Each comparison was calculated from 980 observations (70 cases, seven radiologists, and two devices). PPV: positive predictive value, ROC: receiver operating characteristic, AUC: area under ROC curve, SE: standard error of the mean, Ho: null hypothesis, Ha: alternative hypothesis for testing equivalence, α: significance of the test (0.05), δ: difference of the means allowed to achieve equivalence, : test for difference of compared devices, that is, = (Difference () − δ)/SE, : retained hypothesis equivalence at δ level (“Ha” indicates equivalence achieved and “Ho” indicates failing to reject the null hypothes). Ho: difference () − δ = 0. Ha: difference () − δ < 0.