The National Institute for Health and Clinical Excellence (NICE) has issued full guidance to the NHS in England, Wales, Scotland and Northern Ireland on computed tomographic colonoscopy (virtual colonography).


CT colonography is used to examine the colon and rectum, and detect abnormalities such as polyps and cancer. Polyps are growths in the lining of the colon or rectum that protrude into the intestinal canal. They may be hyperplastic, which are completely benign or adenomatousin type, which have the potential to become malignant.

Conventional colonoscopy and double contrast barium enema are the main methods currently used for examining the entire colon. The bowel must be empty before either of these procedures is performed.

CT colonography is less invasive than a conventional colonoscopy. It involves using a CT scanner to produce 2- and 3-dimensional images of the entire colon and rectum.

CT colonography is performed on an empty bowel. Sedation is not usually required. The colon is distended by insufflation with air or carbon dioxide, via a small rectal tube. Antispasmodic agents and/or contrast agents may be administered intravenously before the scan. The CT scan is done with the patient holding his or her breath for approximately 20 seconds in both the supine and prone positions.

The images are then manipulated and interpreted by a radiologist.

Coding recommendations

U17.5 Computed tomography of colon                                                    

Y97. Radiology with contrast

Y98.1 Radiology of one body area (or < twenty minutes)

Note: A code from category Y97.- Radiology with contrast is only assigned if contrast is used

Your responsibility

This guidance represents the view of NICE, arrived at after careful consideration of the evidence available. When exercising their judgement, healthcare professionals are expected to take this guidance fully into account, and specifically any special arrangements relating to the introduction of new interventional procedures. The guidance does not override the individual responsibility of healthcare professionals to make decisions appropriate to the circumstances of the individual patient, in consultation with the patient and/or guardian or carer. 

All problems (adverse events) related to a medicine or medical device used for treatment or in a procedure should be reported to the Medicines and Healthcare products Regulatory Agency using the Yellow Card Scheme.

Commissioners and/or providers have a responsibility to implement the guidance, in their local context, in light of their duties to have due regard to the need to eliminate unlawful discrimination, advance equality of opportunity, and foster good relations. Nothing in this guidance should be interpreted in a way that would be inconsistent with compliance with those duties. Providers should ensure that governance structures are in place to review, authorise and monitor the introduction of new devices and procedures.

Commissioners and providers have a responsibility to promote an environmentally sustainable health and care system and should assess and reduce the environmental impact of implementing NICE recommendations wherever possible.