Towards a framework for analysis of eye-tracking studies in the three dimensional environment: a study of visual search by experienced readers of endoluminal CT colonography.

Helbren, Emma; Halligan, Steve; Phillips, Peter; Boone, Darren; Fanshawe, Thomas R.; Taylor, Stuart A.; Manning, David; Gale, Alastair; Altman, Douglas G. and Mallett, Susan (2014) Towards a framework for analysis of eye-tracking studies in the three dimensional environment: a study of visual search by experienced readers of endoluminal CT colonography.

View this record at http://insight.cumbria.ac.uk/1670/
Official URL: 10.1259/bjr.20130614

Abstract

Objective: Eye tracking in three dimensions is novel, but established descriptors derived from two-dimensional (2D) studies are not transferable. We aimed to develop metrics suitable for statistical comparison of eye-tracking data obtained from readers of three-dimensional (3D) “virtual” medical imaging, using CT colonography (CTC) as a typical example. Methods: Ten experienced radiologists were eye tracked while observing eight 3D endoluminal CTC videos. Sub-sequently, we developed metrics that described their visual search patterns based on concepts derived from 2D gaze studies. Statistical methods were developed to allow analysis of the metrics. Results: Eye tracking was possible for all readers. Visual dwell on the moving region of interest (ROI) was defined as pursuit of the moving object across multiple frames. Using this concept of pursuit, five categories of metrics were defined that allowed characterization of reader gaze behaviour. These were time to first pursuit, identi-fication and assessment time, pursuit duration, ROI size and pursuit frequency. Additional subcategories allowed us to further characterize visual search between readers in the test population. Conclusion: We propose metrics for the characterization of visual search of 3D moving medical images. These metrics can be used to compare readers’ visual search patterns and provide a reproducible framework for the analysis of gaze tracking in the 3D environment. Advances in knowledge: This article describes a novel set of metrics that can be used to describe gaze behaviour when eye tracking readers during interpretation of 3D medical images. These metrics build on those established for 2D eye tracking and are applicable to increasingly common 3D medical image displays.

Item Type: Article
Keywords: 002 The Work, 616 Diseases & treatment (incl. counselling, radiography & medical imaging, critical & palliative care)
Members: University of Cumbria
Depositing User: ULCC Admin
Date Deposited: 08 Nov 2016 13:05
Last Modified: 08 Nov 2016 13:05
URI: http://collections.crest.ac.uk/id/eprint/12381

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