Description of the test
A computerized tomography scan (CT or CAT scan) is a test that produces a series of X-ray images of the body. The CT scanner passes X-rays through the body and produces cross-sectional pictures so each picture is a "slice" of the body. The images are combined by a computer to create three dimensional images of internal organs and body structures.
The CT scan produces images that are more detailed than conventional X-ray films. Compared to plain X-rays, CT scans allow doctors to better detect and localize abnormalities of the various organs and tissues of the body using extremely accurate images.
CT scan images of a male skull
How often should this test be performed?
Your doctor will decide when and how frequently this test is required.
Why is this test performed?
CT scans are performed to help the doctor to study normal and abnormal organs inside the body and identify medical problems.
CT scans can be performed for many areas of the body, including:
- the head and neck - which can reveal injuries, tumors, strokes, infections, bleeding, and blood vessel abnormalities
- the spine - which may show fractures, tumors, weakened bones, or deformities
- the chest - which can reveal infection, tumors, and bulges in blood vessels (aneurysms)
- the abdomen and pelvis - which may show infections, injuries, tumors and inflammatory conditions
CT scans can also be used to help doctors perform medical procedures or treatments that require high accuracy. Examples of these medical procedures include biopsies, removal of fluid from organs, and drainage of abscesses.
Are there any risks and precautions I should know about?
Although a CT scan is considered safe, because it involves radiation exposure it does have some risk of side effects or complications. Though rare, side effects or complications include:
- an allergic reaction to the dye used for CT scans. A radiologist or technologist will ask you about your medical history and allergies to determine if you are at risk of having an allergic reaction.
- kidney damage caused by the dye, in people with poor kidney function, dehydration, or diabetes. If you have diabetes or kidney problems, talk to your doctor before having a CT scan.
A CT scan is usually not performed during pregnancy because of the risks to the developing fetus. If you are or may be pregnant, inform your doctor and discuss all the risks and benefits of a CT scan.