Table 1.

Performance of the software and clinical reports against reference standards, with 95% CI

Test	Suspicious nodule identified by software	Suspicious nodule identified by software	Any suspicious abnormality on clinical report*
Reference standard	Suspicious nodule on clinical report†	Cancer diagnosis by multidisciplinary team decision
Sensitivity	54.5% (44.2% to 64.4%)	60.9% (50.1% to 70.9%)	66.3% (55.7% to 75.8%)
Specificity	83.2% (82.2% to 84.1%)	83.3% (82.3% to 84.2%)	98.0% (97.7% to 98.4%)
PPV	5.5% (4.6% to 6.6%)	5.6% (4.8% to 6.6%)	35.7% (30.5% to 41.2%)
NPV	99.0% (98.8% to 99.2%)	99.2% (99.0% to 99.4%)	99.4% (99.3% to 99.6%)
Accuracy	82.7% (81.7% to 83.6%)	82.9% (81.9% to 83.9%)	97.5% (97.1% to 97.9%)
FPPI	0.18	0.18	0.02

*Includes nodules, masses and secondary features of malignancy (such as unilateral pleural effusions or lobar collapse).

†Other suspicious abnormalities (including masses and secondary features of cancer, such as lung volume loss) were excluded.

FPPI, false positives per image; NPV, negative predictive value; PPV, positive predictive value.