Table 3. Areas under the ROC curves, diagnostic sensitivity and specificity, and the optimal thresholds for mean susceptibility and the proportion of voxels with susceptibility values lower than 60, 65, 70, 75, and 80 ppb.

	Area under the ROC curve	Sensitivity (%)	Specificity (%)	Optimal threshold	p*
Mean susceptibility	0.932 (0.839–0.980)	86.84	84.00	109.25 ppb	Reference
Proportion of voxels <60 ppb	0.995 (0.933–1.000)	100	96	0.63%	0.0249
Proportion of voxels <65 ppb	0.999 (0.941–1.000)	100	97.37	0.88%	0.0192
Proportion of voxels <70 ppb	1.000 (0.943–1.000)	100	100	1.9%	0.0183
Proportion of voxels <75 ppb	0.999 (0.941–1.000)	97.37	100	2.32%	0.0191
Proportion of voxels <80 ppb	0.999 (0.941–1.000)	97.37	100	6.1%	0.0186

Data are median and 95% confidence-interval values.

^*Pairwise comparisons of ROC curves with that for the mean susceptibility.

ROC: receiver operating characteristics.