Download or read book Scan Acceleration and Motion Correction for Cardiovascular Magnetic Resonance Imaging written by Jieying Luo and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Magnetic resonance imaging (MRI) is a powerful medical imaging modality providing excellent soft-tissue contrast without exposing the patient to ionizing radiation. In particular, MRI plays a critical role in the diagnosis and management of cardiovascular disease with the possibility of obtaining a wide range of anatomical and functional information in a single examination. However, despite technical advancements such as parallel imaging and compressed sensing, the scan time of cardiovascular MRI is still relatively long compared to X-ray or CT. The temporal resolution for functional assessment is limited, and compensation for respiratory and cardiac motion remains challenging. To improve the temporal resolution, an undersampling acquisition scheme and a low-rank matrix-completion reconstruction method recovering the missing data are developed and applied to perfusion imaging in the lower extremities. To exploit the spatial-temporal information redundancy, the proposed method formulates the image construction as an optimization problem with the low-rank constraint and the data-consistency constraint. With the proposed method, dynamic contrast-enhanced perfusion imaging in the lower extremities with high temporal resolution (3 s) and volumetric coverage ( 32x16x32 cm3) is achieved. Pulse sequence design is another approach to achieve scan acceleration. Recognizing that the region of interest (ROI) is smaller than the full spatial extent of the anatomy in coronary magnetic resonance angiography (MRA), a new magnetization preparation sequence that combines outer volume suppression with T2 preparation is designed and implemented, enabling accelerated free-breathing whole-heart coronary MRA with enhanced blood-myocardium contrast in a scan time of less than 3 minutes by reducing the image field-of-view. Two nonrigid motion-correction methods are also developed to reduce the motion artifacts generated during the scan. These two methods extract several motion trajectories from 3D image-based navigators (iNAVs) and compensate for them with an autofocusing algorithm. A bank of motion-corrected images is generated by motion correction with every motion trajectory, and the final image is assembled on a pixel-by-pixel basis with the best-focused pixel chosen from the bank of images according to a localized gradient entropy metric. The first method is developed for free-breathing whole-heart coronary MRA in which the motion is complicated and nonrigid. Both global rigid motion and localized nonrigid motion are extracted from the 3D iNAVs. The second method is designed for abdominal MRA, in which the imaging volume is divided into ROIs with different 3D translational motion patterns. An automatic ROI-clustering method is developed and a translational motion trajectory is estimated for every ROI. Both motion correction methods demonstrate improved vessel sharpness in the in vivo studies. The image reconstruction method, pulse sequence and motion-correction methods developed enable scan acceleration and motion correction to address several challenges in cardiovascular MRI. These methods show promise of extending the diagnostic utility of MRI in this application.
Download or read book Motion Correction in MR written by Andre van der Kouwe and published by Academic Press. This book was released on 2022-10-28 with total page 622 pages. Available in PDF, EPUB and Kindle. Book excerpt: Motion Correction in MR: Correction of Position, Motion, and Dynamic Changes, Volume Eight provides a comprehensive survey of the state-of-the-art in motion detection and correction in magnetic resonance imaging and magnetic resonance spectroscopy. The book describes the problem of correctly and consistently identifying and positioning the organ of interest and tracking it throughout the scan. The basic principles of how image artefacts arise because of position changes during scanning are described, along with retrospective and prospective techniques for eliminating these artefacts, including classical approaches and methods using machine learning. Internal navigator-based approaches as well as external systems for estimating motion are also presented, along with practical applications in each organ system and each MR modality covered. This book provides a technical basis for physicists and engineers to develop motion correction methods, giving guidance to technologists and radiologists for incorporating these methods in patient examinations. Provides approaches for correcting scans prospectively and retrospectively Shows how motion and secondary effects such as field changes manifest in MR scans as artifacts and subtle biases in quantitative research Gives methods for measuring motion and associated field changes, quantifying motion and judging the accuracy of the motion and field estimates
