A computerized tomography scan (CT scan) is a diagnostic test that uses X-rays to produce cross-sectional images of the inside of the body. These images are combined by a computer to produce three-dimensional images of the organs or structures of interest.
Your doctor can use the CT scan to study many different areas of the body (e.g., spine, head and face, chest, abdomen, urinary tract, liver, pancreas, gallbladder, adrenal glands, spleen, pelvis, arm, or leg) and to look for medical problems such as:
- blood clots
- fractured bones
- heart disease
- internal bleeding or injuries
In addition, the CT scan can also guide doctors in medical procedures such as surgery, biopsy, and radiation therapy. Your doctor will decide when it might be appropriate for you to undergo a CT scan.
Risks and precautions
CT scan is usually a straightforward and safe procedure. However, there are some risks of complications or side effects, including:
- allergic reaction to a dye used for CT scans
- slight chance of developing cancer from the radiation used during the test
- slight risk of interfering with medical devices (e.g., pacemakers, insulin pumps)
X-rays can harm the fetus. You should tell your health care provider if you are or may be pregnant.
It is important that you understand all the risks of complications and side effects of the test, and what you or your doctor can do to avoid them. Make sure that your doctor is aware of all your concerns.
Before the test
It is important that you fully understand what the test involves beforehand. Ask your doctor to explain the risks, benefits, and drawbacks of the test, and don't be shy to probe further until you are comfortable with your doctor's responses.
Your doctor may give you different instructions depending on the part of the body being scanned. You may be given a contrast dye by mouth, by injection, or rectally to increase the clarity of the images of some organs or structures. Your doctor may also ask you to fast for a period of time or give you laxatives for some scans.
Be sure to tell your doctor about all your medical conditions, if you are wearing any medical devices, if you have recently had an X-ray test using barium (which can affect the quality of the images seen on the CT scan), or if you may be pregnant.
If you are taking any prescription or over-the-counter (non-prescription) medications, supplements, or herbal products, make sure you inform your doctor or pharmacist. Ask them whether it is necessary for you to stop taking any of these medications and products before the test. It is also important to tell them if you have allergies to certain medications or have certain medical conditions.
If you were given a medication to help you relax for the test, plan to have someone drive you home afterwards.