Abstract
OBJECTIVE: To investigate the predictive value of preoperative [(18)F]fluorodeoxyglucose ([(18)F]FDG) positron emission tomography/computed tomography (PET/CT)-derived heterogeneity index (HI) for occult lymph node metastasis (OLM) in clinical N0 gastric adenocarcinoma. METHODS: This retrospective study included 83 patients with clinical N0 gastric adenocarcinoma who underwent [(18)F]FDG PET/CT scans before radical surgery between March 2018 and June 2024. Patients were classified as OLM-positive (n=40) or OLM-negative (n=43) based on postoperative pathology. Clinical characteristics, PET/CT metabolic parameters [maximum standardized uptake value (SUVmax), mean standardized uptake value (SUVmean), peak standardized uptake value (SUVpeak), tumor-to-liver ratio (TLR), metabolic tumor volume (MTV), and total lesion glycolysis (TLG)], and heterogeneity indices (HI-1 and HI-2) were analyzed. Univariate and multivariate logistic regression models were applied to identify independent predictors of OLM. ROC curve analysis was performed to assess diagnostic performance. Statistical analysis was conducted using SPSS version 26.0, with P<0.05 considered statistically significant. RESULTS: Gender, tumor differentiation, and pathological T stage differed significantly between the two groups (P<0.05). HI-2 was significantly higher, while SUVmax, SUVmean, and HI-1 were significantly lower in the OLM-positive group (P<0.05). Multivariate analysis identified pathological T stage (T3-T4, OR=4.778, P=0.022) and HI-2 >4.959 (OR=6.887, P=0.002) as independent predictors of OLM. ROC analysis revealed that HI-2 had an AUC of 0.711 (95% CI: 0.596-0.824, P=0.001), with 52.5% sensitivity and 88.37% specificity at the optimal threshold. CONCLUSION: HI-2 derived from preoperative [(18)F]FDG PET/CT is a significant independent predictor of OLM in clinical N0 gastric adenocarcinoma patients, alongside pathological T stage.