Development and validation of a visual grading scale for assessing image quality of AP pelvis radiographic images

Mraity, H; England, A; Cassidy, SF; Eachus, P; Hogg, P

Abstract

OBJECTIVE: Apply psychometric theory to develop and validate a visual grading scale for assessing visual perception of AP pelvis digital image quality.
METHODS: Psychometric theory was used to guide scale development. Seven phantom and 7 cadaver images of visually and objectively predetermined quality were used to help assess scale reliability and validity. 151 volunteers scored phantom images; 184 volunteers scored cadaver images. Factor analysis and Cronbach’s alpha were used to assess scale validity and reliability.
RESULTS: A 24 item scale was produced. Aggregated mean volunteer scores for each image correlated with the rank order of the visually and objectively predetermined image qualities. Scale items had good inter-item correlation (≥0.2) and high factor loadings (≥0.3). Cronbach's alpha (reliability) revealed that the scale has acceptable levels of internal reliability for both phantom and cadaver images (α= 0.8 and 0.9, respectively). Factor analysis suggested the scale is multidimensional (assessing multiple quality themes).
CONCLUSION: This study represents the first full development and validation of a visual image quality scale using psychometric theory. It is likely that this scale will have clinical, training and research applications.
ADVANCES IN KNOWLEDGE: This article presents data to create and validate visual grading scales for radiographic examinations. The visual grading scale, for AP pelvis examinations, can act as a validated tool for future research, teaching and clinical evaluations of image quality.

• Journal Article Type: Article
• Acceptance Date: Mar 2, 2016
• Online Publication Date: Mar 31, 2016
• Publication Date: Mar 31, 2016
• Deposit Date: Mar 22, 2016
• Publicly Available Date: Oct 25, 2018
• Journal: British Journal of Radiology
• Print ISSN: 0007-1285
• Electronic ISSN: 1748-880X
• Publisher: British Institute of Radiology
• Volume: 89
• Issue: 1061
• Pages: 20150430
• DOI: https://doi.org/10.1259/bjr.20150430
• Publisher URL: http://dx.doi.org/10.1259/bjr.20150430
• Related Public URLs: http://www.bir.org.uk/publications/journals/