You will need to remove any jewelry that might be in the way of the X-ray picture. You may need to take off some of your clothes. If so, you will be given a gown to use during the test. For some CT scans, you may be able to wear your clothes. If so, wear loose clothes that don't have zippers or snaps.

Small pads or patches called electrodes will be put on your chest. Wires connect these to an EKG, Opens dialog machine that records the electrical activity of your heart on paper. The EKG records when your heart is in the resting stage, which is the best time for the CT scans to be taken.

During the test, you will lie on a table connected to the CT scanner. The scanner is a large doughnut-shaped machine.

The table slides into the round opening of the machine, and the scanner moves around your body. The table will move a little every few seconds to take new pictures. You may hear clicking or buzzing sounds as the table and scanner move.

You may be asked to hold your breath for 20 to 30 seconds while pictures of your heart are taken. It is very important to hold completely still while the pictures are taken.

During the test, you are usually alone in the scanner room. But the technologist will watch you through a window and talk with you during the test.

How long the test takes

A coronary calcium scan takes about 30 minutes.

You won't have any pain from the X-rays during the coronary calcium scan. But the table you lie on may feel hard and the room may be cool. You may find it hard to lie in one position for a long time.

The chance of a coronary calcium scan causing a problem is small.

• There is a risk of damage to cells or tissue from being exposed to radiation, including the small amounts used in CTs, X-rays, and other medical tests. Over time, exposure to radiation may cause cancer and other health problems. But in most cases, the risk of getting cancer from being exposed to small amounts of radiation is low. It is not a reason to avoid these tests for most people.
• Plaque that is not hard (soft plaque) can't be found with a coronary calcium scan. Soft plaque is the earliest form of damage to the arteries of the heart. If you have soft plaque in your arteries, the test may give normal results, but this is a false-negative, Opens dialog result. The buildup of soft plaque can also cause a heart attack.
• It is possible to have false-positive, Opens dialog test results. This means that the test shows a high chance of plaque in the arteries of the heart when it is not true. People with a low chance of heart disease are most likely to have a false-positive test.

After you have the test, talk with your doctor about your results.

Your test result is a number that is your calcium score. The score can range from 0 to more than 400. The higher your score, the greater your chance of having a heart attack. The score might be helpful if you are aren't sure whether to take a statin to lower your risk of a heart attack. Your doctor will look at your calcium score as well as your age, your health, and your other test results such as your cholesterol level.^{footnote 2}