Cerebral amyloid angiopathy and amyloid load distribution detected on amyloid–positron emission tomography: A systematic review and meta-analysis

Abstract Introduction There are limited data regarding the amyloid positron emission tomography (PET) imaging among patients with Cerebral Amyloid Angiopathy (CAA). We sought to assess the amyloid load distribution detected on amyloid-PET among CAA patients compared to patients with Alzheimer’s Disease (AD), patients with hypertension (HTN) related hemorrhage (ICH) and healthy controls (HC). Patients and methods A systematic review and meta-analysis of published studies with available data on global and regional amyloid-PET uptake was conducted. Comparisons with respect to amyloid load distribution were investigated using random-effects models based on the ratio of mean (RoM) amyloid-PET uptake. RoM 1 and RoM 1 indicate lower and higher global or regional amyloid-PET uptake in CAA compared to another population, respectively. Results We identified 16 cohorts, comprising 271 CAA patients (mean age: 72 years; women: 46%) versus 130 AD patients (mean age: 73 years; women: 44%), 180 patients with HTN-related ICH (mean age: 66 years; women: 36%) and 61 HC (mean age: 71 years; women: 46%) with available data on amyloid-PET. Global amyloid PET ratio differentiated CAA from AD RoM: 0.93; 95% CI: 0.90–0.96; p 0.0001, HTN-related ICH RoM: 1.25; 95% CI: 1.20–1.31; p 0.0001, and HC RoM: 1.26; 95% CI: 1.23–1.29; p 0.0001. Occipital amyloid-PET uptake RoM: 1.20; 95% CI: 1.15–1.26; p 0.0001 was higher in CAA compared to HTN-related ICH, and Occipital-to-global RoM: 1.05; 95% CI: 1.03–1.07; p 0.0001 ratio of amyloid-PET uptake differentiated also CAA from AD. Conclusions CAA is characterized by a distinct amyloid-PET burden and distribution compared to AD patients, patients with HTN-related ICH and HC. These findings may contribute to the design and conduct of future randomized controlled clinical trials, aiming to treat CAA at preclinical stages.