CT Colonography Reporting and Data System (C-RADS): Benchmark Values From a Clinical Screening Program

OBJECTIVE. The CT Colonography Reporting and Data System (C-RADS) is a well-recognized standard for reporting findings at CT colonography (CTC). However, few data on benchmark values for clinical performance have been published to date, especially for screening. The purpose of this study was to establish baseline C-RADS values for CTC screening. SUBJECTS AND METHODS. From 2005 to 2011, 6769 asymptomatic adults (3110 men and 3659 women) 50–79 years old (mean [± SD] age, 56.7 ± 6.1 years) were enrolled for first-time CTC screening at a single center. CTC results were prospectively classified according to C-RADS for both colorectal and extracolonic findings. C-RADS classification rates and outcomes for positive patients were analyzed. RESULTS. C-RADS classification rates for colorectal evaluation were C0 (0.7%), C1 (85.0%), C2 (8.6%), C3 (5.2%), and C4 (0.6%). Overall, 14.3% of subjects were positive (C2–C4), and positive findings were more frequent among men (17.5%) than women (11.6%; p < 0.0001). Positivit...