Abstract: Abstract: Objective To retrospectively analyze the outcomes of wake-up stroke (WUS) patients with occlusion of large vessel occlusion (LVO), who were selected for mechanical thrombectomy according to the mismatch of Alberta Stroke Program Early CT Score (ASPECTS) based on arterial spin labeling (ASL) and diffusion-weighted image (DWI) on admission magnetic resonance (MR) scans. Methods Twelve consecutive WUS patients with acute LVO of the anterior circulation undergoing MR scans with ASL and DWI prior to thrombectomy were retrospectively evaluated. The mismatch of ASPECTS was defined as the difference between ASL-ASPECTS and DWI-ASPECTS, and a higher score indicates a greater mismatch. Results The procedures led to successful reperfusion in all the cases (Thrombolysis in Cerebral Infarction Grade 2b-3). Eleven patients (91.7% ) had significantly decreased National Institute of Health Stroke scale (NIHSS) score at discharge. AmRS score of ≤2 at 90 days was achieved in 8 of the 12 patients (66.7%). Conclusion The mismatch between ASPECTS assessed based on ASL and DWI can detect a true mismatch in patients with acute LVO of the anterior circulation, and can be used for rapid screening of patients eligible for thrombectomy.