Utility of shear wave elastography to detect papillary thyroid carcinoma in thyroid nodules: efficacy of the standard deviation elasticity

Background/Aims: The aim of this study was to address the role of the elasticity index as a possible predictive marker for detecting papillary thyroid carcinoma (PTC) and quantitatively assess shear wave elastography (SWE) as a tool for differentiating PTC from benign thyroid nodules. Methods: One hundred and nineteen patients with thyroid nodules undergoing SWE before ultrasound-guided fine needle aspiration and core needle biopsy were analyzed. The mean (E-Mean), minimum (E-Min), maximum (E-Max), and standard deviation (E-SD) of SWE elasticity indices were measured. Results: Among 105 nodules, 14 were PTC and 91 were benign. The E(Mea)n, E-Min, and E-Max values were significantly higher in PTCs than benign nodules (E-Mean 37.4 in PTC vs. 23.7 in benign nodules, p = 0.005; E-Min 27.9 vs. 17.8, p = 0.034; E-Max 46.7 vs. 31.5, p < 0.001). The E-Mean, E-Min, and E-Max were significantly associated with PTC with diagnostic odds ratios varying from 6.74 to 9.91, high specificities (86.4%, 86.4%, and 88.1%, respectively), and positive likelihood ratios (4.21, 3.69, and 4.82, respectively). The ESD values were significantly higher in PTC than in benign nodules (6.3 vs. 2.6, p < 0.001). ESD had the highest specificity (96.6%) when applied with a cut-off value of 6.5 kPa. It had a positive likelihood ratio of 14.75 and a diagnostic odds ratio of 28.50. Conclusions: The shear elasticity index of ESD, with higher likelihood ratios for PTC, will probably identify nodules that have a high potential for malignancy. It may help to identify and select malignant nodules, while reducing unnecessary fine needle aspiration and core needle biopsies of benign nodules.