How the test is performed: You will be asked to lie on a narrow table that slides into the center of the CT scanner. Usually, you will lie on your back with your arms raised above the head.
The health care provider may inject a dye into one of your veins. This helps certain diseases and organs show up better on the images.
Once inside the scanner, the machine's x-ray beam rotates around you. Small detectors inside the scanner measure the amount of x-rays that make it through the abdomen. A computer takes this information and creates several individual images, called slices.
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 actual scan time only takes a few minutes, although the entire procedure usually takes much longer.
How to prepare for the test: Tell the health care provider if you have any allergies or have had difficulty with previous CT scans.
If contrast or sedation is used, you may also be asked not to eat or drink anything for 4-6 hours before the test.
Since x-rays have difficulty passing through metal, you will be asked to remove jewelry and wear a hospital gown during the study.
How the test will feel: The x-rays are painless. Some people may have discomfort from lying on the hard table.
Contrast give 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.
What the risks are: An abdominal CT scan is usually not recommended for pregnant women, because it may harm the unborn child. Women who are or may be pregnant should speak with their health care provider to determine if ultrasound can be used instead.
CT scans and other x-rays are strictly monitored and controlled to make sure they use the least amount of radiation. CT scans do create low levels of ionizing radiation, which has the potential to cause cancer and other defects. However, the risk associated with any individual scan is small. The risk increases as numerous additional studies are performed.
In some cases, a CT scan may still be done if the benefits greatly out weigh the risks. For example, it can be more risky not to have the exam, especially if your health care provider thinks you might have cancer.
The most common dye used is iodine based. A person who is allergic to iodine may have nausea, sneezing, vomiting, itching, or hives. Rarely, the dye may cause anaphylaxis (a life-threatening allergic response ).
