11c-choline and fdg pet/ct imaging of primary cholangiocarcinoma: a comparative analysis

Objective(s): this study aimed to compare the diagnostic values of 11c-choline and 18f-fluorodeoxyglucose (18f-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. 11c-choline and 18f-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 11c-choline pet/ct uptake was observed in primary extrahepatic or intrahepatic cca cases. intense 18f-fdg avidity was detected in the tumors of 8 patients (%80). two patients, who were 18f-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 11c-choline and 18f-fdg were 0.4±0.2 and 2.0±1.0 in all cases of primary cca, respectively; these values were significantly lower for 11c-choline (p<0.005). both fdg and 11c-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 11c-choline, whereas 18f-fdg pet/ct was of value for the detection of most primary cca cases. in contrast to primary lesions, metastatic cca lesions showed 11c-choline avidity.