Prospective Blinded Comparison of Polyp Size on Computed Tomography Colonography and Endoscopic Colonoscopy

BACKGROUND & AIMS: The size of polyps found on computed tomography colonography (CTC) has been suggested as the major determinant of patient management. We compared polyp size as seen on CTC with endoscopic visualization, in vivo probe measurement, and ex vivo size before and after fixation. METHODS: Polyps measured on CTC sent for endoscopic removal were evaluated for polyp size in a blinded fashion by endoscopic estimation, in vivo probe measurement, and after removal. RESULTS: Fifty-six polyps were included in the study. There was no significant difference between CTC polyp size, real-time colonoscopy size estimation, or probe measurement. The size of polyp measured immediately ex vivo and after pathology fixation was significantly smaller. Management would be altered in 6 of 56 polyps (10.7%) on the basis of differences between size of the polyp on endoscopy and CTC. CONCLUSIONS: (1) CTC polyp size measurement is not significantly different from colonoscopy in vivo visual estimation and linear probe measurement. (2) Differences in size of polyps as measured on CTC and endoscopy will affect patient management in 10% of cases.