The Diagnosis Efficiency of Focal Hypermetabolic Thyroid Nodules identified by 18F-FDG PET/CT

1579 Objectives To explore the diagnosis efficiency of focal hypermetabolic thyroid nodules identified by18F-FDG PET/CT in differentiating malignancy from benign thyroid nodules. Methods From January 2011 to October 2014, 3280 patients underwent 18F-FDG PET/CT. Among them, 97 patients were found to have focal hypermetabolic thyroid nodules ( Image 1), 50 patients were conformed with histopathological or clinical follow-up,including 19 with malignancy and 31 with benign nodules ( male 20,female 30,average age 61.60±12.51 y ). According to the properties of nodules, the univariate and multi-variate analysis was performed. Univariate analysis was performed using t test and Chi-Square test. Binary logistic regression was performed for multi-variate analysis.The AUC of traditional SUVmax and the probability of predicting malignancy with logistic regression analysis were compared. Results The incidence of focal hypermetabolic thyroid nodules was 3.0%(97/3280) with malignancy rate 38.0%(19/50). The SUVmax of benign and malignant nodules were 2.98±1.86 and 3.88±2.20 respectively; The average CT value of benign and malignant nodules were 45.93±18.18 and 62.82±19.78, respectively; Nodules with or without coated were 29.0% and 52.9%, respectively. All these data are meaningful in statistics (P 0.05 ,Table 1).Binary logistic regression was carried out on the SUVmax, the average CT value, with or without coated and logistic regression indicated that the SUVmax and average CT value were the main risk factor for predicting malignancy in hypermetabolic thyroid nodules.The SUVmax and the average CT value adding a unit, the incidence of thyroid malignant both increase 1.23(95% CI:1.02-1.48)units and 1.04(95% CI:1.01-1.06)units respectively (P>0.05 ,Table 2). Logistic regression indicates that the AUC of logistic regressive model (AUCL) and SUVmax (AUCS) were 0.73±0.07(95%CI:0.59-0.87)and 0.59±0.09(95%CI:0.42-0.76)respectively (P Conclusions Focal hypermetabolie thyroid nodules identified by 18F-FDG PET/CT come with high rate of thyroid malignancy.The value of SUVmax to differential diagnosis is finite but aided by average CT value is more meaningful. Table 1 Comparison in Two Groups9 Result of T Test and Chi-Square Test ([asterisk]: P<0.05) Table 2 the Result of Logistics Regression Analysis