Leg CT scan - Overview

Definition of Leg CT scan:

How the test is performed:

You will be asked to lie on a narrow table that slides into the center of the CT scanner.

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 body area, called slices. These images can be stored, viewed on a monitor, or printed on film. Three-dimensional models of the leg can be created 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 only 10-15 minutes.

How to prepare for the test:

Certain exams require a special dye, called contrast, to be delivered into the body before the test starts. Contrast helps certain areas show up better on the x-rays.

• Contrast can be given through a vein (IV) in your hand or forearm. If contrast is used, you may also be asked not to eat or drink anything for 4-6 hours before the test.
• Let your doctor know if you have ever had a reaction to contrast. You may need to take medications before the test in order to safely receive this substance.
• Before receving the contrast, tell your health care provider if you take the diabetes medication metformin (Glucophage) because you may need to take extra precautions.

If you weigh more than 300 pounds, find out if the CT machine has a weight limit. Too much weight can cause damage to the scanner's working parts.

You will be asked to remove jewelry and wear a hospital gown during the study.

How the test will feel:

Some people may have discomfort from lying on the hard table.

Contrast given through an IV may cause a slight burning sensation, a metallic taste in the mouth, and a warm flushing of the body. These sensations are normal and usually go away within a few seconds.

Why the test is performed:

CT rapidly creates detailed pictures of the body, including the legs. The test may help detect or diagnose:

• An abscess or infection
• A mass that is felt during a physical exam
• The cause of pain or other problems in the foot, ankle, or knee joints (usually when MRI can't be done)
• A broken bone
• Masses and tumors, including cancer

A CT scan may also be used to guide a surgeon to the right area during a biopsy.