Hepatic arteriography and hepatic angiography are both a type of X-ray in which a dye (contrast medium) is used to show up the blood supply or the lymph system in the liver. A special chemical that is taken up by any tumour, called Lipiodol, is also used. A series of quick X-ray pictures are taken that make up a real-time film of the movement of blood or lymph within the liver. This helps your doctors to see how your liver is working, and to pinpoint any blockages.