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A method to determine the impact of reduced visual function on nodule detection performance

Thompson, John D., Lança, C, Lança, L and Hogg, P 2016, 'A method to determine the impact of reduced visual function on nodule detection performance' , Radiography . (In Press)

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Abstract

Purpose: In this study we aim to validate a method to assess the impact of reduced visual function and observer performance concurrently with a nodule detection task. Materials and methods: Three consultant radiologists completed a nodule detection task under three conditions: without visual defocus (0.00 Dioptres; D), and with two different magnitudes of visual defocus ( 1.00 D and 2.00 D). Defocus was applied with lenses and visual function was assessed prior to each image evaluation. Observers evaluated the same cases on each occasion; this comprised of 50 abnormal cases containing 1e4 simulated nodules (5, 8, 10 and 12 mm spherical diameter, 100 HU) placed within a phantom, and 25 normal cases (images containing no nodules). Data was collected under the free-response paradigm and analysed using Rjafroc. A difference in nodule detection performance would be considered significant at p < 0.05. Results: All observers had acceptable visual function prior to beginning the nodule detection task. Visual acuity was reduced to an unacceptable level for two observers when defocussed to 1.00 D and for one observer when defocussed to 2.00 D. Stereoacuity was unacceptable for one observer when defocussed to 2.00 D. Despite unsatisfactory visual function in the presence of defocus we were unable to find a statistically significant difference in nodule detection performance (F(2,4) 1⁄4 3.55, p 1⁄4 0.130). Conclusion: A method to assess visual function and observer performance is proposed. In this pilot evaluation we were unable to detect any difference in nodule detection performance when using lenses to reduce visual function.

Item Type: Article
Schools: Schools > School of Health Sciences > Centre for Health Sciences Research
Journal or Publication Title: Radiography
Publisher: Elsevier
ISSN: 1078-8174
Related URLs:
Funders: Non funded research
Depositing User: Dr JD Thompson
Date Deposited: 28 Sep 2016 15:11
Last Modified: 28 Sep 2016 15:11
URI: http://usir.salford.ac.uk/id/eprint/40218

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