CT angiography is a type of CT scan that generates high-resolution images of the inside of a patient’s blood vessels. A contrast material (dye) is injected into the patient; as the dye flows through the blood vessels to the various organs of the body, the CT scanner generates a map of the blood vessels. A CT angiogram provides valuable information about the nature of blockages (soft plaque versus hard calcified plaque), the extent of blockages, and about the wall of the vessel. A CT angiogram is minimally invasive compared with traditional coronary angiography, which involves puncturing a major artery in the groin and passing a catheter directly into the coronary arteries.