Multimodal magnetic resonance imaging methods to explore the visual pathway and brain network changes in blindness disease

Multimodal magnetic resonance imaging methods to explore the visual pathway and brain network changes in blindness disease PDF Author: Yan Tong
Publisher: Frontiers Media SA
ISBN: 2832516041
Category : Science
Languages : en
Pages : 153

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Multimodal magnetic resonance imaging methods to explore the visual pathway and brain network changes in blindness disease

Multimodal magnetic resonance imaging methods to explore the visual pathway and brain network changes in blindness disease PDF Author: Yan Tong
Publisher: Frontiers Media SA
ISBN: 2832516041
Category : Science
Languages : en
Pages : 153

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Multimodal MRI Investigation of Eye and Visual Brain

Multimodal MRI Investigation of Eye and Visual Brain PDF Author: Chin-Chak Ho
Publisher:
ISBN: 9781361042274
Category :
Languages : en
Pages :

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This dissertation, "Multimodal MRI Investigation of Eye and Visual Brain" by Chin-chak, Ho, 何阡澤, was obtained from The University of Hong Kong (Pokfulam, Hong Kong) and is being sold pursuant to Creative Commons: Attribution 3.0 Hong Kong License. The content of this dissertation has not been altered in any way. We have altered the formatting in order to facilitate the ease of printing and reading of the dissertation. All rights not granted by the above license are retained by the author. Abstract: Although the eyes are physically isolated from the visual brain, the physiology and integrity of the eye are central to several eye diseases and neurodegeneration in the visual brain. MRI provides non-invasive, longitudinal and multi-parametric assessments of the visual system without depth limitation. The objective of this doctoral work is to develop and apply multimodal MRI for the assessment of aqueous humor dynamics, ocular fibrous tissue and visual pathway integrity in the visual system. The functional response in neural systems were further explored with BOLD and diffusion fMRI. Firstly, dynamic Gd-MRI was applied to visualize and assess aqueous humor dynamics upon sustained intraocular pressure elevation and pharmacological interventions. The results reflect the reduced gadolinium clearance upon microbead occlusion and respective drug actions after ocular hypotensive drug treatment. Abnormal gadolinium leakage into the vitreous was found in compromised aqueous-vitreous or blood-ocular barrier integrity. Gd-MRI allows spatiotemporal and quantitative evaluation of altered aqueous humor dynamics and ocular tissue permeability. Secondly, MAMRI was employed to reveal the structural details of the corneoscleral shell and their changes upon intraocular pressure elevation. At magic angle, high-resolution MRI revealed distinct scleral and corneal lamellar fibers, and collagen fiber crimps. Loaded sclera and cornea possessed significantly higher T2 and T2* than unloaded tissues at magic angle, suggestive of the changes in collagen fiber crimp and alignment. MAMRI can detect ocular fibrous microstructures without contrast agents, and can reveal their MR tissue property changes with IOP loading. Thirdly, multimodal MRI was utilized to investigate the effects of biomechanical or biochemical modulation on the sclera and cornea tissues. T2 in corneoscleral shell increased non-linearly with IOP loading and remained longer than unloaded tissues after being unpressurized. Biomechanical loading increased fractional anisotropy in the corneoscleral shell, while increasing glyceraldehyde and chondroitinase-ABC concentrations decreased diffusivities and increased magnetization transfer in cornea. Glyceraldehyde also increased magnetization transfer in sclera. The changes in MRI contrast mechanisms upon various modulation of the eye provide insight to the pathophysiological mechanisms in the corneoscleral shell and the efficacy of corneoscleral treatments. Fourthly, the effects of excitotoxic retinal injury on the retinal thickness, microstructual integrity and anterograde transport was evaluated in vivo by DTI, MEMRI and OCT. Directional diffusivities in the visual pathway and their correlations with retinal thickness suggested anterograde axonal degeneration and delayed demyelination along the visual pathway. The splenium of corpus callosum was reorganized at 4 weeks post injury. Furthermore, the NMDA-injured visual pathway showed reduced anterograde manganese transport. These results characterized the spatiotemporal changes in white matter integrity, the eye-brain relationships and structural-physiological relationships in the visual system. Lastly, BOLD and diffusion fMRI were used to explore the functional responses of neural systems. The efficacy of using unisensory stimuli to elicit cross-modal activation was examined by BOLD fMRI improving the understanding to cortical cross-modal activity and its influence

