Concomitant Gradients in Low-field NMR Studies of Restricted Diffusion

Concomitant Gradients in Low-field NMR Studies of Restricted Diffusion PDF Author: Jason Louis Hobson
Publisher:
ISBN:
Category : Nuclear magnetic resonance
Languages : en
Pages : 0

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Book Description
Linear magnetic field gradients are used in conventional magnetic resonance (MR) imaging in order to spatially encode and/or resolve nuclear spin distributions. These gradients are normally thought of as being unidirectional, but are always accompanied by orthogonal field components and gradients. These concomitant gradients can largely be ignored as long as the curvature they induce in magnetic field lines is small compared to inverse dimensions of the field of view. Recent attempts to acquire MR images in milliTesla magnetic fields have sparked interest in trying to understand the potential influence of concomitant field gradients. In this thesis a series of NMR experiments intended to probe diffusion of 3He gas within a restricted geometry and in very-low magnetic fields are described. Data from these experiments show clear evidence for the perturbing influence of concomitant gradients, and can be qualitatively understood in terms of a simple model that ignores diffusion.

Concomitant Gradients in Low-field NMR Studies of Restricted Diffusion

Concomitant Gradients in Low-field NMR Studies of Restricted Diffusion PDF Author: Jason Louis Hobson
Publisher:
ISBN:
Category : Nuclear magnetic resonance
Languages : en
Pages : 0

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Book Description
Linear magnetic field gradients are used in conventional magnetic resonance (MR) imaging in order to spatially encode and/or resolve nuclear spin distributions. These gradients are normally thought of as being unidirectional, but are always accompanied by orthogonal field components and gradients. These concomitant gradients can largely be ignored as long as the curvature they induce in magnetic field lines is small compared to inverse dimensions of the field of view. Recent attempts to acquire MR images in milliTesla magnetic fields have sparked interest in trying to understand the potential influence of concomitant field gradients. In this thesis a series of NMR experiments intended to probe diffusion of 3He gas within a restricted geometry and in very-low magnetic fields are described. Data from these experiments show clear evidence for the perturbing influence of concomitant gradients, and can be qualitatively understood in terms of a simple model that ignores diffusion.

Ultra-Low Field Nuclear Magnetic Resonance

Ultra-Low Field Nuclear Magnetic Resonance PDF Author: Robert Kraus Jr.
Publisher: Oxford University Press
ISBN: 0199796513
Category : Medical
Languages : en
Pages : 266

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Book Description
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.

Diffusion MRI

Diffusion MRI PDF Author: Derek K Jones
Publisher: Oxford University Press
ISBN: 0199708703
Category : Science
Languages : en
Pages : 784

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Book Description
Professor Derek Jones, a world authority on diffusion MRI, has assembled most of the world's leading scientists and clinicians developing and applying diffusion MRI to produce an authorship list that reads like a "Who's Who" of the field and an essential resource for those working with diffusion MRI. Destined to be a modern classic, this definitive and richly illustrated work covers all aspects of diffusion MRI from basic theory to clinical application. Oxford Clinical Neuroscience is a comprehensive, cross-searchable collection of resources offering quick and easy access to eleven of Oxford University Press's prestigious neuroscience texts. Joining Oxford Medicine Online these resources offer students, specialists and clinical researchers the best quality content in an easy-to-access format.

Translational Dynamics and Magnetic Resonance

Translational Dynamics and Magnetic Resonance PDF Author: Paul T. Callaghan
Publisher: OUP Oxford
ISBN: 0191621048
Category : Science
Languages : en
Pages : 568

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Book Description
Taking the reader through the underlying principles of molecular translational dynamics, this book outlines the ways in which magnetic resonance, through the use of magnetic field gradients, can reveal those dynamics. The measurement of diffusion and flow, over different length and time scales, provides unique insight regarding fluid interactions with porous materials, as well as molecular organisation in soft matter and complex fluids. The book covers both time and frequency domain methodologies, as well as advances in scattering and diffraction methods, multidimensional exchange and correlation experiments and orientational correlation methods ideal for studying anisotropic environments. At the heart of these new methods resides the ubiquitous spin echo, a phenomenon whose discovery underpins nearly every major development in magnetic resonance methodology. Measuring molecular translational motion does not require high spectral resolution and so finds application in new NMR technologies concerned with 'outside the laboratory' applications, in geophysics and petroleum physics, in horticulture, in food technology, in security screening, and in environmental monitoring.

Quantum Fluids and Solids

Quantum Fluids and Solids PDF Author: S. Trickey
Publisher: Springer Science & Business Media
ISBN: 1468424181
Category : Science
Languages : en
Pages : 458

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Book Description
The second International Symposium on Quantum Fluids and Solids came to pass during 23-27 Jan. 1977 as the fourth and con cluding part of the seventeenth consecutive running of the Sanibel Symposium Series. With approximately 120 participants from eleven countries (including, for the first time, the USSR), we found it easy to obtain a selection of papers which was fairly comprehen sive. Indeed, our problem was an embarrassment of riches; in spite of our solemn vows not to crowd the schedule, we ended up with an intense program! By far, the majority of the papers pre sented are represented in this volume. We are indebted to many persons and organizations for their contributions to the Symposia. First, we thank Prof. Per-Olov Lowdin, Director of the Quantum Theory Project and originator of the Sanibel Symposia. Without his patient, indulgent cooperation our task would have been vastly more difficult. We are grateful to Prof. F. Eugene Dunnam, Chairman of the Dept. of Physics and Astronomy, for providing Departmental support of our initial or ganlzlng expenses. Approximately one-half of the total cost of the Symposium was borne by a joint grant from the National Science Foundation and the U. S. Air Force Office of Scientific Research. We thank the program officers, Dr. C. Satterthwaite and Dr. D.

