Shear wave elastography of thyroid nodules for the prediction of malignancy in a large scale study

OBJECTIVES: The purpose of this study is to validate the usefulness of shear wave elastography (SWE) in predicting thyroid malignancy with a large-scale quantitative SWE data. METHODS: This restrospective study included 476 thyroid nodules in 453 patients who underwent gray-scale US and SWE before US-guided fine-needle aspiration biopsy (US-FNA) or surgical excision were included. Gray-scale findings and SWE elasticity indices (EIs) were retrospectively reviewed and compared between benign and malignant thyroid nodules. The optimal cut-off values of EIs for predicting malignancy were determined. The diagnostic performances of gray-scale US and SWE for predicting malignancy were analyzed. The diagnostic performance was compared between the gray-scale US findings only and the combined use of gray-scale US findings with SWEs. RESULTS: All EIs of malignant thyroid nodules were significantly higher than those of benign nodules (p≤.001). The optimal cut-off value of each EI for predicting malignancy was 85.2kPa of Emean, 94.0kPa of Emax, 54.0kPa of Emin. Emean (OR 3.071, p=.005) and Emax (OR 3.015, p=.003) were the independent predictors of thyroid malignancy. Combined use of gray-scale US findings and each EI showed elevated sensitivity (95.0-95.5% vs 92.9%, p≤.005) and AUC (0.820-0.834 vs 0.769, p≤.005) for predicting malignancy, compared with the use of only gray-scale US findings. CONCLUSIONS: Quantitative parameters of SWE were the independent predictors of thyroid malignancy and SWE evaluation combined with gray-scale US was adjunctive to the diagnostic performance of gray-scale US for predicting thyroid malignancy.ope