Utility of CT colonography in detecting colon polyps as a colon cancer screen

Park, Yun Jung; Jung, Seung Eun; Park, Shin Ae; Kim, Jee Hee; Chang, Eun Hee; Koh, Myoung Beom; Cheung, Dae Young; Kim, Jin Il; Cho, Se Hyun; Park, Soo Heon; Han, Joon Yeol; Kim, Jae Kwang

Abstract

BACKGROUND/AIMS: CT colonography is a rapid and safe imaging method for detecting polyps in the colon and rectum. We assessed the efficacy of CT colonography in colorectal polyp detection.
METHODS
We prospectively studied 84 subjects (mean age 55.7+/-11.1 years; 52 men, 32 women) undergoing CT colonography followed by colonoscopy. Based on the results of CT colonography, all polyps were classified by size (any size, and those larger than 5, 7, and 10 mm) and were checked for location, morphology, and histological characteristics. We determined the sensitivity and specificity of CT colonography using colonoscopy as a reference standard with a segmental unblinding method.
RESULTS
A total of 56 lesions were identified in 26 of 79 subjects undergoing both CT colonography and conventional colonoscopy. The sensitivities of CT colonography for polyps of any size, and larger than 5, 7, and 10 mm were 60.7%, 70.5%, 75.9%, and 81.8%, respectively. The per-subject sensitivities of CT colonography for the polyps of any size, and larger than 5, 7, and 10 mm, were 80.7%, 95.0%, 93.3%, and 90.9%, respectively. The per-subject specificities of CT colonography for polyps were 86.8%, 89.8%, 95.3%, and 100.0%, respectively. The sensitivities of CT colonography for flat, sessile, and pedunculated polyps were 30.8%, 85.0%, and 90.0%, respectively.
CONCLUSIONS
CT colonography is a useful diagnostic method for screening colorectal neoplasias larger than 7 mm diameter, showing 75.9% sensitivity and 71.0% positive predictive value.