The CAD system had a lesion-based sensitivity of 80.4% (41/51) at the operating level of 2.0 false-positive markings per image used in the study. The number of available CAD regions was 587. Table 4 shows that on average 274.2 of the 546 false-positive CAD regions (50.2%) were not queried. It also shows that on average 5 of the 41 true-positive CAD regions (12.2%) were not queried. The radiologists queried far fewer false-positive CAD regions than the non-radiologists.
Table 4 Number of CAD regions queried
Queried CAD regions Non-queried FP CAD regions Non-queried, unreported TP CAD regions Non-queried CAD regions but reported TP finding
Non-radiologists
1 290 293 2 2
2 338 244 3 2
3 330 251 4 2
4 500 83 3 1
5 196 377 7 7
Average 330.8 249.6 3.8 2.8
Radiologists
6 176 396 8 7
7 262 319 6 0
8 209 365 9 4
9 444 140 3 0
Average 272.75 305 6.5 2.75
Reader average 305 274.22 5 2.78
There were 587 CAD regions in total; 546 false-positive CAD regions and 41 true-positive CAD regions