A computerized tomography (CT) coronary angiogram is an imaging test that looks at the arteries that supply blood to your heart. It might be done to diagnose the cause of chest pain or other symptoms.

A CT coronary angiogram uses a powerful X-ray machine to produce images of your heart and its blood vessels. The procedure is noninvasive and doesn't require recovery time. CT coronary angiograms are used to diagnose a variety of heart conditions.

A coronary CT angiogram is different from a standard coronary angiogram. In the traditional procedure (non-CT angiogram), a flexible tube (catheter) is threaded through your groin or arm to your heart or coronary arteries. If you have known coronary artery disease, your doctor might recommend the traditional approach because you can also receive treatment during the procedure.

A coronary CT angiogram is mainly used to check for narrowed or blocked arteries in your heart (coronary artery disease). However, your doctor can use it to check your heart for various conditions.

You'll be exposed to some radiation during the test. The amount varies depending on the type of machine used. The risk of developing cancer from a CT angiogram isn't known, but it's small. However, you shouldn't have a CT angiogram if you're pregnant because of possible harm to your unborn child.

It's possible that you could have an allergic reaction to the dye used in the procedure. Talk to your doctor if you're concerned about having an allergic reaction.

Your doctor should give you instructions about how to prepare for your CT angiogram. You can drive yourself to the appointment, and you'll be able to drive after your test.

Food and medications

Usually, you'll be asked not to eat anything for about four hours before your test. You can drink water. Avoid caffeinated drinks 12 hours before your test because they can increase your heart rate, which can make it difficult to get clear pictures of your heart.

Tell your doctor about the medications that you take. You may be asked to avoid or temporarily stop a medication prior to the test. If you have an allergy to contrast dye, your doctor might ask you to take steroid medication 12 hours before the procedure to reduce your risk of a reaction.

Clothing and personal items

You'll need to remove clothing above your waist, as well as jewelry and glasses, and change into a hospital gown.

CT angiograms are usually performed in the radiology department of a hospital or an outpatient imaging facility.

Before the procedure

You may receive a medication called a beta blocker to slow your heart rate. Doing so provides clearer images on the CT scan. Let your doctor know if you've had side effects from beta blockers in the past.

You might also be given nitroglycerin to widen (dilate) your coronary arteries. The CT scan may be done using contrast, a dye to help your blood vessels show up more clearly. If you're allergic to contrast material, you might be given medication to lower your risk of a reaction.

During the procedure

You'll receive numbing medication, and then the technician will insert an IV into your hand or arm. The dye flows through this IV. You'll also have sticky patches called electrodes placed on your chest to record your heart rate.

You'll lie on a long table that slides through a short, tunnel-like machine (CT scanner). If you're uncomfortable in closed spaces, ask your doctor if you need medication to help you relax.

During the scan you need to stay still and hold your breath as directed. Movement can cause blurry images.

A technician operates the CT machine from a room that's separated from your exam room by a glass window. An intercom system allows you and the technician to talk to each other.

Although the actual scanning portion of the test takes as few as five seconds, it may take up to an hour for the whole process to be completed.

After the procedure

After your CT angiogram is completed, you can return to your normal daily activities. You should be able to drive yourself home or to work. Drink plenty of water to help flush the dye from your system.

The images from your CT angiogram should be ready soon after your test. The doctor who asked you to have the CT angiogram should discuss the results of the test with you.

If your test suggests that you have or are at risk of heart disease, you and your doctor can discuss treatment options.

Regardless of the results of your test, it's a good idea to make lifestyle changes to help protect your heart. These include:

• Exercise regularly. Exercise helps you reach and maintain a healthy weight. It also helps control diabetes, high cholesterol and high blood pressure — all risk factors for heart disease. With your doctor's OK, get at least 150 minutes of moderate aerobic activity or 75 minutes of vigorous aerobic activity a week, or a combination of moderate and vigorous activity. If necessary, break your activity into several 10-minute sessions a day.
• Eat healthy foods. A heart-healthy diet rich in fruits, vegetables and whole grains — and low in saturated fat, cholesterol and sodium — can help you control your weight, blood pressure and cholesterol.
• Stop smoking. Smoking is a major risk factor for heart disease, especially atherosclerosis. If you smoke, quitting is the best way to reduce your risk of heart disease and its complications. If you need help quitting, ask your doctor about smoking cessation methods.
• Manage health conditions. If you have high blood pressure, high cholesterol or diabetes, take your medications as directed. Ask your doctor how often you need follow-up visits.
• Soothe stress. Stress can cause your blood vessels to tighten (constrict), increasing your risk of a heart attack. Ask your doctor about stress management programs in your area. Exercise can help reduce stress too.