Comparative Study of 99mTc-3PRGD2 SPECT/CT and 18F-FDG PET/CT in the Diagnosis of Metastatic Lymph Nodes from Esophageal Squamous Cell Carcinoma

Abstract Objectives Lymph node (LN) metastasis represents a significant prognostic factor for esophageal squamous cell carcinoma (ESCC), and there is a lack of effective methods to accurately predict metastatic LNs. The present study aimed to compare the performance of 99mTc-3PRGD2 SPECT/CT and 18F-FDG PET/CT for diagnosing metastatic LNs in ESCC. Methods Fifteen patients with suspected ESCC were enrolled and underwent 99mTc-3PRGD2 SPECT/CT and 18F-FDG PET/CT examinations preoperatively. High-definition bone carving reconstruction technology (HD-xSPECT Bone) was applied to quantitatively assess the SUVmax of LN in SPECT/CT. A comparison of 99mTc-3PRGD2 SPECT/CT and 18F-FDG PET/CT was performed for the diagnosis of LN metastasis with pathology as the gold standard. Results Among the 15 patients, 23 metastatic LNs were predicted by SPECT/CT with SUVmax of 2.71 ± 1.34, of which 15 were pathologically confirmed. Among the 32 metastatic LNs predicted by PET/CT with SUVmax of 4.41 ± 4.02, 17 were pathologically confirmed. The sensitivity, specificity, accuracy, PPV and NPV of SPECT/CT in diagnosing metastatic LNs were 62.50%, 91.21%, 85.22%, 65.22% and 90.22%, and those of PET/CT were 70.83%, 83.52%, 80.87%, 53.13% and 91.57%, respectively. There was no significant difference in sensitivity (p = 0.061) or specificity (p = 0.058) between the two methods. The AUCSPECT/CT was 0.816 and the SUVmax threshold was 2.5. Conclusion 99mTc-3PRGD2 SPECT/CT is an effective method for quantitatively diagnosing metastatic LNs by HD-xSPECT Bone technology in ESCC, and its diagnostic sensitivity and specificity were not inferior to those of 18F-FDG PET/CT. The SUVmax cut-off value of 2.5 showed the highest agreement with pathology.