Abstract: Objective To investigate the relationship between signal characteristics in enhanced-MRI hepatobiliary phase(HBP)and pathological grade of intrahepatic mass cholangiocarcinoma(IMCC). Methods Patients diagnosed with IMCC were retrospectively analyzed, and the signal characteristics of lesions in HBP were analyzed. Statistical analysis was performed by Chi-square test. Results 49 patients were diagnosed with IMCC. There were 5 cases with well-differentiated, 26 cases with moderately-differentiated and 18 cases with poorly-differentiated. 11 patients with lesion length less than 3 cm; 18 patients with lesion length between 3 cm and 6 cm, 20 patients with lesion length more than 6 cm. In HBP, 21 patients had target sign, 20 patients had multilayer target sign, and 8 patients had low signal. 41 cases had peripheral low. The difference of lesion size between different signal in HBP, and the difference of peripheral low signal ring integrity between different pathological grades were statistically significant(χ²=18.937, P=0.001; χ²=6.618, P=0.037). Conclusion Incomplete peripheral low signal ring in HBP is more common in poorly-differentiated IMCC, and the larger the lesion is, the more it shows multilayer target sign.

Key words: magnetic resonance imaging, intrahepatic mass-forming cholangiocarcinoma, hepatobiliary phase, pathological grade