Abstract: 【Abstract】　Objective : To analyze the features of hepatic biliary cystadenoma and cystadenocarcinoma on MRI, and to discuss the diagnostic value of MRI in the diseases. Methods：The MRI features of 2 cases of cystadenoma and 6 cases of cystadenocarcinoma proved by pathology were analyzed retrospectively and correlated with the pathologic findings. Results：All of 8 cases were revealed as solitary cystic lesions. Variant contents in the intracystic fluid showed different signal intensity on MRI. Hemorrhagic fluid was seen in one cystadenoma and one cystadenocarcinoma respectively. The 2 cases of cystadenoma were well-defined, with smooth cystic wall and internal septa, and showed no enhancement or slightly enhancement after contrast. Irregular thickening in cystic wall and internal septa were found in these cystadenocarcinomas， and mural nodules were found in the 4 cases. After contrast，the solid parts were obviously enhanced, particularly in port vein phase and delay phase, but for the 2 cases which were enhanced particularly in arterial phase. Ductal dilatation near the lesions was seen in 2 cases, furthermore communication between the lesion and the bile duct was seen in one of them. The margins of the cystadenocarcinoms were mostly smooth, except for that of one recured after resection. Conclusions: MRI can reveal the characteristic morphological features of hepatic biliary cystadenoma and cystadenocarcinoma, and play an important role in the diagnosis before the operation. Solid parts enhanced can be seen much more frequently in cystadenocarcinoma than in cystadenoma. Hemorrhagic internal fluid and involved bile ducts are also more common in cystadenocarcinoma. The cystadenocarcinomas with ill-defined margins may have unfavourable prognosis.

Key words: Bile duct neoplasm, Cystadenoma, Cystadenocarcinom, MRI