A CAC test, also known as a heart scan or coronary artery calcium scan, is a CT scan of the heart that measures the amount of calcium in the hearts arteries. The test uses a multidetector CT (MDCT) to take detailed images of the arteries that supply blood to the heart. The amount of calcium in the heart arteries, also known as the calcium score, gives healthcare professionals an idea of how much plaque is in the heart arteries and may help predict the risk of a future heart attack. The test is particularly helpful for people at "intermediate" risk of cardiovascular disease. CAC testing is useful for making treatment decisions, such as whether to start low-dose aspirin, statin therapy, or other medications. The test is not recommended for routine screening of people who dont have symptoms of heart disease and have a low risk of heart attacks unless they have a strong family history of premature coronary heart disease. The test is noninvasive and takes only a few minutes to complete. The risks of the CAC scan are low, but it does expose the patient to a small amount of radiation.