A heart CT scan uses X-rays to create an image of the heart and blood vessels. Healthcare professionals may also refer to it as cardiac CT angiography.

A CT scan is a noninvasive imaging procedure. Doctors may order one to see into different areas of a person’s body, such as the heart, so they can diagnose and treat any issues they uncover.

This article discusses who may need a heart CT scan and its purposes. It also explores what areas it shows, what to expect during the scan, potential risks of CT scans, and the results and next steps.

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CT scans of the heart provide detailed images of the organ using X-rays. A computer then combines these images to create 3D images of the heart. This can help a doctor identify any health problems affecting the organ and surrounding blood vessels.

Possible uses include:

A doctor may also recommend a person have a CT scan if they have one or more risk factors for CAD, such as:

A CT scan of the heart can show the entire heart and the surrounding blood vessels. It can also show calcium buildup in the arteries that can block blood flow. Doctors may call this coronary artery calcium scoring or cardiac CT scan for calcium scoring.

The presence of calcium can indicate a person may have CAD or atherosclerosis.

The following section provides more information on what to expect before, during, and after a heart CT scan.


In most cases, a person does not need to do anything special to prepare for a heart CT scan. The American Heart Association (AHA) advises people to discuss preparation with their doctor, particularly when to stop eating before the procedure.

Some experts recommend people avoid eating, drinking, smoking, and consuming caffeine for 4 hours before the scan. However, a person needs to speak with a doctor, as these instructions may vary.

When getting ready for the scan, an individual needs to:

  • wear loose, comfortable clothing
  • remove bras with metal underwire
  • remove jewelry, glasses, and other metal items or accessories
  • remove piercings, in some cases

A healthcare professional can advise someone if they need to remove anything else before the scan.

During the procedure

A person may need to go to the hospital or outpatient center to have the CT scan. Once there and after checking in, they can expect the following during the procedure:

  • The person will lie on a table in front of a large machine with a small tunnel in the middle.
  • A healthcare professional attaches electrodes to the person’s chest to take an electrocardiogram, which monitors the heart’s electrical activity and helps create clear images.
  • If using a contrast dye, a healthcare professional will inject it into an intravenous line that they have inserted into a person’s arm vein.
  • The patient may need to take other medications that help make any blockages in the heart arteries more visible on the images.
  • Once the person is prepared, the table will slowly enter the tunnel.
  • Periodically, the healthcare professional may instruct the person to hold their breath for about 10–20 seconds, or the table may move back and forth through the machine.

The CT scanning process typically takes about 5–10 minutes.

Following the procedure

A person can return to their usual daily activities following a CT scan.

The computer will compile the scans to create images for a radiologist, who will analyze the results and send a report to the doctor who ordered the CT scan.

The doctor will review the results and schedule an appointment with the person to review the reports and results with them.

CT scans use X-rays, a type of radiation, to scan the body and create the images. A person needs to discuss the potential risks of X-rays with their doctor before the scan.

X-ray exposure may slightly increase someone’s risk of developing cancer. However, the amount of radiation in one test is roughly equal to the amount of natural radiation exposure a person experiences over the course of 1 year. Therefore, people who need multiple scans may have a slightly higher risk of developing cancer.

People who are pregnant or may be pregnant need to let the doctor know. A healthcare professional will help a person decide whether a heart CT scan may be suitable for them and discuss any potential pregnancy-related risks.

Contrast dye may cause kidney damage in some cases. A doctor may assess a person’s kidney function before ordering a CT scan that uses contrast dye.

In rare situations, someone may experience an allergic reaction to the dye. If a person knows they have an allergy, they may be able to take medication with a doctor’s guidance before the scan to prevent a reaction from occurring.

Once a radiologist reviews the images, they will provide a detailed report to the doctor who ordered the CT scan of the heart.

If a radiologist has reviewed the images for a cardiac CT scan for calcium scoring, they will give a score according to the amount of calcium buildup in a person’s coronary arteries.

A score of 0 indicates a typical result with no calcium buildup in the arteries. A person with this score has little risk of having a heart attack within the next 2–5 years. Higher calcium scores indicate an increased risk of a heart attack and better evidence for the presence of coronary artery disease.

After the doctor receives the results, they will discuss any next steps with a person. This may include making lifestyle changes, beginning treatment, or additional testing.

A heart CT scan helps doctors analyze and assess a person’s heart and blood vessels. It can help doctors diagnose heart-related conditions, guide treatment, or offer insight into the next set of tests a person may need to undergo to find underlying conditions.

An individual may need to stop eating and drinking for a few hours before the scan, which only takes about 10 minutes.

Following the procedure, a radiologist will examine the images and send a detailed report to the doctor who ordered the scan. The ordering doctor will then determine what the next steps are, including the need for additional testing or beginning treatment.