Abstract: Objective: To investigate the diagnostic value of extramural vessel invasion (EMVI) in multidetector row computed tomography (MDCT) of lymph node metastasis of gastric cancer. Methods: A total of 105 patients with pathologically confirmed gastric cancer treated at our hospital between January 2020 and June 2022 were retrospectively collected. All patients underwent radical gastrectomy and D2 lymph node dissection within 2 weeks after the CT scan. The EMVI status of gastric cancer was evaluated on portal-phase MDCT images using a 5-point scale. According to the pathological status of lymph node metastasis, the patients were divided into lymph node and non-lymph node metastasis groups, and their clinicopathologic features were compared. We then performed a multivariate logistic regression analysis of lymph node metastasis in gastric cancer. A receiver operating characteristic (ROC) curve was used to evaluate the diagnostic value of CT-detected EMVI (ctEMVI) in lymph node metastasis, and the diagnostic values of ctEMVI and lymph node short diameter in lymph node metastasis were compared. Results: In the lymph node metastasis group, lymphovascular invasion, tumor size (>5 cm), ctEMVI positivity, and CT metastatic lymph node positivity accounted for 60.9% (n=39), 64.1% (n=41), 79.7% (n=51), and 56.2% (n=36) of cases, respectively. In the non-metastatic group, lymphovascular invasion, tumor size (>5 cm), ctEMVI positivity, and CT metastatic lymph node positivity accounted for 21.9% (n=9), 24.4% (n=10), 21.9% (n=9), and 19.5% (n=8), respectively. The intergroup difference was statistically significant. The multivariate logistic regression analysis showed that ctEMVI was an independent factor of lymph node metastasis. The ROC curve showed that the area under the curve of ctEMVI for diagnosing lymph node metastasis was 0.854. The sensitivity and accuracy of ctEMVI were superior to those of lymph node short diameter in the diagnosis of lymph node metastasis. Conclusion: This study found that ctEMVI was an independent factor and of great value in the diagnosis of lymph node metastasis.