Heart CT Scan

Written by Brian Krans | Published on June 26, 2012
Medically Reviewed by George Krucik, MD

What Is a Heart CT Scan?

A computed tomography scan—commonly called a CT scan—is a test that uses X-rays to view your heart and blood vessels. These scans use safe amounts of radiation to create detailed images of the body, which can help your doctor to detect any problems.

During the test, a specialized dye will be injected into your bloodstream. The dye is then viewed under a special camera in a hospital or testing facility.

A heart CT scan may also be called a coronary CT angiogram, if it is meant to view the arteries that bring blood to your heart. It may be called a coronary calcium scan if it meant to determine whether there is a build-up of calcium in your heart.

Why a Heart CT Scan Is Performed

If you’re experiencing symptoms of heart troubles, your doctor may order a heart CT scan to explore their causes. According to the National Institutes of Health, your doctor may order a heart CT for many reasons. (NLM ) These include:

  • birth defects in the heart (congenital heart disease)
  • build-up of a hard substance known as plaque that may be blocking your coronary arteries
  • defects or injury to the heart’s valves
  • tumors in or on the heart

A heart CT scan is a common test for those experiencing heart problems, since it allows your doctor to explore the structure of the heart and the adjacent blood vessels, without making any incisions.

The Risks of a Heart CT Scan

A heart CT scan carries very few risks. Most of the dyes used for CT scans contain iodine—which is later flushed from the body by the kidneys. If your kidneys have already been impacted by disease or infection, such as diabetes, you may need to drink extra fluids after the test to help your kidneys remove the dye. However, newer dyes carry much less risk to the kidneys.

As with any X-ray test, there is some exposure to radiation. While typically harmless, this is an important issue for women who are pregnant or could be pregnant. The levels of radiation are considered safe for adults—there have been no documented side effects from low levels of radiation—but not for a developing fetus.

How to Prepare for a Heart CT Scan

Since the test is non-invasive, you do not need to do much to prepare for a CT scan.

Your doctor will typically ask you to fast for four to eight hours before the scan. You’ll be able to drink water. However, avoid caffeinated drinks since caffeine can affect your heart rate.

You will be required to lie down on a table during the exam, so you may want to wear loose, comfortable clothing. You will also need to remove any jewelry and other metal items from your body, such as piercings.

After the test, you will be able drive yourself home. There is no need to arrange for transportation.

How a Heart CT Scan Is Performed

A heart CT scan is performed in a hospital’s radiology department or a clinic that specializes in diagnostic procedures.

According to the Mayo Clinic, you may be given a beta blocker before the scan. This medication will slow down your heart so that clearer pictures can be taken. (Mayo ) You’ll also be given an IV so that the technician can inject the radioactive dye into your arm. Some small, sticky discs called electrodes will also be placed onto your chest to record the scan.

At the start of the scan, you’ll lie down on a bench. The technician may want you to lie in a specific position. He or she may use pillows or straps to ensure that you stay in the correct position for long enough to get a quality image. You may also have to hold your breath during brief individual scans, which last only 10 to 20 seconds.

To start the scan, the technician will move the table—via a remote from a separate room—into the CT machine. It looks like a giant doughnut made of plastic and metal. You will most likely go through the machine several times. Although you will be in the room by yourself, the technician will be able to talk to you via an intercom.

After a round of scans, you may be required to wait for a few minutes while the technicians review the images to ensure they are clear enough for your doctor to read. However, the whole test should take no more than 10 minutes.

After a Heart CT Scan

After the procedure, you’ll be able to leave and go about your day right away. The dye will naturally work its way out of your body. Drinking more water will help speed up this process.

Getting the results from your heart CT scan doesn’t take long. Your doctor or the technician will go over the results with you.

Depending on what the images show, your doctor will advise you of any lifestyle changes, treatments, or procedures that need to be done.

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