Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 38 for “"Diffusion MRI"”.
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Diffusion MRI of complex tissue structure
Magnetic resonance diffusion imaging provides an exquisitely sensitive probe of tissue microstructure. Owing to the microscopic length scale of diffusion in biological tissues, diffusion imaging can reveal histological architecture irresolvable by conventional magnetic resonance imaging methods. …
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Quantitative analysis of cerebral white matter anatomy from diffusion MRI
… analysis of white matter fiber tracts from diffusion MRI. The presented methods enable us to look at the variation of a diffusion measure along a fiber tract in a single subject or a population, which allows important clinical studies toward understanding the relation between the changes in …
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Advanced Methods for Diffusion MRI Data Analysis and their Application to the Healthy Ageing Brain
Diffusion of water molecules in biological tissues depends on several microstructural properties. Therefore, diffusion Magnetic Resonance Imaging (dMRI) is a useful tool to infer and study microstructural brain changes in the context of human development, ageing and neuropathology. In this thesis, …
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Hyperpolarized 3He-diffusion MRI in evaluation of lung structure in emphysema. Validation and development of the method
… early stages before symptoms present themselves. MRI with hyperpolarized 3He using diffusion weighted sequences has the potential to detect and quantify parenchyma destruction in emphysema, the main manifestation of COPD. Study I investigated the short-term reproducibility of the method and the …
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Mapping Anisotropic Tissue Fiber and Microvasculature Architecture With Diffusion MRI: Application to Skeletal Muscle and White Matter
… as a novel explanation for the asymmetry of the diffusion on the transverse plane. Second, in the study of skeletal muscle fiber architecture, a new technique, labeled, Intravoxel Partially Coherent Motion (IVPCM) technique, is formulated in order to extract information about the capillary …
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Advances in MRI to probe the functional and structural network of the macaque brain
Diffusion MRI and fMRI have provided neuroscientists with non-invasive tools to probe the functional and structural network of the brain. Diffusion MRI is a neuroimaging technique capable of measuring the diffusion of water in neural tissue. It can reveal histological architecture irresolvable by …
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Penalized discriminant analysis for multivariate functional data
… subjects with poor cognitive status from diffusion MRI data. By leveraging a connection to the optimal scoring problem, we bypass minimizing complex objective functions directly and recast the problem into a penalized regression framework. The proposed formulation leads to an efficient …
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Methods for Data Management in Multi-Centre MRI Studies and Applications to Traumatic Brain Injury
… by large multi-centre magnetic resonance imaging(MRI) studies. The methods implemented are then applied to traumatic brain injury (TBI) data.Firstly, a pre-processing pipeline for both anatomical and diffusion MRI was proposed, that allows for a high throughput of MRI scans. After describing the …
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Mapping myocardial structure-function relations with cardiac diffusion and strain MRI
… understood. This thesis establishes noninvasive MRI methods, registered cardiac diffusion and strain MRI, to acquire information about myocardial sheet structure and myocardial strain under identical in vivo conditions, and thus defines the functional role of myocardial sheets. This methodology …
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Quantitative Magnetic Resonance Imaging For The Early Prediction of Treatment Response In Triple Negative Breast Cancer
… <p>Quantitative Magnetic Resonance Imaging (MRI) may be used to probe and measure aspects of the perfusion, diffusion, and mechanical properties of a cancer and its surroundings. In the research setting, several quantitative MRI biomarkers have shown potential for early prediction of response …
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Modelling brain tumours with network neurosciences and deep learning
… impact of gliomas. Meanwhile, quantitative MRI technology, including functional MRI and diffusion MRI, assisted in developing an emerging field called network neurosciences. The network neurosciences model the brain as a network consisting of macro-scale regional connectivity of the brain …
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Biomechanics of Cranial Decompression Procedures in Traumatic Brain Injury
… for clinical herniation monitoring. Finally, diffusion MRI was used to evaluate differences in white matter integrity (fractional anisotropy, FA) at the regions of strain concentration observed in strain modelling and mirror regions on the contralateral to craniectomy (control) hemisphere. A …
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MRI of structured-based ventricular mechanics
… a completely noninvasive method, registered diffusion and strain MRI, to acquire information about myocardial architecture and myocardial strain under identical in-vivo conditions. This noninvasive methodology solves important limitations of existing methods all of which require myocardial …
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MRI for gray matter: statistical modelling for in-vivo application and histological validation of dMRI
… role in brain function. Measures derived from MRI (e.g., structural MRI (sMRI) and diffusion MRI (dMRI)) provide a unique opportunity to non-invasively study GM structure in-vivo and thus can be used to probe GM pathology in development, aging and neuropsychiatric disorders. Investigation of …
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Studies of Lung Micromechanics via Hyperpolarized 3He Diffusion NMR
… are difficult to obtain with conventional proton MRI due to the organ's low tissue density, the advent of techniques in noble gas polarization have enabled MR investigations of the lung's more abundant air space rather than its tissue. In addition to high-resolution images of lung ventilation, …
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Acquisition and reconstruction methods for magnetic resonance imaging
Magnetic Resonance Imaging (MRI) is a non-invasive medical imaging modality that has a wide range of applications in both diagnostic clinical imaging and medical research. MRI has progressively gained in importance in clinical use because of its ability to produce high quality images of soft tissue …
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Models and algorithms of brain connectivity, spatial sparsity, and temporal dynamics for the MEG/EEG inverse problem
… brain connectivity information derived from diffusion MRI (Chapter 3). Overall, I illustrate how dynamic models informed by neurophysiology and neuroanatomy can be used alongside advanced statistical and signal processing methods to greatly improve MEG/EEG source localization. More broadly, …
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Distinct contribution of white matter damage to the clinical syndrome of Alzheimer's disease
… clinical course. In this work, we used sensitive diffusion MRI measures to determine that the tissue properties of WML slightly differed microstructurally between individuals with Alzheimer's disease and non-demented controls, and were strongly related to ventricular enlargement. In order to …
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Pathological and Biomedical Characteristics of Spinal Cord Injury Determined Using Diffusion Tensor Imaging
… contusion models. Magnetic resonance imaging: MRI) is the modality of choice to noninvasively detect the soft tissue injury, particularly suitable for assessing the tissue integrity in SCI. However, the convention MRI lacks capability of detecting and evaluating the injury severity acutely, …
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MRI techniques for quantitative and microstructure imaging
… and neurological diseases. Quantitative MRI has been proved with its high sensitivity to microstructures, providing a safe, non-invasive approach for human in vivo imaging. However, quantitative MRI typically requires the acquisition of multiple images for biophysical model fitting, which …
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