CT

How the Test is Performed:
You are asked to lie on a narrow table (gantry) that slides into the center of the scanner. The scanner looks like a tube surrounded by the imaging equipment. A contrast-media (dye) may be injected into a vein to help define certain tissues. The table will advance slightly (1/4 to 1/2 inch) between each scan to align for the next cross-section image. The technologist operating the computer may indicate when it is necessary to control breathing. A sound system is built into the machine to allow communication with you during the test.

During the test, it is very important to remain still. If a patient is restless or traumatized, you may be given a sedative. Each exposure takes a few seconds. The complete scan takes about 1 hour.

How to Prepare:
The health care provider may advise fasting for 4 to 6 hours if contrast dye is to be used or if sedation is anticipated (consult the health care provider). You wear a hospital gown during the procedure and asked to sign a consent form.

How it Feels:
The X-rays are painless. The primary discomfort may be from the need to lie still on the table.

If a dye is needed to increase the contrast between different tissues or organs, it is administered by injection into a vein. The injection may sting and the site may be tender to the touch for several minutes. Dye injections may cause a cool or warm sensation, a metallic taste and, in a few cases, hives .

Risks:
CT scans and other X-rays are monitored and regulated to provide the minimum amount of radiation exposure needed to produce the image. CT scans provide low levels of radiation. During pregnancy , an abdominal CT scan is usually not recommended, because there is some evidence of risk to the fetus.

The most common dye used is iodine based. A person who is allergic to iodine may experience nausea , sneezing , vomiting , itching , or hives . Rarely, the dye may cause anaphylaxis (a life-threatening allergic response ).

For additional information regarding why the test is performed and normal and abnormal results, please see the specific CT topics:




CT stands for computerized tomography. In this procedure, a thin X-ray beam is rotated around the area of the body to be visualized. Using very complicated mathematical processes called algorithms, the computer is able to generate a 3-D image of a section through the body. CT scans are very detailed and provide excellent information for the physician.