Inflammation in Cerebral Amyloid Angiopathy-Related Transient Focal Neurological Episodes.

Transient focal neurological episodes (TFNE), often associated with convexity subarachnoid hemorrhage (cSAH), are common in cerebral amyloid angiopathy (CAA), but their pathophysiology remains incompletely understood. In six patients with unremitting TFNE, using high-resolution post-contrast magnetic resonance imaging and vessel wall imaging (VWI), we found various combinations of transient leptomeningeal, parenchymal and vessel wall enhancement; in 5 of 6 the enhancement included regions corresponding anatomically to symptoms. Three patients had resolution of TFNE and enhancement (2 with corticosteroid treatment, 1 without). Our observations suggest that inflammation might contribute to the pathophysiology of CAA-related TFNE and cSAH, with potential wider relevance for the associated high risks of recurrent ICH in CAA more generally. ANN NEUROL 2025;97:475-482.