Dynamic Brain Imaging

Dynamic Brain Imaging PDF Author: Hyder Fahmeed
Publisher: Humana Press
ISBN: 9781603279840
Category : Medical
Languages : en
Pages : 379

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Book Description
If a picture is worth a thousand words, then dynamic images of brain activity certainly warrant many, many more. This book will help users learn to decipher the dynamic imaging data that will be critical to our future understanding of complex brain functions. In recent years, there have been unprecedented methodological advancements in the imaging of brain activity. These techniques allow the measurement of everything from neural activity (e.g., membrane potential, ion ?ux, neurotransmitter ?ux) to energy metabolism (e.g., glucose consumption, oxygen consumption, creatine kinase ?ux) and functional hyperemia (e.g., blood ?ow, volume, oxygenation). This book deals with a variety of magnetic resonance, electrophysiology, and optical methods that are often used to measure some of these dynamic processes. All chapters were written by leading experts, spanning three continents, specializing in state-of-the-art methods. Brie?y, the book has ?ve sections. In the introductory section, there are two chapters; the ?rst one contains a brief pre- ble to dynamic brain imaging and the other presents a novel, analytical approach to processing of dynamically acquired data. The second section has four chapters and delves into a wide range of optical imaging methods. I am privileged to include a chapter from Lawrence B. Cohen, considered by many to be the authority on optical imaging and spectroscopy, both in vitro and in vivo [Cohen LB (1973) Physiol Rev.

Application of Multimodal Imaging Combined with Artificial Intelligence in Eye Diseases

Application of Multimodal Imaging Combined with Artificial Intelligence in Eye Diseases PDF Author: Xin Huang
Publisher: Frontiers Media SA
ISBN: 2832536107
Category : Science
Languages : en
Pages : 202

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Handbook of MRI Pulse Sequences

Handbook of MRI Pulse Sequences PDF Author: Matt A. Bernstein
Publisher: Elsevier
ISBN: 0080533124
Category : Mathematics
Languages : en
Pages : 1041

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Book Description
Magnetic Resonance Imaging (MRI) is among the most important medical imaging techniques available today. There is an installed base of approximately 15,000 MRI scanners worldwide. Each of these scanners is capable of running many different "pulse sequences", which are governed by physics and engineering principles, and implemented by software programs that control the MRI hardware. To utilize an MRI scanner to the fullest extent, a conceptual understanding of its pulse sequences is crucial. Handbook of MRI Pulse Sequences offers a complete guide that can help the scientists, engineers, clinicians, and technologists in the field of MRI understand and better employ their scanner. Explains pulse sequences, their components, and the associated image reconstruction methods commonly used in MRI Provides self-contained sections for individual techniques Can be used as a quick reference guide or as a resource for deeper study Includes both non-mathematical and mathematical descriptions Contains numerous figures, tables, references, and worked example problems

Imaging of Orbital and Visual Pathway Pathology

Imaging of Orbital and Visual Pathway Pathology PDF Author: Wibke S. Müller-Forell
Publisher: Springer Science & Business Media
ISBN: 354027989X
Category : Medical
Languages : en
Pages : 454

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Book Description
Deals with imaging of pathology of the visual system. This book is divided into two parts, general and special. In the general part, important basics of modern imaging methods are discussed. The knowledge on the indication, technique, and results of functional MR imaging is also presented.

