Heart CT scan - Overview

Definition of Heart CT scan:

A computed tomography (CT) scan of the heart is an imaging method that uses x-rays to create detailed pictures of the heart and its blood vessels.

• This test is called a coronary calcum scan when it is done to see if you have a buildup of calcium in your arteries.
• It is called CT angiography if it is done to look at the arteries that bring blood to your heart.

How the test is performed:

You will be asked to lie on a narrow table that slides into the center of the CT scanner. You will lie on your back with your head and feet outside the scanner on either end.

Small patches, called electrodes are put on your chest and connected to a machine that records your heart' s electrical activity. You may be given medicine to slow your heart rate.

Once you are inside the scanner, the machine's x-ray beam rotates around you. (Modern "spiral" scanners can perform the exam without stopping.)

A computer creates separate images of the body area, called slices. These images can be stored, viewed on a monitor, or printed on film. Three-dimensional models of the heart can be created by stacking the slices together.

You must be still during the exam, because movement causes blurred images. You may be told to hold your breath for short periods of time.

The entire scan should only take about 10 minutes.

How to prepare for the test:

Certain exams require a special dye, called contrast, to be delivered into the body before the test starts. Contrast helps certain areas show up better on the x-rays.

• Contrast can be given through a vein (IV) in your hand or forearm. If contrast is used, you may also be asked not to eat or drink anything for 4-6 hours before the test.
• Let your doctor know if you have ever had a reaction to contrast. You may need to take medications before the test in order to safely receive this substance.
• Before receiving the contrast, tell your health care provider if you take the diabetes medication metformin (Glucophage) because you may need to take extra precautions.

If you weigh more than 300 pounds, find out if the CT machine has a weight limit. Too much weight can cause damage to the scanner's working parts.

You will be asked to remove jewelry and wear a hospital gown during the study.

How the test will feel:

Some people may have discomfort from lying on the hard table.

Contrast given through an IV may cause a slight burning sensation, a metallic taste in the mouth, and a warm flushing of the body. These sensations are normal and usually go away within a few seconds.

Why the test is performed:

CT rapidly creates detailed pictures of the heart and its arteries. The test may diagnose or detect:

• Plaque build-up in the coronary arteries to determine your risk for heart disease
• Congenital heart disease (heart problems that are present at birth)
• Problems with the heart valves
• Blockage of the arteries that supply the heart
• Tumors of the heart