Computed Tomography (CT), also called CAT scan, is a type of diagnostic test that combines X-rays and computer technology to provide views of soft tissue, bones and blood vessels. The technology creates sectional images, or "slices," of the organs, tissues or vessels under evaluation.

Nearly every part of the body can be viewed with CT. The technology is frequently used to obtain a two-dimensional view of a cross section of the brain and other internal organs, such as the liver, lungs and spine. The technology is valuable in detecting tumors, bleeding, and other abnormalities that may not show up on an ordinary X-ray. Nearly one-third of all emergency department patients undergo a CT procedure.

CT can help diagnose head and spine injuries, lung and liver disease, cancer, tumors, blood clots, internal bleeding and a host of other diseases and injuries. The test is often used when fast diagnosis is critical - it can be lifesaving for auto accident victims and other emergency department patients.

Unlike other imaging techniques, such as X-ray and MRI, CT has the ability to image a combination of soft tissue, bone and blood vessels. This capability proves very useful in evaluating the chest and the abdomen, making the modality a preferred method for diagnosing cancers such as lung, liver and pancreatic among others. Advanced CT systems also are being used extensively in detecting heart disease and other vascular conditions.