Introduction CT colonography (CTC) is now widely available as the radiological imaging test for the colon, replacing barium enema. It is recommended that regular audit processes should be in place to audit the quality of CTC service provision against internationally agreed standards. This is especially important when considering the national bowel cancer screening programme with reference to FOB positive patients unfit for a colonoscopy and/or with incomplete colonoscopic examinations. The other advantage of CTC is the ability to detect extra colonic lesions at the same time as evaluating the colon. We aimed to audit our CTC practice with reference to endoscopic findings and to determine the value of any extra colonic lesions found on CTC, especially in our 2 week wait and bowel cancer screening patients.
Method All patients who had a CTC performed over a period of 13 months were evaluated against the electronic record of endoscopic procedures. Of 264 patients who had a CTC, 78 also had a contemporaneous flexible sigmoidoscopy or colonoscopy performed.
Results The main indications for an investigation of the colon were altered bowel habit (45%), anaemia (11%), abdominal pain (6.8%) and cancer/ polyp follow up (7.9%). The most common indication for CTC in the 264 patients reviewed was exclusion of synchronous colonic tumours in patients who had an incomplete colonoscopy (112 patients); 140 patients had been deemed unfit to have a colonoscopy and 12 patients declined one. 11 BCSP underwent CTC, 5 due to an incomplete scope and 6 were deemed unfit for colonoscopy. 68% of the CTC and endoscopic findings were in agreement. 19/78 endoscopic abnormalities were not picked up on CTC (24%). No cancers were missed on CTC. The most common positive findings were diverticular disease (24%) and polyps (14%). We found that 37.5% of patients had extra colonic abnormalities. There were no recorded complications.
Conclusion It is essential to audit the quality of CTC service provision against standards set by the International CT Colonography Standards Collaboration and the NHS Bowel Cancer Screening Programme. In our institution, the correlation of CTC and endoscopic findings was reassuring. In addition, a large number of extra colonic abnormalities were detected using CTC, some of which were significant – this is especially important in the 2 week wait patients. Colonoscopy, however, still remains the gold standard investigation for the detection of colon related pathology.
Disclosure of interest None Declared.
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NICE guidelines CT Colonography. http://guidance.nice.org.uk/IPG129;2009
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