The characteristics of intracranial plaques of unilateral, anterior circulation embolic stroke of undetermined source: An analysis of different subtypes based on high‐resolution imaging

The aim was to investigate the characteristics of non-stenotic intracranial plaque (NSIP) in embolic stroke of undetermined source (ESUS) subtypes by high-resolution magnetic resonance imaging.Consecutive patients with ESUS who were mandatory for high-resolution magnetic resonance imaging were retrospectively enrolled. Based on the location and arterial supply of the infarct, the ESUS were categorized into three types: cortical ESUS, subcortical ESUS and mixed ESUS. The NSIP parameters including plaque location, morphology (plaque distribution, remodeling index and plaque burden) and composition (thick fibrous cap, discontinuity of plaque surface, intraplaque hemorrhage and complicated plaque) were evaluated amongst the subtypes.Of 243 patients, there were 87 (35.8%) cortical ESUS, 127 (52.3%) subcortical ESUS and 29 (11.9%) mixed ESUS. Significant differences were found in plaque location (p < 0.001), plaque quadrant (p < 0.001), remodeling index (p < 0.001), plaque burden (p < 0.001), discontinuity of plaque surface (p < 0.001), intraplaque hemorrhage (p = 0.001) and complicated plaque (p < 0.001) of ipsilateral NISP amongst the different ESUS subtypes, except for fibrous cap (p = 0.135). However, no differences were found amongst contralateral NISP. In addition, the clinical characteristics of the differences between ESUS subtypes were striking, including age (p = 0.004), initial National Institutes of Health Stroke Scale (p < 0.001), coronary artery disease (p = 0.039), serum urea (p = 0.011) and creatinine (p = 0.002).This is the first report of significantly heterogeneous characteristics of ipsilateral NSIP and clinical findings amongst ESUS subtypes, which may suggest their different underlying mechanisms.