Abdominal Imaging

, Volume 27, Issue 3, pp 292–300

Detection of flat lesions in the colon with CT colonography

Authors

  • J. L. Fidler
    • Department of Radiology, Mayo Clinic and Mayo Foundation, 200 First Street SW, Rochester, MN 55905, USA
  • C. D. Johnson
    • Department of Radiology, Mayo Clinic and Mayo Foundation, 200 First Street SW, Rochester, MN 55905, USA
  • R. L. MacCarty
    • Department of Radiology, Mayo Clinic and Mayo Foundation, 200 First Street SW, Rochester, MN 55905, USA
  • T. J. Welch
    • Department of Radiology, Mayo Clinic and Mayo Foundation, 200 First Street SW, Rochester, MN 55905, USA
  • A. K. Hara
    • Department of Radiology, Mayo Clinic and Mayo Foundation, 200 First Street SW, Rochester, MN 55905, USA
  • W. S. Harmsen
    • Section of Biostatistics, Mayo Clinic and Mayo Foundation, 200 First Street SW, Rochester, MN 55905, USA
Article

DOI: 10.1007/s00261-001-0171-z

Cite this article as:
Fidler, J., Johnson, C., MacCarty, R. et al. Abdom Imaging (2002) 27: 292. doi:10.1007/s00261-001-0171-z

Abstract

Background:We investigated whether flat lesions of the colon could be detected on computed tomographic colonography (CTC).

Methods: CTC and conventional colonoscopy were performed on 547 consecutive patients. A subset of 22 polyps was described as flat on colonoscopy (n= 16) or CTC (n= 6) and are the basis of this report. CTC was performed with a standard technique (5-mm collimation, 3-mm reconstruction intervals). Patients were scanned in supine and prone positions. Examinations were randomly assigned and reviewed in a blinded fashion by two of three radiologists. Prospective interpretations were recorded. All patients had conventional colonoscopy, which served as the gold standard.

Results: Twenty-two flat lesions ranging from 0.4 to 3.5 cm were histologically classified as adenomatous (n= 8) or hyperplastic (n= 14). The sensitivities for detecting all flat lesions and flat adenomas by each reviewer were 43% and 100%, 65% and 100%, and 15% and 13%, respectively. “Double reading” resulted in detection of 68% of all lesions and 100% of adenomas. Of the seven hyperplastic polyps missed by both reviewers, four were identified retrospectively.

Conclusion: Flat lesions of the colon represent an important source of false negative CTC examinations. Awareness of their morphology can assist radiologists in finding most of these challenging lesions.

Key words: Colon, computed tomography—Colon, neoplasms—Colonoscopy—Colon, abnormalities.

Copyright information

© Springer-Verlag New York Inc. 2002