Cerebellar Superficial Siderosis in Cerebral Amyloid Angiopathy

Cerebellar superficial siderosis (SS) has been recently reported to be present in about 10% of both hereditary (n=50) and sporadic (n=46) cerebral amyloid angiopathy (CAA) patients on 3T MRI using susceptibility-weighted imaging (SWI) in the majority of patients. In that study, cerebellar SS was associated with a higher number of supratentorial lobar and superficial cerebellar macrobleeds (although cerebellar SS was not directly located adjacent to these cerebellar macrobleeds). It is unclear if cerebellar SS is caused by in situ leakage of cerebellar leptomeningeal vessels or rather represents hemorrhagic diffusion from cerebellar parenchymal micro/macrobleeds or from supratentorial bleeding sources via the tentorium cerebelli (TC).