Virtual colonoscopy (CT-scan)
The CT Virtual Colonoscopy is a less invasive alternative to the traditional colonoscopy. The test should be expected to take
around 20 minutes, in which you will be asked to change into a hospital gown and lie down on the scanning table. Straps and pillows may be put in place, to help you stay comfortably in one position. Your referring doctor may also request that you receive an injection to help relax the muscles of your bowel wall. You may also have an injection of a dye (contrast medium) at the same time, depending on the reason for your test.
A thin tube will gently be inserted a few centimetres into your rectum. A small amount of carbon dioxide or air is pumped into your bowel to expand it and make the wall easier to view. When this happens, you may briefly feel some discomfort or pain similar to trapped wind.
The table will move into the ring of the CT scanner so that the middle part of your body is lying in the centre of the scanner. The scanner will rotate around you to produce images from every direction.
The scanner is operated from behind a window by a radiographer (a health professional trained to perform imaging procedures). He or she will be able to see, hear and speak to you throughout the procedure. You will have scans taken when you’re lying on your back and others taken when you’re lying on your stomach. At certain points during the scan you may be asked to hold your breath for a few seconds. It can take several minutes for each image to form so it's important to lie very still during the scan.
The advantage of a Virtual Colonoscopy is that we do not need to apply a colonoscope (the long camera that is usually inserted through the entire length of the large intestine) with this procedure; therefore the risk of a tear or perforation is hugely reduced. You also do not require sedation and are usually well enough to go about most daily activities, apart from driving, following the test. The disadvantage is that, Virtual colonoscopy is used to help diagnose your condition rather than to treat it. If the virtual colonoscopy shows that you have polyps, you will need to have another procedure, for example a conventional colonoscopy, to remove them. Large polyps or cancer may need surgery. Because of the use of CT (radiation) we do require a doctor’s referral for you to go ahead with this examination.