Diagnostic Accuracy of Finger-Like Projections and Subarachnoid Hemorrhage for Cerebral Amyloid Angiopathy: Pathological Validation From Lobar Hematoma Evacuation or Brain Biopsy

BACKGROUND: Diagnosing cerebral amyloid angiopathy (CAA) after spontaneous lobar intracerebral hemorrhage has significant clinical implications. A previous postmortem study found that the presence of both subarachnoid hemorrhage (SAH) and hematoma finger-like projections (FLP) on acute-stage computed tomography strongly rules in CAA. In the present study, we assessed the diagnostic value of these imaging markers against histopathologic diagnosis in less severe presentations. METHODS: This retrospective (2002–2022) multicenter study included patients aged ≥45 years with lobar intracerebral hemorrhage of unknown cause, for whom acute-stage computed tomography or magnetic resonance imaging and neuropathological samples from hematoma evacuation or biopsy were available. Centralized consensus reading (2 raters) of imaging and neuropathological data (including Aβ immunohistochemistry) were performed. Analysis was restricted to samples containing at least 10 vessels. The diagnostic performance was evaluated against the neuropathological reference, that is, CAA/no CAA. RESULTS: We analyzed data from 66 patients (age, 65±9 years; men, 33%; hematoma volume, 45±26 mL; death within 1 year, 14%) from 6 French centers. Neuropathological material included samples from hematoma evacuation (n=48) and biopsy (n=18). CAA was present in 38 patients (58%), and FLP and SAH were observed in 29 (44%) and 50 (76%) patients, respectively. FLP had a sensitivity of 0.58 (95% CI, 0.41–0.74) and a specificity of 0.74 (95% CI, 0.54–0.89) for the diagnosis of CAA. SAH demonstrated a high sensitivity of 0.92 (95% CI, 0.78–0.98; negative predictive value=0.80 [0.52–0.96]) but moderate specificity of 0.43 (95% CI, 0.24–0.63). The combined presence of FLP and SAH had a specificity of 0.54 (95% CI, 0.37–0.71) and a sensitivity of 0.79 (95% CI, 0.59–0.92). CONCLUSIONS: This study is the first to evaluate the diagnostic performance of FLP and SAH with histopathologic reference in nonautopsied patients. The results suggest these markers have lower diagnostic performance than previously reported in severe hematomas leading to early death. However, the high sensitivity of SAH suggests its potential clinical utility in ruling out CAA when absent.