Download or read book Motion Artifact Reduction in Steady state Magnetic Resonance Imaging written by Richard Reeve Ingle and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Magnetic resonance imaging (MRI) is a powerful medical imaging modality that offers excellent soft-tissue contrast and numerous contrast-generation mechanisms. However, due to the relatively low signal-to-noise ratio (SNR) of MRI, many volumetric and high-resolution imaging techniques require long acquisition times yielding an increased sensitivity to motion. In many cardiac MRI applications, one of the most significant challenges is the reduction of motion artifacts caused by cardiac and respiratory motion. In these applications, a combination of SNR-efficient balanced steady-state free precession (bSSFP) pulse sequences, high-temporal-resolution motion tracking acquisitions, and retrospective motion correction algorithms are commonly employed to mitigate motion artifacts. Despite recent advances in steady-state pulse sequence development, navigator motion tracking acquisitions, and motion correction algorithms, motion artifact reduction continues to be a significant challenge for many cardiac MRI applications. A novel class of perturbed steady-state free precession (SSFP) pulse sequences is developed and analyzed, yielding new forms of steady-state image contrast. These sequences utilize alternating perturbations of sequence parameters such as the repetition time (TR) and flip angle to produce oscillating steady-state frequency responses. Large oscillations of the signal magnitude and phase occur at specific off-resonant frequencies, and the combination of these signals can yield spectrally selective image contrast. Applications are demonstrated for retrospective motion correction using cardiac fat navigator acquisitions in free-breathing whole-heart cardiac MRI and for positive-contrast imaging of superparamagnetic iron-oxide nanoparticles. The bSSFP pulse sequence is widely used in cardiac imaging due to its high signal per unit time and excellent blood-myocardial contrast. A drawback of this pulse sequence is the generation of bright signal from fat, which can lead to unwanted image artifacts. Alternating repetition time (ATR) SSFP is a recently developed sequence that generates fat-suppressed steady-state contrast, but it requires the addition of an unused time interval every repetition, making it less time efficient than bSSFP. A small modification to the ATR pulse sequence is proposed to enable the acquisition of a one-dimensional self-gating signal during this unused time interval. The self-gating signals are used for retrospective cardiac triggering in breath-held cardiac cine imaging, and the proposed sequence is evaluated in volunteer and patient populations. The resulting ECG-free self-gated images have no statistically significant differences compared with conventional ECG-gated images. The proposed sequence also yields robust suppression of epicardial fat compared with standard bSSFP cardiac cine imaging. In coronary MR angiography (CMRA), high-resolution, whole-heart acquisitions are typically required for visualization of the relatively small coronary vasculature. These acquisitions require long scan times that are carried out during free breathing, which can lead to severe ghosting and blurring artifacts without motion compensation. A nonrigid retrospective motion correction technique is proposed for motion artifact reduction in image-navigated CMRA. The technique reconstructs a bank of motion-compensated CMRA images using many candidate motion estimates derived from navigator images acquired throughout the scan. A metric-based autofocusing approach is used to automatically generate a final nonrigid-motion-corrected image from this bank of images. The proposed technique is evaluated in volunteer and patient studies, leading to improvements in vessel sharpness and image quality compared with rigid-body translational motion correction. These new steady-state pulse sequences, motion tracking acquisitions, and nonrigid reconstruction techniques address several of the challenges to cardiac MRI, enabling the reduction of motion artifacts and improvement of image quality.
Download or read book Motion Correction and Reduction Techniques in Magnetic Resonance Imaging written by Hope Waggener Korin and published by . This book was released on 1991 with total page 334 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A Subspace Approach to Accelerated Cardiovascular Magnetic Resonance Imaging written by and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Heart Mechanics written by El-Sayed H. Ibrahim and published by CRC Press. This book was released on 2017-09-19 with total page 740 pages. Available in PDF, EPUB and Kindle. Book excerpt: Based on research and clinical trials, this book details the latest research in magnetic resonance imaging (MRI) tagging technology related to heart mechanics. It covers clinical applications and examines future trends, providing a guide for future uses of MRI technology for studying heart mechanics.
Download or read book Advanced Motion Correction and Image Reconstruction for Cardiac Magnetic Resonance written by Johannes Frieder Matthias Schmidt and published by . This book was released on 2013 with total page 131 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Coronary Magnetic Resonance Angiography written by Andre J. Duerinckx and published by Springer Science & Business Media. This book was released on 2002 with total page 355 pages. Available in PDF, EPUB and Kindle. Book excerpt: In recent years, there has been increasing interest in the clinical applications of coronary angiography techniques. Coronary MRA can be instrumental in the evaluation of congenital coronary artery anomalies, however, the complexity of advanced MR pulse sequences and strategies may be overwhelming to many. Coronary MR Angiography demystifies the art of coronary MRA by providing a text in plain language with clearly illustrated imaging steps and protocols. Designed to bridge the gap between radiology and cardiology, it is written for physicians and scientists planning to incorporate this technique into their research or practice.
