Diagnostic efficiency of 18F-FDG PET/CT for indeterminate thyroid nodules / 中华核医学与分子影像杂志

ABSTRACT

Objective To investigate the diagnostic efficiency of 18F-FDG PET/CT imaging for indeterminate thyroid nodules.Methods Sixty-eight patients (24 males,44 females,age:(52.8±10.58) years) with indeterminate thyroid nodules who underwent 18F-FDG PET/CT imaging from January 2006 to December 2012 were analyzed retrospectively.The imaging characteristic including clearity of boundary,uniform density,calcification,capsule,mean CT value,nodular size and SUVmax of thyroid nodules were evaluated.The gold standard was postoperative pathological results.Mann-Whitney u test,x2 test and ROC curve analysis were performed to investigate the diagnostic efficiency.Results Among 68 patients with indeterminate thyroid nodules,18 were malignant and 50 were benign according to pathological results.Uniform density,calcification,capsule (x2 =0.21,0.01,0.43,all P＞0.05) and mean CT value,nodular size (all AUCs＜0.5) could not differentiate benign from malignant thyroid nodules.However,whether the nodules had clear boundary was significant to differentiate benign from malignant nodules (x2=8.06,P＜0.05),and the sensitivity,specificity and accuracy were 55.6％ (10/ 18),80.0％ (40/50) and 73.5％ (50/68),respectively.The mean SUVmax of benign and malignant thyroid nodules was 3.16±1.84 and 8.53±7.09,respectively (u=-4.281,P＜0.01).AUC of SUVmax was 0.841 (95％ CI:0.726-0.955).According to the maximal Youden index(0.562),4.25 was chosen as the SUVmax threshold,and its sensitivity,specificity and accuracy were72.2％(13/18),84.0％(42/50) and 80.9％(55/68),respectively.Conclusion Among different characteristics of 18F-FDG PET/CT imaging,SUVmax of thyroid nodules plays an important role in the differential diagnosis of undetermined thyroid nodules,but CT image features have limited value.