Modified method to improve the diagnostic efficiency of 18F-FDG PET/CT in regional lymph node metastasis of esophageal squamous cell carcinoma

Background: Regional lymph node (LN) metastasis is a significant factor influencing the treatment choice of esophageal squamous cell carcinoma (ESCC). The performance PET/CT as an imaging evaluation method for regional LNs in ESCC, is unsatisfactory due to the lack of logical criterion. We explored how a modified criterion improved the diagnostic value of 18F-FDG PET/CT in regional LN metastasis. Methods: The data from 111 patients with ESCC were analyzed retrospectively. All patients underwent preoperative PET/CT examination, resection of the cancer, and regional LN dissection. The PET/CT images were interpreted by two experienced diagnosticians. LNs were allocated to five subregions. Each LN was diagnosed by two diagnostic criteria of PET/CT (traditional criterion and the modified criterion) one by one across the same field, and the accuracy of PET/CT was determined using the histopathologic results as the reference standard. Results: A total of 4,847 LNs were dissected, of which 147 were confirmed as metastases by postoperative pathology. A total of 656 LNs were screened by 18F-FDG PET/CT imaging. The determination of all 656 LNs by PET/CT was compared with the pathological results. The diagnostic accuracy of the modified and traditional criteria for the five subregions (paraesophageal, neck, upper mediastinal, middle-lower mediastinal and ventral subregions) was: 74.60% vs. 61.90%, 86.44% vs. 81.36%, 90.26% vs. 70.78%, 96.19% vs. 75.09%, and 87.91% vs. 85.71%, respectively. Conclusions: The modified diagnostic criterion had better diagnostic efficiency because it combined PET and CT imaging data.