Correlation among maximum standardized 18F-FDG uptake and pathological differentiation, tumor size, and Ki67 in patients with moderately and poorly differentiated intrahepatic cholangiocarcinoma.

OBJECTIVE To investigate the correlation among the maximum standardized uptake value (SUVmax) on fluorine-18-fluorodeoxyglucose (18F-FDG) positron emission tomography/computed tomography (PET/CT) and tumor differentiation, size, and Ki67 in patients with moderately and poorly differentiate dintrahepatic cholangiocarcinoma (ICC). MATERIALS AND METHODS The 18F-FDG PET/CT imaging data of 116 patients with single ICC lesions confirmed by pathology were retrospectively evaluated. Pathological characteristics of the tumor such as the largest tumor diameter, differentiation, Ki67 expression, SUVmax of the primary tumor, and the tumor to normal background ratio (TNR) were recorded. RESULTS Among the 116 lesions, 45, 51, and 20 lesions were classified into the moderately differentiated, moderately-poorly, and poorly differentiated groups, respectively. There were significant differences in the SUVmax (P=0.033) and TNR (P=0.044) among the three groups. Maximum SUV was significantly correlated with differentiation (r=0.244, P=0.008). When the cases were categorized according to the tumor size (group 1, ≤3cm, n=14; group 2, >3 and ≤5 cm, n=37; group 3, >5 and ≤10 cm, n=52; group 4, >10 cm, n=13), there were significant differences in the SUVmax (P<0.001) and TNR (P<0.001) among the four groups. Maximum SUV was significantly correlated with tumor size (r=0.481, P<0.001). Among the 116 lesions, 38 lesions and 78 lesions were classified into the low Ki67 and high Ki67 expression groups, respectively. There were significant differences in the SUVmax (P=0.028) and TNR (P=0.007) between the two groups. Maximum SUV was significantly correlated with Ki67 expression (r=0.242, P=0.009). CONCLUSION In moderately and poorly differentiated ICC, the SUVmax and TNR are significantly associated with tumor differentiation, size, and Ki67 expression.