European Radiology

, Volume 16, Issue 8, pp 1737–1744

Polyp measurement and size categorisation by CT colonography: effect of observer experience in a multi-centre setting

Authors

  • David Burling
    • Intestinal Imaging CentreSt. Marks Hospital
  • Steve Halligan
    • Specialist Radiology, Level 2 PodiumUniversity College Hospital
  • Douglas G. Altman
    • Centre for Medical Statistics
  • Wendy Atkin
    • Cancer Research UKSt Mark’s Hospital
  • Clive Bartram
    • Intestinal Imaging CentreSt. Marks Hospital
  • Helen Fenlon
    • Mater Misericordiae
  • Andrea Laghi
    • La Sapienza
  • Jaap Stoker
    • Amersterdam Medican Centre
  • Stuart Taylor
    • Specialist Radiology, Level 2 PodiumUniversity College Hospital
  • Roger Frost
    • Salisbury District Hospital
  • Guido Dessey
    • Stedelijk Ziekenhuis
  • Melinda De Villiers
    • Intestinal Imaging CentreSt. Marks Hospital
  • Jasper Florie
    • Amersterdam Medican Centre
  • Shane Foley
    • Mater Misericordiae
  • Lesley Honeyfield
    • Intestinal Imaging CentreSt. Marks Hospital
  • Riccardo Iannaccone
    • La Sapienza
  • Teresa Gallo
    • Candiolo Oncologic Hospital
  • Clive Kay
    • Bradford Royal Infirmary
  • Philippe Lefere
    • Stedelijk Ziekenhuis
  • Andrew Lowe
    • Bradford Royal Infirmary
  • Filipo Mangiapane
    • La Sapienza
  • Jesse Marrannes
    • Stedelijk Ziekenhuis
  • Emmanuele Neri
    • University of Pisa
  • Giulia Nieddu
    • Candiolo Oncologic Hospital
  • David Nicholson
    • Hope Hospital
  • Alan O’Hare
    • Mater Misericordiae
  • Sante Ori
    • La Sapienza
  • Benedetta Politi
    • University of Pisa
  • Martin Poulus
    • Amersterdam Medican Centre
  • Daniele Regge
    • Candiolo Oncologic Hospital
  • Lisa Renaut
    • Hope Hospital
  • Velauthan Rudralingham
    • Hope Hospital
  • Saverio Signoretta
    • Candiolo Oncologic Hospital
  • Paola Vagli
    • University of Pisa
  • Victor Van der Hulst
    • Amersterdam Medican Centre
  • Jane Williams-Butt
    • Bradford Royal Infirmary
Gastrointestinal

DOI: 10.1007/s00330-006-0189-2

Cite this article as:
Burling, D., Halligan, S., Altman, D.G. et al. Eur Radiol (2006) 16: 1737. doi:10.1007/s00330-006-0189-2

Abstract

The extent measurement error on CT colonography influences polyp categorisation according to established management guidelines is studied using twenty-eight observers of varying experience to classify polyps seen at CT colonography as either ‘medium’ (maximal diameter 6-9 mm) or ‘large’ (maximal diameter 10 mm or larger). Comparison was then made with the reference diameter obtained in each patient via colonoscopy. The Bland-Altman method was used to assess agreement between observer measurements and colonoscopy, and differences in measurement and categorisation was assessed using Kruskal-Wallis and Chi-squared test statistics respectively. Observer measurements on average underestimated the diameter of polyps when compared to the reference value, by approximately 2–3 mm, irrespective of observer experience. Ninety-five percent limits of agreement were relatively wide for all observer groups, and had sufficient span to encompass different size categories for polyps. There were 167 polyp observations and 135 (81%) were correctly categorised. Of the 32 observations that were miscategorised, 5 (16%) were overestimations and 27 (84%) were underestimations (i.e. large polyps misclassified as medium). Caution should be exercised for polyps whose colonographic diameter is below but close to the 1-cm boundary threshold in order to avoid potential miscategorisation of advanced adenomas.

Keywords

CT colonComputerised tomographyVirtual colonoscopy

Copyright information

© Springer-Verlag 2006