help you retain the most important information and concepts in the text.NEW! Two MRI practice exams that mirror the test items in each ARRT category have been added to the end of the text to help you replicate the ARRT exam experience.NEW! Chapter on Partially Parallel Magnetic Resonance Imaging increases the comprehensiveness of the text.NEW! Updated key terms have been added to each chapter with an updated glossary defining each term.
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: Frank G. Shellock
Publisher: Lippincott Williams & Wilkins
Release Date: 1996
University of Southern California, Los Angeles. Handbook on the bioeffects of MR and its safety issues, for radiologists. Discusses potential risks to patients and professionals. Offers guidelines for daily practice. Softcover. DNLM: Magnetic Resonance Imaging - adverse effects.
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.