CT Perfusion in lacunar stroke: a powerful tool to enhance lacunar stroke detection and prediction of patients' outcome

Introduction: Lacunar strokes are caused by occlusion of small penetrating arteries. Although CT perfusion (CTP) is widely used in the acute settings, automated core/penumbra software often fails to detect lacunar perfusion abnormalities, so its diagnostic and prognostic roles remain unclear. This study aimed to assess the ability of CTP to detect perfusion asymmetries in patients with lacunar stroke and to determine whether such asymmetries are associated with clinical characteristics and functional outcomes. Material and methods: We retrospectively analyzed 68 patients with lacunar stroke who underwent whole-brain CTP within 4.5 h from stroke onset or recognition. CTP maps (MTT, CBF, CBV, and summary) were visually assessed. Demographic, clinical and imaging data along with stroke metrics and outcomes measurements were collected. Statistical analyses explored CTP detection rate, the association between admission variables and the presence of CTP asymmetries and between these asymmetries and 3-month mRS (dichotomized as either mRS 0–1 or ≥ 2). Results: 41.18% of patients exhibited CTP-detected asymmetries, with the MTT map showing the highest detection rate (39.71%). No demographic or clinical factors predicted CTP positivity. The presence of CTP asymmetries was associated with larger infarct volumes and was independently associated with lower odds of excellent functional recovery (3-month mRS 0–1) (OR 0.232; p = 0.012). Conclusions: Qualitative assessment of individual CTP maps, and especially of MTT map, improves detection of lacunar strokes, particularly with whole-brain coverage. Asymmetries may reflect impaired microvascular perfusion and predict worse outcomes. Therefore, CTP is a valuable diagnostic and prognostic tool in lacunar stroke.