Usefulness of ¹⁸F-fluorodeoxyglucose positron emission tomography in differential diagnosis and staging of cholangiocarcinomas

Background and Aim: ¹⁸F-Fluoro-2-deoxy-d-glucose positron emission tomography (¹⁸FDG-PET) is promising for diagnosis and treatment of various malignancies. The aim of this study was to evaluate the clinical usefulness of ¹⁸FDG-PET in differential diagnosis and staging of cholangiocarcinomas according to the intrahepatic, perihilar and common bile duct lesions and to compare with computerized tomography (CT) scan. Methods: From January 2000 to September 2003, 54 patients with suspected cholangiocarcinoma underwent abdominal CT scan and ¹⁸FDG-PET within a 2-week period. The PET images were analyzed visually and semiquantitatively. Results: The overall accuracy of ¹⁸FDG-PET for discriminating malignant diseases of bile duct from benign conditions was slightly higher than that of CT scan (88.9% vs 81.5%). The sensitivity of ¹⁸FDG-PET in perihilar cholangiocarcinoma was lower than the value of intrahepatic and common bile duct cancers (83.3% vs 91.3%, 90.9%); moreover, in cases of perihilar cancer, the sensitivity of ¹⁸FDG-PET was lower than that of CT scans (83.3% vs 91.7%). ¹⁸FDG-PET detected nine distant metastatic lesions not found by other imaging studies and excluded two patients who potentially had resectable condition in other imaging studies from unnecessary laparotomy. Conclusion: The clinical usefulness of ¹⁸FDG-PET in differential diagnosis of bile duct cancers is related to the site of primary disease. Although it is a helpful method for differential diagnosis especially in cases of intrahepatic and common bile duct cancers, ¹⁸FDG-PET can not provide confirmative clues in perihilar cholangiocarcinoma. ¹⁸FDG-PET may hold promise in the detection of hidden distant metastasis and can play an additional role in the evaluation of resectability. ¹⁸FDG-PET can be complementary to CT scan in diagnosing and staging of cholangiocarcinoma.