Crawling Wave Sonoelastography of Benign and Malignant Thyroid Nodules

Objective: The purpose of this study is to determine if Crawling Wave (CrW) Elastography, a novel sonoelastography technique, can be utilized to provide quantitative measurements of thyroid tissue shear velocity (a measure of tissue stiffness) and distinguish between benign and malignant thyroid nodules. Method: Fresh thyroid specimens (N = 21) with 44 regions of interest were imaged over a 9-month period in 2010 at a single institution. CrW sonoelastography was performed and shear velocity (SV) estimations with contrast to noise ratios (CNR) were calculated. Histologic diagnosis was correlated with SV and CNR values. Results: The SV and CNR of Papillary Thyroid Ca (PTC) (N = 11, CNR = 4.04, SV = 2.39 m/s) was significantly higher than benign nodules (N = 22, CNR = -0.988, SV = 1.90 m/s) (for CNR pp = 0.003, [95% CI 0.199 - 0.801]). CNR values have a sensitivity and specificity of 100% and 90.9%, respectively, for differentiating PTC from benign nodules. Additionally, SV has a sensitivity and specificity of 81.8% and 68.2%, respectively. Insufficient samples were obtained for SV and CNR comparison of other histologic types. Conclusion: Crawling wave sonoelastography can provide quantitative estimations of shear velocity (SV) depicting the elastic properties of thyroid nodules. The SV with CNR can differentiate between benign thyroid nodules and papillary thyroid carcinoma. However, prospective in-vivo studies are needed to verify the accuracy and utility of CrW elastography.