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The impact of greyscale inversion for nodule detection in an anthropomorphic chest phantom: a free-response observer study

Thompson, John D., Thomas, NB, Manning, DJ and Hogg, P 2016, 'The impact of greyscale inversion for nodule detection in an anthropomorphic chest phantom: a free-response observer study' , The British Journal of Radiology, 89 (1064) , p. 20160249.

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Objective: The aim of this work was to assess the impact of greyscale inversion on nodule detection on poster- oanterior chest X-ray images. Previous work has attemp- ted this, with no consensus opinion formed. We assessed the value of “fast-flicking” between standard and inverted display modes for nodule detection. Methods: Six consultant radiologists (with 5–32 years’ reporting experience) completed an observer task under the free-response paradigm. An anthropomorphic chest phantom was loaded with 50 different configurations of simulated nodules (1–4 nodules per case) measuring 5, 8, 10 and 12mm in spherical diameter; each configuration represented a single case. In addition, 25 cases contained no nodules. Images were displayed in three modes: (i) standard, (ii) inverted and (iii) fast-flicking between standard and inverted display modes. Each observer completed the study in a different order of display (i, ii, iii) using a calibrated 5-megapixel monitor. Nodules were localized with mouse clicks and ratings assigned using a 1–10 discrete slider-bar confidence scale. Rjafroc (Pitts- burgh, PA) was used for data analysis; differences in nodule detection performance were considered significant at 0.05. Results: The observer-averaged weighted jackknife alter- native free-response receiver-operating characteristic figures of merit were 0.715 (standard), 0.684 (inverted) and 0.717 (fast-flicking). Random-reader fixed-case anal- ysis revealed no statistically significant difference be- tween any treatment pair [F(2,8) 5 1.22; p 5 0.345]. Conclusion: No statistically significant difference in nodule detection was found for the three display conditions. Advances in knowledge: We have investigated the impact of fast-flicking between standard and inverted display modes for the detection of nodules. We found no benefit.

Item Type: Article
Schools: Schools > School of Health Sciences > Centre for Health Sciences Research
Journal or Publication Title: The British Journal of Radiology
Publisher: British Institute of Radiology
ISSN: 0007-1285
Related URLs:
Funders: Non funded research
Depositing User: Dr JD Thompson
Date Deposited: 28 Sep 2016 15:17
Last Modified: 28 Sep 2016 15:17

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