During the scan, a thin beam of x-rays is focused on a specific part of your body, such as the head, chest, liver, spleen, pancreas, adrenal glands, kidneys, or spine. The x-ray tube moves rapidly around this site, enabling multiple images to be made from different angles to create cross-sectional picture. The x-ray beam is picked up by an electronic detector which records the information and feeds it into a computer.
As with other important diagnostic procedures, you may be asked to sign an informed consent to undergo a CT scan. That is your opportunity to ask any questions following a description of the risks, benefits, and alternatives of the procedure. The contents of this guide are for your information only and are not to be interpreted as taking the place of informed consent. Do not hesitate to discuss your upcoming CT exam with your physician or the radiologist.
You will be asked to lie on a table that is connected to the CT scanner. Then the part of your body that is to be scanned will be positioned in the middle of the large, doughnut-shaped scanner ring. This ring holds the x-ray tube and the electronic detector that sends information to the computer.
If a contrast medium is to be used during your exam, the technologist will probably take some preliminary scans before the radiologist injects the material.
If a contrast medium is used, the radiologist or technologist will usually inject it into a vein, probably in your arm. Some or all of the solution may be injected by a syringe or by an automatic injector. Some or all of it may run slowly into your vein from an intravenous (IV) bottle that hangs on a pole next to the table. A tourniquet may be used to make the vein stand out for easier injection. A tourniquet is simply a band that is wrapped tightly around your arm, similar to, but smaller than, the cuff that is wrapped around your arm when you have your blood pressure taken.
You will remain alone in the room after the procedure begins, but the radiologist and the radiologic technologist will watch you closely through an observation window and you can talk to them through a two-way intercom.
After the exam is over, the radiologist will look at all the images to make sure they contain all the needed information. You will be asked to wait while this is done because sometimes it is necessary to do repeat scans or take additional scans.
After the radiologist has a complete set of scans, you may change back into your clothes and go home. If you are a hospitalized patient, you may go back to your room.
Unless you have other tests scheduled, you may eat normal meals after the exam and your doctor will suggest that you drink plenty of fluids. Fluids will help eliminate the contrast medium from your body by natural routes.
The radiologist will study all the scans, prepare a report, and forward it to your personal physician and sometimes will gives it to you according to the rules applied by the radiology department. This may take one or two days. Then your physician will discuss the results with you and tell you what they mean to your health.