How does wide-angle breast tomosynthesis depict calcifications in comparison to digital mammography? A retrospective observer study

Digital breast tomosynthesis (DBT) provides superior breast cancer detection performance compared to digital mammography (DM), but it is unclear whether DBT alone is sufficient to accurately visualize lesions with calcifications, or supplemental DM is needed. In this work, we performed a retrospective observer study to assess and compare the depiction of calcifications on DM, DBT, and synthetic mammography (SM). Eighty views from 40 lesions with calcifications in 39 patients acquired with a wide-angle DBT system were included (two views per case - cranio-caudal and medio-lateral oblique). Four experienced researchers (3, 10, 11, 21 years) in breast imaging scored the images. For each case, the regions-of-interest containing calcifications in DM, DBT and SM were shown simultaneously. The readers ranked (ties allowed) the three modalities for the depiction of calcifications and assessed if more blurring was present in DM or DBT. DM was ranked as the best modality to depict calcification lesions in 84% of the cases, DBT in 22%, and SM in 7% (P<0.001). Similarly, for 86% of the views, DBT had more blurring of the calcifications than DM. In some cases, DBT showed higher contrast of calcifications providing better visualization, but worse characterization due to signal blurring. For cases with subtle calcifications, the higher noise of DBT images deteriorated their visualization. SM was preferred over DBT for large clusters, while it failed in some cases to display any calcifications. In conclusion, our results show the current limitations of DBT and its derived SM to depict calcifications in comparison to DM.