Multiparametric Neuroimaging and Its Association with Non-Contrast Computed Tomography in Late-Window Large Vessel Occlusion Acute Stroke

Introduction: Endovascular treatment (EVT) for acute ischemic stroke (AIS) between 6 and 24 h is established as a standard of care among patients selected by multiparametric neuroimaging. We aimed to explore neuroimaging parameters in late-window large vessel occlusion (LVO) patients and its association with non-contrast computed tomography (NCCT) findings. Methods: We included consecutive AIS patients within 6-24 h from the symptoms onset with LVO. We described multiparametric imaging findings, the rate of patients who fulfilled imaging perfusion criteria according to the DAWN and DEFUSE-3 trials that define the computed tomography perfusion mismatch (CTP-MM) group and its association with NCCT focused on Alberta Stroke Program Early CT Score (ASPECTS). We also analyzed the association between neuroimaging parameters and the clinical outcome determined by the 90-day modified Rankin scale (mRS). Results: We included 206 patients, of them, 176 (85.4%) presented CTP-MM and 184 (89.3%) presented an ASPECTS ≥6 on admission. The rate of CTP-MM was 90.8% in patients with ASPECTS ≥6, compared with 40.9% in those with low ASPECTS. ASPECTS was moderately correlated with ischemic core determined by cerebral blood flow <30% volume (rS = -0.557, p < 0.001). In EVT-treated patients (185, 89.8%), after adjusting for identifiable confounders, the presence of CTP-MM was a predictor of 90-day functional independence (OR: 3.38; 95% CI: 1.01-11.29; p = 0.048). We did not find an association between CTP-MM and 90-day functional disability (ordinal mRS shift, aOR: 1.39; 95% CI: 0.58-3.34; p = 0.459). Conclusions: A great majority of patients who presented a LVO in the late window fulfilled guidelines imaging criteria to undergo EVT, especially those with high ASPECTS (≥6). Our data suggest that NCCT with CT angiography could be a reasonable approach for AIS treatment selection also in the late window.