 The reason for this study is to see if a new radiologic technique called computerized tomographic cholangiography CT cholangiography could be helpful to demonstrate the bile ducts features and measure the amount of space of bile duct canals that should be filled with bile fluid. It may be useful to find out how well these findings correlate with the previously known clinical predictors in term of the clinical outcomes that will happen in the future for patients with primary sclerosing cholangitis PSC. 