Fig. 2

Preoperative abdominal ultrasonography and CT. a Abdominal ultrasonography indicated the dilation of bile duct (red arrow). b Non-enhanced phase of CT showed that the intrahepatic bile duct was marked dilated (red arrow) and the tumor was located in the common hepatic duct (blue arrow). c Arterial-phase of CT showed the tumor was of higher density than liver parenchyma (blue arrow). d Portal-venous phase of CT showed the tumor was of higher density was of higher density than liver parenchyma (blue arrow)