Table 5 Sensitivity and false positive ratios according to nodule size (variation in chest radiograph and CT thresholds)

	Size
	>2 mm	>5 mm	>10 mm	>20 mm
Se (CT scan)	0.83	0.79	0.62	0.38
Sp (CT scan)	0.78	0.92	0.98	1.00
Se (radiograph)	0.33	0.33	0.17	0.17
Sp (radiograph)	0.95	0.97	0.99	1.00
RSN	2.50 [1.46 to 4.28]	2.38 [1.40 to 4.03]	3.75 [1.62 to 8.68]	2.50 [1.17 to 5.34]
RFP	4.77 [3.63 to 6.26]	3.09 [2.08 to 4.59]	2.71 [1.14 to 6.46]	1.50 [0.25 to 8.98]
Ratio FP/TP	17.58 [9.77 to 31.64]	6.09 [3.09 to 11.99]	1.09 [0.39 to 3.03]	0.20 [0.00 to 17.47]

95% confidence interval is shown in square brackets.
FP, false positive; RFP, ratio of false positive rates; RSN, ratio of sensitivities; Se, sensitivity; Sp, specificity; TP, true positive.