Does Shear Wave Elastography Provide Additional Value in the Evaluation of Thyroid Nodules That Are Suspicious for Malignancy?

OBJECTIVES

We aimed to determine whether the integration of shear wave elastography (SWE) with conventional ultrasonography (US) improves diagnostic performance for suspicious thyroid lesions.

METHODS

For 215 thyroid lesions in 185 patients classified as Thyroid Imaging Reporting and Data System category 4 or 5 according to the findings of conventional US, SWE elasticity indices were automatically calculated. A receiver operating characteristic curve analysis was used to determine the threshold. Thyroid Imaging Reporting and Data System categories were upgraded for high-stiffness nodules and unchanged for low- and normal-stiffness nodules. The diagnostic performances were assessed and compared with histologic findings. Intraobserver and interobserver variability of SWE was assessed.

RESULTS

Elasticity indices were significantly higher in malignant versus benign nodules (P≤ .001). The minimum elasticity index (cutoff, 40.7 kPa) of the stiffest part combined with conventional US showed the highest area under the curve (0.774; 95% confidence interval, 0.682-0.866) but was not superior to conventional US (0.791; 95% confidence interval, 0.706-0.876; P = .48). Combined with the standard deviation of the elasticity index for the whole lesion (cutoff, 6.8 kPa), US yielded the highest sensitivity (95.5%; P < .001) and lowest specificity (42.1%; P < .001). Sensitivity increased and specificity decreased by adding any other SWE elasticity index. The intraobserver and interobserver reliability of SWE was fair to excellent according to the interclass correlation coefficients, with correlation coefficients of 0.765 to 0.846 (all P < .001).

CONCLUSIONS

The SWE elasticity indices of malignant thyroid nodules were significantly high. Adding SWE to conventional US did not improve diagnostic performance.