International Interobserver Variability of Breast Density Assessment

Leah H Portnow; Lina Choridah; Kardinah Kardinah; Triwulan Handarini; Ruud Pijnappel; Adriana M J Bluekens; Lucien E M Duijm; Peter K Schoub; Pamela S Smilg; Liat Malek; Jessica W T Leung; Sughra Raza

doi:10.1016/j.jacr.2023.03.010

International Interobserver Variability of Breast Density Assessment

J Am Coll Radiol. 2023 Jul;20(7):671-684. doi: 10.1016/j.jacr.2023.03.010. Epub 2023 Apr 29.

Authors

Affiliations

¹ Division of Breast Imaging, Department of Radiology, Brigham and Women's Hospital, Boston, Massachusetts; and Instructor, Department of Radiology, Harvard Medical School, Boston, Massachusetts. Electronic address: lportnow@bwh.harvard.edu.
² Vice Dean of Research and Development, Department of Radiology, Faculty of Medicine, Public Health and Nursing, Universitas Gadjah Mada, Jalan Farmako, Sekip Utara, Yogyakarta, Indonesia.
³ Director of Early Breast Cancer Detection Program for the Ministry of Health and Medical Committee Leader of Quality Assurance; Department of Radiology, Faculty of Medicine, Dharmais Cancer Hospital/National Cancer Center, Jakarta, Indonesia.
⁴ Chair of the Radiology Medical Staff, Department of Radiology, Faculty of Medicine, Airlangga University-Dr Soetomo Academic General Hospital, Surabaya, Indonesia.
⁵ Department of Radiology, University Medical Center, Utrecht, the Netherlands; Professor, Utrecht University, Utrecht, the Netherlands; Chair, Dutch Expert Centre for Screening; and President, European Society of Breast Imaging.
⁶ Department of Radiology, Elisabeth-TweeSteden Ziekenhuis, Tilburg, the Netherlands.
⁷ Department of Radiology, Canisius-Wilhelmina Ziekenhuis, Nijmegen, the Netherlands.
⁸ Department of Radiology, Parklane Radiology, Johannesburg, South Africa; Chair, Breast Imaging Society of South Africa.
⁹ Department of Radiology, Parklane Radiology, Johannesburg, South Africa; Department of Radiology, Donald Gordon Medical Centre, Johannesburg, South Africa.
¹⁰ The Breast Wellness Centre, Johannesburg, South Africa.
¹¹ Deputy Chair, Department of Breast Imaging, Division of Diagnostic Imaging, The University of Texas MD Anderson Cancer Center, Houston, Texas; and Chair, Ultrasound Subcommittee, BI-RADS Committee, American College of Radiology. Electronic address: https://twitter.com/DrJessicaLeung.
¹² Department of Radiology, Beth Israel Deaconess Medical Center, Boston, Massachusetts; Dartmouth Hitchcock Medical Center, Hanover, NH; and Editor-in-Chief, Journal of Global Radiology.

PMID: 37127220
DOI: 10.1016/j.jacr.2023.03.010

Abstract

Purpose: The aim of this study was to determine variability in visually assessed mammographic breast density categorization among radiologists practicing in Indonesia, the Netherlands, South Africa, and the United States.

Methods: Two hundred consecutive 2-D full-field digital screening mammograms obtained from September to December 2017 were selected and retrospectively reviewed from four global locations, for a total of 800 mammograms. Three breast radiologists in each location (team) provided consensus density assessments of all 800 mammograms using BI-RADS® density categorization. Interreader agreement was compared using Gwet's AC2 with quadratic weighting across all four density categories and Gwet's AC1 for binary comparison of combined not dense versus dense categories. Variability of distribution among teams was calculated using the Stuart-Maxwell test of marginal homogeneity across all four categories and using the McNemar test for not dense versus dense categories. To compare readers from a particular country on their own 200 mammograms versus the other three teams, density distribution was calculated using conditional logistic regression.

Results: For all 800 mammograms, interreader weighted agreement for distribution among four density categories was 0.86 (Gwet's AC2 with quadratic weighting; 95% confidence interval, 0.85-0.88), and for not dense versus dense categories, it was 0.66 (Gwet's AC1; 95% confidence interval, 0.63-0.70). Density distribution across four density categories was significantly different when teams were compared with one another and one team versus the other three teams combined (P < .001). Overall, all readers placed the largest number of mammograms in the scattered and heterogeneous categories.

Conclusions: Although reader teams from four different global locations had almost perfect interreader agreement in BI-RADS density categorization, variability in density distribution across four categories remained statistically significant.

Keywords: Breast density; global radiology; mammography.

MeSH terms

Breast / diagnostic imaging
Breast Density*
Breast Neoplasms* / diagnostic imaging
Female
Humans
Mammography
Observer Variation
Retrospective Studies