What is a heart CT scan?
A CT scan (Computed Tomography) is a medical imaging technique which uses X-rays to view specific areas of your body. These scans use safe amounts of radiation to make a detailed picture, which can help your doctor to find any complications. A heart, or cardiac, CT scan is used to view your heart and blood vessels.
When performing the test, a special dye is 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’s used to view the arteries that supply blood to your heart muscles. The test may be called a coronary calcium scan if it’s meant to detect whether there’s a buildup of calcium in your heart.
Why is a heart CT scan performed?
Your doctor may order a heart CT scan to look for certain conditions which are the following:
- congenital heart disease, or birth defects in the heart
- buildup of a fatty substance known as lipid plaque that may be obstructing your coronary arteries
- defects or injury to the heart’s four main valves
- blood clots within the heart’s chambers
- tumors inside or on the heart
A heart CT scan is a common test for people facing heart problems. This is because it allows your doctor to investigate the structure of the heart and the adjacent blood vessels without making any incisions.
What are the risks of a heart CT scan?
A heart CT scan carries very few risks.
Most of the contrast material, sometimes referred to as dye, used for CT scans contains iodine. This iodine is later removed from the body by the kidneys.
If your kidneys have been affected by disease or infection, such as diabetes, you may require to drink enough fluids after the test to help your kidneys excrete the dye. However, newer dyes have lower risk to the kidneys.
Allergic or adverse reactions to iodine-based materials are classified as mild, moderate, and severe. You should inform your doctor if you experience any of the these symptoms:
- Mild reactions to the contrast material which can be itching and skin flushing.
- Moderate reactions can include severe skin rash or hives.
- Severe reactions can have difficulty breathing and cardiac arrest.
You are at higher risk of an allergic or adverse reaction to iodine-based material if you’ve had a prior reaction or if you’ve received a huge quantity of contrast material within the past 24 hours.
Other risk factors are:
taking medications such as nonsteroidal anti-inflammatory drugs (NSAIDs)
Consult your doctor if you feel you have risk of a reaction. There may be medication available to help you avoid reactions.
As with any X-ray, there’s some exposure to radiation. While normally harmless, this is an essential issue for women who are pregnant or want to be pregnant. The levels of radiation are considered safe for adults — there have been no listed side effects from low levels of radiation — but not for a growing fetus.
How do you prepare for a heart CT scan?
Your doctor will usually tell you to fast for four to eight hours before the scan. You’ll be able to drink water. However, don’t take caffeinated drinks since caffeine can affect your heart rate.
You’ll be needed to lie down on a table during the examination, so you may want to wear loose and comfortable clothing. You’ll also need to remove any jewelery and other metal items from your body, like piercings.
Most people will be able to drive themselves home after the scan. Unless you’ve been sedated, there’s no requirement to arrange for transportation.
How is a heart CT scan performed?
A heart CT scan is done in a hospital’s radiology department or a clinic that specializes in diagnostic procedures.
You may be given a beta-blocker before the scan. This medication slows down your heart function so that clearer images can be taken. Small, sticky discs called electrodes are placed onto your chest to record the test. The radiology technician inserts an intravenous line (IV) into a vein so that they can inject the radioactive dye into your arm. You may feel warm or flushed briefly or have a short term metallic taste in your mouth when they inject the dye.
Before the beginning of the scan, you lie down on a bench, probably in a specific position. The radiologist may use pillows or straps to make sure that you stay in the right position for long enough to get a proper image. You may also have to hold your breath during long individual scans, which last only 10 to 20 seconds.
To start the scan, the technician moves the table — via a remote from a separate room — into the CT machine. The CT machine looks like a giant doughnut made of plastic and metal. You’ll most likely go through the machine several times. Although you’re in the room by yourself, the technician can talk to you via an intercom.
After a round of scans, you may be needed to wait for a few minutes while the technicians review the images to ensure they’re clear enough for your doctor to read. The complete test shouldn’t take more than 10 minutes.
What happens after a heart CT scan?
After the procedure, you’ll be able to leave and go about your day. The dye will naturally make its way out of your body. Drinking plenty of water will help fasten this process.
Getting the results from your heart CT scan doesn’t take much time. Your doctor or the radiologist will go over the results with you.
Depending on what the images show, your doctor will suggest you of any lifestyle changes, treatments, or procedures that required to be performed Common follow-up tests include a stress test and coronary catheterization.
- Cardiac CT for calcium scoring. (2017).
- Cardiac CT scan. (n.d.).
- Contrast materials. (2017).
- Mayo Clinic Staff. (2017). CT coronary angiogram.