During the test, you will lie on a table that is attached to the CT scanner, which is a large doughnut-shaped machine. The CT scanner sends X-rays through the body area being studied. Each rotation of the scanner takes less than a second and provides a picture of a thin slice of the organ or area. All of the pictures are saved as a group on a computer. They also can be printed.
An iodine dye (contrast material) is often used to make structures and organs easier to see on the CT pictures. The dye may be used to check blood flow, find tumors, and look for other problems. The dye can be used in different ways. It may be put in a vein (IV) in your arm, or it may be placed into other parts of your body (such as the rectum or a joint) to see those areas better. For some types of CT scans you drink the dye. CT pictures may be taken before and after the dye is used.
A CT scan can be used to study all parts of your body, such as the chest, belly, pelvis, or an arm or leg. It can take pictures of body organs, such as the liver, pancreas, intestines, kidneys, bladder, adrenal glands, lungs, and heart. It also can study blood vessels, bones, and the spinal cord.
A CT scan usually takes 15 to 30 minutes.
If you have a CT scan of your belly, you may be asked to not eat any solid foods starting the night before your scan. For a CT scan of the belly, you may drink contrast material. For some CT scans, you may need a laxative or an enema before the test.
You may need to take off any jewelry. You will need to take off all or most of your clothes, depending on which area is studied. You may be able to wear your underwear for some scans. You will be given a gown to use during the test.