MRI and NMR Spectroscopy in the Earth's Field


Book Description

This book details constructional information for a Nuclear Magnetic Resonance (NMR) spectrometer using the natural magnetic field of the Earth as B0, and presents experiments exploring the impressive range of concepts and techniques which can be demonstrated with such a machine. These include the Free Induction Decay, T1 and T2 time constants, spin echoes with 90 degree and 180 degree B1 pulses, and the effects of B0 field inhomogeneity and shimming. Although chemical shifts of parts per million in spectral line frequency cannot be resolved, the splitting of lines by heteronuclear J-coupling is clearly displayed. The machine can make geomagnetic measurements accurate to 5 significant figures. And it can demonstrate the core principle of Magnetic Resonance Imaging: the encoding of spatial information in the phase and frequency domains using the Pulsed Gradient Spin Echo sequence.




Ultra-Low Field Nuclear Magnetic Resonance


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.




Introduction to Functional Magnetic Resonance Imaging


Book Description

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.




Principles of Nuclear Magnetic Resonance Microscopy


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.




Understanding NMR Spectroscopy


Book Description

This text is aimed at people who have some familiarity with high-resolution NMR and who wish to deepen their understanding of how NMR experiments actually ‘work’. This revised and updated edition takes the same approach as the highly-acclaimed first edition. The text concentrates on the description of commonly-used experiments and explains in detail the theory behind how such experiments work. The quantum mechanical tools needed to analyse pulse sequences are introduced set by step, but the approach is relatively informal with the emphasis on obtaining a good understanding of how the experiments actually work. The use of two-colour printing and a new larger format improves the readability of the text. In addition, a number of new topics have been introduced: How product operators can be extended to describe experiments in AX2 and AX3 spin systems, thus making it possible to discuss the important APT, INEPT and DEPT experiments often used in carbon-13 NMR. Spin system analysis i.e. how shifts and couplings can be extracted from strongly-coupled (second-order) spectra. How the presence of chemically equivalent spins leads to spectral features which are somewhat unusual and possibly misleading, even at high magnetic fields. A discussion of chemical exchange effects has been introduced in order to help with the explanation of transverse relaxation. The double-quantum spectroscopy of a three-spin system is now considered in more detail. Reviews of the First Edition “For anyone wishing to know what really goes on in their NMR experiments, I would highly recommend this book” – Chemistry World “...I warmly recommend for budding NMR spectroscopists, or others who wish to deepen their understanding of elementary NMR theory or theoretical tools” – Magnetic Resonance in Chemistry




Compact NMR


Book Description

The goal of this book is to provide an introduction to the practical use of mobile NMR at a level as basic as the operation of a smart phone. Each description follows the same didactic pattern: introduction, basic theory, pulse sequences and parameters, beginners-level measurements, advanced-level measurements, and data processing. Nuclear Magnetic Resonance (NMR) spectroscopy is the most popular method for chemists to analyze molecular structures while Magnetic Resonance Imaging (MRI) is a non-invasive diagnostic tool for medical doctors that provides high-contrast images of biological tissue depicting the brain function and the beating heart. In both applications large super-conducting magnets are employed which magnetize atomic nuclei of an object positioned inside the magnet. Their circulating motion is interrogated by radio-frequency waves. Depending on the operating mode, the frequency spectrum provides the chemist with molecular information, the medical doctor with anatomic images, while the materials scientist is interested in NMR relaxation parameters, which scale with material properties and determine the contrast in magnetic resonance images. Recent advances in magnet technology led to a variety of small permanent magnets, by which NMR spectra, images, and relaxation parameters can be measured with mobile and low-cost instruments.




Electromagnetics in Magnetic Resonance Imaging


Book Description

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.




High Magnetic Field Science and Its Application in the United States


Book Description

The Committee to Assess the Current Status and Future Direction of High Magnetic Field Science in the United States was convened by the National Research Council in response to a request by the National Science Foundation. This report answers three questions: (1) What is the current state of high-field magnet science, engineering, and technology in the United States, and are there any conspicuous needs to be addressed? (2) What are the current science drivers and which scientific opportunities and challenges can be anticipated over the next ten years? (3) What are the principal existing and planned high magnetic field facilities outside of the United States, what roles have U.S. high field magnet development efforts played in developing those facilities, and what potentials exist for further international collaboration in this area? A magnetic field is produced by an electrical current in a metal coil. This current exerts an expansive force on the coil, and a magnetic field is "high" if it challenges the strength and current-carrying capacity of the materials that create the field. Although lower magnetic fields can be achieved using commercially available magnets, research in the highest achievable fields has been, and will continue to be, most often performed in large research centers that possess the materials and systems know-how for forefront research. Only a few high field centers exist around the world; in the United States, the principal center is the National High Magnetic Field Laboratory (NHMFL). High Magnetic Field Science and Its Application in the United States considers continued support for a centralized high-field facility such as NHFML to be the highest priority. This report contains a recommendation for the funding and siting of several new high field nuclear magnetic resonance magnets at user facilities in different regions of the United States. Continued advancement in high-magnetic field science requires substantial investments in magnets with enhanced capabilities. High Magnetic Field Science and Its Application in the United States contains recommendations for the further development of all-superconducting, hybrid, and higher field pulsed magnets that meet ambitious but achievable goals.




The Magnetic Field of the Earth


Book Description

Topics involved in studies of the Earth's magnetic field and its secular variation range from the intricate observations of geomagnetism, to worldwide studies of archeomagnetism and paleomagnetism, through to the complex mathematics of dynamo theory. Traditionally these different aspects of geomagnetism have in the main been studied and presented in isolation from each other. This text draws together these lines of inquiry into an integrated framework to highlight the interrelationships and thus to provide a more comprehensive understanding of the geomagnetic field.




New Applications of Electron Spin Resonance


Book Description

This is the first book covering an interdisciplinary field between microwave spectroscopy of electron paramagnetic resonance (EPR) or electron spin resonance (ESR) and chronology science, radiation dosimetry and ESR (EPR) imaging in material sciences. The main object is to determine the elapsed time with ESR from forensic medicine to the age and radiation dose in earth and space science. This book is written primarily for earth scientists as well as for archaeologists and for physicists and chemists interested in new applications of the method. This book can serve as an undergraduate and graduate school textbook on applications of ESR to geological and archaeological dating, radiation dosimetry and microscopic magnetic resonance imaging (MRI). Introduction to ESR and chronology science and principle of ESR dating and dosimetry are described with applications to actual problems according to materials.