A computed tomography angiogram (CT angiogram) is a test that uses X-rays to provide detailed pictures of the heart and the blood vessels that go to the heart, lung, brain, kidneys, head, neck, legs, and arms. The test uses a special dye that is put into a vein (I.V.) to make very detailed pictures of the blood vessels.

A CT angiogram can show whether a blood vessel is narrowed or blocked. The test can also show whether there is a bulge (aneurysm) or a buildup of fatty material called plaque in a blood vessel.