Difference in the Location and Risk Factors of Cerebral Microbleeds According to Ischemic Stroke Subtypes

Background and Purpose The location of cerebral microbleeds (CMBs) may differ according to ischemic stroke subtype, and the underlying pathomechanism may differ by their location. Here, we investigated the characteristics of CMBs according to various ischemic stroke subtypes to verify this issue. Methods Patients with acute ischemic stroke were consecutively included. The presence of CMBs was determined by gradient echo image sequence. The distribution of CMBs was classified as deep, lobar, or diffuse (both deep and lobar). The prevalence, risk factors, and distribution of CMBs were compared among patients with different stroke subtypes. Factors associated with the distribution of CMBs were investigated. Results Among the 1033 patients included in this study, ischemic stroke subtypes were classified as large artery atherosclerosis (LAA; n=432), small vessel occlusion (SVO; n=304), and cardioembolism (CE; n=297). The prevalence of CMBs was highest in patients with SVO (40.5%), followed by CE (33.0%) and LAA (24.8%; P<0.001). The locations of CMBs was different according to subtype (P=0.004). CE [odds ratio (OR)= 1.85 (1.02-3.34); P=0.042] and the use of antithrombotics [OR=1.80 (1.10-2.94); P=0.019] were associated with lobar CMBs, and old age [OR=1.02 (1.00-1.04); P=0.015] and hypertension [OR=1.61 (1.08-2.40); P=0.020] were associated with deep CMBs. Conclusions CMBs were frequently located in the lobar area in patients with CE. Previous use of antithrombotic agents is associated with lobar CMBs. The pathogenic mechanism of CMB may differ according to ischemic stroke subtype and location.