An angiogram is a test that allows physicians to see how blood flows through a specific blood vessel (an artery or a vein). The procedure uses a dye that makes blood vessels visible on X-rays. An angiogram can be used to look at the blood vessels in the head, chest, back, abdomen, arms or legs. An angiogram can reveal the presence of any blockage or damage in an artery or vein, an aneurysm, as well as coronary artery disease and its extent.