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.

CT rapidly creates detailed pictures of the heart and its arteries. The test may be used to:

• Assess your risk for heart disease by looking for the buildup of calcium plaque on the walls of the arteries that supply blood to the heart (coronary arteries)
• Find congenital heart disease
• Identify a blockage of the arteries that supply the heart
• Look for tumors of the heart

Based on the amount of plaque in the arteries, the health care provider will calculate your cardiac calcium score.

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 electrodes will be placed on your chest and connected to an electrocardiograph (ECG) machine, which 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 in one continuous motion.)

Small detectors inside the scanner measure the amount of x-rays that make it through the heart. A computer takes this information and uses it to create several individual images, called slices. These images can be stored, viewed on a monitor, or printed on film. Three-dimensional models of organs can be created by stacking the individual 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.

Certain exams require a special dye, called contrast, to be delivered into the body before the test starts. Contrast can highlight the heart, which creates a clearer image.

Contrast can be given through a vein (IV) in your hand or forearm. Some people have allergies to IV contrast and may need to take medications before their test in order to safely receive this substance.

If contrast is used, you may also be asked not to eat or drink anything for 4 - 6 hours before the test.

If you weigh more than 300 pounds, have your doctor contact the scanner operator before the exam. CT scanners have a weight limit. Too much weight can cause damage to the scanner's working parts.

Since x-rays have difficulty passing through metal, you will be asked to remove jewelry and wear a hospital gown during the study.

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.