Table 4.

ROC curve analyses

Quantitative indicators	AUC	p	Critical value	Sensitivity	Specificity	Youden index
TLD (cm)	0.724	0.000	1.39	0.792	0.553	0.345
TSD (cm)	0.669	0.004	0.91	0.906	0.404	0.310
TVD (cm)	0.702	0.000	1.28	0.698	0.638	0.336
CT-LAP(HU)	0.666	0.004	−597.45	0.698	0.638	0.336
RCT-LAP	0.623	0.034	1.43	0.717	0.553	0.270

TLD Tumor length diameter on the largest axial plane, TSD Tumor short diameter on the largest axial plane, TVD Tumor vertical diameter on the largest coronal plane, CT-LAP CT value on the largest axial plane, RCT-LAP relative CT value on the largest axial plane, NLD-LAP normal lung density measured on the same plane with LAP, HU Hounsfield units