Portal vein surgery. Sequence of coloured angio computed tomography (CT) scans of a patient's liver during abdominal surgery to treat a thrombosis of the hepatic portal vein. The hepatic portal vein supplies the liver with blood, but has become narrowed by a thrombus (blood clot, upper centre of top left image). During the surgical procedure a catheter (wire) is inserted into the vein, and a balloon is inflated (upper right image) to open the vein. A stent (wire mesh tube) is put in place (lower images) to keep the vein open and re-establish blood flow. This surgery aims to reduce the pressure in the portal vein.