Florbetapir imaging in cerebral amyloid angiopathy-related hemorrhages

Abstract

Objective:To assess whether 18F-florbetapir, a PET amyloid tracer, could bind vascular amyloid in cerebral amyloid angiopathy (CAA) by comparing cortical florbetapir retention during the acute phase between patients with CAA-related lobar intracerebral hemorrhage (ICH) and patients with hypertension-related deep ICH.Methods:Patients with acute CAA-related lobar ICH were prospectively enrolled and compared with patients with deep ICH. 18F-florbetapir PET, brain MRI, and APOE genotype were obtained for all participants. Cortical florbetapir standard uptake value ratio (SUVr) was calculated with the whole cerebellum used as a reference. Patients with CAA and those with deep ICH were compared for mean cortical florbetapir SUVr values.Results:Fifteen patients with acute lobar ICH fulfilling the modified Boston criteria for probable CAA (mean age = 67 ± 12 years) and 18 patients with acute deep ICH (mean age = 63 ± 11 years) were enrolled. Mean global cortical florbetapir SUVr was significantly higher among patients with CAA-related ICH than among patients with deep ICH (1.27 ± 0.12 vs 1.12 ± 0.12, p = 0.001). Cortical florbetapir SUVr differentiated patients with CAA-ICH from those with deep ICH (area under the curve = 0.811; 95% confidence interval [CI] 0.642–0.980) with a sensitivity of 0.733 (95% CI 0.475–0.893) and a specificity of 0.833 (95% CI 0.598–0.948).Conclusions:Cortical florbetapir uptake is increased in patients with CAA-related ICH relative to those with deep ICH. Although 18F-florbetapir PET can label vascular β-amyloid and might serve as an outcome marker in future clinical trials, its diagnostic value in acute CAA-related ICH seems limited in clinical practice.