Virtual colonoscopy (also known as CT colonoscopy) is an investigation of the large bowel. The patient undergoes a CT scan that focuses on the colon, specifically looking for physical abnormalities such as polyps, diverticular disease or colorectal cancer. It is an alternative investigation to colonoscopy. Images produced by the CT scanner can be reconstructed to give a 3D image of the colon, which allows the radiologist to “fly through” the colon, mimicking what would be seen at colonoscopy.
The day before the test you will need to eat a special diet and take a laxative to clear the bowel out; you will be given detailed information about this. Occasionally, especially in frail patients, a special protocol can be adopted that limits the amount of laxative taken. The test itself involves a special protocol CT scan. A small catheter (plastic tube) is inserted into the rectum that allows the radiographer to insert gas into the colon. Images are taken with the patient lying on their back and their front. The test usually lasts about 45 minutes.
After the test is complete you will be able to go home. The images will be analysed by one of our specialist gastrointestinal radiologists. The results are then sent to your consultant who will be able to discuss the findings and future plans with you.
Virtual colonoscopy is a safe test that is well tolerated by most patients. Your consultant will discuss with you before the test what is involved, as well as any risks and alternatives.