A CT scan is a diagnostic test that uses X-rays to allow images of the body to be made. CT stands for “Computed Tomography”. CT scans use an X-ray machine that rotates around the patient who lies on a table. The table moves the patient through the X-ray machine. Instead of X-ray film however, a detector that works somewhat like a digital camera detector, relays the information to a computer. The computer takes the information from the detector and creates a picture of the organ and surrounding structures that is displayed on a computer screen. Often, prints of these pictures may be made in much the same way that digital pictures from a digital camera can either be viewed on a screen or printed on film. The pictures are slices of the body much like a slice of bread is one part of the whole loaf. These “slices” are called tomograms and since the computer makes the slices each picture is called a computed tomograph.

The newest models of CT scanners allow pictures of the heart to be taken. Because the heart is constantly moving, the CT scans that are used to take pictures of the heart must be “fast”, meaning that they can take “stop action” pictures of the heart much like a camera can take a stop action photo of a fast moving object. The most promising application of CT scans for the heart will be to allow pictures of the coronary arteries to be taken without the need, in some cases, for an invasive procedure such as a heart catheterization.