[PDF] Diffusional Effects In Magnetic Resonance Microscopy eBook

Author : Daniel Barsky
Publisher :
Page : 366 pages
File Size : 35,2 MB
Release : 1994
Category :
ISBN :

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Improvements in the information content of nuclear magnetic resonance (NMR) images have recently been sought through the development of new contrast mechanisms for magnetic resonance imaging (MRI) and NMR microscopy. This thesis addresses the role of molecular diffusion in NMR and develops new methods to obtain image contrast and to infer diffusional action. NMR microscopy of liquid samples provides a means of imaging the spatial distribution of the magnetization arising from nuclei in the liquid, at a resolution of several microns. Usually, the effect of molecular diffusion in NMR microscopy is to degrade resolution and sensitivity due to destructive interference of signals from the moving spins. In this thesis it is demonstrated, both theoretically and experimentally, that diffusional barriers, such as exist in biological tissues, can be made to appear extraordinarily bright in NMR micrographs. These effects are described by the line shape function of the magnetization signal, and by numerical evaluation of the diffusive phase dispersion of the signal. This "edge enhancement" provides a means of visualizing structures as thin and permeable as cell membranes which would otherwise be invisible in NMR microscopy. In the realm of clinical MRI, a description of nuclear spin relaxation mediated by MRI contrast agents and transport processes in compartmentalized systems is given. The relaxation-enhancing action of contrast agents can be most generally explained by exchange and diffusional dephasing, and simple analytic expressions are derived for typical situations. More complex solutions are obtained by efficient numerical methods, including the so-called generalized moment expansion. For appropriate models, it is demonstrated that while the extended influence of contrast agents through diffusion of water can contribute to blurring, such a loss of contrast may be avoided if the multiexponential character of the signal decay is exploited.

Author : Richard B. Buxton
Publisher : Cambridge University Press
Page : 479 pages
File Size : 50,95 MB
Release : 2009-08-27
Category : Medical
ISBN : 1139481304

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Functional Magnetic Resonance Imaging (fMRI) has become a standard tool for mapping the working brain's activation patterns, both in health and in disease. It is an interdisciplinary field and crosses the borders of neuroscience, psychology, psychiatry, radiology, mathematics, physics and engineering. Developments in techniques, procedures and our understanding of this field are expanding rapidly. In this second edition of Introduction to Functional Magnetic Resonance Imaging, Richard Buxton – a leading authority on fMRI – provides an invaluable guide to how fMRI works, from introducing the basic ideas and principles to the underlying physics and physiology. He covers the relationship between fMRI and other imaging techniques and includes a guide to the statistical analysis of fMRI data. This book will be useful both to the experienced radiographer, and the clinician or researcher with no previous knowledge of the technology.

Author : Committee on the Mathematics and Physics of Emerging Dynamic Biomedical Imaging
Publisher : National Academies Press
Page : 261 pages
File Size : 47,10 MB
Release : 1996-03-13
Category : Science
ISBN : 0309552923

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This cross-disciplinary book documents the key research challenges in the mathematical sciences and physics that could enable the economical development of novel biomedical imaging devices. It is hoped that the infusion of new insights from mathematical scientists and physicists will accelerate progress in imaging. Incorporating input from dozens of biomedical researchers who described what they perceived as key open problems of imaging that are amenable to attack by mathematical scientists and physicists, this book introduces the frontiers of biomedical imaging, especially the imaging of dynamic physiological functions, to the educated nonspecialist. Ten imaging modalities are covered, from the well-established (e.g., CAT scanning, MRI) to the more speculative (e.g., electrical and magnetic source imaging). For each modality, mathematics and physics research challenges are identified and a short list of suggested reading offered. Two additional chapters offer visions of the next generation of surgical and interventional techniques and of image processing. A final chapter provides an overview of mathematical issues that cut across the various modalities.

Author : Zhi-Pei Liang
Publisher : Wiley-IEEE Press
Page : 442 pages
File Size : 25,72 MB
Release : 2000
Category : Medical
ISBN :

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In 1971 Dr. Paul C. Lauterbur pioneered spatial information encoding principles that made image formation possible by using magnetic resonance signals. Now Lauterbur, "father of the MRI", and Dr. Zhi-Pei Liang have co-authored the first engineering textbook on magnetic resonance imaging. This long-awaited, definitive text will help undergraduate and graduate students of biomedical engineering, biomedical imaging scientists, radiologists, and electrical engineers gain an in-depth understanding of MRI principles. The authors use a signal processing approach to describe the fundamentals of magnetic resonance imaging. You will find a clear and rigorous discussion of these carefully selected essential topics: Mathematical fundamentals Signal generation and detection principles Signal characteristics Signal localization principles Image reconstruction techniques Image contrast mechanisms Image resolution, noise, and artifacts Fast-scan imaging Constrained reconstruction Complete with a comprehensive set of examples and homework problems, Principles of Magnetic Resonance Imaging is the must-read book to improve your knowledge of this revolutionary technique.

Author : Luisa Ciobanu
Publisher : CRC Press
Page : 139 pages
File Size : 36,21 MB
Release : 2017-09-08
Category : Medical
ISBN : 1351606727

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In the past two decades, significant advances in magnetic resonance microscopy (MRM) have been made possible by a combination of higher magnetic fields and more robust data acquisition technologies. This technical progress has enabled a shift in MRM applications from basic anatomical investigations to dynamic and functional studies, boosting the use of MRM in biological and life sciences. This book provides a simple introduction to MRM emphasizing practical aspects relevant to high magnetic fields. It focuses on biological applications and presents a number of selected examples of neuroscience applications. The text is mainly intended for those who are beginning research in the field of MRM or are planning to incorporate high-resolution MRI in their neuroscience studies.