CT (Computed Tomography)

What is CT?

CT (computed tomography), also called a CAT scan, uses x-ray and computers to produce cross-sectional images of the body.

What are some common uses of CT?

  • Locating internal bleeding and organ damage in trauma patients.
  • Detecting stroke, and determining whether it is caused by arterial blockage or bleeding into the brain.
  • Detecting and staging tumors of various body parts.
  • Diagnosis and analysis of fractures and other bone abnormalities, especially if complex.
  • Detecting deep abscesses and sources of infection.
  • Detecting urinary stone disease.
  • Performing non-invasive blood vessel imaging (CT angiography).
  • Planning radiation therapy treatment fields.
  • Guiding needle biopsies and drainage procedures.

How should I prepare for a CT scan?

  • On the day of your exam, wear comfortable, loose-fitting clothing.
  • Avoid clothing with zippers and snaps as metal objects can affect the image.
  • Depending on the part of the body that is being scanned, you may also be asked to remove hair pins, jewelry, eyeglasses, hearing aids, or dentures.
  • You may be asked not to eat or drink anything for one or more hours before the exam.
  • Women should inform their doctor or CT technologist if there is any possibility that they are pregnant.

What can I expect during this procedure?

A CT examination usually takes five minutes to half an hour.

The technologist positions you on the CT table and pillows are used to help keep you still and in the proper position during the scan. The table will move slowly into the CT scanner opening. Depending on the area of the body being examined, the increments of movement may be very small and almost undetectable, or large enough to feel the motion.

  • To enhance the visibility of certain tissues or blood vessels, use of different contrast materials (“x-ray dye”) may be required. Depending on the type of examination, contrast material may be injected through an IV, swallowed or administered by enema. Before administering the contrast material, you should inform the radiologist or technologist of the following:
    • Any allergies, especially prior allergic reactions to radiologic contrast agents.
    • Whether you have a history of diabetes, asthma, kidney problems, heart or thyroid conditions. These conditions may indicate a higher risk of reaction to the contrast material or potential problems eliminating the material from the patient's system after the exam.
  • The CT technologist will step out of the CT exam room into an adjacent control room but will be in constant visual and verbal contact with you during the brief time that the scan is actually being performed.
  • To determine if more images are needed, you may be asked to wait until the images are reviewed.