Abstract WP449: Distribution of Cerebellar Microbleeds and Their Correlation with Underlying Microangiopathy in Patients with Spontaneous Supratentorial Intracerebral Hemorrhage

Abstract

Background: Cerebral amyloid angiopathy (CAA) and hypertensive cerebral small vessel disease (HTN-cSVD) exhibit distinct distributions of intracerebral hemorrhages (ICHs) and microbleeds (MBs), but little is known about cerebellar hemorrhage patterns and how they relate to the underlying microangiopathy. The Boston criteria for CAA do not discriminate between lobar and deep cerebellar hemorrhages. We investigated if distinct topographical patterns of MBs exists in the cerebellum. Methods: Patients with spontaneous symptomatic supratentorial ICH were included if they had brain MRI with gradient echo T2*-weighted sequence. Cerebellar MBs were classified into lobar or superficial (cortical/corticosubcortical), deep (dentate/peridentate) and mixed patterns. We compared the frequency and distribution of cerebellar MBs between lobar and deep/mixed ICH and correlated with supratentorial MBs (dichotomized into lobar and deep/mixed MBs). Results: 130 patients were included (median age 68.6-years [IQR 57.9-79.0]; 50% male); 87 patients (67%) had lobar ICH (possible CAA, n=26; probable CAA, n=37; nonCAA, n=24) and 43 (33%) had deep/mixed ICH. Cerebellar MBs were seen in 26 patients (20.0%); lobar pattern among 16 patients (61.5%), deep in 4 (15.4%), and mixed pattern in 6 patients (23.1%). Lobar ICH patients often had superficial cerebellar MBs (81.3% vs deep/mixed in 18.8%) while deep/mixed ICH patients more often demonstrated deep/mixed cerebellar MBs (66.7% vs superficial in 23.5%) [ P =0.046]. The distribution of supratentorial MBs correlated with the distribution of cerebellar MBs ( P= 0.047). Two patients with possible CAA had MBs confined to superficial cerebellum and incorporation of cerebellar MBs into the Boston criteria would have resulted in their reclassification into probable CAA, while another two probable CAA had deep/mixed cerebellar MBs reclassifying them into nonCAA ICH. Conclusion: Distinct superficial and deep cerebellar MB patterns can be distinguished which segregate with lobar and deep/mixed ICH locations, suggesting differential cerebellar involvement by CAA and HTN-cSVD. If validated, lobar (superficial) cerebellar MBs might be used to further improve the accuracy of the Boston criteria for CAA.