An angiogram is an imaging test that uses x-rays and dye to map the blood vessels. A catheter is inserted into an artery and threaded to the targeted blood vessels where dye is injected to make blockages visible on x-rays. Angiograms are performed to detect blockages in arteries of the heart, brain, legs, and other organs to help diagnose and plan treatment for conditions like heart disease. While it provides detailed images of blood vessels, risks include bleeding or reaction to the dye where the catheter is inserted.