What it is:
A computed tomography (CT) scan (also sometimes called a computerized tomography scan) is a type of x-ray that provides a cross-sectional view of the body. The images obtained during a CT scan show the organs and tissues inside the body. The output of a CT scan is electronic, and therefore can be displayed on a computer, emailed, or transferred to a CD or a mobile device. A CT scan is a painless and non-invasive procedure.
What it's used for:
The images from a CT scan can be used for a wide variety of purposes in diagnosing and monitoring diseases and conditions. In cases of abdominal pain or digestive disease, a CT scan may be used for diagnosing and monitoring:
- Cancerous tumors
- Diverticular disease
- Inflammatory bowel disease (IBD)
- Kidney stones
- Traumatic injury to the abdomen
CT scans are also used to aid physicians in taking biopsies and performing or monitoring the results of other surgical procedures.
In general, there is no special preparation needed for a CT scan other than fasting for a few hours before the test. Similar to a regular x-ray, you will be asked to remove any jewelry or other items, such as eyeglasses. You may also be asked to remove dentures and hearing aids.
How it's done:
You will be asked to lie on a table, either flat with arms at your sides or with your arms back and lying next to your head. The table will slide into the center of a large, spherical x-ray machine. This machine will rotate around you during the test. While inside the machine, there may be whirring or mechanical noises. You will be asked to lie very still, and you may be asked to hold your breath at certain points during the test. The test can take anywhere from 15 minutes to one hour, depending on the parts of the body being pictured. Most tests are completed in about half an hour.
In some cases, contrast dye may be given. Contrast dye will help certain body structures to show up more clearly in the final images from the scan. The contrast dye might be drunk, injected into a vein, or given as an enema.
A CT scan will expose a patient to a certain amount of radiation -- this is more radiation than a typical flat x-ray. The risks associated with the amount of radiation exposure should be carefully weighed against the benefits of having the test.
Rarely, a patient may have an allergic reaction to the contrast dye. This allergic reaction could cause symptoms of nausea, vomiting, hives, itching, trouble breathing or swelling. If you experience these or any other symptoms during or after a CT scan, you should notify the radiology technician and/or your physician. If you have a known allergy to contrast material, you may be given some antihistamine medication to reduce the chance of an allergic reaction.
Women who may be pregnant should inform the radiology technician and their physician. In general, CT scans are not recommended during pregnancy except in certain circumstances.
Your physician will review the images from the CT scan with you and discuss any further testing that may be needed.
Food And Drug Administration. "Computed Tomography (CT)." FDA.gov, 9 Nov 2010. Accessed 23 May 2011.
Radiological Society of North America, Inc (RSNA). "CT - Abdomen and Pelvis." RadiologyInfo.org, 2011. Accessed 23 May 2011.