Cardiac CT is done in a hospital or outpatient office. A doctor who has experience with CT scanning will supervise the test.
The doctor may want to use an iodine-based dye (contrast dye) during the cardiac CT scan. If so, a needle connected to an intravenous (IV) line will be put in a vein in your hand or arm.
The doctor will inject the contrast dye through the IV line during the scan. You may have a warm feeling when this happens. The dye will make your blood vessels visible on the CT scan pictures.
The technician who runs the cardiac CT scanner will clean areas on your chest and apply sticky patches called electrodes. The patches are attached to an EKG (electrocardiogram) machine. The machine records your heart's electrical activity during the scan.
The CT scanner is a large machine that has a hollow, circular tube in the middle. You will lie on your back on a sliding table. The table can move up and down, and it goes inside the tunnel-like machine.
The table will slide slowly into the opening in the machine. Inside the scanner, an x-ray tube moves around your body to take pictures of different parts of your heart. A computer will put the pictures together to make a three-dimensional (3D) picture of the whole heart.
The technician controls the CT scanner from the next room. He or she can see you through a glass window and talk to you through a speaker.
Moving your body can cause the pictures to blur. You'll be asked to lie still and hold your breath for short moments, while each picture is taken.
A cardiac CT scan usually takes about 15 minutes to complete. However, it can take more than an hour to get ready for the test and for the medicine to slow your heart rate. (For more information, go to "What To Expect Before Cardiac CT.")