Coronary arteries are scanned using spiral CT after intravenous injection of contrast material. Computerized reconstruction results in imaging of the coronary arteries of the heart. Mild manifestations appear as plaque with 25% to 49% stenosis of the vessel. Coronary artery anomalies appear when CT plain scanning is used to evaluate coronary artery calcification. Enhanced scans with iodine contrast are used to evaluate coronary plaque, especially non-calcified plaque. On CTA, black clumps of blood vessels are seen, blocking the vessels, and generally about 25% to 49% of the vessels will be stenotic, which can lead to reduced cardiac motion. Cardiac CT density values are significantly reduced, typically less than 5 HU. The presence of coronary atherosclerosis requires medical treatment as soon as possible to avoid further blockage of blood vessels.