CT Angiogram

A computed tomography (CT) angiogram is an imaging test to view your blood vessels and tissues. It uses an injection of contrast dye and specialized X-rays. Often, healthcare providers use these tests to check for heart conditions. When you have a CT angiogram to look at your heart, it’s called a CT coronary angiogram.


Male patient lies on table that slides into the doughnut-shaped CT scanner.
A CT angiogram allows your healthcare provider to see your blood vessels and tissues.

What is a CT angiogram?

A computed tomography (CT) angiogram is a test to view your blood vessels and tissues. During the test, your provider injects a dye that highlights your blood vessels and tissues. Then your provider takes a CT scan, a specialized X-ray, to view the highlighted areas.

What is a CT coronary angiogram?

Your provider uses a CT angiogram specifically to view your coronary arteries. Your coronary arteries are the blood vessels that supply blood to your heart muscle.


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Why might I need a CT angiogram?

The most common reason to have a CT angiogram is to see if you have narrowed or blocked coronary arteries. But your healthcare provider may use a CT angiogram to diagnose any condition involving your blood vessels, including:

What is the difference between a CT angiogram and a traditional angiogram (or cardiac catheterization)?

CT angiograms and traditional angiograms are both tests to view your blood vessels. CT angiograms are less invasive than traditional angiograms.

With traditional angiography, your provider inserts a long, hollow tube (catheter) through a large blood vessel called an artery, usually in your groin or your wrist. Then, the provider injects contrast dye through the catheter and uses X-ray fluoroscopy to image your coronary arteries (blood vessels).

With a CT angiogram, your provider injects the contrast dye through an IV into your vein (intravenously). They usually insert the IV into a vein in your arm or hand.


What is the difference between a cardiac CT scan and a CT coronary angiogram?

Both cardiac CT scans and CT coronary angiograms use specialized X-rays to look inside your body. CT coronary angiograms are slightly more invasive because they use a contrast dye injection. Cardiac CT scans don’t use dye injections.

Who performs a CT angiogram?

Typically, a radiologist performs this test. Radiologists are doctors who specialize in taking and interpreting imaging scans. If you’re having a CT coronary angiogram, a radiologist specializing in cardiovascular images performs the test.


Test Details

How do I prepare for a CT angiogram?

Your healthcare provider will give you specific instructions to prepare for a CT angiogram. You may have to stop certain medications, such as vasodilators (Viagra®, Levitra®), temporarily before the test.

Typically, you’ll stop eating around four hours before the test. You can drink water as usual.

If you’re having a coronary CT angiogram, you’ll need to avoid caffeine within 12 hours of the test. Caffeine can increase your heart rate and make it more difficult to get a clear picture of your coronary arteries.

What to expect on the day of the CT angiogram?

You usually have a CT angiogram in an outpatient imaging facility or the radiology department at a hospital. When you arrive, you’ll change into a hospital gown. You’ll remove eyeglasses and all metal objects, such as jewelry, hairpins or dentures that contain metal. If you have a pacemaker, joint replacement or other metal implants in your body, you can usually still have a CT angiogram because most implants are made of titanium. Tell your healthcare provider if you have a metal implant.

What to expect during a CT angiogram?

During a CT angiogram:

  1. A technician gives you a numbing medicine and inserts an IV through your arm or hand. Contrast dye flows through the IV.
  2. For a coronary CT angiogram, the technician attaches sticky patches (electrodes) to your chest. The electrodes connect to a machine that records your heart rate and rhythm.
  3. You lie on a table that glides into a machine shaped like a doughnut (CT scanner).
  4. A technician operates the CT scanner from another room, taking images from several angles. They may instruct you to hold your breath for a few seconds to prevent chest movement during the scan.

The actual CT scan may only take a few seconds to minutes. With setup time, the procedure typically takes around an hour.

What to expect after a CT angiogram?

You can return home and resume usual activities the same day as a CT angiogram. Your provider will tell you to drink plenty of water to help flush the contrast dye out of your system.

What are the risks of a CT angiogram?

CT angiograms are safe tests for most people. If you have a history of allergic reactions, especially to the contrast dye used for prior CT scans, your provider may give you medicine, such as steroids you take by mouth, to lower your risk of having a reaction to the contrast dye. If you have known kidney disease, your kidneys are more susceptible to injury from contrast dye.

Who shouldn’t get a CT angiogram?

There’s a small risk that the contrast dye could damage your kidneys if you have certain health conditions, such as diabetes or kidney disease. Your provider may recommend a different test if you have such conditions.

Tell your provider if you’re pregnant or think you could be. CT angiograms use small amounts of radiation, so providers don’t usually recommend them for pregnant people.

Results and Follow-Up

When should I know the results of the test?

Your provider typically reviews test results with you in several days or weeks. Depending on the test results, you may need follow-up exams. Or, if the test shows a risk of heart disease, your provider may discuss treatment options with you.

A note from Cleveland Clinic

A CT angiogram is an imaging test to view your blood vessels and tissues. Healthcare providers often use it to look at your coronary arteries. CT angiograms are less invasive than traditional coronary angiograms. They use an IV to inject the contrast dye. This dye highlights your blood vessels on the CT scan. CT angiograms are usually quick and painless. You can return home the same day as the test.

Medically Reviewed

Last reviewed on 05/23/2022.

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