Detection of Klatskin’s Tumor in Extrahepatic Bile Duct Strictures Using Delayed 18F-FDG PET/CT: Preliminary Results for 22 Patient Studies

Detection of cholangiocarcinoma in extrahepatic bile duct strictures is a continuing challenge in clinical practice because brush cytology taken at endoscopic retrograde cholangiography has an average sensitivity of 50%. The aim of this study was to evaluate the effectiveness of dual-modality PET/CT using 1 8 F-FDG for noninvasive differentiation of extrahepatic bile duct strictures. Methods: Twenty-two PET/CT studies were performed on 20 patients (10 women, 10 men; mean age ′ SD, 63 ′ 14 y) with extrahepatic bile duct strictures on endoscopic retrograde cholangiography. PET imaging was started 101 ′ 22 min after injection of 369 ′ 48 MBq of 1 8 F-FDG. Blood glucose was 100 ′ 20 mg/dL. PET images were reconstructed iteratively with attenuation correction based on a rescaling of the CT image. CT was performed within 1 min before the PET study, with the patient in the same position. CT was used to place a volume of interest 5 cm in diameter at the liver hilus for quantitative evaluation of PET images by means of standardized uptake values (SUVs). Results: Final diagnosis was histologically proven cholangiocarcinoma in 14 cases and benign causes of strictures in 8 cases without evidence of malignancy during a follow-up of 18 ′ 3 mo. All patients with cholangiocarcinoma presented with focal increased uptake in the liver hilus with an SUV of 6.8 ′ 3.3 (range, 3.9-15.8), compared with 2.9 ′ 0.3 (range, 2.5-3.3) in patients with benign causes of strictures (P = 0.003). There was a clear cutoff SUV of 3.6 for detection of malignancy in the liver hilus. Conclusion: 1 8 F-FDG PET/CT provided high accuracy for noninvasive detection of perihilar cholangiocarcinoma in extrahepatic bile duct strictures.