Abstract WP130: Prevalence and Predictors of Hemorrhagic Foci on Long-Term Follow-Up MRI of Recent Single Subcortical Infarcts

Abstract

Background: Hemorrhagic foci surrounding the lacune in the long-term evolution of recent single subcortical infarcts (RSSIs) remains largely unexplored. We aimed to determine the prevalence, characteristics, and predictors of hemorrhagic foci in patients with RSSI. Methods: From a prospective, longitudinal study of RSSIs, we recruited patients who underwent multimodal MRI assessments at baseline and approximately one year after stroke onset. Hemorrhagic foci were identified using susceptibility-weighted imaging (SWI). Results: Among 72 patients with RSSI, nearly half (n = 35, 48.6%) had hemorrhagic foci within the index RSSI lesions on follow-up SWI. RSSIs with hemorrhagic foci formation were associated with a longer time to follow-up imaging (median 484 versus 425 days, P = 0.008) and higher likelihood of being located in the anterior circulation compared to those without hemorrhagic foci (100.0% versus 75.7%, P = 0.001). Hemorrhagic foci were also associated with larger lesion size (P < 0.001), higher proportion of cavitation formation (P = 0.042), and poorer functional outcome (P = 0.036). In the subset of RSSIs in the LSA territory, after adjustment for covariates, larger initial lesion volume (OR 1.63, 95% CI 1.06-2.53; P = 0.027) and greater reduction in LSA total length (OR 0.60, 95% CI 0.37-0.97; P = 0.035) were independently associated with hemorrhagic foci formation. Conclusion: Half of RSSI patients developed hemorrhagic foci within the lacunes during follow-up SWI. This hemorrhagic feature might represent hemosiderin deposits from a previously thrombosed perforating artery. The pathophysiologic mechanism and clinical implications remain to be determined.