Impact of MRI Characterization of the Carotid Artery in the Understanding of Stroke

Carotid artery stenosis accounts for approximately 10% of ischemic strokes. Improved methods of diagnosis of cerebrovascular atherosclerosis would result in significant improvement in quality of life and major savings in health care costs. Imaging plays a critical role evaluating patients suspected of acute stroke. Magnetic Resonance Imaging (MRI's) significant advantages over DUS in carotids imaging can pay off its cost by means of improved patient outcome. Although DUS is frequently performed to evaluate carotid disease, there is nonuniformity in practice among laboratories. MRI can detect and quantify major compositional features of the carotid plaque and comprehensively evaluate its complications. A high level of agreement exists between high-resolution in vivo MRI, gross, and histological findings on the thickness and sites of potential rupture of the fibrous cap in advanced carotid artery atherosclerosis. MRI is capable of classifying and distinguishing different stages of atherosclerotic lesions. It can also examine the mechanisms of regression, progression, and endothelial dysfunction of the carotid plaque. Carotid MRI is a histologically validated, non-invasive imaging method that can track atherosclerotic disease progression and regression. It can quantitatively evaluate parameters associated with plaque morphology and composition. MRI is able to quantify high-grade carotid artery stenosis and occlusion with good accuracy and reproducibility and provides an opportunity to prospectively examine the relationship between plaque features and subsequent cerebrovascular events. The aim of this article is to examine the efficacy of MRI versus DUS in identifying vulnerable carotid lesions in the acute stroke patient that can account for stroke etiology or mechanism.