Expert opinions? What kind of conditions is not associated with gas in the biliary system?

GB and liver surgery. Pneumobilia, is accumulation of air in the biliary tree that is distinct from portal venous gas. While the latter is assocated with inflammatory disease of the bowel, pneumobilia is associated with recent ERCP and an incompetent sphincter of Oddi allowing gas to enter the bile ducts from the GI tract. Surgery of GB and SB rarely present with pneumobilia.