Supplementary Material for: A Clinico-Radiological Study of Cerebral Amyloid Angiopathy-Related Inflammation

<b><i>Objective:</i></b> To describe the clinico-radiological features and long-term prognosis in patients with cerebral amyloid angiopathy-related inflammation (CAA-ri). <b><i>Methods:</i></b> Twenty-eight CAA-ri patients were recruited retrospectively from 6 neurological centers. We recorded the clinico-radiological and biological data, at baseline and during follow-up. Baseline characteristics associated with relapse risk and prognosis were assessed. <b><i>Results:</i></b> Five patients had pathologically confirmed CAA-ri whereas 23 had probable (<i>n</i> = 21) or possible (<i>n</i> = 2) CAA-ri. The mean age was 72 years; main clinical symptoms included confusion (54%), hemiparesis (36%), and aphasia (29%). Cerebral MRI disclosed a brain parenchymal lesion (89%), which was usually multifocal (82%) and bilateral (89%). It was associated with gadolinium enhancement (84%), small ischemic lesions (39%), cortical superficial siderosis (CSS; 50%), and a high number of microbleeds (mean 240 ± 277). An isolated leptomeningeal involvement was observed in 3 patients with pathological confirmation. Despite a favorable initial evolution after treatment, we observed a 42% risk of relapse, mostly within the first year (83%). After a mean follow-up of 2 years, 29% died and 25% had a marked disability. Disseminated CSS was associated with death. <b><i>Conclusion:</i></b> Despite an apparently favorable initial evolution, CAA-ri is characterized by a poor prognosis. Diagnostic criteria should consider patients with isolated leptomeningeal involvement.