• Andreas Charidimou, Sergi Martinez-Ramirez, Ashkan Shoamanesh, Jamary Oliveira-Filho, Matthew Frosch, Anastasia Vashkevich, Alison Ayres, Jonathan Rosand, Mahmut Edip Gurol, Steven M Greenberg, and Anand Viswanathan.
• From the Department of Brain Repair and Rehabilitation (A.C.), UCL Institute of Neurology and The National Hospital for Neurology and Neurosurgery, London, UK; and the Hemorrhagic Stroke Research Program, Stroke Research Center, Department of Neurology (A.C., S.M.-R., A.S., J.O.-F., A. Vashkevich, A.A., J.R., M.E.G., S.M.G., A. Viswanathan), C.S. Kubik Laboratory for Neuropathology (M.F.), Division of Neurocritical Care and Emergency Neurology (J.R.), and Center for Human Genetic Research (J.R.), Massachusetts General Hospital, Harvard Medical School, Boston. acharidimou@mgh.harvard.edu.
• Neurology. 2015 Mar 24;84(12):1206-12.

ObjectiveTo gain insight into different cerebral amyloid angiopathy (CAA) phenotypes and mechanisms, we investigated cortical superficial siderosis (CSS), a new imaging marker of the disease, and its relation with APOE genotype in patients with pathologically proven CAA, who presented with and without intracerebral hemorrhage (ICH).MethodsMRI scans of 105 patients with CAA pathologic confirmation and MRI were analyzed for CSS (focal, ≤3 sulci; disseminates, ≥4 sulci) and other imaging markers. We compared pathologic, imaging, and APOE genotype data between subjects with vs without ICH, and investigated associations between CSS and APOE genotype.ResultsOur cohort consisted of 54 patients with CAA with symptomatic lobar ICH and 51 without ICH. APOE genotype was available in 53 patients. More than 90% of pathology samples in both groups had neuritic plaques, whereas neurofibrillary tangles were more commonly present in the patients without ICH (87% vs 42%, p < 0.0001). There was a trend for patients with CAA with ICH to more commonly have APOE ε2 (48.7% vs 21.4%, p = 0.075), whereas patients without ICH were more likely to be APOE ε4 carriers (85.7% vs 53.9%, p = 0.035). Disseminated CSS was considerably commoner in patients with ICH (33.3% vs 5.9%, p < 0.0001). In logistic regression, disseminated CSS was associated with APOE ε2 (but not APOE ε4) (odds ratio 5.83; 95% confidence interval 1.49-22.82, p = 0.011).ConclusionsThis neuropathologically defined CAA cohort suggests that CSS and APOE ε2 are related to the hemorrhagic expression of the disease; APOE ε4 is enriched in nonhemorrhagic CAA. Our study emphasizes the concept of different CAA phenotypes, suggesting divergent pathophysiologic mechanisms.© 2015 American Academy of Neurology.

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