Figure 7. Venn diagrams demonstrate variability among the three readers in the number of TP detections with a confidence level of 3-5 for, A, nodules with a diameter of 3 mm or more and, B, nodules with a diameter of 5 mm or more. Inside the circles, numbers in parentheses represent TP detections that were not detected by the CAD system. Inside the boxes, numbers indicate total TP detections with CAD used at an upper threshold of 15 FP detections per patient; numbers in parentheses indicate TP detections by the CAD system that were not seen by any reader. These diagrams show that at the selected thresholds all three readers made unique detections and that only 33% of nodules with a diameter of 3 mm or more and 64% of nodules with a diameter of 5 mm or more were detected by all three readers. The CAD system detected a majority of the readers’ detections and made 35 unique detections (
3-mm-diameter nodules)—more than any reader.