This book presents the first in-depth introduction to parallel imaging techniques and, in particular, to the application of parallel imaging in clinical MRI. It will provide readers with a broader understanding of the fundamental principles of parallel imaging and of the advantages and disadvantages of specific MR protocols in clinical applications in all parts of the body at 1.5 and 3 Tesla.
MRI is a continually evolving and expanding subject making an ever-increasing impact on medical practice. There are many comprehensive large MRI textbooks on the market but there is a distinct lack of short pocket-sized reference books to suit the growing number of people from various disciplines working in the medical imaging field today. This book provides an easily accessible source of reference material to supplement existing large texts.
The objective of this 5th edition of the book, as with the prior editions, is to teach through images a practical approach to magnetic resonance (MR) physics and image quality. Unlike other texts covering this topic, the focus is on clinical images rather than equations. A practical approach to MR physics is developed through images, emphasizing knowledge of fundamentals important to achieve high image quality. Pulse diagrams are also included, which many at first find difficult to understand. Readers are encouraged to glance at these as they go through the text. With time and repetition, as a reader progresses through the book, the value of these and the knowledge thus available will become evident (and the diagrams themselves easier to understand). The text is organized into concise chapters, each discussing an important point relevant to clinical MR and illustrated largely with images from routine patient exams. The topics covered encompass the breadth of the field, from imaging basics and pulse sequences to advanced topics including contrast-enhanced MR angiography, spectroscopy, perfusion and advanced parallel imaging/data sparsity techniques. Discussion of the latest hardware and software innovations, for example next generation low field MR, deep learning, MR-PET, 7 T, interventional MR, 4D flow, CAIPIRINHA, spiral techniques, radial acquisition, simultaneous multislice, compressed sensing and MR fingerprinting, is included because these topics are critical to current clinical practice as well as to future advances. Included in the fifth edition are a large number of new topics, keeping the text up to date in this increasingly complex field. The text has also been thoroughly revised to include additional relevant clinical images, to improve the clarity of descriptions, and to increase the depth of content. The book is highly recommended for radiologists, physicists, and technologists interested in the background of image acquisition used in standard as well as specialized clinical settings.
This book offers practical guidelines for performing efficient and cost-effective MRI examinations. By adopting a practical protocol-based approach the work-flow in a MRI unit can be streamlined and optimized. All chapters have been thoroughly reviewed, and new techniques and figures are included. There is a new chapter on MRI of the chest. This book will help beginners to implement the protocols and will update the knowledge of more experienced users.
Magnetic resonance imaging (MRI) has become the leading cross-sectional imaging method in clinical practice. Continuous technical improvements have significantly broadened the scope of applications. At present, MR imaging is not only the most important diagnostic technique in neuroradiology and musculoskeletal radiology, but has also become an invaluable diagnostic tool for abdominal, pelvic, cardiac, breast and vascular imaging. This book offers practical guidelines for performing efficient and cost-effective MRI examinations in daily practice. The underlying idea is that, by adopting a practical protocol-based approach, the work-flow in a MRI unit can be streamlined and optimized.
The fourth edition of The Physics of Clinical MR Taught Through Images The Physics of Clinical MR Taught Through Images Fourth Edition by Val Runge, Wolfgang Nitz, and Johannes Heverhagen presents a unique and highly practical approach to understanding the physics of magnetic resonance imaging. Each physics topic is described in user-friendly language and accompanied by high-quality graphics and/or images. The visually rich format provides a readily accessible tool for learning, leveraging, and mastering the powerful diagnostic capabilities of MRI. Key Features More than 700 images, anatomical drawings, clinical tables, charts, and diagrams, including magnetization curves and pulse sequencing, facilitate acquisition of highly technical content. Eight systematically organized sections cover core topics: hardware and radiologic safety; basic image physics; basic and advanced image acquisition; flow effects; techniques specific to the brain, heart, liver, breast, and cartilage; management and reduction of artifacts; and improvements in MRI diagnostics and technologies. Cutting-edge topics including contrast-enhanced MR angiography, spectroscopy, perfusion, and advanced parallel imaging/data sparsity techniques. Discussion of groundbreaking hardware and software innovations, such as MR-PET, 7 T, interventional MR, 4D flow, CAIPIRINHA, radial acquisition, simultaneous multislice, and compressed sensing. A handy appendix provides a quick reference of acronyms, which often differ from company to company. The breadth of coverage, rich visuals, and succinct text make this manual the perfect reference for radiology residents, practicing radiologists, researchers in MR, and technologists.
MR is a powerful modality. At its most advanced, it can be used not just to image anatomy and pathology, but to investigate organ function, to probe in vivo chemistry, and even to visualise the brain thinking. However, clinicians, technologists and scientists struggle with the study of the subject. The result is sometimes an obscurity of understanding, or a dilution of scientific truth, resulting in misconceptions. This is why MRI from Picture to Proton has achieved its reputation for practical clarity. MR is introduced as a tool, with coverage starting from the images, equipment and scanning protocols and traced back towards the underlying physics theory. With new content on quantitative MRI, MR safety, multi-band excitation, Dixon imaging, MR elastography and advanced pulse sequences, and with additional supportive materials available on the book's website, this new edition is completely revised and updated to reflect the best use of modern MR technology.
