PSC

CT findings

On the CT the liver looks quite normal.
However if you look at the common bile duct in the pancreatic head you will notice the soft tissue density.
The differential diagnosis would include an impacted stone or cholangiocarcinoma, but since this patient had no obstruction, it was thought to be the result of bile wall thickening.
The gallbladder wall is also thickened. 

PSC with thickening of the wall of the bile duct (arrow)