Colorectal polyp detection with virtual colonoscopy (computed tomographic colonography); The reliability of the method

Background/Aims: The aim of this study was to compare the reliability of virtual colonoscopy with conventional colonoscopy in detection of colorectal polyps, Methodology: Between November 1997 and February 2000, 23 patients (14 males, 9 females) aged 4386 years (mean: 63) with colorectal polyps who underwent colonoscopy in our endoscopy unit, were referred for virtual colonoscopy. The colon was distended with an enema tube for rectal insufflation and subsequently was scanned by helical CT (Toshiba X-vision) using the following parameters: KV 120, mAs 200, table feed 5mm/sec, slice thickness 5mm and reconstruction intervals 2.5mm. Using SPARC Station 20, virtual colonoscopy was generated. Results: A total of 30 polyps (19 with diameter 8-15mm and 11 larger than 15mm) were detected with conventional colonoscopy. Virtual colonoscopy visualized 27 polyps (17 with diameter 8-15mm and 10 with diameter >15mm). Conclusions: Virtual colonoscopy is a non-invasive, well-tolerated, safe technique and can be useful for detection of colorectal polyps. Weaknesses of the method are the inability to detect small lesions and to perform biopsies.