Download or read book Acquisition and Processing Techniques for Rapid Robust and Patient specific Measurement of Cerebral Diffusion and Perfusion Using Magnetic Resonance Imaging written by Nora-Josefin Breutigam and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Magnetic resonance imaging (MRI) is a powerful technique that enables accurate medical diagnoses. Not only does it allow the visualization of static tissue contrasts, but it also provides the ability to measure the function and physiology behind important life processes. This dissertation presents two methods for imaging physiological effects, namely diffusion and perfusion. For diffusion-weighted imaging, but not limited to this application, a technique called simultaneous multi-contrast (SMC) imaging is introduced to acquire multiple image contrasts from different scan types within a single measurement. This technique offers new opportunities in clinical protocols where examination time is a critical factor and multiple image contrasts need to be acquired. The method was tested in a phantom and healthy subjects. The results showed that simultaneous acquisition of two contrasts (here diffusion-weighted imaging and T2*-weighting) with SMC imaging is possible with robust contrast separation and minimal impact on image quality. Thereby, the simultaneous acquisition of multiple contrasts reduces the overall examination time and there is inherent registration between contrasts. For cerebral perfusion-weighted imaging, the goal of this work was to increase the robustness of time-encoded arterial spin labeling (ASL) to image artifacts by adjusting the timing of imaging during active scanning individually for each subject. One of the major challenges in ASL imaging is the high variability of arterial transit times (ATT), which leads to arterial transit delay (ATD) artifacts. In particular, in patients with pathologic changes, these artifacts occur when post-labeling delay (PLD) and bolus duration are not optimally matched to the individual, resulting in difficult quantification of cerebral blood flow (CBF) and ATT. This is also true for the free-lunch (FL) approach in Hadamard-encoded pseudocontinuous ASL (H-pCASL). The method was tested in healthy subjects, with FL-bolus timing individualized by the developed and implemented adaptive H-pCASL sequence in combination with an automatic feedback algorithm. Automatic subject-specific adjustment of the FL-bolus PLD during an ongoing measurement may reduce uncertainties in perfusion quantification and reduce the number of cases in which measurements have to be repeated because the recommended timing does not fit the patient.
Download or read book Measuring Resting Cerebral Perfusion using Magnetic Resonance Imaging MRI written by James Duffin and published by Frontiers Media SA. This book was released on 2024-07-12 with total page 170 pages. Available in PDF, EPUB and Kindle. Book excerpt: The acquisition of resting cerebral perfusion measures using magnetic resonance imaging (MRI) is one of the assessments of cerebrovascular health used to discern how well patients are coping with anatomical changes such as stenosis, and other factors impacting the supply of blood flow to the brain. Perfusion measures may be obtained using several MRI based techniques including arterial spin labeling (ASL) and dynamic contrast enhanced methods that rely on injected contrast agents such as gadolinium. Recently hypoxia-induced changes in deoxyhemoglobin have been used as a non-invasive contrast agent, measuring the resulting changes in blood oxygen dependent (BOLD) signals with MRI. With each approach, the means through which voxel-wise cerebral perfusion information is derived differs, leading to the development a variety of analysis methods in recent studies. This Research Topic is intended to attract manuscripts that advance the use of resting cerebral perfusion measures in clinical assessments of cerebrovascular health. In pursuit of this aim a better understanding of several aspects are needed.
Download or read book Cerebral MR Perfusion Imaging written by A. Gregory Sorensen and published by Thieme. This book was released on 2000 with total page 174 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book will familiarize the reader with the basic principles of perfusion MR imaging. Relevant technical aspects, contrast agents, and the postprocessing of images are presented, and imaging protocols are provided. Dedicated software for personal use on the postprocessing of images is provided on a CD-ROM containing hundreds of images and movie clips that demonstrate all concepts. In addition to the technical details of acquisition and postprocessing, numerous examples of the application of these tools in the clinical setting are also shown. In particular, the book includes a discussion of the role of perfusion MRI in the current evaluation of cerebrovascular disease, including an integrative approach using diffusion in conjunction with perfusion imaging. This text covers: all relevant technical aspects of perfusion MR imaging imaging protocols application of these tools in a clinical setting integration of diffusion imaging with perfusion imaging for enhanced diagnostic capabilities Also addressed are the role of perfusion MRI in the assessment of cerebral neoplasia, challenges and opportunities for treatment that tumors present, and the particular strengths of perfusion MRI, such as its relatively high resolution and possible microvascular specificity. For both newcomers and experienced practitioners, this is a nuts-and-bolts description of an important new technique.
