title: Tracking eye gaze during interpretation of endoluminal three-dimensional CT colonography: visual perception of experienced and inexperienced readers.
abstract: OBJECTIVE
  To identify and compare key stages of the visual process in experienced and inexperienced readers and to examine how these processes are used to search a moving three-dimensional ( 3D three-dimensional ) image and their relationship to false-negative errors.
  
  
  METHODS
  Institutional review board research ethics approval was granted to use anonymized computed tomographic (CT) colonographic data from previous studies and to obtain eye-tracking data from volunteers. Sixty-five radiologists (27 experienced, 38 inexperienced) interpreted 23 endoluminal 3D three-dimensional CT colonographic videos. Eye movements were recorded by using eye tracking with a desk-mounted tracker. Readers indicated when they saw a polyp by clicking a computer mouse. Polyp location and boundary on each video frame were quantified and gaze data were related to the polyp boundary for each individual reader and case. Predefined metrics were quantified and used to describe and compare visual search patterns between experienced and inexperienced readers by using multilevel modeling.
  
  
  RESULTS
  Time to first pursuit was significantly shorter in experienced readers (hazard ratio, 1.22 [95% confidence interval: 1.04, 1.44]; P = .017) but other metrics were not significantly different. Regardless of expertise, metrics such as assessment, identification period, and pursuit times were extended in videos where polyps were visible on screen for longer periods of time. In 97% (760 of 787) of observations, readers correctly pursued polyps.
  
  
  CONCLUSIONS
  Experienced readers had shorter time to first eye pursuit, but many other characteristics of eye tracking were similar between experienced and inexperienced readers. Readers pursued polyps in 97% of observations, which indicated that errors during interpretation of 3D three-dimensional CT colonography in this study occurred in either the discovery or the recognition phase, but rarely in the scanning phase of radiologic image inspection.
authors.affiliation: From the Department of Primary Care Health Sciences, University of Oxford, Radcliffe Observatory Quarter, Woodstock Road, Oxford OX2 6GG, England (S.M., T.R.F.); Health and Medical Sciences Group, University of Cumbria, Lancaster, England (P.P.); Centre for Medical Imaging, University College London, London, England (E.H., S.A.T., S.H., D.B.); Applied Vision Research Centre, Loughborough University, Loughborough, England (A.G.); School of Medicine, Lancaster University, Lancaster, England (D.M.); and Centre for Statistics in Medicine, University of Oxford, Oxford, England (D.G.A.).
authors.forename: Susan
authors.initials: S
authors.lastname: Mallett
authors.forename: Peter
authors.initials: P
authors.lastname: Phillips
authors.forename: Thomas R
authors.initials: TR
authors.lastname: Fanshawe
authors.forename: Emma
authors.initials: E
authors.lastname: Helbren
authors.forename: Darren
authors.initials: D
authors.lastname: Boone
authors.forename: Alastair
authors.initials: A
authors.lastname: Gale
authors.forename: Stuart A
authors.initials: SA
authors.lastname: Taylor
authors.forename: David
authors.initials: D
authors.lastname: Manning
authors.forename: Douglas G
authors.initials: DG
authors.lastname: Altman
authors.forename: Steve
authors.initials: S
authors.lastname: Halligan
mesh_terms: D000328:Adult; D002983:Clinical Competence; D003111:Colonic Polyps / Q000000981:diagnostic imaging*; D023881:Colonography, Computed Tomographic; D005133:Eye Movements / Q000502:physiology*; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional; D008297:Male; D015203:Reproducibility of Results; D014741:Video Recording; D014796:Visual Perception / Q000502:physiology*