Automated polyp measurement with CT colonography: Preliminary observations in a phantom colon model

Joel G. Fletcher, Fargol Booya, Zachary Melton, Kristina Johnson, Lutz Guendel, Bernhard Schmidt, Cynthia H. McCollough, Brett Young, Jeff L. Fidler, William S. Harmsen

Research output: Contribution to journalArticlepeer-review

13 Scopus citations


OBJECTIVE. The purpose of this study was to evaluate the accuracy and precision of polyp measurements obtained with an automated tool in a colon phantom containing polyps of multiple sizes, morphologic types, and locations. MATERIALS AND METHODS. A colon phantom was scanned at 12, 25, 50, and 100 mA with standard CT colonographic acquisition parameters. Four reviewers using manual 2D methods and an automated polyp measurement tool measured 24 polyps of varying sizes and morphologic types, some at ahaustral fold tip and some not at a fold tip. The accuracy (difference from true value) of manual and automated methods was compared across polyp sizes, morphologic types, locations, and doses. Precision (closeness of different measures) was compared for intraobserver and interobserver measurements. RESULTS. The accuracy of automated polyp measurement was dependent on morphologic type (p ≤ 0.02), size (for three of four reviewers, p ≤ 0.05), and location of polyps with respect to haustral folds (two of four reviewers, p ≤ 0.01). For two of four reviewers, automated measures were less accurate for 5-mm polyps, flat polyps, and polyps at the tips of folds (p ≤ 0.04). Intraobserver precision was high, two automated measurements being within 0.1 mm of each other 82-93% of the time. Interobserver precision values for automated measures were more similar 85% of the time (82/96; p < 0.001). CONCLUSION. Accuracy of automated polyp measurements depends on polyp size, morphologic type, and location. When using an automated tool, radiologists should visually inspect automated polyp measurements, particularly for small and flat polyps and those located on folds, because manual measurements may be more accurate in this setting. Automated polyp measurements are more precise than manual measurements.

Original languageEnglish (US)
Pages (from-to)945-952
Number of pages8
JournalAmerican Journal of Roentgenology
Issue number4
StatePublished - Apr 1 2007


  • CT colonography
  • Colon cancer
  • Polyps

ASJC Scopus subject areas

  • Radiology Nuclear Medicine and imaging


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