Development and content validity evaluation of a candidate instrument to assess image quality in digital mammography: A mixed-method study. Issue 134 (January 2021)

• Record Type: Journal Article
• Authors: Boita, Joana; Bolejko, Anetta; Zackrisson, Sophia; Wallis, Matthew G.; Ikeda, Debra M.; Van Ongeval, Chantal; van Engen, Ruben E.; Mackenzie, Alistair; Tingberg, Anders; Bosmans, Hilde; Pijnappel, Ruud; Sechopoulos, Ioannis; Broeders, Mireille
• Is Part Of: European journal of radiology. Issue 134(2021)
• Publication Date: 2021-01
• Subjects: CVI Content Validity Index -- DM Digital Mammography -- I-CVI Item-Content Validity Index -- k* Modified Kappa Index -- VGA Visual Grading Analysis; Digital mammography -- Image quality evaluation -- Visual grading analysis -- Content validity evaluation -- Directed content analysis -- Content validity index; Medical radiology -- Periodicals; Radiology -- Periodicals; Radiologie médicale -- Périodiques; Medical radiology; Periodicals; 616.075705
• DOI: 10.1016/j.ejrad.2020.109464
• Languages: English
• ISSNs: 0720-048X

Abstract

Highlights: Mixed methods were used to develop a candidate DM image quality evaluation instrument. The method resulted in identification of image features affected by image quality. The instrument may be used to identify clinically-relevant issues in image quality. Abstract: Purpose: To develop a candidate instrument to assess image quality in digital mammography, by identifying clinically relevant features in images that are affected by lower image quality. Methods: Interviews with fifteen expert breast radiologists from five countries were conducted and analysed by using adapted directed content analysis. During these interviews, 45 mammographic cases, containing 44 lesions (30 cancers, 14 benign findings), and 5 normal cases, were shown with varying image quality. The interviews were performed to identify the structures from breast tissue and lesions relevant for image interpretation, and to investigate how image quality affected the visibility of those structures. The interview findings were used to develop tentative items, which were evaluated in terms of wording, understandability, and ambiguity with expert breast radiologists. The relevance of the tentative items was evaluated using the content validity index (CVI) and modified kappa index (k*). Results: Twelve content areas, representing the content of image quality in digital mammography, emerged from the interviews and were converted into 29 tentative items. Fourteen of these items demonstrated excellent CVI ≥ 0.78 (k* > 0.74), one showed good CVI < 0.78 (0.60 ≤ k* ≤ 0.74), while fourteen were of fair or poor CVI < 0.78 (k* ≤ 0.59). In total, nine items were deleted and five were revised or combined resulting in 18 items. Conclusions: By following a mixed-method methodology, a candidate instrument was developed that may be used to characterise the clinically-relevant impact that image quality variations can have on digital mammography.