title: Meta-analysis comparing CT colonography, air contrast barium enema, and colonoscopy.
abstract: BACKGROUND
  Published studies have reported a wide range of sensitivities and specificities for computed tomographic (CT) colonography for polyp detection, generating controversy regarding its diagnostic accuracy.
  
  
  METHODS
  A meta-analysis of published studies comparing the accuracies of CT colonography and colonoscopy for polyp detection was performed. The pooled per-patient sensitivities and specificities were calculated at various thresholds for polyp size. Summary receiver operating characteristic (sROC) curves were also constructed.
  
  
  RESULTS
  Thirty studies were included in the meta-analysis of CT colonography. The pooled per-patient sensitivity of CT colonography was higher for polyps greater than 10 mm (0.82, 95% confidence interval [CI], 0.76-0.88) compared with polyps 6 to 10 mm (0.63, 95% CI, 0.52-0.75) and polyps 0 to 5 mm (0.56, 95% CI, 0.42-0.70). Similarly, the exact area under the sROC curve (area +/- standard error) was higher using a threshold greater than 10 mm (0.898 +/- 0.063) compared with thresholds of greater than 5 mm and any size (0.884 +/- 0.033 and 0.822 +/- 0.059, respectively). There were no significant differences in the diagnostic characteristics of 2-dimensional versus 3-dimensional CT colonography. At a threshold greater than 5 mm, the exact area under the sROC curve was significantly higher for endoscopic colonoscopy compared with CT colonography (0.998 +/- 0.006 vs 0.884 +/- 0.033, P < .005).
  
  
  CONCLUSIONS
  CT colonography has a reasonable sensitivity and specificity for detecting large polyps but was less accurate than endoscopic colonoscopy for smaller polyps. Thus, CT colonography may not be a reasonable alternative in situations in which a small polyp may be clinically relevant.
authors.affiliation: Section of Gastroenterology and Medicine Program, James J. Peters VA Medical Center and Mount Sinai School of Medicine, New York, NY 10468, USA. Alan.Rosman@Med.VA.Gov
authors.forename: Alan S
authors.initials: AS
authors.lastname: Rosman
authors.forename: Mark A
authors.initials: MA
authors.lastname: Korsten
mesh_terms: D001466:Barium Sulfate; D003111:Colonic Polyps / Q000175:diagnosis*; D023881:Colonography, Computed Tomographic / Q000379:methods*; D003113:Colonoscopy / Q000379:methods*; D015179:Colorectal Neoplasms / Q000517:prevention & control; D016001:Confidence Intervals; D004733:Enema / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D011336:Probability; D012372:ROC Curve; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D001466:Barium Sulfate