A computerized tomography (CT) coronary angiogram is an imaging test that looks at the arteries that supply blood to the heart. A CT coronary angiogram uses a powerful X-ray machine to make images of the heart and its blood vessels. The test is used to diagnose many different heart conditions.

A CT coronary angiogram involves no surgical cuts in the body. And it doesn't require recovery time.

A CT coronary angiogram mainly is done to check for narrowed or blocked arteries in the heart. It may be done if you have symptoms of coronary artery disease. But the test can look for other heart conditions too.

A CT coronary angiogram is different from a standard coronary angiogram. With a standard coronary angiogram, a healthcare professional makes a small cut in the groin or wrist. A flexible tube called a catheter is threaded through the artery in the groin or wrist to the heart arteries. For those with known coronary artery disease, this approach also can be used as treatment.

A CT coronary angiogram also is different from a test called a CT coronary calcium scan. A CT coronary angiogram looks for buildups of plaque and other substances in the coronary artery walls. A CT coronary calcium scan looks only at how much calcium is in the artery walls.

A CT coronary angiogram exposes you to radiation. The amount varies depending on the type of machine used. If you're pregnant or you may be pregnant, you ideally should not have a CT angiogram. There's a risk that the radiation may harm an unborn child. But some people with serious health conditions may need CT imaging during pregnancy. For these people, steps are taken to minimize any possible radiation exposure to the unborn children.

A CT coronary angiogram is done using dye called contrast. Tell your healthcare professional if you're breastfeeding, because the dye can get into breast milk. Also, be aware that some people have an allergic reaction to the contrast dye. Talk to your healthcare professional if you're concerned about having an allergic reaction.

If you have a contrast dye allergy, you may be asked to take steroid medicine 12 hours before a CT coronary angiogram. This lowers the risk of a reaction. Rarely, contrast dye also may damage the kidneys, especially in people with chronic kidney conditions.

A healthcare professional tells you how to prepare for a CT coronary angiogram. Driving yourself to and from the test should be OK.

Food and medicines

Usually, a CT coronary angiogram requires not eating anything for at least 8 hours before the test. Drinking water is OK. Don't have drinks that contain caffeine 12 hours before. Caffeine can raise the heart rate, making it hard to get clear pictures of the heart.

Tell your healthcare team about the medicines that you take. You may be asked not to take a certain medicine before the test.

Clothing and personal items

The procedure requires removing jewelry, glasses and clothing above the waist. You'll be asked to change into a hospital gown.

A CT coronary angiogram usually is done in the radiology department of a hospital or an outpatient imaging facility.

Before the procedure

Before a CT coronary angiogram, a healthcare professional may give you medicine called a beta blocker. This slows your heart rate to help the CT scanner make clearer images. Let your healthcare professional know if you've had side effects from beta blockers in the past.

You also may be given nitroglycerin to widen your coronary arteries. This helps your healthcare professional see the arteries more easily in the images.

During the procedure

A healthcare professional places a thin tube called an IV into the hand or arm. Dye, called contrast, flows through this IV. The dye helps blood vessels show up better on the images taken during the test. Sticky patches called electrodes also are attached to your chest to record your heart rate.

You lie on a long table that slides through a short, tunnel-like machine called a CT scanner. If you're not comfortable in closed spaces, ask your healthcare professional about medicine to help you relax. Do this before the day of your test.

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

A healthcare professional controls the CT machine from a room that's separated from your exam room by a glass window. An intercom system lets you and the healthcare professional talk to each other.

The scanning parts of the test take as few as five seconds. But the whole process may take up to an hour if you're given medicines such as beta blockers or nitroglycerin.

After the procedure

After your CT coronary angiogram is done, you usually can return to your daily activities. You should be able to drive yourself home or to work as long as the CT scan causes no complications. Drink plenty of water to help flush the dye from your body.

The images from your CT coronary angiogram should be ready soon after your test. The healthcare professional who asked you to have the test gives you the results.

If your test suggests that you have or are at risk of heart disease, you and your healthcare professional can talk about treatment options.

Regardless of the test results, it's always a good idea to make lifestyle changes to help protect the heart. Try these heart-healthy habits:

• Get regular exercise. Exercise helps manage weight and control diabetes, high cholesterol and high blood pressure — all risk factors for coronary artery disease. 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.
• Eat healthy foods. Eat plenty of fruits, vegetables, whole grains, legumes and nuts. Avoid saturated fats and trans fats. Reduce salt and sugar. Eating one or two servings of fish a week also may help keep the heart healthy.
• Lose extra weight. Reaching a healthy weight and staying at it is good for your heart. Losing even a small amount of weight can help reduce risk factors for coronary artery disease. You can ask your healthcare professional to set a goal weight for you.
• Don't smoke or use tobacco. Smoking is a major risk factor for coronary artery disease. Nicotine tightens blood vessels and forces the heart to work harder. Not smoking is one of the best ways to lower the risk of a heart attack. If you need help quitting, talk with your healthcare professional.
• Manage health conditions. For high blood pressure, high cholesterol or diabetes, take medicines as directed. Ask your healthcare professional how often you need health checkups.
• Lower stress. Stress can cause blood vessels to tighten. This raises the risk of a heart attack. Some ways to ease stress are to get more exercise, practice mindfulness and connect with others in support groups.
• Get enough sleep. Adults should try to get 7 to 9 hours of sleep a night.