Download or read book Cardiovascular Magnetic Resonance Imaging written by Raymond Y. Kwong and published by Springer. This book was released on 2019-01-31 with total page 473 pages. Available in PDF, EPUB and Kindle. Book excerpt: The significantly updated second edition of this important work provides an up-to-date and comprehensive overview of cardiovascular magnetic resonance imaging (CMR), a rapidly evolving tool for diagnosis and intervention of cardiovascular disease. New and updated chapters focus on recent applications of CMR such as electrophysiological ablative treatment of arrhythmias, targeted molecular MRI, and T1 mapping methods. The book presents a state-of-the-art compilation of expert contributions to the field, each examining normal and pathologic anatomy of the cardiovascular system as assessed by magnetic resonance imaging. Functional techniques such as myocardial perfusion imaging and assessment of flow velocity are emphasized, along with the exciting areas of artherosclerosis plaque imaging and targeted MRI. This cutting-edge volume represents a multi-disciplinary approach to the field, with contributions from experts in cardiology, radiology, physics, engineering, physiology and biochemistry, and offers new directions in noninvasive imaging. The Second Edition of Cardiovascular Magnetic Resonance Imaging is an essential resource for cardiologists and radiologists striving to lead the way into the future of this important field.
Download or read book Cardiovascular Magnetic Resonance written by Saul G. Myerson and published by OUP Oxford. This book was released on 2013-04-25 with total page 313 pages. Available in PDF, EPUB and Kindle. Book excerpt: Cardiovascular Magnetic Resonance (CMR) is a rapidly expanding imaging method in cardiology which provides unparalleled diagnostic information about the heart. It is however a complex technique and though the availability of scanners is increasing quickly, the expertise required to perform the scans is limited. While no book is a substitute for experience, this handbook provides an invaluable guide to performing and interpreting the scans which should aid both new and experienced operators. Cardiovascular Magnetic Resonance is an indispensable guide to performing and interpreting CMR scans. What to look for, which sequences to include, how to acquire them, and how to interpret the images are all included in the handbook. The information is provided in a quick-reference, easy-to-use format with many images from real cases, and is designed to sit on the scanning console or in the office, providing a step-by-step guide to aid the CMR practitioner at every stage. All areas of cardiovascular imaging are covered, including tips and tricks for optimal imaging and how to avoid and spot artefacts. From patient safety to differential diagnoses of tricky images, to an easy to understand section on the science behind magnetic resonance, all aspects are covered in this concise yet comprehensive guide to this specialist area. Whether a novice or expert in the field, all readers should find this book a useful tool. It is an invaluable reference that no CMR department should be without.
Download or read book Magnetic Resonance Angiography written by James C. Carr and published by Springer Science & Business Media. This book was released on 2011-12-22 with total page 416 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book Handbook of Cardiovascular Magnetic Resonance Imaging written by Gerald M. Pohost and published by CRC Press. This book was released on 2006-10-27 with total page 480 pages. Available in PDF, EPUB and Kindle. Book excerpt: Cardiovascular Magnetic Resonance (CMR) is well established in clinical practice for the diagnosis and management of a wide array of cardiovascular diseases. This expertly written source offers a wealth of information on the application and performance of CMR for diagnosis and evaluation of treatment.
Download or read book Cardiovascular Magnetic Resonance E Book written by Warren J. Manning and published by Elsevier Health Sciences. This book was released on 2010-04-05 with total page 668 pages. Available in PDF, EPUB and Kindle. Book excerpt: Cardiovascular Magnetic Resonance provides you with up-to-date clinical applications of cardiovascular MRI for the broad spectrum of cardiovascular diseases, including ischemic, myopathic, valvular, and congenital heart diseases, as well as great vessel and peripheral vascular disease. Editors Warren J. Manning and Dudley J. Pennell and their team of international contributors cover everything from basic MR physics to sequence design, flow quantification and spectroscopy to structural anatomy and pathology. Learn the appropriate role for CMR in a variety of clinical settings with reference to other modalities, practical limitations, and costs. With the latest information on contrast agents, MR angiography, MR spectroscopy, imaging protocols, and more, this book is essential for both the beginner and expert CMR practitioner. Covers both the technical and clinical aspects of CMR to serve as a comprehensive reference. Demonstrates the full spectrum of the application of cardiac MR from ischemic heart disease to valvular, myopathic, pericardial, aortic, and congenital heart disease. Includes coverage of normal anatomy, orientation, and function to provide you with baseline values. Discusses advanced techniques, such as interventional MR, to include essential information relevant to the specialist. Features appendices with acronyms and CMR terminology used by equipment vendors that serve as an introduction to the field. Uses consistent terminology and abbreviations throughout the text for clarity and easy reference. Covers both the technical and clinical aspects of CMR to serve as a comprehensive reference. Demonstrates the full spectrum of the application of cardiac MR from ischemic heart disease to valvular, myopathic, pericardial, aortic, and congenital heart disease. Includes coverage of normal anatomy, orientation, and function to provide you with baseline values. Discusses advanced techniques, such as interventional MR, to include essential information relevant to the specialist. Features appendices with acronyms and CMR terminology used by equipment vendors that serve as an introduction to the field. Uses consistent terminology and abbreviations throughout the text for clarity and easy reference.
