Evaluation of the Perinodular Stiffness Potentially Predicts the Malignancy of Thyroid Nodules

Objectives To evaluate the surrounding tissue stiffness measured by sound touch elastography for differential diagnosis of thyroid nodules (TNs). Methods Thirty‐nine benign and 90 malignant TNs were included in this study. The conventional ultrasound features, the maximum Young modulus value of the stiffness of the TNs (recorded as E), and the stiffness of the 0.5‐, 1.0‐, 1.5‐, and 2.0‐mm perinodular regions of the TNs (recorded as E shell0.5 , E shell1.0 , E shell1.5 , and E shell2.0 , respectively) were prospectively analyzed and compared to histopathologic results. The abundance of collagen fibers at various widths in the perinodular regions of the TNs was evaluated by Masson staining and ImageJ software (National Institutes of Health, Bethesda, MD). The fibrous structures in the perinodular regions of the TNs were classified. Results The various E shell values of malignant TNs were significantly higher than those of benign TNs ( P < .001 for all). E shell0.5 correlated highly with E in the malignant TNs and in all samples ( r = 0.722 and 0.772; P < .001 for both). Eshell2 yielded the highest area under the receiving operating characteristic curve value (0.96) for the differential diagnosis of TNs. The abundance of collagen fibers in the 2‐mm perinodular region of the TNs was closely correlated with E shell2 in the malignant TNs and in all samples ( r =0.729 and 0.867; P < .001). The E shell2 values for different levels of disorder of the tissue surrounding TNs were significantly different ( P < .01 for all). Conclusions Perinodular stiffness measured by sound touch elastography improved the diagnostic accuracy in TNs.