Diagnostic Performance of a Combination of Shear Wave Elastography and B-Mode Ultrasonography in Differentiating Benign From Malignant Thyroid Nodules

Abstract

Objectives: This study was conducted to compare clinicopathologic and radiologic factors between benign and malignant thyroid nodules and to evaluate the diagnostic performance of shear wave elastography (SWE) combined with B-mode ultrasonography (US) in differentiating malignant from benign thyroid nodules.

Methods: This retrospective study included 92 consecutive patients with 95 thyroid nodules examined on B-mode US and SWE before US-guided fine-needle aspiration biopsy or surgical excision. B-mode US findings (composition, echogenicity, margin, shape, and calcification) and SWE elasticity parameters (maximum [Emax], mean, minimum, and nodule-to-normal parenchymal ratio of elasticity) were reviewed and compared between benign and malignant thyroid nodules. The diagnostic performance of B-mode US and SWE for predicting malignant thyroid nodules was analyzed. The optimal cutoff values of elasticity parameters for identifying malignancy were determined. Diagnostic performance was compared between B-mode US only, SWE only, and the combination of B-mode US with SWE.

Results: On multivariate logistic regression analysis, age (odds ratio [OR], 0.90; P=0.028), a taller-than-wide shape (OR, 11.3; P=0.040), the presence of calcifications (OR, 15.0; P=0.021), and Emax (OR, 1.22; P=0.021) were independent predictors of malignancy in thyroid nodules. The combined use of B-mode US findings and SWE yielded improvements in sensitivity, the positive predictive value, the negative predictive value, and accuracy compared with the use of B-mode US findings only, but with no statistical significance.

Conclusion: When SWE was combined with B-mode US, the diagnostic performance was better than when only B-mode US was used, although the difference was not statistically significant.

Keywords: Clinicopathologic and Radiologic Factors; Diagnostic Performance; Shear Wave Elastography; Thyroid; Ultrasound.

Fig. 1.

A 53-year-old woman with surgically proven papillary thyroid carcinoma. B-mode ultrasound showed hypoechoic mass with irregular margin and microcalcifications which was assessed as a high suspicion. Shear wave elastography (SWE) displayed heterogenous color elasticity signal with peripheral high SWE (red). Measured elasticity parameters of E_mean of 78.0 kPa, E_max of 82.7 kPa and E_min of 56.8 kPa were obtained.

Fig. 2.

A 36-year-old man with surgically proven papillary thyroid carcinoma. B-mode ultrasound showed mixed echoic mass with well-defined margin and oval shape which was assessed as an intermediate suspicion. Shear wave elastography (SWE) displayed relatively heterogenous color elasticity signal. Measured elasticity parameters of E_mean of 40.0 kPa, E_max of 54.7 kPa and E_min of 10.3 kPa were obtained.

Fig. 3.

A 57-year-old woman with surgically proven nodular hyperplasia. B-mode ultrasound showed isoechoic mass with well-defined margin and oval shape which was assessed as a low suspicion. Shear wave elastography (SWE) displayed relatively homogenous color elasticity signal. Measured elasticity parameters of E_mean of 39.8 kPa, E_max of 68.4 kPa and E_min of 11.0 kPa were obtained.