look to the image and describe
rhd,lhd=right and left hepatic biliary ducts are dilated centrally without evidence of peripheral dilatation.
black arrow=high density material found.
open arrow=gas in the bile duct.
AB=right peri hepatic abscess.

1-There is irregular, segmental dilatation of the intrahepatic bile ducts, with a predilection for the lateral segment of the left lobe and posterior segment of the right lobe. The dilatation primarily involves the larger central ducts, which taper and end abruptly. The peripheral ducts frequently are not visualized. The dilatation can be fusiform, varicose, or cavitary. The extrahepatic bile duct can be markedly dilated, even in the absence of dilatation of the intrahepatic ducts.


2-Intraductal stones can be detected by CT in 63% to 81% of patients. The stones can be in the intrahepatic ducts, in both the intra- and extrahepatic ducts, or only in the extrahepatic ducts.

Reference:BiblioMed Textbook-Computed Body Tomography