Author: Samantha ByPublisher:
ISBN:
Category : Electronic dissertations
Languages : en
Pages : 126
Book Description
Diffusion Magnetic Resonance Imaging of the Human Spinal Cord in Vivo
Author: Samantha ByPublisher:
ISBN:
Category : Electronic dissertations
Languages : en
Pages : 126
Book Description
Quantitative MRI of the Spinal Cord
Author: Julien Cohen-AdadPublisher: Academic Press
ISBN: 0123972825
Category : Medical
Languages : en
Pages : 331
Book Description
Quantitative MRI of the Spinal Cord is the first book focused on quantitative MRI techniques with specific application to the human spinal cord. This work includes coverage of diffusion-weighted imaging, magnetization transfer imaging, relaxometry, functional MRI, and spectroscopy. Although these methods have been successfully used in the brain for the past 20 years, their application in the spinal cord remains problematic due to important acquisition challenges (such as small cross-sectional size, motion, and susceptibility artifacts). To date, there is no consensus on how to apply these techniques; this book reviews and synthesizes state-of-the-art methods so users can successfully apply them to the spinal cord. Quantitative MRI of the Spinal Cord introduces the theory behind each quantitative technique, reviews each theory’s applications in the human spinal cord and describes its pros and cons, and suggests a simple protocol for applying each quantitative technique to the spinal cord. Chapters authored by international experts in the field of MRI of the spinal cord Contains “cooking recipes —examples of imaging parameters for each quantitative technique—designed to aid researchers and clinicians in using them in practice Ideal for clinical settings
Diffusion Tensor Magnetic Resonance Imaging in the Human Spinal Cord with a Single Shot, Fast Spin Echo Sequence
Author: Hardave Singh KharbandaPublisher:
ISBN:
Category : Medicine
Languages : en
Pages : 210
Book Description
Assessing Cellular Microstructure in Biological Tissues using In Vivo Diffusion-Weighted Magnetic Resonance
Author: Julien ValettePublisher: Frontiers Media SA
ISBN: 2889458415
Category :
Languages : en
Pages : 193
Book Description
Magnetic resonance imaging (MRI) and spectroscopy (MRS) techniques have opened new doors for examining biological tissues in vivo. By combining sensitization to diffusion using magnetic field gradients with a variety of imaging and localization schemes, diffusion-weighted MRI and diffusion-weighted MRS allow investigating translational diffusion of endogenous molecules, such as water or metabolites, in biological tissues, most commonly the brain but also other organs such as the prostate. The typical voxel resolution of MRI or MRS is in the millimeter to centimeter range, much lower than the cellular scale. However, as molecules are typically diffusing over just a few µm during the duration of the measurement (the “diffusion time”) and encounter numerous biological membranes at these scales, the average cellular microstructure has a critical influence on the measured diffusion signal. Hence, diffusion-weighted MRI and diffusion-weighted MRS are sensitive to tissue microstructure at a scale well below the nominal imaging resolution. However, the connection between diffusion properties and tissue microstructure remains indirect, so any attempt to quantify microstructure will rely on modeling. The goal of this Research Topic was to gather experts in various acquisition and modeling strategies and show how these approaches, despite their own strengths and weaknesses, can yield unique information about cellular microstructure, and sometimes complement each other.