Magnetoencephalography

Magnetoencephalography PDF Author: Selma Supek
Publisher: Springer
ISBN: 3642330452
Category : Technology & Engineering
Languages : en
Pages : 999

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Book Description
Magnetoencephalography (MEG) is an invaluable functional brain imaging technique that provides direct, real-time monitoring of neuronal activity necessary for gaining insight into dynamic cortical networks. Our intentions with this book are to cover the richness and transdisciplinary nature of the MEG field, make it more accessible to newcomers and experienced researchers and to stimulate growth in the MEG area. The book presents a comprehensive overview of MEG basics and the latest developments in methodological, empirical and clinical research, directed toward master and doctoral students, as well as researchers. There are three levels of contributions: 1) tutorials on instrumentation, measurements, modeling, and experimental design; 2) topical reviews providing extensive coverage of relevant research topics; and 3) short contributions on open, challenging issues, future developments and novel applications. The topics range from neuromagnetic measurements, signal processing and source localization techniques to dynamic functional networks underlying perception and cognition in both health and disease. Topical reviews cover, among others: development on SQUID-based and novel sensors, multi-modal integration (low field MRI and MEG; EEG and fMRI), Bayesian approaches to multi-modal integration, direct neuronal imaging, novel noise reduction methods, source-space functional analysis, decoding of brain states, dynamic brain connectivity, sensory-motor integration, MEG studies on perception and cognition, thalamocortical oscillations, fetal and neonatal MEG, pediatric MEG studies, cognitive development, clinical applications of MEG in epilepsy, pre-surgical mapping, stroke, schizophrenia, stuttering, traumatic brain injury, post-traumatic stress disorder, depression, autism, aging and neurodegeneration, MEG applications in cognitive neuropharmacology and an overview of the major open-source analysis tools.

Magnetic Resonance Imaging

Magnetic Resonance Imaging PDF Author: Robert W. Brown
Publisher: John Wiley & Sons
ISBN: 0471720852
Category : Medical
Languages : en
Pages : 976

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Book Description
New edition explores contemporary MRI principles and practices Thoroughly revised, updated and expanded, the second edition of Magnetic Resonance Imaging: Physical Principles and Sequence Design remains the preeminent text in its field. Using consistent nomenclature and mathematical notations throughout all the chapters, this new edition carefully explains the physical principles of magnetic resonance imaging design and implementation. In addition, detailed figures and MR images enable readers to better grasp core concepts, methods, and applications. Magnetic Resonance Imaging, Second Edition begins with an introduction to fundamental principles, with coverage of magnetization, relaxation, quantum mechanics, signal detection and acquisition, Fourier imaging, image reconstruction, contrast, signal, and noise. The second part of the text explores MRI methods and applications, including fast imaging, water-fat separation, steady state gradient echo imaging, echo planar imaging, diffusion-weighted imaging, and induced magnetism. Lastly, the text discusses important hardware issues and parallel imaging. Readers familiar with the first edition will find much new material, including: New chapter dedicated to parallel imaging New sections examining off-resonance excitation principles, contrast optimization in fast steady-state incoherent imaging, and efficient lower-dimension analogues for discrete Fourier transforms in echo planar imaging applications Enhanced sections pertaining to Fourier transforms, filter effects on image resolution, and Bloch equation solutions when both rf pulse and slice select gradient fields are present Valuable improvements throughout with respect to equations, formulas, and text New and updated problems to test further the readers' grasp of core concepts Three appendices at the end of the text offer review material for basic electromagnetism and statistics as well as a list of acquisition parameters for the images in the book. Acclaimed by both students and instructors, the second edition of Magnetic Resonance Imaging offers the most comprehensive and approachable introduction to the physics and the applications of magnetic resonance imaging.

Principles of Nuclear Magnetic Resonance Microscopy

Principles of Nuclear Magnetic Resonance Microscopy PDF Author: Paul T. Callaghan
Publisher:
ISBN: 9780198539971
Category : Science
Languages : en
Pages : 520

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Book Description
Although nuclear magnetic resonance is perhaps best known for its spectacular utility in medical tomography, its potential applicability to fields such as biology, materials science, and chemical physics is being increasingly recognized as laboratory NMR spectrometers are adapted to enable small scale imaging. This excellent introduction to the subject explores principles and common themes underlying two key variants of NMR microscopy, and provides many examples of their use. Methods discussed are not only important to fundamental biological and physical research, but have applications to a wide variety of industries, including those concerned with petrochemicals, polymers, biotechnology, food processing, and natural product processing. The wide range of scientists interested in NMR microscopy will want to own a copy of this book.

Diffusion NMR of Confined Systems

Diffusion NMR of Confined Systems PDF Author: Rustem Valiullin
Publisher: Royal Society of Chemistry
ISBN: 1782621903
Category : Science
Languages : en
Pages : 594

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Book Description
With the increasing role of porous solids in conventional and newly emerging technologies, there is an urgent need for a deeper understanding of fluid behaviour confined to pore spaces of these materials especially with regard to their transport properties. From its early years, NMR has been recognized as a powerful experimental technique enabling direct access to this information. In the last two decades, the methodological development of different NMR techniques to assess dynamic properties of adsorbed ensembles has been progressed. This book will report on these recent advances and look at new broader applications in engineering and medicine. Having both academic and industrial relevance, this unique reference will be for specialists working in the research areas and for advanced graduate and postgraduate studies who want information on the versatility of diffusion NMR.

NMR Studies of Translational Motion

NMR Studies of Translational Motion PDF Author: William S. Price
Publisher: Cambridge University Press
ISBN: 0521806968
Category : Medical
Languages : en
Pages : 417

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Book Description
Overview of NMR theory and applications in fluid systems, fully referenced for research use.