Introduction: The best technique for selecting acute stroke patients for reperfusion therapies is not defined yet. ASPECTS is a useful score for assessing the extent of early ischemic signs in the anterior circulation on non-contrast CT (CT). Cerebral blood volume (CBV) on CT perfusion (CTP) defines the core lesion assumed to be irreversibly damaged. Whether CBV provides additional information over CT in the initial ASPECTS assessment is unknown. We aim to explore the advantages of CBV_ASPECTS over CT_ASPECTS in the prediction of final infarct volume. Methods: Consecutive patients with middle cerebral or internal carotid artery occlusion who underwent endovascular reperfusion treatment according to initial CT_ASPECTS≥7 were studied. CBV_ASPECTS was assessed blindly later-on. Recanalization was defined as TICI2b3. Final infarct volumes were measured on follow-up imaging. We defined an irrelevant ASPECTS difference (IAD) as: CT_ASPECTS - CBV_ASPECTS≤1. Results: Sixty-five patients, mean age 67±14, median NIHSS:16(10-20) were studied. Recanalization rate was: 78.5%. Median CT_ASPECTS was 9(8-10), and CBV_ASPECTS 8(8-10). Mean time from symptom onset to CT was 219±143 min. 50 patients (76.9%) showed an IAD. The ASPECTS difference was inversely correlated to the time from symptom onset to CT (r:-0.36, p<0.01). A ROC curve defined 120 minutes as the best cut-off time point after which the ASPECTS difference becomes irrelevant. The rate of IAD was significantly higher after 120 minutes (89.5% Vs 37.5; p<0.01). CBV_ASPECTS but not CT_ASPECTS correlated to the final infarct (r:-0.33, p<0.01). However, if CT was done >2 hours after symptom onset, then CT_ASPECTS was correlated to final infarct (r:-0.39, p=0.01). No other variables were associated with CT-CBV_ASPECTS difference. Conclusions: In acute stroke patient CBV_ASPECTS correlates with final infarct volume. However, when CT is performed after 120 minutes from symptoms onset CBV_ASPECTS does not add relevant information to CT_ASPECTS.