Download or read book A Navigator based Rigid Body Motion Correction for Magnetic Resonance Imaging written by Marcus Görge Ullisch and published by . This book was released on 2012 with total page 148 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Cardiovascular Magnetic Resonance written by E. Nagel and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 324 pages. Available in PDF, EPUB and Kindle. Book excerpt: Magnetic resonance imaging of the heart allows a quick and exact evaluation of global and regional pump function, regional myocardial wall motion, myocardial perfusion and coronary blood flow. Some of these parameters must also be analyzed under stress conditions to identify myocardial ischemia. By combining these functional parameters with high-resolution anatomical images, which are even sufficient to depict the coronary arteries, magnetic resonance imaging has become one of the most important noninvasive procedures to study the condition of the heart and is being increasingly used in the clinical setting. Therefore, it is important not only to optimize and evaluate the technique in specialized centers, but also for a broad variety of users to become familiar with the wide range of applications for this method. In this book, which is aimed at cardiologists, radiologists, and technical assistants, the physical fundamentals and scanning techniques are clearly described. In addition, practical guidelines for the anatomical planning of the examination and for patient care are offered. The accompanying CD-ROM contains additional figures and numerous videos.
Download or read book Motion Correction Techniques for Magnetic Resonance Imaging written by Edward Brian Welch and published by . This book was released on 2003 with total page 318 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Detection and Correction of Patient Motion in Magnetic Resonance Imaging written by Murat Aksoy and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Due to the sequential nature of magnetic resonance imaging (MRI) data acquisition, correction of image artifacts originating from involuntary patient motion is essential for reliable diagnostic quality. Especially during MRI scans of certain patient populations such as children, elderly or patients with certain medical conditions (e.g. stroke, Parkinson's), motion correction methods must be incorporated into the MR imaging protocol for adequate image quality. With increased demands for higher resolution or time-resolved examinations (e.g. functional MRI), examination times also increase and even willing patients might have trouble staying still during the course of the examination. The first part of this thesis provides a method for retrospective correction of head motion artifacts using a multi-shot spiral-in \ & out readout and parallel-imaging based iterative image reconstruction. The spiral-in part provided a low resolution image that was used for measurement of head motion. Due to rotational motion, locally undersampled areas appear in MR acquisition space (i.e., k-space), which violate the Nyquist theorem and cause artifacts even after motion correction. These artifacts were addressed through the data redundancy provided by multiple receiver channels that is present in modern receiver coils and an iterative conjugate-gradient based reconstruction. This method was then applied to diffusion tensor imaging (DTI) with multi-shot readout. Since DTI uses directional gradients to encode diffusion, rotational motion causes the image contrast to change, and it becomes incorrect to combine data with varying diffusion encodings on them. To address this issue, a non-linear conjugate gradient based reconstruction is presented and it is shown that this method provided more accurate description of white matter pathways compared to traditional methods. In the second part of this thesis, a prospective motion correction system using an optical tracking device is presented. Such systems are preferable compared to retrospective navigator-based methods due to various reasons, such as ability to perform motion correction independent of the MR data acquisition and immunity to spin history effects. The system proposed used a single camera mounted on the head coil and a self-encoded checkerboard marker mounted on the patient's forehead. Results on structural and diffusion imaging revealed that prospective motion correction outperforms retrospective navigator-based schemes. In the last part of the thesis, entropy-based retrospective autofocusing was used in combination with motion data obtained from prospective tracking to remove residual motion artifacts in the images. This method was especially useful for removing errors caused by inaccurate cross-calibration between the scanner and camera frame-of-references. It was also shown that prospective tracking can be the enabling technology for autofocusing in 3D acquisitions.
