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 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 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 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 Advanced Neuro MR Techniques and Applications written by In-Young Choi and published by Academic Press. This book was released on 2021-11-17 with total page 640 pages. Available in PDF, EPUB and Kindle. Book excerpt: Advanced Neuro MR Techniques and Applications gives detailed knowledge of emerging neuro MR techniques and their specific clinical and neuroscience applications, showing their pros and cons over conventional and currently available advanced techniques. The book identifies the best available data acquisition, processing, reconstruction and analysis strategies and methods that can be utilized in clinical and neuroscience research. It is an ideal reference for MR scientists and engineers who develop MR technologies and/or support clinical and neuroscience research and for high-end users who utilize neuro MR techniques in their research, including clinicians, neuroscientists and psychologists. Trainees such as postdoctoral fellows, PhD and MD/PhD students, residents and fellows using or considering the use of neuro MR technologies will also be interested in this book. Presents a complete reference on advanced Neuro MR Techniques and Applications Edited and written by leading researchers in the field Suitable for a broad audience of MR scientists and engineers who develop MR technologies, as well as clinicians, neuroscientists and psychologists who utilize neuro MR techniques in their research

Download or read book Ultra High Field Neuro MRI written by Karin Markenroth Bloch and published by Elsevier. This book was released on 2023-08-21 with total page 628 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ultra-High Field Neuro MRI is a comprehensive reference and educational resource on the current state of neuroimaging at ultra-high field (UHF), with an emphasis on 7T. Sections cover the MR physics aspects of UHF, including the technical challenges and practical solutions that have enabled the rapid growth of 7T MRI. Individual chapters are dedicated to the different techniques that most strongly benefit from UHF, as well as chapters with a focus on different application areas in anatomical, functional and metabolic imaging. Finally, several chapters highlight the neurological and psychiatric applications for which 7T has shown benefits. The book is aimed at scientists who develop MR technologies and support clinical and neuroscience research, as well as users who want to benefit from UHF neuro MR techniques in their work. It also provides a comprehensive introduction to the field. Presents the opportunities and technical challenges presented by MRI at ultra-high field Describes advanced ultra-high field neuro MR techniques for clinical and neuroscience applications Enables the reader to critically assess the specific UHF advantages over currently available techniques at clinical field strengths

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 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 Understanding and Overcoming Head Motion in Ultra high Field Magnetic Resonance Imaging with Parallel Radio frequency Transmission written by Alix Plumley and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Magnetic Resonance and Brain Function Approaches from Physics written by Società italiana di fisica and published by IOS Press. This book was released on 1999 with total page 602 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the last decade, NMR has set the basis for the understanding of the function and disfunction of the human brain. Particularly, Magnetic Resonance Imaging (MRI) has a leading position among the methodologies used for investigation and diagnostic of the Central Nervous System. In the 1990's the objective of finding new investigating means drove scientists towards different approaches, including: 1) Blood Oxygen Level Dependent (BOLD) MRI; 2) Double Magnetic Resonance (DMR); 3) Hyperpolarized Gases. These 3 methods are aimed at detecting brain metabolites with increasing sensitivity and resolution. This Enrico Fermi Course is of interest to researchers who work at the development of these interdisciplinary areas, i.e. physicists, chemists, engineers, but also the biomedical aspects of brain function in connection to the NMR potentialities.

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.

