Objective:To determine the association between early post-endovascular treatment (EVT) contrast extravasation (CE) on dual-energy CT (DECT) and stroke outcomes.Methods:EVT records in 2010–2019 were screened. Exclusion criteria included the occurrence of immediate post-procedural intracranial haemorrhage (ICH). Hyperdense areas on iodine overlay maps were scored according to the Alberta Stroke Programme Early CT Score (ASPECTS), thus forming a CE-ASPECTS. Maximum parenchymal iodine concentration and maximum iodine concentration relative to the torcula were recorded. Follow-up imaging was reviewed for ICH. The primary outcome measure was the modified Rankin Scale (mRS) at 90 days.Results:Out of 651 records, 402 patients were included. CE was found in 318 patients (79%). Thirty-five patients developed ICH on follow-up imaging. Fourteen ICHs were symptomatic. Stroke progression occurred in 59 patients. Multivariable regression showed a significant association between decreasing CE-ASPECTS and the mRS at 90 days (adjusted (a)cOR: 1.10, 95% CI: 1.03–1.18), NIHSS at 24–48 h (aβ: 0.57, 95% CI: 0.29–0.84), stroke progression (aOR: 1.14, 95% CI: 1.03–1.26) and ICH (aOR: 1.21, 95% CI: 1.06–1.39), but not symptomatic ICH (aOR 1.19, 95% CI: 0.95–1.38). Iodine concentration was significantly associated with the mRS (acOR: 1.18, 95% CI: 1.06–1.32), NIHSS (aβ: 0.68, 95% CI: 0.30–1.06), ICH (aOR: 1.37, 95% CI: 1.04–1.81) and symptomatic ICH (aOR: 1.19, 95% CI: 1.02–1.38), but not stroke progression (aOR: 0.99, 95% CI: 0.86–1.15). Results of the analyses with relative iodine concentration were similar and did not improve prediction.Conclusions:CE-ASPECTS and iodine concentration are both associated with short- and long-term stroke outcomes. CE-ASPECTS is likely a better predictor for stroke progression.