Paired assessment study data Baseline data Breast cancer cases Non breast cancer controls     Non-   US+ US- Total   US+ US- Total   Cases Cases Mx+ 148 34 182 Mx+ 8 21 29 Mx+ 98 1062 Mx- 48 10 58 Mx- 20 184 204 Mx- 40 9208 Total 196 44 240   28 205 233   138 10270

Table 1: Results of mammogram (Mx) and ultrasound (US) screening from the parallel assessment study of Houssami et al. [16] and mammogram baseline data from Kavanagh et al. [17].