Microstructural Imaging of the Human Spinal Cord with Advanced Diffusion MRI
Author: Francesco GrussuDiffusion MRI
Author: Heidi Johansen-BergPublisher: Academic Press
ISBN: 0080878512
Category : Psychology
Languages : en
Pages : 507
Book Description
Diffusion MRI is a magnetic resonance imaging (MRI) method that produces in vivo images of biological tissues weighted with the local microstructural characteristics of water diffusion, providing an effective means of visualizing functional connectivities in the nervous system. This book is the first comprehensive reference promoting the understanding of this rapidly evolving and powerful technology and providing the essential handbook for designing, analyzing or interpreting diffusion MR experiments.The book presents diffusion imaging in the context of well-established, classical experimental techniques, so that readers will be able to assess the scope and limitations of the new imaging technology with respect to techniques available previously. All chapters are written by leading international experts and cover methodology, validation of the imaging technology, application of diffusion imaging to the study of variation and development of normal brain anatomy, and disruption to the white matter in neurological disease or psychiatric disorder. • Discusses all aspects of a diffusion MRI study from acquisition, through analysis, to interpretation, providing an essential reference text for scientists designing or interpreting diffusion MR experiments• Practical advice on running an experiment• Full color throughout
High-resolution Diffusion MRI of Targeted Regions
Author: Emine Ülkü SarıtaşPublisher: Stanford University
ISBN:
Category :
Languages : en
Pages : 131
Book Description
Diffusion magnetic resonance imaging (MRI) is an MRI method that provides information about random microscopic motion of water molecules in biological tissues. In addition to offering a higher sensitivity for the diagnosis of white matter diseases such as stroke and multiple sclerosis, and producing connectivity maps of the brain, it is a promising prognostic tool in the assessment and treatment response monitoring of cancer in the body. While high in-plane resolution is desirable for all diffusion MRI applications, it is particularly essential for imaging of small structures. Unfortunately, the performance of diffusion MRI techniques is often hindered by a variety of factors including susceptibility variations, field inhomogeneities and bulk physiologic motion. This thesis presents a reduced field-of-view (FOV) single-shot echo-planar imaging (ss-EPI) method to address these problems and enable high-resolution diffusion MRI of targeted regions. The proposed method utilizes a two-dimensional (2D) echo-planar radio-frequency (RF) excitation pulse to achieve a sharp reduced-FOV profile, while still allowing contiguous multi-slice imaging and suppressing the fat signal. Extensive clinical evaluation of the technique demonstrated that sub-mm diffusion-weighted imaging (DWI) on human spinal cords is feasible with minimal artifacts. High-resolution fiber tractography of the spinal cord successfully visualized the connectivity between the cord and the medulla oblongata, delineating internal structures such as gray/white matter. In vivo DWI of the larynx, breast and prostate validated the effectiveness of this technique in providing detailed depiction of the morphology outside the central nervous system. When the exponential diffusion attenuation is combined with high spatial resolution, DWI may suffer from poor signal-to-noise ratio (SNR). The last part of this thesis presents an optimization strategy for the DWI parameters as a function of the imaging SNR. Specifically, the optimum b-value is shown to be a monotonically increasing function of the imaging SNR, with a convergence asymptote identical to the previously proposed values in literature. The effects of T2 relaxation are also incorporated for a more accurate optimization. In vitro and in vivo experiments demonstrated reduced error in ADC estimations and improved SNR in the diffusion-weighted images with the proposed technique.
In-vivo Human Spinal Cord and Brain Magnetic Resonance Spectroscopy in Multiple Sclerosis and Spinal Cord Injury Patients
Author: Patrik O. WyssIn Vivo Diffusion Magnetic Resonance Imaging to Evaluate Microstructure of the Human Brain
Author: 李鴻禧World Congress on Medical Physics and Biomedical Engineering 2018
Author: Lenka LhotskáPublisher:
ISBN: 9789811090363
Category : Biomedical engineering
Languages : en
Pages :
Book Description
This book presents the proceedings of the IUPESM World Congress on Biomedical Engineering and Medical Physics, a tri-annual high-level policy meeting dedicated exclusively to furthering the role of biomedical engineering and medical physics in medicine. The book offers papers about emerging issues related to the development and sustainability of the role and impact of medical physicists and biomedical engineers in medicine and healthcare. It provides a unique and important forum to secure a coordinated, multileveled global response to the need, demand, and importance of creating and supporting strong academic and clinical teams of biomedical engineers and medical physicists for the benefit of human health.