In general, no special preparation is required for a CT scan. Comfortable, loose clothing should be worn, although in some cases a patient will be asked to change into a hospital gown for the examination. It is also important to remove any metal prior to the exam: jewelry, dentures, eyeglasses, belt buckles, and metal zippers and buttons can interfere with the images.
A patient may be asked to limit eating and drinking to clear liquids, such as water, black coffee and tea, and broth for several hours prior to the appointment for a CT scan. This request will be dependent upon the facility and the type of examination.
For many CT examinations, a contrast agent (a liquid that enhances imaging of certain organs or blood vessels) will be administered. Depending on the type of examination, the contrast may be given orally, intravenously, or as an enema. If certain types of contrast will be used during an examination, the patient may be required to fast for several hours or use an enema to cleanse the colon prior to his/her appointment.