Download or read book Spiral Imaging and Motion Artifact Reduction for Dynamic Magnetic Resonance Imaging written by Jan-Ray Liao and published by . This book was released on 1997 with total page 272 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Motion Artifact Reduction in Magnetic Resonance Imaging written by Shreyas Vasanawala and published by . This book was released on 2000 with total page 214 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Motion Artifact Reduction in Magnetic Resonance Imaging Through Navigator Processing written by Robert W. Schaffer and published by . This book was released on 2009 with total page 110 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 Image Artifact Reduction for Fast Magnetic Resonance Imaging written by Joseph Yitan Cheng and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Magnetic resonance imaging (MRI) is a rich source for diagnostic information. It has the ability to obtain excellent soft-tissue contrast at a very high spatial resolution. The imaging process of this modality can be conveniently described as a linear system with Fourier encoding. However, to increase flexibility and robustness, imaging techniques are used that cause basic assumptions of this model to fall apart. As a result, image artifacts arise, decreasing the clinical quality of the scans. More sophisticated methods that take these effects into account must be considered. Many of the errors reside in both the spatial and frequency domain, so simple linear solutions do not suffice. Two sources of image artifacts are investigated: (1) concomitant gradient field and field inhomogeneity and (2) nonrigid motion in free-breathing acquisitions. Each image-artifact source has specific effects which are dependent on the application. For real-time cardiac imaging with spiral k-space trajectories, concomitant gradient field and field inhomogeneity errors result in image blurring. Two fast and practical solutions are developed and applied to real-time cardiac studies and high-resolution cardiac studies. MRI is also a compelling choice for imaging pediatric patients as they are highly susceptible to risks of ionizing radiation of computed tomography and nuclear scintigraphy studies. However, this imaging modality is highly sensitive to motion. The motion can result in destructive image artifacts. To enable free-breathing volumetric exams, novel data acquisition strategies and image reconstruction techniques are developed to compensate for nonrigid respiratory motion. These methods are demonstrated in select pediatric patient studies. Image artifacts fromrespiratory motion are reduced from the free-breathing abdominal scans.
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 Artifact Reduction Techniques in FMRI Spiral Imaging and Spectroscopic Imaging written by Keith Arron Heberlein and published by . This book was released on 2003 with total page 306 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Magnetic Resonance Imaging Gradient Modulation Technique for Motion Artifact Reduction and Flow Quantification written by Jeffrey Lewis Duerk and published by . This book was released on 1987 with total page 798 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Mathematics and Physics of Emerging Biomedical Imaging written by Committee on the Mathematics and Physics of Emerging Dynamic Biomedical Imaging and published by National Academies Press. This book was released on 1996-03-13 with total page 261 pages. Available in PDF, EPUB and Kindle. Book excerpt: This cross-disciplinary book documents the key research challenges in the mathematical sciences and physics that could enable the economical development of novel biomedical imaging devices. It is hoped that the infusion of new insights from mathematical scientists and physicists will accelerate progress in imaging. Incorporating input from dozens of biomedical researchers who described what they perceived as key open problems of imaging that are amenable to attack by mathematical scientists and physicists, this book introduces the frontiers of biomedical imaging, especially the imaging of dynamic physiological functions, to the educated nonspecialist. Ten imaging modalities are covered, from the well-established (e.g., CAT scanning, MRI) to the more speculative (e.g., electrical and magnetic source imaging). For each modality, mathematics and physics research challenges are identified and a short list of suggested reading offered. Two additional chapters offer visions of the next generation of surgical and interventional techniques and of image processing. A final chapter provides an overview of mathematical issues that cut across the various modalities.
Download or read book Magnetic Resonance Image Reconstruction written by Mehmet Akcakaya and published by Academic Press. This book was released on 2022-11-04 with total page 518 pages. Available in PDF, EPUB and Kindle. Book excerpt: Magnetic Resonance Image Reconstruction: Theory, Methods and Applications presents the fundamental concepts of MR image reconstruction, including its formulation as an inverse problem, as well as the most common models and optimization methods for reconstructing MR images. The book discusses approaches for specific applications such as non-Cartesian imaging, under sampled reconstruction, motion correction, dynamic imaging and quantitative MRI. This unique resource is suitable for physicists, engineers, technologists and clinicians with an interest in medical image reconstruction and MRI. Explains the underlying principles of MRI reconstruction, along with the latest research“/li> Gives example codes for some of the methods presented Includes updates on the latest developments, including compressed sensing, tensor-based reconstruction and machine learning based reconstruction
Download or read book Reduction of Motion Artifacts in Magnetic Resonance Diffusion Imaging written by Archie Chih-Ching Chu and published by . This book was released on 2000 with total page 296 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Biomedical Magnetic Resonance written by Thomas L. James and published by . This book was released on 1984 with total page 488 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Artifact Reduction in Functional Magnetic Resonance Imaging written by and published by . This book was released on 1997 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Motion Artifact Mitigation in Magnetic Resonance Angiography written by Srivathsan Prabu Koundinyan and published by . This book was released on 2020 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Magnetic Resonance Imaging (MRI) is a safe, effective, and non-invasive method for examining the human body with excellent soft-tissue contrast. However, because of prolonged scan times, MRI is particularly sensitive to motion. Motion can arise from any number of sources, including respiration, pumping action of the four cardiac chambers, and even sudden involuntary patient movement. This dissertation describes several novel strategies to reduce motion artifacts in cardiovascular magnetic resonance angiography (MRA), which encompasses a class of techniques to image blood vessels with high contrast.
Download or read book Motion Compensation in MRI Using Variable Density Spiral Trajectories microform written by General Leung and published by National Library of Canada = Bibliothèque nationale du Canada. This book was released on 2004 with total page 172 pages. Available in PDF, EPUB and Kindle. Book excerpt: A novel technique is presented to compensate for motion artefacts in magnetic resonance imaging (MRI) using a variable density spiral (VDS) trajectory. In this thesis, a technique is shown to register each of the VDS interleaves prior to reconstruction. The technique is demonstrated in motion phantoms as well as human volunteers. Evaluation of the registration accuracy of the technique shows good agreement with an external monitoring device. Furthermore, it is shown that motion artefacts can be significantly reduced when compared to VDS trajectory acquisitions without compensation. An evaluation of the trajectory parameters is also presented and an optimal trajectory for compensating for respiratory motion is proposed.
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.
Download or read book Artifact Reduction in Functional Magnetic Resonance Imaging written by Brian Wowk and published by . This book was released on 1997 with total page 306 pages. Available in PDF, EPUB and Kindle. Book excerpt:
