Comparison of hard-copy and soft-copy reading for digital mammography in population-based mass screening

To evaluate the influence of soft-copy reading for digital mammography when switching from hard-copy reading, we examined the recall rate, positive predictive value (PPV), and cancer detection rate for population-based mass screening in Miyagi prefecture. There was no significant difference in the recall rate for mass-finding. In cases showing calcification, the recall rate for hard-copy reading and soft-copy reading was 0.84% and 0.67% respectively, and the difference was significant (p=0.01). On the other hand, for other findings, the recall rate for soft-copy reading (1.50%) was significantly higher than that for hard-copy reading (1.02%). There was no significant difference in the cancer detection rate between hard-copy and soft-copy reading, although a high recall rate for other findings was the prime cause of the low PPV for hardcopy reading. (author)