Objective: The purpose of this study was to comparatively evaluate the two different shear wave speed (SWS) imaging systems of Toshiba shear wave elastography (T-SWE) and SuperSonic SWE (S-SWE) in distinguishing malignant from benign thyroid nodules (TNs).
Materials and methods: 140 patients with 140 focal TNs were enrolled and underwent T-SWE and S-SWE before fine-needle aspiration (FNA) biopsy or surgery. SWE indices of mean, standard deviation and maximum values (E-mean, E-SD and E-max) of elastic modulus in TNs were measured on a color-coded mapping. The receiver operating characteristic (ROC) curve was performed to assess the diagnostic performance.
Results: Of the 140 nodules, 47 were thyroid carcinomas and 93 were benign. Areas under the receiver operating characteristic curve (AUC) were the highest with E-max among the three SWE parameters both for T-SWE and S-SWE (0.816 and 0.799). The most accurate cut-off values, sensitivity, specificity, accuracy, positive predictive value (PPV) and negative predictive value (NPV) were 26.6 kPa versus 42.9 kPa, 83.0% versus 63.8%, 68.8% versus 88.2%, 72.9% versus 80.0%, 56.5% versus 73.2% and 88.7% versus 82.8% with E-max for T-SWE and S-SWE, respectively. Among these comparisons, the sensitivity in T-SWE was statistically higher than S-SWE (83.0% versus 63.8%, p = 0.022), whereas specificity was statistically lower than S-SWE (68.8% versus 88.2%, p < 0.001).
Conclusion: T-SWE is equal to S-SWE with comparable and promising results for diagnosis of TNs. In clinical using, the selection of E-max should be recommended both for T-SWE and S-SWE.
Keywords: Acoustic radiation force impulse; diagnostic performance; fine-needle aspiration; shear wave elastography; thyroid nodules; ultrasound.