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CT Scan (used to see internal structures)

What is a CT scan?

A CT scan stands for Computed Tomography scan. It is also known as a CAT (Computer Axial Tomography) scan. A CT scan combines a series of X-ray views taken from many different angles to produce cross-sectional images of the bones and soft tissues inside your body.

Preparing for a CT Scan

  • You may be asked to fast (not eat) for 4 hours prior to the exam.
  • In some cases, you may be asked to drink up to 1000mL (4 cups) of water before the exam.
  • You may be asked to drink a contrast agent the night before the test.
  • If you are having a CT colonography exam, you will be required to follow a detailed bowel preparation. Instructions will be given to you before your scheduled appointment.
  • You may require routine blood work prior to your CT scan.
  • Please inform your doctor and technologist if you are or might be pregnant.

Risks or Complications:

Minimal exposure to radiation

Although rare, the intravenous (IV) contrast material involved in some CT scans may cause medical problems or allergic reactions in some people. Most reactions are mild and result in hives or itchiness. In rare instances, an allergic reaction can be serious. Make sure to tell your doctor if you have had a prior reaction to contrast material (X-ray dye) during medical tests.

How long will a CT scan take?

The scan can take from 10 to 30 minutes, depending on the type of test being done.

After Your Procedure

  • You can return to your normal routine.
  • If you were given a contrast material, your doctor, a nurse or the CT technologist performing the scan may give you special instructions.
  • You may be asked to wait for a short time in the Radiology Department to ensure that you feel well after the exam.
  • After the scan, you will likely be told to drink lots of fluids to help your kidneys remove the contrast material from your body.

Diabetic Patients Taking Oral Glucophage (Metformin)

  • You may be required to withhold taking your Glucophage medication for 48 hours after this examination.
  • You will be asked to drink plenty of fluids.

If you have any questions regarding your diabetes control during this time frame, please contact your family doctor.

If Your Child Has Been Sedated

If your child has been sedated in order to do the necessary exam, he/she will be kept at the hospital until it is felt that he/she can be discharged. Once your child is okay to leave the hospital, he/she may exhibit some symptoms of this sedation for the next few hours.

Foods and Fluids:

If your child seems fully awake and alert, usual foods and fluids may be given but avoid large chunky foods such as hot dogs.


Your child's coordination, balance and perception may be affected. It is advised that he or she be carefully supervised for a few hours and to avoid climbing of any kind or descending stairs. Watching T.V. or reading are good activities to do with your child.

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