CT Colonoscopy

Reasons for the Examination

The test is performed to examine the lining of the colon (large bowel) mainly as a screening method to detect polyps, which may over a period of time develop into more serious growths. It must be appreciated that if a significant polyp is found, the patient may be referred for conventional colonoscopy, at which time the polyp can be removed or biopsied.

The Procedure

You will change into a gown with your underwear removed. Lying on your right side on the x-ray table, a radiologist will introduce a soft rubber catheter into the rectum and then pump in air or Carbon Dioxide to inflate the colon. It is important to have the colon fully inflated and insufflation will proceed until you inform the radiologist that you feel discomfort. A small intravenous injection of an antispasmodic may be administered to facilitate inflation and reduce discomfort. Two scans through the abdomen will then be performed, one lying on your back and the other on your tummy. Each scan lasts approximately 20 seconds during which time you will be asked to hold your breath.

After the procedure

A visit to the toilet immediately afterwards will help evacuate some of the air but you will probably need more visits for a few hours thereafter. Although a sensation of uncomfortable bloating may be experienced, this should only cause discomfort rather than pain and lasts no more than a few hours. It will be possible to drive home and return to work immediately.

The Results

Processing and interpreting the scan is time consuming and results will not be available immediately after the test. They will be sent to your doctor as soon as they are available.

Points to remember

  1. A clean colon is essential and it is important to follow the bowel preparation instructions.
  2. The procedure is painless and simple but may cause mild bloating and discomfort lasting for a few hours at most.
  3. You may drive home and return to work immediately after the procedure.
  4. If a significant polyp is found you may be referred for a colonoscopy

Diet Instructions

The day before the examination you are required to eat a low residue diet.

  • Breakfast:
    • Boiled or poached egg with white bread, butter/margarine and jam.
    • Tea/coffee with milk and sugar if desired, or fruit juice.
    • Thereafter only clear liquids eg. clear soups and Bovril drinks, jelly, black tea/coffee, energy drinks (Energade/Powerade), clear fruit juices (apple or grape), Sprite. (NO milk or dairy products).
  • Midday:
    • Drink 225ml Readicat (1/2 bottle).
  • 16:00:
    • Mix one sachet Picoprep in 200ml warm water and stir to form a clear solution.
    • Add ice to chill and drink, followed by a glass of water or Sprite.
  • 18:00:
    • Repeat second Picoprep as above.
  • 18:30:
    • Drink 225ml (2nd half) Readicat.20:00 : Repeat third Picoprep as above.
  • 20:30:
    • Add 20ml Gastrografin to a glass of water/juice and drink.

To keep hydrated, please drink only clear juices as required until midnight. Thereafter remain nil per mouth until after the examination.

Note : The Readicat and Gastrografin are used to tag any residual fluid or stool content. Picoprep produces watery stools which will become clear with no solid matter. It is advisable to remain near a toilet and to apply a thin layer of Vaseline around the anus before taking the Picoprep and after each bowel movement.