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Abdominal CT scan

Spleen metastasis - CT scan
Normal external abdomen

Definition

An abdominal CT scan is an imaging method that uses x-rays to create cross-sectional pictures of the belly area. CT stands for computed tomography.

Alternative Names

Computed tomography scan - abdomen; CT scan - abdomen; CAT scan - abdomen

How the Test is Performed

You will lie on a narrow table that slides into the center of the CT scanner. Most often, you will lie on your back with your arms raised above the head.

Once you are inside the scanner, the machine's x-ray beam rotates around you. Modern "spiral" scanners can perform the exam without stopping.

A computer creates separate images of the belly area, called slices. These images can be stored, viewed on a monitor, or printed on film. Three-dimensional models of the belly area can be made by stacking the slices together.

You must be still during the exam, because movement causes blurred images. You may be told to hold your breath for short periods of time.

The scan should take less than 30 minutes.

How to Prepare for the Test

You need to have a special dye, called contrast, put into your body before some exams. Contrast helps certain areas show up better on the x-rays.

Too much weight can damage the scanner.  Find out if the CT machine has a weight limit if you weigh more than 300 pounds.

You will need to take off your jewelry and wear a hospital gown during the study.

How the Test Will Feel

Lying on the hard table may be a little bit uncomfortable.

If you have contrast through a vein (IV), you may have:

 These feelings are normal and go away within a few seconds.

Why the Test is Performed

An abdominal CT scan makes detailed pictures of the structures inside your belly (abdomen) very quickly.

This test may be used to look for: 

What Abnormal Results Mean

The abdominal CT scan may show some cancers, including:

The abdominal CT scan may show problems with the gallbladder, liver, or pancreas, including:

The abdominal CT scan may reveal the following kidney problems:

Abnormal results may also be due to:

Risks

Risks of CT scans include:

CT scans expose you to more radiation than regular x-rays. Many x-rays or CT scans over time may increase your risk for cancer. However, the risk from any one scan is small. Talk to your doctor about this risk and the benefit of the test for getting a correct diagnosis of your medical problem.

Some people have allergies to contrast dye. Let your doctor know if you have ever had an allergic reaction to injected contrast dye.

Rarely, the dye may cause a life-threatening allergic response called anaphylaxis. Tell the scanner operator right away if you have any trouble breathing during the test.. Scanners come with an intercom and speakers, so the operator can hear you at all times.

References

Kim DH, Pickhardt PJ. Diagnostic imaging procedures in gastroenterology. In: Goldman L, Schafer AI, eds. Cecil Medicine. 24th ed. Philadelphia, Pa: Saunders Elsevier; 2011:chap 135.

Shaw AS, Dixon AK. Multidetector computed tomography. In: Adam A, Dixon AK, eds. Grainger & Allison's Diagnostic Radiology: A Textbook of Medical Imaging. 5th ed. New York, NY: Churchill Livingstone; 2008:chap 4.


Review Date: 11/9/2012
Reviewed By: David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine. Also reviewed by A.D.A.M. Health Solutions, Ebix, Inc., Editorial Team: David Zieve, MD, MHA, David R. Eltz, Stephanie Slon, and Nissi Wang.