Performance Gaps of Artificial Intelligence Models Screening Mammography -- Towards Fair and Interpretable Models

Purpose: To analyze the demographic and imaging characteristics associated with increased risk of failure for abnormality classification in screening mammograms. Materials and Methods: This retrospective study used data from the Emory BrEast Imaging Dataset (EMBED) which includes mammograms from 115,931 patients imaged at Emory University Healthcare between 2013 to 2020. Clinical and imaging data includes Breast Imaging Reporting and Data System (BI-RADS) assessment, region of interest coordinates for abnormalities, imaging features, pathologic outcomes, and patient demographics. Multiple deep learning models were developed to distinguish between patches of abnormal tissue and randomly selected patches of normal tissue from the screening mammograms. We assessed model performance overall and within subgroups defined by age, race, pathologic outcome, and imaging characteristics to evaluate reasons for misclassifications. Results: On a test set size of 5,810 studies (13,390 patches), a ResNet152V2 model trained to classify normal versus abnormal tissue patches achieved an accuracy of 92.6% (95% CI = 92.0-93.2%), and area under the receiver operative characteristics curve 0.975 (95% CI = 0.972-0.978). Imaging characteristics associated with higher misclassifications of images include higher tissue densities (risk ratio [RR]=1.649; p=.010, BI-RADS density C and RR=2.026; p=.003, BI-RADS density D), and presence of architectural distortion (RR=1.026; p<.001). Conclusion: Even though deep learning models for abnormality classification can perform well in screening mammography, we demonstrate certain imaging features that result in worse model performance. This is the first such work to systematically evaluate breast abnormality classification by various subgroups and better-informed developers and end-users of population subgroups which are likely to experience biased model performance.