Objective: To investigate the value of dual-source CT dual-energy virtual plain scan in the preoperative diagnosis of extramural vascular invasion (EMVI) in rectal cancer. Methods: A total of 150 patients with rectal cancer (64 females (42.7%) and 86 males (57.3%), with an average age of (62.3±11.8) years) who were scheduled for surgical treatment in our hospital from November 2019 to December 2021 were selected for the preoperative dual-source CT dual-energy virtual plain scan;. Two senior radiologists independently analyzed preoperative imaging data (including ctEMVI status, local lymph node infiltration, and distant metastasis) to determine the existence of preoperative EMVI. With pathological results as the gold standard, the sensitivity, specificity, accuracy, positive predictive value, and negative predictive value of VNC in the diagnosis of EMVI were evaluated, and the area under the receiver operating characteristic curve (ROC) was used to evaluate the diagnostic efficiency. Results: Among 150 patients with rectal cancer, 56 (37.3%) were positive for EMVI and 94 (62.7%) were negative for EMVI. The accuracy, sensitivity, specificity, positive predictive value, and negative predictive value of EMVI evaluation by physician 1 were 86%, 80.36%, 89.36%, 81.82%, and 88.42%, respectively, and the AUC was 0.831 (95%CI, 0.756～0.905). The accuracy, sensitivity, specificity, positive predictive value, and negative predictive value of physician 2 were 88.67%, 80.36%, 93.62%, 88.24%, and 88.89%, respectively, and the AUC was 0.870 (95%CI, 0.802−0.938). The consistency of the evaluation results between physician 1 and physician 2 was high (k
=0.943). Conclusion: Dual-source CT dual-energy virtual plain scan has a certain diagnostic value in the preoperative evaluation of EMVI of rectal cancer.