Computed Axial Tomography (CAT or CT)/ Ultrafact Computed Tomography (CT) Scan

Why is the doctor performing this procedure?

To use sophisticated x-ray technology to obtain clear and detailed three-dimensional images of the heart and vascular system.

What is the procedure?

Computed tomography (CT or CAT Scan) is a very detailed x-ray that provides information about internal tissues and organs in cross-sections (thin slices). A computer takes the cross-section x-rays and uses them to create three-dimensional images. The x-rays used in CT scanning are much narrower than the x-rays used in standard x-rays, avoiding much of the scatter inherent in routine x-rays. A CT scan of the heart can provide detailed images of the following structures:

• Heart muscle
• Heart (coronary) arteries
• Lungs
• The aorta
• Pulmonary veins
• The sac surrounding the heart (called the pericardium)

For a CT scan, the patient changes into a hospital gown, and an intravenous line is started so that contrast dye may be injected for enhanced visualization. Sticky patches called electrodes, each with a wire, are attached to the skin of the chest. Each wire is connected to an ECG machine to monitor the heart's electrical activity throughout the procedure. The patient lies down (with the arms above the head) on a moveable table that slides into the CT machine. An x-ray tube (called the x-ray sensing unit) rotates within the CT machine and around the body of the patient. The table itself slowly moves the patient forward as images continue to be taken. Then a computer analyzes and combines these x-rays to create three-dimensional images with precise detail.

An ultrafast CT provides images of the beating heart, and reveals calcium deposits in the heart (coronary) arteries. The calcium deposits are actually measured during an ultrafast CT, and reported as a coronary artery calcium (CAC) score. The physician uses this score to determine the amount of plaque (atherosclerosis) present within the coronary arteries, and to predict the patient's risk of future coronary artery disease and/or heart attack.

Where is the procedure performed?

In the Imaging Department of the hospital.

How long does this procedure take?

A CT scan of the heart or an ultrafast CT usually takes about 10-60 minutes.