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 Motion Correction in Orbital Imaging Using MRI Compatible Eye Tracker written by Anita Dushyanth and published by . This book was released on 2014 with total page 98 pages. Available in PDF, EPUB and Kindle. Book excerpt: The body motion of patients during magnetic resonance imaging (MRI) causes significant artifacts in the reconstructed image. Artifacts are manifested as a motion induced blur and ghost repetitions of the moving structures, which obscure vital anatomical and pathological detail. The techniques that have been proposed for suppressing motion artifacts fall into two major categories. Realtime techniques that attempt to prevent the motion from corrupting the data by restricting the data acquisition times or motion of the patients, and post-processing techniques that use information embedded in the corrupted data to restore the image. The post-processing techniques usually demand an appropriate model of the motion that requires the parameters be determined in order to invert the data degradation process. However, motion is manifested differently depending on the time and duration it occurred during Magnetic Resonance (MR) data acquisition. Estimating motion parameters from such cases are heavily based on assumptions and the reconstructed image is compromised on either contrast or resolution. A major challenge in high resolution MR imaging of the orbit (eyeball and associated tissues in the eye socket) is image degradation by artifacts resulting from eye movements and eyelid blinks. In this thesis a novel method for motion correction has been developed by incorporating an optical sensor that detects these eye movements during MR scan acquisition without generating signal artifacts, and which is not affected by either the strong static magnetic field or the pulsed field gradients. Detection of the subjects eye movements and blinks is essential for determining the exact times during the MR scan when each such movement occurred. This thesis presents a method for refining orbital MRI techniques to compensate for the effects of blinking and fixation instability. It employs an eye tracker system to track eye/eyelid movements in the MRI studies of strabismus in humans that is based on infrared (IR) light reflection. It incorporates custom-fabricated optical fiber probes that illuminate the eye with low intensity infrared light, while eye/eyelid movements are detected by changes in ocular surface reflectance transmitted by another optical fiber cable coupled to a photodiode. Additionally, there is another light source that serves as a visible point target for ocular fixation during MRI scanning. The volunteer's eye movements are recorded simultaneously while the orbit is scanned using MRI. The output signal from the detector is amplified and synchronized in time with the MR acquired data. Image data corrupted by motion is flagged so that the affected data can be removed during image reconstruction. The purpose of this experiment is to outline experimental protocols for acquiring and correcting the above mentioned images in high quality, discuss these protocols from a wide range of perspectives, and finally present some observations on pilot data from volunteer subjects as well as patient with pathology. The MRI methodology developed was able to suppress motion artifacts considerably to provide interpretable MRI images.

Download or read book Handbook of Pediatric Brain Imaging written by Hao Huang and published by Academic Press. This book was released on 2021-10-27 with total page 582 pages. Available in PDF, EPUB and Kindle. Book excerpt: Handbook of Pediatric Brain Imaging: Methods and Applications presents state-of-the-art research on pediatric brain image acquisition and analysis from a broad range of imaging modalities, including MRI, EEG and MEG. With rapidly developing methods and applications of MRI, this book strongly emphasizes pediatric brain MRI, elaborating on the sub-categories of structure MRI, diffusion MRI, functional MRI, perfusion MRI and other MRI methods. It integrates a pediatric brain imaging perspective into imaging acquisition and analysis methods, covering head motion, small brain sizes, small cerebral blood flow of neonates, dynamic cortical gyrification, white matter tract growth, and much more. Presents state-of-the-art pediatric brain imaging methods and applications Shows how to optimize the pediatric neuroimaging acquisition and analysis protocols Illustrates how to obtain quantitative structural, functional and physiological measurements

Download or read book 7T MRI An Issue of Magnetic Resonance Imaging Clinics of North America written by Meng Law and published by Elsevier Health Sciences. This book was released on 2020-11-30 with total page 164 pages. Available in PDF, EPUB and Kindle. Book excerpt: This issue of MRI Clinics of North America focuses on 7T MRI and is edited by Dr. Meng Law. Articles will include: 3T vs 7T MRI: Is It Really Worth It?; High Resolution Structural MRI & Quantitative Susceptibility Mapping; High Resolution Neurovascular Imaging at 7T: Arterial Spin Labeling Perfusion, 4-dimensional MR Angiography and Black blood MRI; 7T and Beyond Functional MRI; Sodium and Other UHF MRI; MR-EYE: Ultra High Field MRI of the Human Eye and Orbit at 7T; 7T MRI of Perivascular Spaces; 7T MRI in “Non Lesional" Epilepsy/ Perivascular Spaces; 7T Multiple Sclerosis; 7T Brain Tumors and Radiation Therapy; 7T Musculoskeletal MRI; Body Applications for 7T; MRI Safety at 7T/Implants; 7T Simultaneous MRI PET with PET Insert; GluCest 7T MRI; and more!

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 Three dimensional Magnetic Resonance Imaging Acquired with the Elliptical Centric View Order Or the Shells Trajectory written by Yunhong Shu and published by . This book was released on 2006 with total page 338 pages. Available in PDF, EPUB and Kindle. Book excerpt: