CT Colonography is used to look for cancer or polyps, in the large bowel. Polyps are growths arising from the surface of the colon that can grow into cancers of the colon. CT Colonography is also excellent for diagnosing diverticulitis (where pouches develop in the wall of the colon) or if you have symptoms suggestive of bowel problems.

CT Colonography may also be performed if you have had a difficult or incomplete conventional colonoscopy, when the whole bowel may not have been completely or confidently assessed.

Lake Imaging performs CT Colonography at the following locations:

What to bring

  • A referral from your doctor or specialist is required for this examination, please ensure you bring this to your appointment.
  • Medicare or concession card
  • Previous imaging not performed at Lake Imaging


The preparation for a CT Colonoscopy involves cleansing of the bowel using a bowel preparation. The success of your examination depends on the bowel being as clear as possible; otherwise the examination may need to be repeated.

When you make your appointment, you will be given detailed instructions for your bowel preparation, commencing two days prior to your procedure.

It is recommended that someone accompany you to and from your appointment.

What to expect during my procedure

When you arrive at Lake Imaging for your procedure will be asked to change into an examination gown and to remove your underwear.

You will then be asked a few safety questions before being asked to lie on the CT examination table. A lubricated enema tube will be gently inserted into your rectum. This enables air to be introduced to expand the colon and improve the quality of images.

The tube that is used to introduce the air has a small balloon near its tip. When positioned at the entrance of your rectum, the balloon helps keep the air inside your body. As your colon fills with air, you may feel the urge for a bowel movement. You will be asked to take long deep breaths and resist the urge to expel the tube. Abdominal cramping may sometimes be experienced. This will resolve shortly after the air is removed.

You will need to keep very still for the duration of the scan, as the table moves through the gantry opening and the image data is acquired. You may hear a humming noise during the scan, but no moving parts will touch you.

The CT scanning procedure will take just a few minutes to complete.

Risks and side effects

CT scans involve the use of ionising radiation.  CT scans will only be performed when any potential risks are far outweighed by the benefits to the patient. Lake Imaging’s state of the art CT scanners and staff trained in radiation reduction techniques use the latest in CT dose efficient technology to ensure the minimum dose necessary is used to produce the best quality images for an accurate diagnosis.

If it is possible that you may be pregnant, please inform our radiology team before your examination to avoid any risks to your unborn child.

For further information regarding radiation safety please visit:

Contrast injections can make some patients feel nauseous or on rare occasions cause an allergic reaction. 

If you are worried or concerned about having a CT scan you should discuss this with your referring doctor or medical specialist before coming for your examination.

Who will perform and report my examination

At Lake Imaging your CT examination will be performed by a radiographer (or medical imaging technologist), who has a degree in medical imaging. A Radiologist (a doctor specialising in the interpretation of medical images), will prepare and send a report to your referring doctor detailing the findings of your examination.

What to expect after my procedure

You will be free to leave our clinic shortly after your CT scan has been completed. You may, then eat and drink normally and resume your normal activities.

It is recommended that you have someone attend with you who can drive you home following the procedure.

How do I receive my results?

If your CT results are urgent, or you have an appointment straight after the scan with your doctor or health care provider, Lake Imaging will arrange to have your results available immediately delivered to your referring doctor.

Otherwise your referring doctor or health care provider will receive your report within 48 hours of your examination.

Please ensure that you make a follow up appointment with your referring doctor or health care provider to discuss your results.