Diagnosis and prognostic predictive value of delineation methods from ¹⁸F-FDG PET/CT and PET/MR in pancreatic lesion

The aim was to utilize three segmentation methods on ¹⁸F-FDG PET/CT and PET/MR images of pancreatic neoplasm patients, and further compare the effectiveness in differentiating benign from malignant, TNM-stage and prognosis. We conducted a retrospective analysis of 51 patients with pancreatic neoplasm who had undergone ¹⁸F-FDG PET/CT and PET/MR before treatment. The patients were categorized into malignant and benign groups. For each patient, the lesion was segmented by 3 thresholds and we recorded TNM-stage, treatment strategy, time to death, and the performance status of survivors. We used receiver operating characteristic (ROC) analysis to compare the diagnostic performance of different threshold delineations between benign and malignant, as well as TNM-stage of adenocarcinoma patients. The optimal model of prognostic value was also assessed by Cox proportional hazards regression analysis and Kaplan-Meier survival analysis. For both PET/CT and PET/MR, SUV_max had the best diagnostic efficacy in identifying malignant tumors. The background method of PET/MR exhibited the outstanding performance in M-stage (sensitivity/specificity, 92.90%/88.20%), with the weighted factor being whole-body total lesion glycolysis (WBTLG). In multivariate analysis, WBTLG (Exp [B] = 1.009; P = 0.009), and surgery (Exp [B] = 15.542; P = 0.008) were independent predictive factors associated with prognosis. This study found that SUV_max from PET/CT had the best diagnostic efficacy in identifying malignancy, while PET/MR showed higher specificity and accuracy for M-stage. The treatment strategy and WBTLG were independent prognostic factors in pancreatic neoplasm patients. PET/MR using the background method was identified as the optimal predictive model for prognosis.