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CT Colonography

Doctors perform a CT colonography – also called a virtual colonoscopy – using a CT scanner to obtain a detailed picture of what is going on inside the large bowel (colon) and rectum. It may be used in place of a colonoscopy to detect growths inside the bowel.

We use a CT colonography to examine the colon and rectum using the CT scanner. Unlike a colonoscopy, which involves inserting a flexible plastic tube all the way around the colon, a CT colonography passes a plastic tube only a small way into your rectum.

This allows gas to be gently pumped into the colon which opens it out as much as possible. This smooths out any folds or wrinkles to enable the radiographer to obtain clear images and show up any polyps or growths.

You might need to undergo a CT colonography to detect polyps or growths inside your colon or rectum. These are normally harmless but can sometimes develop into bowel cancer and so removal is generally recommended.

You may be referred for a CT colonography if you are experiencing symptoms such as blood in your poo, weight loss or changes in bowel habits. You may also need this type of scan if you are high risk of developing bowel cancer. In addition the procedure can be used if you are unsuitable for a colonoscopy, due to high levels of frailty, for example.

Prior to your scan we will ask you to follow a special diet for a few days. In addition we will ask you to take a laxative to fully empty your bowel. You should avoid eating and drinking for a few hours before the procedure. Your doctor will advise you for how long. It is important that you follow the instructions on your appointment letter.

Once you are in the scan room, we may give you an injection of muscle relaxant to assist the bowel muscle to relax. In some cases, we may also inject contrast dye. We will ask you to lie down on the CT scan table. After this we will pass a small flexible tube a small way into your rectum. We can then gently pump gas into the colon.

This may cause abdominal pain, similar to trapped wind. As the table moves through the CT scanner we may ask you to hold your breath and stay as still as possible to obtain clear images. The scan takes between five and 30 minutes. Once complete, the tube is removed and you will be able to get down from the table. You may feel bloated and need to pass wind for a time after the test but this should settle down fairly quickly.

CT colonography is a safe and routine procedure and the risks are small. You may experience diarrhoea from the laxatives or feel sick. Some people have an allergic reaction to the contrast dye and rarely this can cause a small amount of kidney damage in people with kidney problems. There is a small risk of bleeding or infection. CT scans expose you to radiation which carries some risk although advanced technology means the level of the radiation dose is now very small and the advantages are believed to outweigh any risk. Your radiologist will discuss the individual risks with you.

Why choose Berkshire Imaging?

We are one of the largest private radiology groups in Berkshire, providing imaging for patients across the county. We also provide interventional radiology procedures for patients in Berkshire, Oxfordshire, Hampshire, Bucks and London. We are leaders in medical imaging and image guided treatments. As a result we use cutting edge technologies to diagnose and treat many different and often complex conditions.

When you are concerned about your health, you want a doctor to see and treat you as quickly as possible. With Berkshire Imaging you will receive a prompt and accurate diagnosis. This can help ensure better outcomes if you need treatment or put your mind at ease if you don’t.

Where Are You Based?

We provide imaging for patients right across Berkshire. From Newbury and Thatcham in the West along the M4 corridor to Reading, Bracknell and Wokingham and as far as Maidenhead and Slough, we have helped hundreds of patients in Berkshire. Our strong relationships with all the major private hospitals across Berkshire enable us to offer rapid access to private scans in several locations.

Contact Us

If you have any questions our friendly patient care team will be happy to help. Contact us by calling 0118 338 2500 or emailing for more details about this procedure.


Frequently asked questions – CT scans

A CT colonography may be used to diagnose polyps or growths in the bowel which can be linked to bowel cancer.

We do not recommend having a CT colonography if you are pregnant. This is because the X-rays pose a small risk to your unborn child. Tell your doctor if you think you might be pregnant.

We offer a broad range of treatments at Berkshire Imaging, at a number of different locations. For this reason the price will vary. Please call 0118 338 2500 or email for an accurate price. You can also get in touch via our contact page. You can read more information relating to payments and insurance on our payment information page.

We will send your results promptly to your referring clinician. They will then get in touch to discuss them with you.