MR imaging findings of early bile duct cancer

To retrospectively evaluate the MR imaging features of early bile duct cancer and to correlate them with the clinicopathologic findings.

This retrospective study was approved by our institutional review board, and informed consent was waived. Seventeen patients with surgically proven early bile duct cancer who had undergone preoperative MR cholangiopancreatography with gadolinium-enhanced MR imaging, were included in this study. Two, experienced radiologists evaluated the MR images in consensus regarding the following findings: tumor number and morphology; signal intensity of the tumor; sharpness of the outer border of the bile duct wall; enhancement pattern of the tumor; and the presence of enlarged peribiliary lymph nodes. Another radiologist measured the SNR of the tumor and bile duct wall on gadolinium-enhanced MRI during the dynamic phases to evaluate the tumor enhancement degree.

In all patients, MR imaging demonstrated single or multiple intraluminal bile duct masses showing a sharply defined outer margin. The most common enhancement pattern of the biliary lesions showed heterogeneous amorphous enhancement or heterogeneous enhancement with central, dot-like structures or vascular structures (76.5%, 13/17 patients). The difference of SNR between bile duct and tumor was greatest in the equilibrium phase (P < 0.05).

MRCP combined with dynamic contrast-enhanced MRI can be useful for detecting early bile duct cancers. Common MR findings of early bile duct cancer include one or more inhomogeneously enhancing intraductal masses with clear outer margins and preservation of the bile duct wall.