Microbleeds of Lacunar Infarction and Middle Cerebral Artery Flow Velocity of Branch Atheromatous Disease Are Essential Factors of Stroke Etiology

Background: Although subcortical infarction patients sometimes show larger infarction size than the definition of small vessel occlusion (SVO), there are no specific predictors of larger size. The aim of this study was to identify the factors, including magnetic resonance imaging (MRI) and ultrasonographic parameters, to predict larger subcortical infarction. Methods: Consecutive patients with acute supratentorial subcortical infarction were studied. Patients were classified into 2 groups (L: larger group, ≥15 mm and ≥3 slices; S: smaller group, SVO based on the TOAST classification). Clinical information, MRI findings including the presence of microbleeds, and ultrasonography findings were evaluated and compared between the 2 groups. Results: A total of 120 patients (81 male, mean 67 years old) were enrolled. The L group included 22 patients (18%), and the S group had 98 patients (82%). On neuroimaging, microbleeds were seen less frequently in the L group than in the S group (23 vs. 53%, p = 0.017), and peak systolic velocity (PSV) by transcranial color-coded sonography was faster in the L group than in the S group (121 ± 39.8 vs. 83.4 ± 25.4 cm/s, p = 0.002). On multivariate logistic regression analysis, no evidence of microbleeds (OR 4.4, 95% CI 1.41–13.68, p = 0.011) and PSV over 92 cm/s (OR 3.1, 95% CI 1.007–9.719, p = 0.049) were found to be independently associated with larger size. Conclusion: Microbleeds is related to smaller size and middle cerebral artery PSV > 92 cm/s indicate larger size in supratentorial subcortical infarcts.