Stroke remains the most common cause of long-term disability with approximately two-thirds of ischaemic strokes resulting from underlying carotid atherosclerotic disease. The clinical management of carotid artery disease relies primarily on the evaluation of the severity of carotid artery luminal stenosis. However, there is growing evidence that morphological and functional information about carotid plaques may also be crucial for the assessment of the severity of atherosclerosis. High-resolution magnetic resonance (MR) imaging is an emerging imaging technique, which has shown great promise in providing detailed information about plaque pathobiology besides luminal stenosis. Using a special contrast medium called ultrasmall superparamagnetic particles of iron oxide (USPIO), MR imaging can also help in the assessment of carotid plaque inflammation. In this dissertation, I explore the different MR imaging modalities for the assessment of morphological, biomechanical and functional characteristics of the atherosclerotic plaques in different patient cohorts, to assess the efficacy of these techniques in identifying high-risk atherosclerotic plaques. It is important to identify these individuals with vulnerable plaques and are the risk of future cerebrovascular events so that they receive optimal medical therapy and timely surgical intervention.

Overall the results of this dissertation provide strong support for the use of functional MR imaging techniques i.e. USPIO-enhanced and Dynamic contrast-enhanced MR imaging for detailed morphological and functional assessment of plaques. This may help refine risk stratification especially in subgroups of patients with asymptomatic carotid disease. This may assist in in improving our standing of the pathogenesis of cardiovascular disease in different patient cohorts and help to determine disease severity and prognosis, as well as providing a biomarker to assess the efficacy of established or novel therapeutic interventions