Diagnostic accuracy of contrast-enhanced dual-energy computed tomography for detecting metastatic lymph nodes in patients with malignant tumors: a systematic review and meta-analysis

Background: This meta-analysis evaluated the diagnostic accuracy of contrast-enhanced dual-energy computed tomography (DECT) for detecting metastatic lymph nodes in patients with cancer.Methods: PubMed, Embase and Cochrane Library databases were searched for literature published from database inception until September 2022. Only studies that investigated the diagnostic accuracy of DECT for metastatic lymph nodes in patients with malignant tumors and surgically removed metastatic lymph nodes for pathological confirmation were included. The quality of the included studies was evaluated using the Quality Assessment of Diagnostic Accuracy Studies tool. The threshold effect was determined by calculating Spearman correlation coefficients and summary receiver operating characteristic (SROC) curve patterns. Deeks test was used to assess publication bias.Results: All of the included studies were observational studies. A total of 16 articles involving 984 patients were included (2,577 lymph nodes) in this review. A total of 15 variables were included in the meta-analysis, including 6 individual parameters and 9 combined parameters. Normalized iodine concentration (NIC) in the arterial phase combined with the slope in the arterial phase showed better identification of metastatic lymph nodes. The spearman correlation coefficient was -0.371 (P=0.468), and the SROC curve did not show a "shoulder-arm" shape, suggesting that there was no threshold effect and that heterogeneity was present. The combined sensitivity was 94% [95% confidence interval (CI): 86-98%], the specificity was 74% (95% CI: 52-88%), and the area under the curve was 0.94. The Deeks test suggested no significant publication bias in the included studies (P=0.06).Conclusions: NIC in arterial phase combined with the slope in the arterial phase has some diagnostic value in differentiating between metastatic and benign lymph nodes, but this should be further evaluated in additional studies with rigorous design and high homogeneity.