[High-resolution magnetic resonance imaging of carotid atherosclerotic plaque]

Stroke is the third most common cause of mortality in the United States with an incidence rate of approximately 700 000 deaths per year. As a means to prevent cerebrovascular events, current concepts advocate endarterectomy or carotid stenting in patients with advanced carotid disease. Arterial stenosis alone has been shown to be a poor predictor of cardiovascular events and therefore both arterial stenosis and patient symptom status are taken as indications for interventional therapy. Several studies have shown that symptomatic subjects benefit more from a carotid endarterectomy than asymptomatic subjects: 3-6 carotid endarterectomies are needed to prevent one stroke per year in symptomatic subjects with > 70 % stenosis compared to 14 - 17 carotid endarterectomies in asymptomatic patients with > 50 % stenosis. It is commonly accepted today that factors other than the degree of luminal stenosis can determine a patient's symptom status, such as the composition or the superficial structure of atherosclerotic plaque. High-resolution magnetic resonance imaging has overcome the limitations of current angiographic techniques and has emerged as a leading non-invasive imaging modality for atherosclerotic disease, especially within carotid arteries and other large vessels. In this review, the state of the art in MRI of atherosclerosis is presented in terms of hardware and image acquisition protocols. Also, the results of validation studies for measuring lesion size, composition and inflammation will be summarized. Finally, the status of several clinical trials involving MRI of atherosclerosis will be reviewed.