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Do prevalence expectations affect patterns of visual search and decision-making in interpreting CT colonography endoluminal videos?

Fanshawe, TR; Phillips, P; Plumb, A; Emma, H; Halligan, S; Taylor, SA; Gale, A; (2016) Do prevalence expectations affect patterns of visual search and decision-making in interpreting CT colonography endoluminal videos? British Journal of Radiology , Article 20150842. 10.1259/bjr.20150842. Green open access

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Abstract

OBJECTIVES: To assess the effect of expected abnormality prevalence on visual search and decision-making in CT Colonography (CTC). METHODS: Thirteen radiologists interpreted endoluminal CTC fly-throughs of the same group of ten patient cases, three times each. Abnormality prevalence was fixed (50%) but readers were told, before viewing each group, that prevalence was either 20%, 50% or 80% in the population from which cases were drawn. Infra-red visual search recording was used. Readers indicated seeing a polyp by clicking a mouse. Multilevel modelling quantified the effect of expected prevalence on outcomes. RESULTS: Differences between expected prevalences were not statistically significant for time to first pursuit of the polyp (median 0.5s, each prevalence), pursuit rate when no polyp was on-screen (median 2.7s(-1), each prevalence) or number of mouse clicks (mean 0.75/video (20% prevalence), 0.93 (50%), 0.97 (80%)). There was weak evidence of increased tendency to look outside the central screen area at 80% prevalence, and reduction in positive polyp identifications at 20% prevalence. CONCLUSIONS: This study did not find a large effect of prevalence information on most visual search metrics or polyp identification in CTC. Further research is required to quantify effects at lower prevalences and in relation to secondary outcome measures. Advances in Knowledge: Prevalence effects in evaluating CTC have not previously been assessed. In this study, providing expected prevalence information did not have a large effect on diagnostic decisions or patterns of visual search.

Type: Article
Title: Do prevalence expectations affect patterns of visual search and decision-making in interpreting CT colonography endoluminal videos?
Open access status: An open access version is available from UCL Discovery
DOI: 10.1259/bjr.20150842
Publisher version: http://dx.doi.org/10.1259/bjr.20150842
Language: English
Additional information: © The Authors. Published by the British Institute of Radiology.
Keywords: Colon; Colonic Polyps; Colonography, Computed Tomographic; Diagnosis, ComputerAssisted; Visual Perception
UCL classification: UCL
UCL > Provost and Vice Provost Offices
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Medical Sciences
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Medical Sciences > Div of Medicine
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Medical Sciences > Div of Medicine > Metabolism and Experi Therapeutics
URI: https://discovery.ucl.ac.uk/id/eprint/1476132
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