Use this URL to cite or link to this record in EThOS:
Title: In-vivo MRI characterization of atherosclerotic plaques
Author: Biasiolli, Luca
ISNI:       0000 0004 2722 8507
Awarding Body: Oxford University
Current Institution: University of Oxford
Date of Award: 2011
Availability of Full Text:
Full text unavailable from EThOS.
Please contact the current institution’s library for further details.
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:  DOI: Not available