Magnetic Resonance Imaging (MRI) is a non-invasive and highly flexible medical imaging modality that does not expose patients ionizing radiation. MR Image acquisitions can be designed by varying a large number of contrast-generation parameters, and many clinical diagnostic applications exist. However, imaging speed is a fundamental limitation to many potential applications. Traditionally, MRI data have been collected at Nyquist sampling rates to produce alias-free images. However, many recent scan acceleration techniques produce sub-Nyquist samplings. For example, Parallel Imaging is a well-established acceleration technique that receives the MR signal simultaneously from multiple receive channels. Compressed sensing leverages randomized undersampling and the compressibility (e.g. via Wavelet transforms or Total-Variation) of medical images to allow more aggressive undersampling. Reconstruction of clinically viable images from these highly accelerated acquisitions requires powerful, usually iterative algorithms. Non-Cartesian pulse sequences that perform non-equispaced sampling of k-space further increase computational intensity of reconstruction, as they preclude direct use of the Fast Fourier Transform (FFT). Most iterative algorithms can be understood by considering the MRI reconstruction as an inverse problem, where measurements of un-observable parameters are made via an observation function that models the acquisition process. Traditional direct reconstruction methods attempt to invert this observation function, whereas iterative methods require its repeated computation and computation of its adjoint. As a result, na\"ive sequential implementations of iterative reconstructions produce unfeasibly long runtimes. Their computational intensity is a substantial barrier to their adoption in clinical MRI practice. A powerful new family of massively parallel microprocessor architectures has emerged simultaneously with the development of these new reconstruction techniques. Due to fundamental limitations in silicon fabrication technology, sequential microprocessors reached the power-dissipation limits of commodity cooling systems in the early 2000's. The techniques used by processor architects to extract instruction-level parallelism from sequential programs face ever-diminishing returns, and further performance improvement of sequential processors via increasing clock-frequency has become impractical. However, circuit density and process feature sizes still improve at Moore's Law rates. With every generation of silicon fabrication technology, a larger number of transistors are available to system architects. Consequently, all microprocessor vendors now exclusively produce multi-core parallel processors. Additionally, the move towards on-chip parallelism has allowed processor architects a larger degree of freedom in the design of multi-threaded pipelines and memory hierarchies. Many of the inefficiencies inherent in superscalar out-of-order design are being replaced by the high efficiency afforded by throughput-oriented designs. The move towards on-chip parallelism has resulted in a vast increase in the amount of computational power available in commodity systems. However, this move has also shifted the burden of computational performance towards software developers. In particular, the highly efficient implementation of MRI reconstructions on these systems requires manual parallelization and optimization. Thus, while ubiquitous parallelism provides a solution to the computational intensity of iterative MRI reconstructions, it also poses a substantial software productivity challenge. In this thesis, we propose that a principled approach to the design and implementation of reconstruction algorithms can ameliorate this software productivity issue. We draw much inspiration from developments in the field of computational science, which has faced similar parallelization and software development challenges for several decades. We propose a Software Architecture for the implementation of reconstruction algorithms, which composes two Design Patterns that originated in the domain of massively parallel scientific computing. This architecture allows for the most computationally intense operations performed by MRI reconstructions to be implemented as re-usable libraries. Thus the software development effort required to produce highly efficient and heavily optimized implementations of these operations can be amortized over many different reconstruction systems. Additionally, the architecture prescribes several different strategies for mapping reconstruction algorithms onto parallel processors, easing the burden of parallelization. We describe the implementation of a complete reconstruction, $\ell_1$-SPIRiT, according to these strategies. $\ell_1$-SPIRiT is a general reconstruction framework that seamlessly integrates all three of the scan acceleration techniques mentioned above. Our implementation achieves substantial performance improvement over baseline, and has enabled substantial clinical evaluation of its approach to combining Parallel Imaging and Compressive Sensing. Additionally, we include an in-depth description of the performance optimization of the non-uniform Fast Fourier Transform (nuFFT), an operation used in all non-Cartesian reconstructions. This discussion complements well our description of $\ell_1$-SPIRiT, which we have only implemented for Cartesian samplings.
Magnetic Resonance Angiography: Principles and Applications is a comprehensive text covering magnetic resonance angiography (MRA) in current clinical use. The first part of the book focuses on techniques, with chapters on contrast-enhanced MRA, time of flight, phase contrast, time-resolved angiography, and coronary MRA, as well as several chapters devoted to new non-contrast MRA techniques. Additionally, chapters describe in detail specific topics such as high-field MRA, susceptibility-weighted imaging, acceleration strategies such as parallel imaging, vessel wall imaging, targeted contrast agents, and low dose contrast-enhanced MRA. The second part of the book covers clinical applications of MRA, with each chapter describing the MRA techniques and protocols for a particular disease and vascular territory, as well as the pathology and imaging findings relevant to the disease state being discussed. Magnetic Resonance Angiography: Principles and Applications is designed to bring together into a single textbook all of the MRA techniques in clinical practice today and will be a valuable resource for practicing radiologists and other physicians involved in the diagnosis and treatment of vascular diseases, as well as biomedical physicists, MRI technologists, residents, and fellows. Editors James C. Carr, MD, is the Director of Cardiovascular Imaging and Associate Professor of Radiology and Medicine at Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA. Timothy J. Carroll, PhD, is the Director of MRI Research and Associate Professor in the Departments of Biomedical Engineering and Radiology at Northwestern University, Evanston, Illinois, USA. Magnetic Resonance Angiography: Principles and Applications is designed to bring together into a single textbook all of the MRA techniques in clinical practice today and will be a valuable resource for practicing radiologists and other physicians involved in the diagnosis and treatment of vascular diseases, as well as biomedical physicists, MRI technologists, residents, and fellows. Editors James C. Carr, MD, is Director of Cardiovascular Imaging and Associate Professor of Radiology and Medicine at Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA. Timothy J. Carroll, PhD, is Assistant Professor in the Department of Radiology at Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA. Editors James C. Carr, MD, is Director of Cardiovascular Imaging and Associate Professor of Radiology and Medicine at Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA. Timothy J. Carroll, PhD, is the Director of MRI Research and Associate Professor in the Departments of Biomedical Engineering and Radiology at Northwestern University, Evanston, Illinois, USA.
