Abstract

1Carotid stenosis severity is widely used as an imaging marker for stroke risk, with the degree of stenosis used as a key inclusion criterion in several multicenter, large ran-domized trials of surgery versus medical treatment of carotid atherosclerotic disease.1,2 However, recent evidence suggests that specific elements of plaque composition are stroke risk factors independent of stenosis severity.3 Moreover, recent studies have demonstrated that MRI techniques can character-ize these specific components of carotid plaque accurately in vivo compared with histopathology.4,5 Given the reduction in stroke risk with advances in medical therapy during the past 2 decades, there has been increasing interest in investigating markers of plaque vul-nerability to aid in selecting high-risk patients.6 However, MRI of plaque composition is a relatively new technique and individual studies have generally been small, thereby making it challenging to draw definite conclusions of the value of MRI carotid plaque characterization. Furthermore, it is unclear whether there are differences in the risk profiles of specific plaque components such as intraplaque hemor-rhage (IPH), lipid-rich necrotic core (LRNC), or thinning/ rupture of the fibrous cap (TRFC). In addition, it is unknown whether certain techniques for plaque characterization, such as those involving high-resolution protocols with dedicated carotid surface coils, are superior to techniques that can be performed with widely available, standard MRI neck coils. For these reasons, we performed a systematic review and meta-analysis to evaluate whether MRI of plaque composi-tion is a predictor of ispsilateral ischemic events in carotid atherosclerotic disease.