Neuroimaging of Pain

Neuroimaging of Pain PDF Author: Luca Saba
Publisher: Springer
ISBN: 3319480464
Category : Medical
Languages : en
Pages : 509

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Book Description
Authored by world renowned scientists, this book expertly reviews all the imaging techniques and exciting new methods for the analysis of the pain, including novel tracers, biomarker, metabolomic and gene-array profiling, together with cellular, genetic, and molecular approaches. Recent advances in human brain imaging techniques have allowed a better understand of the functional connectivity in pain pathways, as well as the functional and anatomical alterations that occur in chronic pain patients. Modern imaging techniques have permitted rapid progress in the understanding of networks in the brain related to pain processing and those related to different types of pain modulation. Neuroimaging of Pain is designed to be a valuable resource for radiologists, neuroradiologists, neurologists and neuroscientists, working in hospitals and universities from junior trainees to consultants.

Pattern Analysis of the Human Connectome

Pattern Analysis of the Human Connectome PDF Author: Dewen Hu
Publisher: Springer
ISBN: 9789813295254
Category : Medical
Languages : en
Pages : 0

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Book Description
This book presents recent advances in pattern analysis of the human connectome. The human connectome, measured by magnetic resonance imaging at the macroscale, provides a comprehensive description of how brain regions are connected. Based on machine learning methods, multiviarate pattern analysis can directly decode psychological or cognitive states from brain connectivity patterns. Although there are a number of works with chapters on conventional human connectome encoding (brain-mapping), there are few resources on human connectome decoding (brain-reading). Focusing mainly on advances made over the past decade in the field of manifold learning, sparse coding, multi-task learning, and deep learning of the human connectome and applications, this book helps students and researchers gain an overall picture of pattern analysis of the human connectome. It also offers valuable insights for clinicians involved in the clinical diagnosis and treatment evaluation of neuropsychiatric disorders.

MR Spectroscopy of Pediatric Brain Disorders

MR Spectroscopy of Pediatric Brain Disorders PDF Author: Stefan Blüml
Publisher: Springer Science & Business Media
ISBN: 1441958649
Category : Medical
Languages : en
Pages : 405

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Book Description
Magnetic resonance spectroscopy (MRS) is a modality available on most clinical MR scanners and readily integrated with standard MR imaging (MRI). For the brain in particular, MRS has been a powerful research tool providing additional clinically relevant information for several disease families such as brain tumors, metabolic disorders, and systemic diseases. The most widely-available MRS method, proton (1H; hydrogen) spectroscopy, is FDA approved for general use in the US and can be ordered by clinicians for patient studies if indicated. There are several books available that describe applications of MRS in adults. However, to the best of our knowledge there is currently no book available that focuses exclusively on applications in pediatrics. MR spectroscopy in the pediatric population is different from adults for two main reasons. Particularly in the newborn phase the brain undergoes biochemical maturation with dramatic changes of the "normal" biochemical fingerprint. Secondly, brain diseases in the pediatric population are different from adult disorders. For example, brain tumors, which are mostly gliomas in the adults, often originate from different cell types and are also more diverse even within the same type and grade of tumor. This diversity of diseases and its implications for MR spectroscopy has not been addressed sufficiently in the literature, we believe. The target audience for "MR Spectroscopy of Pediatric Brain Disorders" are thus both clinicians and researchers involved with pediatric brain disorders. This includes radiologists, neurologists, neurooncologists, neurosurgeons, and more broadly the neuroscience and neurobiology community. This book will provide the necessary background information to understand the basics of MR spectroscopy. This will be followed by a detailed discussion of the normal biochemical maturation which will highlight the metabolic differences between the pediatric and adult brain. Thereafter, in SECTION I individual chapters will address various pediatric brain disease families. Of particular importance for pediatrics are case studies. For that reason, SECTION II will contain a large number of case studies. This will be particularly important for clinicians who may want to see examples of MRS for various conditions. A standardized format will be used for case reports that allow the reader to quickly understand the history of each case presented and the significance of the findings. The case reports will also include information from other imaging modalities to point out any added value of MRS in addition to conventional studies and clinical information. This section is necessary because the format of providing more complete information about individual patients is not practical for the chapters in SECTION I.

Introduction to Brain & Behavior

Introduction to Brain & Behavior PDF Author: Bryan Kolb
Publisher: Worth Pub
ISBN: 9781464107870
Category : Psychology
Languages : en
Pages :

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