CT Virtual Colonography

CT Virtual Colonography is an examination of the large bowel. It involves the introduction of carbon dioxide gas into the colon via a small flexible tube inserted into the rectum. The gas distends the colon and scans are taken using the CT scanner with the patient lying on their back and on their stomach. This allows for a detailed investigation of all areas of the colon.


CT virtual colonography is used to image the large bowel, usually when a conventional colonoscopy has not been successful. Following the introduction of gas inside the bowel we perform CT scan which provides us with the ability to construct 3D images of the colon.  CT virtual colonography is used to diagnose colon and bowel disease including polyps and cancer.

Our sister practice Norwest Medical Imaging at nearby Bella Vista offers CT virtual colonography examinations in a comfortable and caring environment.

Preparing for a CT Virtual Colonography

Please bring your referral (letter from your doctor) and your Medicare and/or Pension Health care card with you to your appointment. It is important to bring all previous films and reports relating to the region being imaged.

A good bowel preparation is essential for this examination. A 2 day diet and laxative preparation is undertaken. You will need to collect your bowel preparation kit before your CT virtual colonography. It is essential that the bowel is clear as possible otherwise the examination may need to be repeated.

Before the scan is taken a small injection of Buscopan may be given to relax the bowel wall muscles.


Carbon dioxide gas is introduced into the colon via a small flexible tube inserted into the rectum. The gas distends the colon and may cause slight abdominal discomfort. You will be asked to lie both on your back and front while scans are taken using the CT scanner.

After the scans are taken, the tube will be removed from the rectum. Carbon dioxide is more comfortable for the patient than air, so any discomfort will pass quickly and normal activities can be resumed.


CT virtual colonography does require detailed processing of the data acquired from the scans. This may take some hours, but results are usually available on the afternoon of the examination. The examination usually takes place in the morning.

Norwest Medical Imaging strongly advises that you return to your referring doctor, in order for your doctor to discuss your radiology report with you.

We understand that some patients are anxious about having tests performed. If you have any questions or concerns, please do not hesitate to ask our staff.


What is CT Colonography?
CT colonography often referred to as virtual colonoscopy, is a CT scan designed to simulate colonoscopy to look for large bowel polyps and cancers.

Does it require bowel cleansing?
Yes. Bowel cleansing preparation is the same as that for colonoscopy. You will need to follow the 2 day preparation kit instructions provided.

Can I continue my medication before a CT Virtual Colonography?
Yes, all medication can be continued.

How long will the CT Virtual Colonography scan take?
The examination usually takes approximately 10-30 minutes to perform.  Please enquire when you make your appointment.

Can I eat and drive after a CT Virtual Colonography?
You have no restrictions after having a CT virtual colonography and can go about your normal activities.

Do I have to take my clothes off for my CT Virtual Colonography?
You will need to change into a gown.

Will the radiographer performing my scan tell me what’s wrong?
The radiographer is not qualified to read your x-rays. It is the radiographer’s duty to perform the test and ensure the images are of high quality for the radiologist (specialist doctor) to interpret them.