title: Automated polyp measurement with CT colonography: preliminary observations in a phantom colon model.
abstract: 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.
  
  
  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 a haustral 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 < or = 0.02), size (for three of four reviewers, p < or = 0.05), and location of polyps with respect to haustral folds (two of four reviewers, p < or = 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 < or = 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).
  
  
  CONCLUSIONS
  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.
authors: Department of Radiology, Mayo Clinic, 200 First St. SW, Mayo E-2, Rochester, MN 55905, USA. fletcher.joel@mayo.edu
authors: Joel G
authors: JG
authors: Fletcher
authors: Fargol
authors: F
authors: Booya
authors: Zachary
authors: Z
authors: Melton
authors: Kristina
authors: K
authors: Johnson
authors: Lutz
authors: L
authors: Guendel
authors: Bernhard
authors: B
authors: Schmidt
authors: Cynthia H
authors: CH
authors: McCollough
authors: Brett
authors: B
authors: Young
authors: Jeff L
authors: JL
authors: Fidler
authors: William S
authors: WS
authors: Harmsen
mesh_terms: D003111:Colonic Polyps / Q000000981:diagnostic imaging*; D023881:Colonography, Computed Tomographic; D019047:Phantoms, Imaging; D015203:Reproducibility of Results