Two-year audit of computed tomographic colonography in a teaching hospital: Are we meeting the standard?

Objective:  We aimed to determine whether adopting the published recommendations has led to successful implementation of computed tomographic colonography (CTC) in a teaching hospital setting outside the context of a clinical trial. Method:  An audit of all the CTC examinations between April 2005 and June 2007 was conducted to determine the following: adequacy of bowel preparation, CTC indications and findings (compared with available colonoscopy), complications and experience of reporting radiologist. Results:  The most common indications for the 111 CTC patients reviewed included exclusion of synchronous colonic tumours, incomplete colonoscopy and altered bowel habit. Only 16% of ascending colon/caecal segments was clear of faecal or fluid contamination. The rectum and sigmoid colon were free of contamination in 78% and 74% of cases respectively. Appropriately trained radiologists reported 91% of studies. Thirty-two percent of studies were normal. The most common positive findings were diverticular disease or a rectal tumour. Sensitivity, specificity and positive predictive value were 89%, 94% and 90% respectively (all polyps) with a sensitivity of 98.5% for lesions > 5 mm in size. Twenty-five percent of patients had extra colonic abnormalities. There were no recorded complications. Conclusion:  Our CTC practice is within accepted published guidelines. Bowel preparation is suboptimal in a significant proportion of cases and faecal tagging is being implemented.