Diagnostic accuracy of laxative-free computed tomographic colonography for detection of adenomatous polyps in asymptomatic adults, A prospective evaluation

Michael E. Zalis, Michael A. Blake, Wenli Cai, Peter F. Hahn, Elkan F. Halpern, Imrana G. Kazam, Myles Keroack, Cordula Magee, Janne J. Näppi, Rocio Perez-Johnston, John R. Saltzman, Abhinav Vij, Judy Yee, Hiroyuki Yoshida

Research output: Contribution to journalArticlepeer-review

103 Scopus citations


Background: Colon screening by optical colonoscopy (OC) or computed tomographic colonography (CTC) requires a laxative bowel preparation, which inhibits screening participation. Objective: To assess the performance of detecting adenomas 6 mm or larger and patient experience of laxative-free, computeraided CTC. Design: Prospective test comparison of laxative-free CTC and OC. The CTC included electronic cleansing and computer-aided detection. Optical colonoscopy examinations were initially blinded to CTC results, which were subsequently revealed during colonoscope withdrawal; this method permitted reexamination to resolve discrepant findings. Unblinded OC served as a reference standard. (ClinicalTrials.gov registration number: NCT01200303) Setting: Multicenter ambulatory imaging and endoscopy centers. Participants: 605 adults aged 50 to 85 years at average to moderate risk for colon cancer. Measurements: Per-patient sensitivity and specificity of CTC and first-pass OC for detecting adenomas at thresholds of 10 mm or greater, 8 mm or greater, and 6 mm or greater; per-lesion sensitivity and survey data describing patient experience with preparations and examinations. Results: For adenomas 10 mm or larger, per-patient sensitivity of CTC was 0.91 (95% CI, 0.71 to 0.99) and specificity was 0.85 (CI, 0.82 to 0.88); sensitivity of OC was 0.95 (CI, 0.77 to 1.00) and specificity was 0.89 (CI, 0.86 to 0.91). Sensitivity of CTC was 0.70 (CI, 0.53 to 0.83) for adenomas 8 mm or larger and 0.59 (CI, 0.47 to 0.70) for those 6 mm or larger; sensitivity of OC for adenomas 8 mm or larger was 0.88 (CI, 0.73 to 0.96) and 0.76 (CI, 0.64 to 0.85) for those 6 mm or larger. The specificity of OC at the threshold of 8 mm or larger was 0.91 and at 6 mm or larger was 0.94. Specificity for OC was greater than that for CTC, which was 0.86 at the threshold of 8 mm or larger and 0.88 at 6 mm or larger (P = 0.02). Reported participant experience for comfort and difficulty of examination preparation was better with CTC than OC. Limitations: There were 3 CTC readers. The survey instrument was not independently validated. Conclusion: Computed tomographic colonography was accurate in detecting adenomas 10 mm or larger but less so for smaller lesions. Patient experience was better with laxative-free CTC. These results suggest a possible role for laxative-free CTC as an alternate screening method. Primary Funding Source: GE Healthcare and the American Cancer Society.

Original languageEnglish (US)
Pages (from-to)692-702
Number of pages11
JournalAnnals of internal medicine
Issue number10
StatePublished - 2012
Externally publishedYes

ASJC Scopus subject areas

  • Internal Medicine


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