FIGURE 4.  ROC curves of PET/CT when maximum SUV or maximum SUV with CT attenuation and ¹⁸F-FDG uptake pattern was applied for differentiation between benign and malignant focal thyroid lesions. The AUC of PET/CT was significantly increased when analysis of CT attenuation and ¹⁸F-FDG uptake pattern was added to maximum SUV (0.701 ± 0.079 vs. 0.878 ± 0.049; P < 0.01).