Abstract：Objective: To explore the value of extra-pancreatic lesions on 18F-FDG PET/CT image in the diagnosis of pancreatic cancer. Methods: Seventy-three patients, 52 male and 21 female, suspected of having pancreatic cancer underwent 18F-FDG PET/CT scan. Surgical operation(18 cases), open abdominal surgery for exploration(4 cases), fine-needle aspiration(25 cases), imaging and clinical follow-up(28 cases), confirmed malignancy in 47 cases and benignity in 26 cases. Preliminary diagnoses were based on the SUV value and CT characteristics of the primary lesions in pancreas, and the confidential level of diagnoses as malignancy as graded as affirmative and probable. Extra-pancreatic lesions detected on 18F-FDG PET/CT image were classified as metastatic and non-metastatic, and the diagnoses were modified by extra-pancreatic lesions. Sensitivity, specificity, accuracy, positive predictive value and negative predictive value before and after modification were calculated. Results: Extra-pancreatic lesions were identified on PET/CT image in 29 patients, among which 26 were metastatic and 3 were non-metastatic lesions. Those lesions modified the diagnoses in 21 cases. Sensitivity, specificity, accuracy, positive predictive value and negative predictive value before and after modification were 83.0%, 69.2%, 78.0%, 83.0%, 69.2% and 93.6%, 76.9%, 87.7%, 88.0%, 87.0% respectively. For the 6 false positive cases on PET/CT, 3 of them were proved to be solid pseudopapillary tumors(SPT). Conclusion: Extra-pancreatic lesions, especially metastatic lesions identified on 18F-FDG PET/CT image improved the diagnostic accuracy of pancreatic cancer. SPT was identified as the most important reason of false positive diagnoses after modification by extra-pancreatic lesions.
2011, Vol. 22 
