title: Image Size Influences Visual Search and Perception of Hemorrhages When Reading Cranial CT: An Eye-Tracking Study.
abstract: OBJECTIVE
  The aim of this study was to explore reader gaze, performance, and preference during interpretation of cranial computed tomography (cCT) in stack mode at two different sizes.
  
  
  BACKGROUND
  Digital display of medical images allows for the manipulation of many imaging factors, like image size, by the radiologists, yet it is often not known what display parameters better suit human perception.
  
  
  METHODS
  Twenty-one radiologists provided informed consent to be eye tracked while reading 20 cCT cases. Half of these cases were presented at a size of 14 × 14 cm (512 × 512 pixels), half at 28 × 28 cm (1,024 × 1,024 pixels). Visual search, performance, and preference for the two image sizes were assessed.
  
  
  RESULTS
  When reading small images, significantly fewer, but longer, fixations were observed, and these fixations covered significantly more slices. Time to first fixation of true positive findings was faster in small images, but dwell time on true findings was longer. Readers made more false positive decisions in small images, but no overall difference in either jackknife alternative free-response receiver operating characteristic or reading time was found.
  
  
  CONCLUSIONS
  Overall performance is not affected by image size. However, small-stack-mode cCT images may better support the use of motion perception and acquiring an overview, whereas large-stack-mode cCT images seem better suited for detailed analyses.
  
  
  CONCLUSIONS
  Subjective and eye-tracking data suggest that image size influences how images are searched and that different search strategies might be beneficial under different circumstances.
authors.affiliation: Technische Universität Berlin, Berlin, Germany ave@mms.tu-berlin.de.
authors.forename: Antje C
authors.initials: AC
authors.lastname: Venjakob
authors.affiliation: Charité Universitätsmedizin Berlin, Berlin, Germany.
authors.forename: Tim
authors.initials: T
authors.lastname: Marnitz
authors.affiliation: University of Cumbria, Lancaster, United Kingdom.
authors.forename: Peter
authors.initials: P
authors.lastname: Phillips
authors.affiliation: University of Sydney, Sydney, Australia.
authors.forename: Claudia R
authors.initials: CR
authors.lastname: Mello-Thoms
mesh_terms: D005133:Eye Movements / Q000502:physiology*; D005260:Female; D006801:Humans; D020300:Intracranial Hemorrhages / Q000000981:diagnostic imaging*; D008297:Male; D000072177:Radiologists / Q000706:statistics & numerical data; D014057:Tomography, X-Ray Computed / Q000379:methods*
keywords: computer interface; eye movements, tracking; radiology and medical imaging; visual search