Download or read book Progress in Brain Research written by J. P. Schadé and published by . This book was released on 1963 with total page 438 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Combined Spin and Gradient echo Perfusion MRI written by Heiko Hans Schmiedeskamp and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Dynamic susceptibility-contrast perfusion-weighted imaging (DSC PWI) is a magnetic resonance imaging (MRI) technique that measures the delivery of arterial blood to the tissue capillary bed using a contrast agent. DSC PWI can reveal important information in stroke patients by assessing hypoperfused brain tissue, while in tumor patients it is used to evaluate the tumor vasculature. For clinical applications, DSC PWI relies on both accurate and rapid image formation. Gradient-echo echo-planar imaging (EPI) is the most commonly used MRI pulse sequence for DSC PWI, mainly due to its fast image acquisition capability, a relatively high contrast-to-noise ratio, and its availability on most clinical MRI systems. However, quantification of perfusion parameters with gradient-echo EPI remains challenging. Gradient-echo EPI is most sensitive to larger vessels, including arteries and veins. These measurements do not provide specific information about true perfusion within the microvasculature, the site of oxygen and nutrient extraction to brain tissue. To acquire perfusion measurements that are more confined to the microvasculature, spin-echo EPI acquisition techniques have been proposed. Spin-echo EPI is most sensitive to smaller vessels, providing a clear advantage over gradient-echo EPI. Unfortunately, spin-echo EPI suffers from lower sensitivity to the contrast agent passage, and the determination of arterial contrast agent concentrations required for quantitative perfusion MRI remains an unsolved problem when using spin-echo EPI data. In the first part of this dissertation, a combined approach for simultaneous spin- and gradient-echo (SAGE) perfusion MRI is presented. The proposed imaging technique combines the advantages of higher overall sensitivity to contrast agent passage of gradient-echo EPI with superior microvascular selectivity of spin-echo EPI, resulting in complementary perfusion information. The combined method enabled improved detection of abnormal brain perfusion compared to conventionally processed DSC PWI data, as illustrated in cases of stroke and brain tumors. Specifically, reduced sensitivity to larger blood vessels of spin-echo data generated from SAGE perfusion MRI measurements improved the visibility of hypoperfused tissue. In the second part, the gradient-echo and spin-echo signal contributions to the proposed SAGE perfusion MRI acquisition technique are analyzed in detail. The development of an optimized pair of MRI excitation and refocusing pulses enhanced the contrast-to-noise ratio of the spin-echo signal. Moreover, augmented perfusion parameter estimation improved the accuracy of both gradient-echo and spin-echo signals to reduce perfusion quantification errors. In the last part, implications of contrast agent leakage from the brain vasculature are discussed. Considerable contrast agent extravasation, caused by blood-brain barrier leakage commonly observed in brain tumors and subacute strokes, results in additional quantification errors of brain perfusion parameters. To mitigate these errors, pharmacokinetic modeling of contrast agent distribution was applied to SAGE perfusion MRI data. Intravascular contrast agent concentrations could then be separated from extravascular concentrations, resulting in leakage-corrected perfusion data. Moreover, the applied pharmacokinetic modeling approach facilitated the extraction of permeability parameters. The combined evaluation of perfusion and permeability parameters, derived from SAGE perfusion MRI data, showed potential utility in brain tumor imaging with the goal of improving the diagnostic value of perfusion MRI in the assessment of brain tumor progression.
Download or read book MRI from Picture to Proton written by Donald W. McRobbie and published by Cambridge University Press. This book was released on 2017-04-13 with total page 405 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book Brain Network Analysis written by Moo K. Chung and published by Cambridge University Press. This book was released on 2019-06-27 with total page 343 pages. Available in PDF, EPUB and Kindle. Book excerpt: This coherent mathematical and statistical approach aimed at graduate students incorporates regression and topology as well as graph theory.
Download or read book MRI of the Lung written by Hans-Ulrich Kauczor and published by Springer Science & Business Media. This book was released on 2008-11-12 with total page 315 pages. Available in PDF, EPUB and Kindle. Book excerpt: During the past decade significant developments have been achieved in the field of magnetic resonance imaging (MRI), enabling MRI to enter the clinical arena of chest imaging. Standard protocols can now be implemented on up-to-date scanners, allowing MRI to be used as a first-line imaging modality for various lung diseases, including cystic fibrosis, pulmonary hypertension and even lung cancer. The diagnostic benefits stem from the ability of MRI to visualize changes in lung structure while simultaneously imaging different aspects of lung function, such as perfusion, respiratory motion, ventilation and gas exchange. On this basis, novel quantitative surrogates for lung function can be obtained. This book provides a comprehensive overview of how to use MRI for imaging of lung disease. Special emphasis is placed on benign diseases requiring regular monitoring, given that it is patients with these diseases who derive the greatest benefit from the avoidance of ionizing radiation.
Download or read book Intravoxel Incoherent Motion IVIM MRI written by Denis Le Bihan and published by CRC Press. This book was released on 2018-11-05 with total page 651 pages. Available in PDF, EPUB and Kindle. Book excerpt: Intravoxel incoherent motion (IVIM) refers to translational movements which within a given voxel and during the measurement time present a distribution of speeds in orientation and/or amplitude. The concept was introduced in 1986 together with the foundation of diffusion MRI because it had been realized that flow of blood in capillaries (perfusion) would mimic a diffusion process and impact diffusion MRI measurements. IVIM-based perfusion MRI, which does not require injection of any tracer or contrast agent, has been first investigated in the brain, but is now experiencing a remarkable revival for applications throughout the body, especially for oncologic applications, from diagnosis to treatment monitoring. This book addresses a number of highly topical aspects of the field from leading authorities, introducing the concepts behind IVIM MRI, outlining related methodological issues, and summarizing its current usage and potential for clinical applications. It also presents future research directions, both in terms of methodological development and clinical application fields, extending to new, non-perfusion applications of IVIM MRI, such as virtual MR elastography.
