Key Points

• A coronary calcium scan is a test that can help show whether you have coronary heart disease (CHD).
• A coronary calcium scan looks for specks of calcium (called calcifications) in the walls of the coronary (heart) arteries. Calcifications are an early sign of CHD.
• Two machines can show calcium in the coronary arteries—electron beam computed tomography (EBCT) and multidetector computed tomography (MDCT). Both use an x-ray machine to make detailed pictures of your heart.
• A coronary calcium scan is most useful for people who are at moderate risk for a heart attack. You or your doctor can calculate your 10-year risk using the Risk Assessment Tool from the National Cholesterol Education Program. People who are at moderate risk have a 10–20 percent chance of having a heart attack within the next 10 years.
• A coronary calcium scan may help doctors decide who within the moderate risk group needs treatment.
• No special preparation is needed for a coronary calcium scan. Your doctor may ask you to avoid caffeine and smoking for 4 hours before the test.
• Coronary calcium scans are done in a hospital or outpatient office. The x-ray machine that's used is called a computed tomography (CT) scanner.
• A coronary calcium scan takes about 10 to 15 minutes. During the scan, you'll lie quietly on your back, while the CT scanner takes pictures of your heart.
• You'll be able to return to your normal activities after the calcium scan is done. Your doctor will discuss your calcium scan results with you.
• The test is negative if your coronary arteries have no calcifications. This means your chance of having a heart attack in the next 2 to 5 years is low.
• The test is positive if calcifications are found in your coronary arteries. Calcifications are a sign of atherosclerosis and CHD.
• After the scan, you'll receive a calcium score called an Agatston score. The higher your Agatston score is, the more severe the atherosclerosis.
• You can use this calculator from the National Heart, Lung, and Blood Institute to see how your Agatston score compares with scores of people of your age and ethnic background.
• An Agatston score of 0 is normal. In general, the higher your score, the more likely you are to have CHD. If your score is high, your doctor may recommend more tests.
• Coronary calcium scanning has very few risks. The test isn't invasive, which means that no surgery is done and no instruments are inserted into your body. Coronary calcium scanning doesn't require an injection of contrast dye to make your heart or arteries visible on x-ray images.
• Because an x-ray machine is involved, you'll be exposed to a small amount of radiation. The amount of radiation is less than or equal to the amount of radiation you're naturally exposed to in a single year.