Use this URL to cite or link to this record in EThOS: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.558196
Title: In-vivo MRI characterization of atherosclerotic plaques
Author: Biasiolli, Luca
Awarding Body: Oxford University
Current Institution: University of Oxford
Date of Award: 2011
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Abstract:
Acute ischemic events associated with atherosclerosis are most often caused by rupture or erosion of unstable plaques. Clinical studies have demonstrated that in-vivo multi- contrast MRI can characterize plaque morphology and composition to evaluate the vulnerability of atherosclerotic plaques. The standard protocol for carotid imaging uses the Double-Inversion-Recovery (DIR) Fast-Spin-Echo (FSE) pulse sequence to acquire black-blood 2D high-resolution cross-sectional T\W, PDW and T2W images. With the addition of bright-blood Time-of-Flight images, it was demonstrated that in-vivo multi- contrast MRI could discriminate the major plaque components: lipid-rich necrotic core, intra-plaque haemorrhage, fibrous tissue and calcification. Given the nature and the large amount of multi-contrast MRI data, clinical studies of atherosclerosis would benefit from the availability of reliable and accurate automated techniques for image registration, segmentation and plaque classification. Recent multi-contrast MRI studies presented automatic plaque characterization methods that showed promising results under ex-vivo and in-vivo conditions. This thesis investigates some weaknesses in the current image acquisition and analysis techniques, which can affect the results of in- vivo MRI plaque characterization, and then proposes novel methods to advance the understanding of atherosclerosis in the carotid arteries. An automated multi -contrast registration algorithm that corrects for misalignments between carotid images caused by patient motion using sub-pixel accuracy and different similarity metrics was developed and validated. This project also used an alternative in-vivo carotid imaging approach based on the DIR Multi-Echo-Spin-Echo (Multi-SE) pulse sequence that acquired a series of black-blood 2D high-resolution cross-sectional images at different echo times. Quantitative T2 maps and synthetic multi-contrast images of carotid arteries were calculated from the Multi-SE images. T2 maps were automatically segmented and classified to provide in-vivo T2 measurements of the main plaque components, while Multi-SE synthetic images were compared with FSE images to demonstrate that the FSE acquisition strategy causes a significant loss of vessel edge sharpness.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.558196  DOI: Not available
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