Table 2.

Performance of the models derived from the training subset assessed in terms of the mean and standard deviation (SD) of the cross-validation AUC. AUCs are also given for the test subset, indicating the bootstrap p-value of the difference with respect to the model with only $P_{90\mathrm{\%}}^{\mathrm{FDG}}$.

Modality	Feature pre-selection	Interaction terms	AUC
	Training		mean ± SD
CT	None	No	0.78 ± 0.03
	None	Yes	0.78 ± 0.03
	ε↑, $V_{>70}^{\downarrow }$	No	0.841 ± 0.007
PET	None	No	0.852 ± 0.008
	None	Yes	0.853 ± 0.007
	$P_{90\mathrm{\%}}^{\mathrm{FDG}}$	No	0.855 ± 0.005
	$P_{90\mathrm{\%}}^{\mathrm{FDG}}$, ${\stackrel{\sim }{\mu }}_3^{\mathrm{FDG}}$	No	0.861 ± 0.007
PET + CT	$P_{90\mathrm{\%}}^{\mathrm{FDG}}$, ${\mathcal{E}}_{\uparrow }$	No	0.873 ± 0.008
	Test		value (p)
PET	$P_{90\mathrm{\%}}^{\mathrm{FDG}}$	No	0.756
PET	$P_{90\mathrm{\%}}^{\mathrm{FDG}}$, ${\stackrel{\sim }{\mu }}_3^{\mathrm{FDG}}$	No	0.767 (p < 0.001)
CT	ε↑, $V_{>70}^{\downarrow }$	No	0.828 (p < 0.0001)
PET + CT	$P_{90\mathrm{\%}}^{\mathrm{FDG}}$, ${\mathcal{E}}_{\uparrow }$	No	0.833 (p < 0.0001)