Interhemispheric distribution of amyloid and small vessel disease burden in cerebral amyloid angiopathy‐related intracerebral hemorrhage

Abstract

Background Intracerebral hemorrhage (ICH) is a devastating presentation of Cerebral Amyloid Angiopathy (CAA), but mechanisms leading from vascular amyloid deposition to ICH are not well known. We investigated whether amyloid burden and MRI markers of small vessel disease (SVD) are increased in the ICH‐affected hemisphere compared to ICH‐free hemisphere in patients with a symptomatic CAA‐related ICH (CAA‐ICH). Methods We prospectively enrolled 18 patients with CAA‐ICH and 18 controls with deep‐ICH who underwent brain MRI and amyloid‐PET using ¹⁸F‐florbetapir. We evaluated in each hemisphere amyloid uptake using the standardized uptake value ratio (SUVr) and the burden of MRI markers of SVD including cerebral microbleeds, chronic ICH, cortical superficial siderosis (cSS), white matter hyperintensities and lacunes. Interhemispheric comparisons were assessed by non‐parametrical matched‐pair tests within each patients’ group. Results Amyloid burden was similarly distributed across brain hemisphere in patients with CAA‐ICH (SUVr value 1.11 vs. 1.12; p = 0.74). cSS tended to be more common in the ICH‐affected hemisphere compared to the ICH‐free hemisphere (61% vs. 33%; p = 0.063). Other MRI markers of SVD did not differ across brain hemispheres. In controls with deep ICH, we did not observe any interhemispheric difference neither for amyloid burden, nor for MRI markers of SVD. Conclusions Brain hemorrhage does not appear to be directly linked to amyloid burden in patients with CAA‐related ICH. These findings provide new insights into the mechanisms leading to hemorrhage in CAA.