Diagnostic value of dual-time-point 18F-fluorodeoxyglucose PET/computed tomography in differentiating benign and malignant extrahepatic bile duct occupying lesions.

OBJECTIVE

To investigate the diagnostic value of dual-time-point 18F-fluorodeoxyglucose (FDG) PET/computed tomography (CT) in characterizing extrahepatic bile duct occupying lesions.

METHODS

A retrospective analysis was performed on 157 patients with suspected extrahepatic bile duct occupying lesions who underwent dual-time-point 18F-FDG PET/CT at the Affiliated Hospital of Chengde Medical University between January 2021 and February 2026. According to lesion nature, patients were divided into a malignant group and a benign group. The Mann-Whitney U test and χ2 test were used to compare clinical characteristics, laboratory indices, PET parameters, and diagnostic efficacy between groups. Multivariate logistic regression analysis was used to identify independent risk factors for diagnosing extrahepatic cholangiocarcinoma. A logistic regression model was established based on the selected variables, and receiver operating characteristic (ROC) curve analysis was used to evaluate diagnostic performance. A P value is less than 0.05 was considered statistically significant.

RESULTS

Among the 157 patients with suspected extrahepatic bile duct occupying lesions, 126 cases (80.2%) were malignant and 31 cases (19.8%) were benign. Compared with the benign group, the malignant group showed statistically significant differences in jaundice (yes/no), intrahepatic bile duct dilatation (yes/no), extrahepatic bile duct dilatation (yes/no), CA19-9, retention index, maximum standard uptake value, early lesion-to-liver ratio (LLR), and delayed LLR (all P < 0.05). These variables were included in stepwise multivariate logistic regression to construct a regression equation. The area under the ROC curve was 0.912. The sensitivity, specificity, accuracy, positive predictive value, and negative predictive value of dual-time-point 18F-FDG PET/CT for evaluating lesion nature were 95.10, 90.00, 85.10, 97.50, and 81.80%, respectively.

CONCLUSION

Dual-time-point 18F-FDG PET/CT combined with CA19-9 and jaundice (yes/no) has important value in diagnosing the nature of extrahepatic bile duct occupying lesions.