Application of digital breast tomosynthesis for the analysis of non-calcified BI-RADS 4A lesions on mammograms

Abstract Background: The study aimed to evaluate the role of digital breast tomosynthesis (DBT) in the differential diagnosis of digital mammography (DM) lesions classified as 4A according to the Breast Imaging Reporting and Data System (BI-RADS). Methods: The DM and DBT of patients diagnosed with non-calcified BI-RADS 4A lesions at our institution between January 2019 and August 2020 were analyzed retrospectively. The BI-RADS 4A lesions on DM were downgraded to BI-RADS 3 if the lesion on DBT was more visible than on the mammogram and more than 50% of its boundary was sharp without suspicious signs of malignancy. Conversely, the lesions were upgraded to BI-RADS 4B and 4C if they presented with an irregular shape or showed non-circumscribed margins on DBT. The Mann-Whitney U test was used to compare the categorical variables, and the T-test was used to analyze the continuous variables between the benign and malignant pathologically confirmed cases. Results: A total of 191 lesions were evaluated, of which 129 were confirmed to be benign on pathology examination, and the rest were malignant.After plus DBT,25.1% of lesions showed lesion type change which was asymmetry on DM but presented mass or architectural distortion on DBT, and 46.3 % of the asymmetric DM lesions were seen as a uniform mass on DBT. DBT showed superior or equal visualization to DM for circumscribed masses. Most (97.2%) of the circumscribed masses on DBT were confirmed benign on pathology, while 91.7% of the non-circumscribed were confirmed to be malignant on pathology. After plus DBT,61.8% of the lesions had BI-RADS change, for the lesions downgraded to BI-RADS 3 on DBT, there were 54.3% confirmed to be benign on pathology, while 64.5% of upgraded to BI-RADS 4B or 4C lesions were malignant on pathology. Conclusion: DBT can be used to facilitate the discrimination of benign and malignant BI-RADS 4A lesions on DM and hence reduce the need for unnecessary biopsies.