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

Thompson, JD; Thomas, NB; Manning, DJ; Hogg, P

Abstract

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.

Citation

Thompson, J., Thomas, N., Manning, D., & Hogg, P. (2016). The impact of greyscale inversion for nodule detection in an anthropomorphic chest phantom: a free-response observer study. British Journal of Radiology, 89(1064), 20160249. https://doi.org/10.1259/bjr.20160249

• Journal Article Type: Article
• Acceptance Date: Jun 6, 2016
• Online Publication Date: Jun 23, 2016
• Publication Date: Jun 23, 2016
• Deposit Date: Sep 28, 2016
• Publicly Available Date: Sep 28, 2016
• Journal: British Journal of Radiology
• Print ISSN: 0007-1285
• Electronic ISSN: 1748-880X
• Publisher: British Institute of Radiology
• Volume: 89
• Issue: 1064
• Pages: 20160249
• DOI: https://doi.org/10.1259/bjr.20160249
• Publisher URL: http://dx.doi.org/10.1259/bjr.20160249
• Related Public URLs: http://www.bir.org.uk/publications/journals/
• Additional Information: Access Information : Open Access Publication accessible from BJR: http://www.birpublications.org/doi/pdf/10.1259/bjr.20160249