Low-Density Carotid Plaques and the Risk of Stroke

Abstract

Ischemic stroke is the second cause of death worldwide, and at least a quarter of all ischemic strokes are associated with carotid atherosclerotic disease, the diagnosis of which relies primarily on imaging methods. Traditional risk assessment in carotid atherosclerotic disease has long been based on the measurement of stenosis severity, but there is strong evidence that only stenosis grading falls short in predicting near-future events. Moreover, numerous histopathologic studies gathered increasing evidence that plaque vulnerability depends on its composition and morphology, therefore, the new concept of "vulnerable plaque" analysis is necessary, independent of the carotid narrowing. Follow-up studies concluded that the presence of a large-lipid necrotic core and thin fibrous cap are significantly more likely to result in future ischemic events and thereby are hallmarks for unstable lesions. Under these conditions, magnetic resonance imaging (MRI) and multi-detector computed tomography (MDCT) characterization of specific plaque properties can provide additional information on ischemic stroke risk that are not provided by the simple measurement of luminal stenosis. Therefore, besides the stenosis degree, plaque morphology assessment using noninvasive methods could be useful to identify rupture-prone plaques and may be a suitable prognosis tool that will help improve risk stratification and the effectiveness of therapeutic strategies.