An observer study to assess the detection of calcification clusters using 2D mammography, digital breast tomosynthesis, and synthetic 2D imaging

The purpose of the study is to test the performance of the combination of digital breast tomosynthesis (DBT) and synthetic views on the detection for cancers presenting as calcifications compared to the performance of planar mammography combined with DBT. A pilot study is presented. A set of 22 cases without cancer were collected from a Siemens Inspiration mammography system. Twenty-two simulated calcification clusters were inserted into the planar and DBT projections of 16 cases. For each case one breast and one view were used. The images were processed using Siemens proprietary software. Seven experienced mammography readers viewed the cases in three study arms: planar alone (ArmP), planar with DBT (ArmP&D) and synthetic 2D with DBT (ArmS&D). The observers marked the suspected location of the clusters and classified the likelihood of there being a suspicious calcification clusters for each case. A JAFROC figure of merit (FoM) was calculated for each study arm. The detection fractions of all cases were 46±16% (P and P&D), 34±19% (S&D). For lesion marked for recall then the maximum detection rate was 19%. The FoMs were 0.48±0.15 (P) and 0.42±0.17 (P&D), but significantly lower (p≤0.003) for S&D (0.32±0.16). This pilot study demonstrated the feasibility of undertaking a larger study. The overall detection were lower (<50%) than optimal for a virtual clinical trial. We plan to increase the detection rate by using less subtle clusters in the final study. When using synthetic 2D images instead of planar images alongside DBT, the FoM was lower for subtle calcification clusters.