We evaluated the best methods for predicting various infarct core thresholds for endovascular treatment of ischemic stroke using parameters obtained by multiphase computed tomographic angiography (mCTA). Consecutive patients evaluated for endovascular treatment who concomitantly underwent mCTA and stroke magnetic resonance imaging (MRI) were analyzed. The ability of CTA-based collaterals (single-phase [sCTAc] and multiphase [mCTAc]) and ASPECTS or their combined interpretation for the selection of patients with cores of <31 ml and <70 ml, and ≥100 ml, were compared. In the total 142 patients, the combined interpretation of collateral scores and ASPECTS score indicated significant added benefit for the prediction of smaller infarct volume thresholds (<31 ml) compared to ASPECTS alone. Selection of cases that satisfied both sCTAc 3-5 and ASPECTS 6-10 had the optimal predictive capability and inter-rater reliability. While the combined interpretation did not provide a significant added benefit for the prediction of larger infarct volume thresholds, sCTAc 0-2 and mCTAc 0-2 performed as well as ASPECTS 0-5 in prediction of core volumes ≥100 ml with better inter-rater reliability. sCTA and mCTA can improve the selection of patients for EVT by more accurately predicting lower infarct core volume cutoffs. When excluding patients with large infarct cores, they can improve inter-rater reliability.