Pneumobilia

The radiologic finding of gas within the intrahepatic or extrahepatic biliary tree. Typically indicating biliary-enteric fistula (eroding gallstone), prior biliary instrumentation (ERCP, sphincterotomy, Whipple procedure), malfunctioning Sphincter of Oddi, infection with gas-forming organisms (emphysematous eholangitis), or abdominal trauma.