11C-Choline and FDG PET/CT Imaging of Primary Cholangiocarcinoma: A Comparative Analysis

OBJECTIVES This study aimed to compare the diagnostic values of (11)C-choline and (18)F-fluorodeoxyglucose ((18)F-FDG) positron emission tomography/computed tomography (PET/CT) in patients with cholangiocarcinoma (CCA). METHODS This prospective study was conducted on 10 patients (6 males and 4 females), aged 42-69 years, suspected of having CCA based on CT or magnetic resonance imaging (MRI) results. (11)C-choline and (18)F-FDG PET/CT studies were performed in all patients over 1 week. PET/CT results were visually analyzed by 2 independent nuclear medicine physicians and quantitatively by calculating the tumor-to-background ratio (T/B). RESULTS No (11)C-choline PET/CT uptake was observed in primary extrahepatic or intrahepatic CCA cases. Intense (18)F-FDG avidity was detected in the tumors of 8 patients (%80). Two patients, who were (18)F-FDG negative, had primary extrahepatic CCA. Ki-67 measurements were positive in all patients (range; 14.2%-39.9%). The average T/B values of (11)C-choline and (18)F-FDG were 0.4±0.2 and 2.0±1.0 in all cases of primary CCA, respectively; these values were significantly lower for (11)C-choline (P<0.005). Both FDG and (11)C-choline PET/CT detected metastatic CCA foci in all 8 patients (two patients had no metastases). CONCLUSION As the results suggested, primary CCA lesions showed a poor avidity for (11)C-choline, whereas (18)F-FDG PET/CT was of value for the detection of most primary CCA cases. In contrast to primary lesions, metastatic CCA lesions showed (11)C-choline avidity.