After mechanical thrombectomy (MT) for acute ischemic stroke, contrast extravasation may be observed. Therefore, the diagnosis of intracranial hemorrhage (ICH) as the complication is difficult via conventional computed tomography (CT). This study aimed to evaluate the diagnostic accuracy of dual-energy CT (DECT) in differentiating ICH from contrast extravasation after MT. A retrospective study was conducted on patients who underwent MT from January 2019 to May 2022. Single-energy CT and DECT were conducted to estimate the ICH immediately after MT. Diagnostic confirmation of ICH and the diagnostic accuracy of DECT were evaluated via magnetic resonance imaging (MRI). Fifty-eight patients were assigned to this study. One patient (1.7%) had symptomatic ICH, and 18 (31.0%) had asymptomatic. The diagnostic accuracy of DECT based on MRI was 52.6% for sensitivity and 97.4% for specificity. Although DECT has been indicated to have high specificity for diagnosing hemorrhage after MT, MRI-based studies of DECT need improvement.