title: Thin-section CT of the lungs: eye-tracking analysis of the visual approach to reading tiled and stacked display formats.
abstract: OBJECTIVE
  To use eye-tracking analysis to identify the differences in approach to and efficiency of reading thin-section CT of the lungs presented tiled and stacked soft-copy displays.
  
  
  METHODS
  Four chest radiologists read 16 thin-section CT examinations displayed in either a tiled (four images at once) or stacked (full screen cine) format. Eye-movements were recorded and analysed in terms of movement type; saccade distance (classified by the calculated range of useful peripheral vision), number of fixations, duration and direction of gaze-comparison of the areas of the images viewed.
  
  
  RESULTS
  Cases presented in stacked format were read quicker than when presented in tiled format with a greater fixation frequency (5 fixations versus 4.5 fixations points per 100 data points; p<0.001) and a greater proportion of short saccades (97% versus 94%; p<0.005). The consistency with which the observers viewed equivalent areas of the scan images in different cases was greater when viewing in stacked format (mean kappa 0.45 versus 0.36; p<0.05) suggesting a more systematic approach to reading.
  
  
  CONCLUSIONS
  Eye-tracking data demonstrates why thin-section CT examinations of the lungs are read more efficiently when displayed in a stack as opposed to a tiled format.
authors.affiliation: Department of Radiology, London Chest Hospital, Bonner Road, London E2 9JX, UK. Stephen.ellis@bartsandthelondon.nhs.uk
authors.forename: S M
authors.initials: SM
authors.lastname: Ellis
authors.forename: X
authors.initials: X
authors.lastname: Hu
authors.forename: L
authors.initials: L
authors.lastname: Dempere-Marco
authors.forename: G Z
authors.initials: GZ
authors.lastname: Yang
authors.forename: A U
authors.initials: AU
authors.lastname: Wells
authors.forename: D M
authors.initials: DM
authors.lastname: Hansell
mesh_terms: D003626:Data Display; D005133:Eye Movements / Q000502:physiology*; D005403:Fixation, Ocular; D008168:Lung / Q000000981:diagnostic imaging*; D008171:Lung Diseases / Q000000981:diagnostic imaging*; D015588:Observer Variation; D011859:Radiography; D011873:Radiology Information Systems; D015898:Tomography Scanners, X-Ray Computed; D014584:User-Computer Interface