What is it?

A computed tomography (CT) scan uses X-rays to make detailed pictures of parts of your body and the structures inside your body. A CT of the heart looks at the structures and blood vessels of the heart.

During the test, you lie on a table that passes through a doughnut-shaped opening in the scanner. A special dye (contrast material) may be put in a vein (I.V.) in your arm or hand to make the blood vessels easier to see on the scan.

Why is this test done?

A CT of the heart is done to look at the structures and blood vessels of the heart. These may include:

• The heart muscle and the sac around the heart (pericardium).
• The heart valves.
• The coronary arteries. These are the blood vessels that bring blood to your heart muscle.
• The blood vessels that carry blood from the lungs to the heart.
• The aorta. It's the large blood vessel that carries blood from the heart to the rest of the body.

How do you prepare for the test?

In general, there's nothing you have to do before this test, unless your doctor tells you to.

Tell your doctor if you get nervous in tight spaces. You may get a medicine to help you relax. If you think you'll get this medicine, be sure you have someone to take you home.

You may be asked not to eat or drink anything for several hours before the test. Your doctor will let you know if there are certain foods or liquids you should avoid.

How is the test done?

Before the test

• You may have to take off jewellery.
• You may need to take off some of your clothes. You will be given a gown to wear during the test. If you do leave some clothes on, make sure you take everything out of your pockets.
• You may be given a medicine to slow your heart rate before or during the test.
• You may have contrast material (dye) put into your arm or hand through a tube called an I.V.

During the test

• You will lie on a table that is attached to the CT scanner.
• Small pads or patches (electrodes) will be placed on your skin on each arm and leg and on your chest. The electrodes are hooked to a machine that traces your heart activity onto a paper.
• The table will slide into the round opening of the scanner and move slightly while the scanner takes pictures. You may hear a click or buzz as the table and scanner move.
• You will be asked to hold still during the scan. You may be asked to hold your breath for short periods.
• You may be alone in the scanning room. But a technologist will watch you through a window and talk with you during the test.

How does the test feel?

The test will not cause pain, but some people feel nervous inside the CT scanner.

If a medicine to help you relax (sedative) or dye is used, you may feel a quick sting or pinch when the I.V. is started. The dye may make you feel warm and flushed and give you a metallic taste in your mouth. Some people feel sick to their stomach or get a headache. Tell the technologist or your doctor how you are feeling.

How long does the test take?

The test will take about 30 to 60 minutes. Most of this time is spent getting ready for the scan. The actual test takes a few minutes.

What happens after the test?

• You will probably be able to go home right away.
• You can go back to your usual activities right away.
• If dye was used, drink lots of liquids for 24 hours after the test, unless your doctor says not to.