Download or read book Motion Correction in Magnetic Resonance Imaging Using the Signal of Free Induction Decay written by Maryna Volodimirivna Waszak and published by . This book was released on 2016 with total page 89 pages. Available in PDF, EPUB and Kindle. Book excerpt: Mots-clés de l'autrice: structural MRI ; FID navigator ; motion detection ; motion correction.
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 Head Motion Correction in Magnetic Resonance Imaging Using NMR Field Probes written by and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 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 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 Novel Approaches for Magnetic Resonance Imaging written by Hichem Habib Garnaoui and published by . This book was released on 1994 with total page 268 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Farr s Physics for Medical Imaging written by Penelope J. Allisy-Roberts and published by Elsevier Health Sciences. This book was released on 2007-11-14 with total page 216 pages. Available in PDF, EPUB and Kindle. Book excerpt: This title is directed primarily towards health care professionals outside of the United States. The new edition has been fully updated to reflect the latest advances in technology and legislation and the needs of today's radiology trainees. Invaluable reading, particularly for those sitting the primary and final examinations of the Royal College of Radiology, UK, the book will also be of value to radiographers and personnel interested in medical imaging. The concise text is also accompanied by clear line drawings and sample images to illustrate the principles discussed. Closely matches needs of FRCR examination candidates. Updated to reflect changes to FRCR examination. More medically orientated. Covers new legislation concerning radiological safety etc. 'Must-know' summaries at end of each chapter. Completely new design.
Download or read book Comprehensive Head Motion Correction For Functional Magnetic Resonance Imaging written by Zahra Faraji-Dana and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Head motion artifacts are major confounds that limit use of functional magnetic resonance imaging (fMRI) in neuroscience research and clinical settings. Prospective motion correction is a promising candidate solution for head motion in fMRI that ideally allows the image plane to remain fixed with respect to the moving head (i.e., in the moving reference frame). Prospective motion correction has been shown to correct successfully for rigid body movement artifacts, but residual geometric distortion due to dynamic magnetic field nonuniformities and dynamic changes in receiver coil sensitivity profiles in the moving reference frame still remain a problem. This thesis focuses on three objectives. First, I investigated and corrected for the influence of respiratory effects on the performance of dynamic geometric correction using Phase Labeling for Additional Coordinate Encoding (PLACE). It was demonstrated that PLACE combined with the dynamic off-resonance in k-space (DORK) method, and temporal averaging substantially improved fMRI data quality in comparison to the results obtained by standard processing and static geometric distortion correction. Second, I verified that appreciable signal artifacts occur due to coil sensitivity changes in fMRI maps in presence of overt head motion with prospective motion correction using Prospective Acquisition CorrEction (PACE) technique [1]. Sensitivity map compensations were shown to suppress these artifacts and provide improved fMRI results Third, I studied signal artifacts resulted from the head motion between the coil sensitivity map measurement (i.e., the calibration step) and data acquisition for fMRI with parallel-imaging reconstruction methods using two parallel imaging schemes: sensitivity encoding (SENSE) and generalized autocalibrating partially parallel acquisitions (GRAPPA) with acceleration factors 2 and 4. Coil sensitivity map compensations were shown to improve fMRI results obtained with PACE in the presence of overt head motion compared to those obtained with no overt head motion. Overall, prospective motion correction, integrated dynamic geometric distortion correction, and coil sensitivity map correction present an appealing compound approach for suppressing rigid and non-rigid motion artifacts during fMRI. This thesis has developed robust and comprehensive head motion correction strategies that ultimately will expand the patient populations for which fMRI can be performed robustly.
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 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 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 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 Motion Correction Method in Magnetic Resonance Image Reconstruction written by and published by . This book was released on 2012 with total page 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 Characterization and Correction of Artifacts in and Implementation of Fast Linogram Imaging in MRI written by Neville Gai and published by . This book was released on 1997 with total page 210 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Adaptive Motion Correction in 2DFT Magnetic Resonance Imaging written by Joel Patrick Felmlee and published by . This book was released on 1992 with total page 426 pages. Available in PDF, EPUB and Kindle. Book excerpt:
