CT (or computerized tomography) is sometimes called a CAT scan. CT uses special x-ray equipment that gives doctors a better look at bones, blood vessels, organs, and tissues.

While regular x-rays show all of these areas, they are seen as overlapping each other. Regular x-rays are fine for diagnosing some health problems, but the CT scanner gives a more detailed picture because it makes an x-ray image of many very thin slices of a section of the body. With the help of a computer, these slices are put together to show a much better cross-section.

Doctors often use CT scans to help diagnose kidney, lung, liver, spine, and blood diseases; cancer, tumors, and cysts; as well as blood clots, hemorrhages and infections.

During a CT exam, you will lie down on a table. The part of your body to be studied will be moved into a large ring-like opening of the scanner. You will hear the sound of gears and motors as the equipment scans your body.

Some preparation is needed for certain scans.