Modern methods for imaging carotid atheroma

Atherosclerotic disease of the carotid arteries has been identified as a major cause of stroke and thromboembolism from ruptured atheroma plaques within the walls of these vessels, has been proposed as the putative pathophysiological event underlying cerebral ischaemia. Carotid endarterectomy has been shown to be superior to pharmacotherapy in reducing the likelihood of further disabling stroke or death, in selected individuals. It is, therefore, necessary to identify those individuals at highest risk of stroke, for whom the risks of aggressive intervention may be worthwhile. Our understanding of atherosclerosis suggests that plaque rupture is precipitated by inflammation that causes alteration in the morphological composition and functional activity within the plaque resulting in exposure of thrombogenic material to the circulation. Identification of this in vivo biological process or surrogate markers suggesting 'vulnerability' to plaque rupture could, therefore, aid the selection of individuals for whom the risks of aggressive intervention may be warranted. This review outlines the imaging modalities that have been evaluated for in vivo structural assessment of carotid plaques and risk stratification for selection for aggressive interventions. More recent strategies appear to be moving toward a combination of morphological and functional imaging in order to visualize the pathophysiological mechanisms that underlie plaque rupture.