Role of 18F-FDG PET/CT imaging in intrahepatic cholangiocarcinoma

Objectives Although intrahepatic cholangiocarcinoma (ICC) is the second most common primary hepatic malignancy, little experience of PET/CT is applied in ICC. This study was to retrospectively evaluate the role of 18F-FDG PET/CT in ICC.

Methods FDG PET/CT findings were reviewed in 65 patients with ICC confirmed by pathology. PET/CT was mainly evaluated based on the visual interpretation and semi-quantitative indice of SUVmax, which was then analyzed and compared with tumor localization, differentiation, size and so on. Moreover, 45 of all 65 cases underwent abdominal MRI examinations, which were compared with PET/CT results.

Results Among 65 cases with ICC, there are 19 patients with hilar ICC and 46 peripheral ICC. Among 65 patients with ICC, 60 cases displayed obvious FDG uptake with average SUVmax of 8.33, and 5 located in hilar was misdiagnosed. Compared with hilar ICC, SUVmax of peripheral ICC is significantly higher(P<0.05). Compared with moderately differentiated ICC, SUVmax of poor group was obviously higher(P<0.05). There was also correlation between tumor size and corresponding SUVmax, while no relationship between serum levels CA199 and SUVmax. For 45 cases taking MRI examination, the sensitivity, specificity, accuracy of PET/CT and MRI in the diagnosis of regional lymph node metastasis were 70.00% vs. 50.00%, 91.67% vs. 83.33%, and 81.82% vs. 68.18%, respectively.

Conclusions 18F-FDG PET/CT is very useful in detecting cases with suspected primary ICC, and SUVmax of ICC is correlated with tumor location, tumor differentiation, and tumor size. Compared with MRI examinations, FDG PET/CT display better value in diagnosing and detecting local lymph nodes invasion and metastases. Moreover, the combination of FDG PET/CT and abdominal MRI could elevate the diagnostic accuracy of ICC.

Research Support This study is in part support by National Science Foundation for Scholars of China (Grant No.81271608 to Hongcheng Shi and No. 81101072 to Lei Jiang).