Download or read book Diffusion MRI written by Derek K. Jones and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Medical Imaging Systems written by Andreas Maier and published by Springer. This book was released on 2018-08-02 with total page 263 pages. Available in PDF, EPUB and Kindle. Book excerpt: This open access book gives a complete and comprehensive introduction to the fields of medical imaging systems, as designed for a broad range of applications. The authors of the book first explain the foundations of system theory and image processing, before highlighting several modalities in a dedicated chapter. The initial focus is on modalities that are closely related to traditional camera systems such as endoscopy and microscopy. This is followed by more complex image formation processes: magnetic resonance imaging, X-ray projection imaging, computed tomography, X-ray phase-contrast imaging, nuclear imaging, ultrasound, and optical coherence tomography.
Download or read book Handbook of MRI Pulse Sequences written by Matt A. Bernstein and published by Elsevier. This book was released on 2004-09-21 with total page 1041 pages. Available in PDF, EPUB and Kindle. Book excerpt: Magnetic Resonance Imaging (MRI) is among the most important medical imaging techniques available today. There is an installed base of approximately 15,000 MRI scanners worldwide. Each of these scanners is capable of running many different "pulse sequences", which are governed by physics and engineering principles, and implemented by software programs that control the MRI hardware. To utilize an MRI scanner to the fullest extent, a conceptual understanding of its pulse sequences is crucial. Handbook of MRI Pulse Sequences offers a complete guide that can help the scientists, engineers, clinicians, and technologists in the field of MRI understand and better employ their scanner. - Explains pulse sequences, their components, and the associated image reconstruction methods commonly used in MRI - Provides self-contained sections for individual techniques - Can be used as a quick reference guide or as a resource for deeper study - Includes both non-mathematical and mathematical descriptions - Contains numerous figures, tables, references, and worked example problems
Download or read book Acute Ischemic Stroke written by R. Gilberto González and published by Springer Science & Business Media. This book was released on 2010-10-05 with total page 299 pages. Available in PDF, EPUB and Kindle. Book excerpt: This updated second edition of Acute Ischemic Stroke: Imaging and Intervention provides a comprehensive account of the state of the art in the diagnosis and treatment of acute ischemic stroke. The basic format of the first edition has been retained, with sections on fundamentals such as pathophysiology and causes, imaging techniques and interventions. However, each chapter has been revised to reflect the important recent progress in advanced neuroimaging and the use of interventional tools. In addition, a new chapter is included on the classification instruments for ischemic stroke and their use in predicting outcomes and therapeutic triage. All of the authors are internationally recognized experts and members of the interdisciplinary stroke team at the Massachusetts General Hospital and Harvard Medical School. The text is supported by numerous informative illustrations, and ease of reference is ensured through the inclusion of suitable tables. This book will serve as a unique source of up-to-date information for neurologists, emergency physicians, radiologists and other health care providers who care for the patient with acute ischemic stroke.
Download or read book Medical Imaging Technology written by Victor I. Mikla and published by Elsevier. This book was released on 2013-08-23 with total page 156 pages. Available in PDF, EPUB and Kindle. Book excerpt: Medical Imaging Technology reveals the physical and materials principles of medical imaging and image processing, from how images are obtained to how they are used. It covers all aspects of image formation in modern imaging modalities and addresses the techniques, instrumentation, and advanced materials used in this rapidly changing field. Covering conventional and modern medical imaging techniques, this book encompasses radiography, fluoroscopy, computed tomography, magnetic resonance imaging, ultrasound, and Raman spectroscopy in medicine. In addition to the physical principles of imaging techniques, the book also familiarizes you with the equipment and procedures used in diagnostic imaging. - Addresses the techniques, instrumentation, and advanced materials used in medical imaging - Provides practical insight into the skills, tools, and procedures used in diagnostic imaging - Focuses on selenium imagers and chalcogenide glasses
Download or read book Neuroimaging and Neurophysiology in Psychiatry written by David Linden and published by Oxford University Press. This book was released on 2016 with total page 161 pages. Available in PDF, EPUB and Kindle. Book excerpt: Neuroimaging and Neurophysiology in Psychiatry is an invaluable guide through the methods and applications of neuroimaging and neurophysiology.
Download or read book Magnetic Resonance Imaging written by Robert W. Brown and published by John Wiley & Sons. This book was released on 2014-06-23 with total page 976 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book Introduction to Functional Magnetic Resonance Imaging written by Richard B. Buxton and published by Cambridge University Press. This book was released on 2009-08-27 with total page 479 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
