Relationship Between Hematoma Location and Underlying Small Vessel Disease in Cerebellar Intracerebral Hemorrhage

In supratentorial intracerebral hemorrhage (ICH), hematoma location serves as a useful proxy for the underlying cerebral small vessel disease (cSVD) subtype, especially in the context of the Boston criteria. Whether this framework applies to spontaneous cerebellar ICH (cICH) remains unclear. We investigated whether hematoma location in cICH reflects distinct cerebral small vessel pathologies and explored an approach to support the diagnosis of underlying cerebral amyloid angiopathy (CAA) in this setting.

We performed a retrospective multicenter study of consecutive patients with spontaneous cICH admitted to 3 tertiary hospitals in Berlin, Germany, between 2010 and 2024. Clinical, neuroimaging (CT/MRI), and neuropathologic data were collected. cICH location was categorized as superficial, deep, or mixed. Deep and mixed cICH locations were grouped together. MRI-based cSVD markers and neuropathology-confirmed diagnoses were analyzed. CAA was categorized as probable vs no CAA (i.e., nonprobable) using the Boston criteria v2.0. Univariate regression analyses were performed for associations with cICH location. Subsequently, we proposed pilot clinical-MRI criteria that might support the presence of CAA as the cause of cICH.

Among 221 patients with cICH (median age 75 years, interquartile range 65.5-84.5, 57% female), 31 (14%) had superficial and 190 (86%) had deep/mixed cICH. MRI was available in 100 and neuropathology in 35 patients. Superficial cICH location was associated with probable CAA per Boston criteria v2.0 (odds ratio [OR] 8.14, 95% CI 1.25-53.25), whereas deep/mixed cICH was linked to higher systolic blood pressure (OR 1.03, 95% CI 1.01-1.05 per mm Hg) and more severe cSVD burden on MRI (OR 5.37, 95% CI 1.97-14.58). Among patients with available pathology (n = 35), 33.3% of patients with superficial cICH had evidence of CAA vs 3.1% in deep/mixed cICH. Our exploratory construct-"Boston criteria v2.0-cICH with supporting CAA features"-showed a specificity of 94.4% and sensitivity of 60.0% against a probable CAA diagnosis (based on supratentorial findings) in the total patient sample.

Superficial and deep/mixed cICH exhibit distinct clinical, neuroimaging, and neuropathologic profiles, suggestive of divergent cSVD etiologies. Limitations include the sample size and the retrospective design. Our proposed criteria represent a proof-of-concept tool to support CAA diagnosis in cICH within the Boston criteria v2.0 framework but require further validation.