Florbetapir imaging in cerebral amyloid angiopathy-related hemorrhages.

Abstract

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. Patients with acute CAA-related lobar ICH were prospectively enrolled and compared with patients with deep ICH. ¹⁸F-florbetapir PET, brain MRI, and <i>APOE</i> 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. 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, <i>p</i> = 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). 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.