ULTRASOUND ELASTOGRAPHY IN THE DIFFERENTIATION OF THYROID NODULES

Abstract

PURPOSE: To evaluate the diagnostic performance of real-time freehand ultrasound (US) elastography in differentiating malignant from benign thyroid nodules MATERIALS &METHODS: Conventional ultrasonography (CUS) and real-time US elastography were performed in 203 thyroid nodules (117 malignant; 86 benign) of 114 patients (F: M=101:13, mean age of 47.8 years). According to the findings of gray-scale US, the result of CUS were divided into three categories; benign, indeterminate, and malignancy. The elasticity (E) score was assigned from 1 to 5 according to the degree and distribution of strain induced by light compression. Mean E scores in malignant and benign lesions were examined by using a Student t-test. We evaluated the diagnostic performance to differentiate malignancy from benign lesions by using a ROC analysis to compare the area under the curve, sensitivity, specificity and accuracy at the optimal cut-off value. RESULTS: For E score, the mean + standard deviation was 3.7 + 1.0 for malignant lesions and 2.0 + 0.7 for benign lesions (P<.001). The area under the curve of CUS and E score was 0.864 and 0.899, respectively. There was no significant difference of AUC between CUS and E score (p=0.181). Sensitivity, specificity, and accuracy of CUS at the cut-off value between indeterminate and malignancy were 83.6%, 86.0%, and 84.6%, respectively. Those of E score at the cut-off value between 2 and 3 were 88.8%, 79.1%, and 82.5%, respectively. CONCLUSION: For the differential diagnosis of thyroid nodules, the diagnostic performance of elasticity score had at least equivalent value compared to CUS.