Table 1.

Sensitivity per polyp for single-mark and double-mark CAD true positive presentation

	Sensitivity (n=21)
Reader	Single-mark	Double-mark
1	8 38%	12 57%
2	15 71%	19 91%
3	15 71%	19 91%
4	12 57%	10 48%
Average	60% [51%, 68%]	71% [63%, 80%]

Numbers are polyps (%). Patients had at most one polyp. Note that per patient and per polyp sensitivities are not necessarily identical because radiologists could miss the true polyp and instead inappropriately mark a false positive as a polyp, leading to a TP patient and FN polyp. The differences between single-mark and double-mark reads for individual readers (Fisher exact test) were not statistically significant. The differences between single-mark and double-mark reads for the average reader (p =.03, three-factor ANOVA) was statistically significant. 95% confidence intervals are given for the sensitivities for the average reader. There was no statistically significant difference amongst readers for the single mark reads but there was a statistically significant difference amongst readers for the double mark reads (p=.002, Cochran’s Q).