Computed tomography (CT), also known as CAT, is a painless, sophisticated x-ray procedure. Multiple images are taken during a CT or CAT scan, and a computer compiles them into complete, cross-sectional pictures ("slices") of soft tissue, bone, and blood vessels. A CT scan obtains images of parts of the body that cannot be seen on a standard x-ray. Therefore, these scans often results in earlier diagnosis and promotes successful treatment of many diseases.