Density is in the eye of the beholder: visual versus semi-automated assessment of breast density on standard mammograms

• Published in: Insights into imaging Vol. 3; no. 1; pp. 91 - 99
• Main Authors: Lobbes, M. B. I., Cleutjens, J. P. M., Lima Passos, V., Frotscher, C., Lahaye, M. J., Keymeulen, K. B. M. I., Beets-Tan, R. G., Wildberger, J., Boetes, C.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.02.2012; Springer-Verlag
• Subjects: Diagnostic Radiology; Imaging; Internal Medicine; Interventional Radiology; Medicine; Medicine & Public Health; Neuroradiology; Original; Original Article; Radiology; Ultrasound; Breast density; Threshold method; Breast cancer; Breast neoplasms; Mammography
• ISSN: 1869-4101; 1869-4101
• DOI: 10.1007/s13244-011-0139-7

Objectives Visual inspection is generally used to assess breast density. Our study aim was to compare visual assessment of breast density of experienced and inexperienced readers with semi-automated analysis of breast density. Methods Breast density was assessed by an experienced and an inexperienced reader in 200 mammograms and scored according to the quantitative BI-RADS classification. Breast density was also assessed by dedicated software using a semi-automated thresholding technique. Agreement between breast density classification of both readers as well as agreement between their assessment versus the semi-automated analysis as reference standard was expressed as the weighted kappa value. Results Using the semi-automated analysis, agreement between breast density measurements of both breasts in both projections was excellent (ICC >0.9, P  < 0.0001). Reproducibility of the semi-automated analysis was excellent (ICC >0.8, P  < 0.0001). The experienced reader correctly classified the BI-RADS breast density classification in 58.5% of the cases. Classification was overestimated in 35.5% of the cases and underestimated in 6.0% of the cases. Results of the inexperienced reader were less accurate. Agreement between the classification of both readers versus the semi-automated analysis was considered only moderate with weighted kappa values of 0.367 (experienced reader) and 0.232 (inexperienced reader). Conclusion Visual assessment of breast density on mammograms is inaccurate and observer-dependent.