Abstract:Objective To analyze the value of contrast-enhanced computed tomography (CT) combined with diffusion-weighted magnetic resonance imaging (MRI-DWI) in the diagnosis of thymoma.Methods A retrospective analysis was conducted on 204 patients diagnosed with thymoma and thymic carcinoma at the Affiliated Hospital of Nantong University from January 2017 to December 2022. Among them, there were 98 patients in the low-risk thymoma group, 62 patients in the high-risk thymoma group, and 44 patients in the thymic carcinoma group. All patients underwent contrast-enhanced CT and MRI-DWI examinations. The parameters of contrast-enhanced CT and MRI-DWI in the three groups of patients were compared, and the value of contrast-enhanced CT combined with MRI-DWI in diagnosing thymic carcinoma was analyzed. The quantitative parameters of contrast-enhanced CT and MRI-DWI in the high-risk thymoma group and low-risk thymoma group were compared, and the value of contrast-enhanced CT combined with MRI-DWI in diagnosing high-risk thymoma was analyzed.Results The proportion of unclear boundaries in the thymic carcinoma group was higher than that in the low-risk thymoma group and the high-risk thymoma group (P < 0.05), and the proportion of unclear boundaries in the high-risk thymoma group was higher than that in the low-risk thymoma group (P < 0.05). The maximum enhancement CT value, the maximum difference before and after enhancement, and the apparent diffusion coefficient (ADC) value in the thymic carcinoma group were lower than those in the low-risk thymoma group and the high-risk thymoma group (P < 0.05), and those in the high-risk thymoma group were lower than those in the low-risk thymoma group (P < 0.05). The results of ROC curve analysis showed that the sensitivity of the maximum enhancement CT value, the maximum difference before and after enhancement, ADC value, and the combined diagnosis of thymic carcinoma were 68.19% (95% CI: 0.451, 0.853), 72.73% (95% CI: 0.496, 0.884), 77.27% (95% CI: 0.542, 0.913), and 81.82% (95% CI: 0.590, 0.940), respectively, and the specificity were 71.25% (95% CI: 0.599, 0.806), 77.50% (95% CI: 0.665, 0.858), 76.25% (95% CI: 0.652, 0.848), and 92.50% (95%CI: 0.838, 0.969), respectively, with AUCs of 0.711 (95% CI: 0.604, 0.817), 0.702 (95% CI: 0.594, 0.810), 0.703 (95% CI: 0.586, 0.821), and 0.892 (95% CI: 0.824, 0.960). The maximum enhancement CT value and the maximum difference before and after enhancement in the high-risk thymoma group were lower than those in the low-risk thymoma group (P < 0.05), and there was no significant difference in the plain CT value between the two groups (P > 0.05). The ADC value in the high-risk thymoma group was lower than that in the low-risk thymoma group (P < 0.05). The results of ROC curve analysis showed that the sensitivity of the maximum enhancement CT value, the maximum difference before and after enhancement, ADC value, and the combined diagnosis of high-risk thymoma were 67.74% (95% CI: 0.485, 0.827), 70.97% (95% CI: 0.518, 0.851), 74.19% (95% CI: 0.551, 0.875), and 83.87% (95% CI: 0.655, 0.939), respectively, and the specificity were 79.59% (95% CI: 0.652, 0.893), 73.47% (95% CI: 0.587, 0.846), 71.43% (95% CI: 0.565, 0.830), and 85.71% (95% CI: 0.721, 0.936), respectively, with AUCs of 0.709 (95% CI: 0.603, 0.816), 0.701 (95% CI: 0.588, 0.814), 0.722 (95% CI: 0.608, 0.836), and 0.900 (95% CI: 0.835, 0.965).Conclusion The maximum enhancement CT value, the maximum difference before and after enhancement combined with ADC value have good efficacy in the diagnosis of high-risk thymoma and thymic carcinoma, and have certain clinical value.