acute cholangitis is a bacterial infection generally related to biliary obstruction. the obstruction increases the risk of bacterial infestation in the cholestatic patient.
it can also occur post surgery/procedures that allow access of contaminants to the normally sterile bile. the most common such procedure being ercp.
on ultrasound, you may see thick walled ducts or pyogenic debris within the ducts.
see pictures & video.
primary sclerosing cholangitis is a chronic liver condition (thought to be auto-immune). it is characterised by fibrosis, cirrhosis and liver failure. there are no ultrasonically visible bile duct changes till later stage. early diagnosis is difficult with ultrasound.