ETIOLOGY OF PRIMARY CEREBELLAR INTRACEREBRAL HEMORRHAGE BASED ON TOPOGRAPHIC LOCALIZATION

Background Cerebellar intracerebral hemorrhage (cICH) is often attributed to hypertension or cerebral amyloid angiopathy (CAA). However, deciphering the exact etiology can be challenging. A recent study reported a topographic etiologic relationship with superficial cICH secondary to CAA. We aimed to re-examine this relationship between topography and etiology in a separate cohort of patients and using the most recent Boston criteria version 2.0. Methods Retrospective analysis of consecutive patients with primary cICH admitted to a tertiary academic center between 2000-2022. cICH location on brain CT/MRI scan(s) was divided into strictly superficial (cortex, surrounding white matter, vermis), vs deep (cerebellar nuclei, deep white matter) or mixed (both regions). MRIs were rated for markers of cerebral small vessel disease. We assigned possible/probable vs absent CAA using Boston criteria 2.0. Results We included 197 patients; 106 (53.8%) females, median age 74 (63-82) years. Fifty-six (28%) patients had superficial cICH and 141 (72%) deep/mixed cICH. MRI was available for 112 (57%) patients [30(26.8%) with superficial and 82(73.2%) with deep/mixed cICH]. Superficial cICH patients were more likely to have possible/probable CAA (48.3% vs 8.6%; OR 11.43, 95%CI 3.26-40.05; p<0.001), strictly lobar cerebral microbleeds (CMBs) (51.7% vs 6.2%; OR 14.18, 95%CI 3.98-50.50; p<0.001), and cortical superficial siderosis (13.8% vs 1.2%; OR 7.70, 95%CI 0.73-80.49; p=0.08). Patients with deep/mixed cICH patients were more likely to have deep/mixed CMBs (59.2% vs 3.4%; OR 41.39, 95% CI 5.01-341.68; p=0.001), lacunes (54.9% vs 17.2%; OR 6.14, 95% CI 1.89-19.91; p=0.002), severe basal ganglia enlarged perivascular spaces (36.6% vs 7.1%; OR 7.63, 95% CI 1.58-36.73; p=0.01), hypertension (84.4% vs 62.5%; OR 3.43, 95% CI 1.61,-7.30; p=0.001), and higher admission systolic blood pressure (172 [146-200] vs 146 [124-158] mmHg, p<0.001). Conclusions Our results suggest that superficial cICH is strongly associated with CAA whereas deep/mixed cICH is almost exclusively linked to hypertensive arteriopathy.