Limited diagnostic and predictive values of dual-time-point 18F FDG PET/CT for differentiation of incidentally detected thyroid nodules

To assess usefulness of dual-time-point F-18 FDG PET/CT to differentiate malignant from benign thyroid nodules and predict the potential factor for malignancy. Fifty patients (age 38-83 years, mean 58 +/- A 10.6 years) with thyroid nodule were recruited. The F-18 FDG PET/CT images were analyzed visually and quantitatively. The optimal visual grade of early and delayed images was > grade 3. When SUVmax1 of > 2.9 was used as cut off point, the sensitivity and specificity were 55.5 and 63.4%. When SUVmax2 was > 3.1, the sensitivity and specificity were 88.8 and 43.9%. When %Delta SUVmax was a parts per thousand currency sign9.09%, the sensitivity and specificity were 33.3 and 87.8%. ROC analyses showed that all indices had similar efficacy without significances. No definite predictor could be found for malignant nodules. The dual-time-point F-18 FDG PET/CT is not a useful method for differentiating malignant and benign nodules.