Quantitative assessment of shear-wave ultrasound elastography in thyroid nodules: diagnostic performance for predicting malignancy

Abstract

OBJECTIVES: To evaluate the predictability of shear-wave ultrasound elastography (SWE) for thyroid malignancy and to compare the diagnostic performances of SWE and B-mode US. METHODS: Retrospective review of 99 patients who underwent SWE before US-guided fine-needle aspiration of thyroid nodules was performed. SWE elasticity indices of the mean (Emean ), maximum (Emax), and minimum (Emin) of nodules were measured. Diagnostic performance of SWE was compared with that of B-mode US. RESULTS: Among a total of 99 nodules, 21 were papillary thyroid carcinoma (PTC) and 78 were benign. Emean, Emax, and Emin were significantly higher in PTCs than in benign nodules (P < 0.001). Sensitivity and specificity for predicting malignancy were 76.1 %, 64.1 % with Emax (65 kPa), 61.9 %, 76.1 % with Emin (53 kPa), and 66.6 %, 71.6 % with Emean (62 kPa). Areas under the ROC curves (Az) of SWE values were not significantly different from those of US categories on B-mode US. However, combining Emean and Emin with B-mode US of probably benign lesions improved the specificity (P = 0.02, 0.007) for predicting PTC. CONCLUSIONS: The quantitative parameter of SWE was significantly higher in PTC than in benign nodules, and combined use of quantitative SWE and B-mode US provided higher specificity for predicting malignancy. KEY POINTS: • Quantitative shear-wave elastography (SWE) helps differentiate benign from malignant nodules • SWE and conventional ultrasound have comparable diagnostic performance for predicting thyroid malignancy • Combined quantitative SWE and B-mode ultrasound is highly specific for thyroid malignancy.