Portal venous gas
Portal venous gas. This is an ominous sign – gas in the portal venous system is usually caused by bowel ischaemia (resulting in loss of integrity of the bowel wall, with bowel gas then gaining access to blood vessels in the wall). It is often a pre-terminal finding. This example shows an erect CXR from an elderly woman who presented with severe abdominal pain. There is a branching pattern of gas projected over the liver (arrows) – this could either represented portal venous gas or gas in the biliary tree (pneumobilia). Subsequent CT shows a large amount of gas in portal vein branches in the liver. Laparotomy was performed but extensive small bowel necrosis was found and the patient passed away shortly afterwards.