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CT colonoscopy

CT scanner.

CT colonoscopy

CT colonoscopy, also known as a “virtual colonoscopy”, involves the use of a CT scanner to produce 3-dimensional images of the large bowel and rectum.

During the procedure, gas is used to inflate the bowel using a thin, flexible tube placed in your bottom. CT scans are then taken from several different angles.

As with a colonoscopy, you may need to have a special diet for a few days and take a laxative before the test to ensure your bowels are empty when it’s carried out. You may also be asked to take a liquid called Omnipaque before the test. This helps to highlight any stool left in the bowel. The hospital will you send some instructions to follow.

This procedure is less invasive than a colonoscopy and takes around 30 minutes.

While you are waiting for your CT Colonography, ensure you maintain a healthy diet, reduce alcohol, and consider stopping smoking. Try and avoid being too constipated by taking regular laxatives if needed. This will also help to ensure that your bowel is fully emptied when you take the bowel preparation before the procedure. Avoid any foods that make your bowel symptoms worse.

The hospital will send you some instructions on how to prepare for this procedure. Your bowel will need to be empty for the procedure. You will either be asked to take medication (laxatives) the day before or you’ll be asked to drink a special liquid called gastrografin 1 to 2 days before. You may also be asked to eat a low fibre diet 1 or 2 days before. It will also be important for you to drink plenty of clear fluids.

If you are taking iron tablets, then stop these 7 days before the test.

It is very important you follow the instructions you get from the hospital.

What should you do if your health is deteriorating?

If you develop new symptoms such as blood mixed in your stools, severe pain, not passing stools or wind, or rapid weight loss then contact your GP or specialist as you may need a more urgent review. Equally, if you have existing symptoms that have changed in nature or deteriorated quickly then you should seek further advice and reassessment.

If your appointment has come through but your condition is getting worse, you should contact the hospital team or Patient Advice and Liaison Service (PALS). The number and email for this should be on the hospital appointment letter.

If you haven’t yet received your hospital appointment and your condition is getting worse, you should contact your GP practice. Your GP cannot get you seen quicker at the hospital as they don’t have access to the waiting list or appointment system. However, if your condition is getting worse or if you are experiencing new symptoms they can assess the situation, give you some advice and may be able to update your specialist to consider upgrading your procedure.

Last Updated: 12 April 2024

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