Key Points

• Cardiac computed tomography (CT) is a painless test that uses an x-ray machine to take clear, detailed pictures of your heart. This common test is used to look for problems in the heart.
• During a cardiac CT scan, the x-ray machine will move around your body in a circle. The machine will take a picture of each part of your heart. A computer can put the pictures together to make a three-dimensional (3D) picture of the whole heart.
• Because an x-ray machine is used, cardiac CT involves radiation. Although the amount of radiation used is considered small, it's similar to the amount of radiation you're naturally exposed to over a 3-year period.
• There's a small chance that cardiac CT will cause cancer because of the radiation involved. The risk is higher for people younger than 40 years old, especially children. However, new cardiac CT methods are available that reduce the amount of radiation used for this test.
• Cardiac CT is a common test for finding and/or evaluating calcium buildup in the walls of the coronary arteries, coronary heart disease (CHD), problems with heart function and heart valves, problems with the aorta, blood clots in the lungs, problems with the pulmonary veins, and pericardial disease.
• Cardiac CT also may be used before or after certain heart procedures. The test can help your doctor prepare for the procedure or check your heart after the procedure.
• Your doctor will tell you how to prepare for the cardiac CT scan. People usually are asked to avoid drinks that contain caffeine before the test. Normally, you're allowed to drink water, but you're asked not to eat for 4 hours before the scan.
• The cardiac CT scan will take place in a hospital or outpatient office. A doctor who has experience with CT scanning will supervise the test.
• The CT scanner is a large machine that has a hollow, circular tube in the middle. You lie on your back on a sliding table. The table can move up and down, and it goes inside the tunnel-like machine.
• Inside the scanner, an x-ray tube moves around your body to take pictures of different parts of your heart. A computer puts the pictures together to make a 3D picture of the whole heart.
• A cardiac CT scan usually takes about 15 minutes to complete. However, it can take more than an hour to get ready for the test.
• After the cardiac CT scan is done, you'll be able to return to your normal activities. A doctor who has experience with CT will provide your doctor with the results of your cardiac CT. Your doctor will discuss the findings with you.
• Cardiac CT scans are painless. Some people feel side effects from the contrast dye that's sometimes used during the scan. Serious complications are rare.
• Researchers are studying new ways to use cardiac CT.