Comparison of the relative sensitivity of CT colonography and double-contrast barium enema for screen detection of colorectal polyps

Abstract

Background & Aims: In a population reflective of a screening setting, our aim was to compare the relative sensitivity and specificity of computed tomography (CT) colonography with double-contrast barium enema (DCBE) for detection of colorectal polyps and to assess the added value of double reading at CT colonography, using endoscopy as the arbiter. Methods: This prospective, blinded study comprised 837 asymptomatic persons at higher than average risk for colorectal cancer who underwent CT colonography followed by same-day DCBE. Examinations with polyps ≥5 mm in diameter were referred to colonoscopy. Results: CT colonography readers detected 56%–79% of polyps ≥10 mm in diameter. In comparison, the sensitivity at DCBE varied between 39% and 56% for the 31 polyps ≥1 cm. All of the readers detected more polyps at CT colonography than DCBE, but the difference was statistically significant for only a single reader ( P = 0.02). Relative specificity for polyps ≥10 mm on a per-patient basis ranged from 96% to 99% at CT colonography, and 99%–100% at DCBE. Doubly read CT colonography detected significantly more polyps than DCBE (81% vs. 45% for polyps ≥1 cm [ P = <0.01], and 72% vs. 44% for polyps 5–9 mm [ P ≤ 0.01]). Conclusions: Double-read CT colonography is significantly more sensitive in detecting polyps than single-read double contrast barium enema. DCBE was significantly more specific than CT colonography.