DETECTION OF COLORECTAL POLYPS BY COMPUTED TOMOGRAPHIC COLOGRAPHY - FEASIBILITY OF A NOVEL TECHNIQUE

Background & Aims: Computed tomographic colography (CTC) represents a novel technique for colorectal polyp detection, A prospective study wa s undertaken to determine the optimal CTC scanning parameters based on an artificial colon model and to assess the feasibility of CTC to det ect clinically significant colorectal polyps, Methods: A colon model w as scanned by helical computed tomography at multiple parameters. Refo rmatted two-dimensional and three-dimensional images were then graded for polyp detection and image quality, Subsequently, 10 patients with known colon polyps underwent CTC immediately before colonoscopy, The n umber of polyps detected by two radiologists using CTC were compared w ith colonoscopy results that served as the gold standard, Results: The optimal scanning parameters in the colon model were 5-mm collimation, 5 mm/s table speed, and 1-mm reconstruction interval. Ten patients ha d 30 polyps (range, 0.2-2.0 cm) by cotonoscopy, and all polyps greater than or equal to 0.5 cm were adenomas, Polyp detection by CTC for bot h observers was 100% (5 of 5) greater than or equal to 1 cm, 71% (5 of 7) between 0.5 and 0.9 cm, and 11%-28% (2-5 of 18) <0.5 cm. Conclusio ns: Based on this small, unblinded pilot study, CTC is feasible for co lorectal polyp detection greater than or equal to 0.5 cm in diameter.