Shear wave elastography in the differential diagnosis of benign and malignant thyroid nodules

Shear wave elastography was performed using the Aixplorer ultrasound system (SuperSonic Imagine, Aix-en-Provence, France) to evaluate patients with thyroid nodules. Tissue stiffness was measured quantitatively in kilopascals (kPa). The data were then used to form an image that was coded in colour: stiffer tissues were coded in red and softer tissues in green and blue.This technique was used to assess the stiffness in 182 regions of the normal thyroid gland without nodules, in 495 regions of thyroid nodules irrespective of their morphology, in 176 regions of benign thyroid tumors, and in 39 regions of malignant thyroid tumors. Nonparametric statistics were used and analyses of receiver operating characteristic (ROC) curve were performed. The median stiffness values were determined to be 15.6 kPa (2,5-97,5 percentiles, range: 6,5-29,7 kPa) for normal thyroid tissues, 17,5 kPa (2,5-97,5 percentiles, range: 0,03-198,2 kPa) for thyroid nodules, 20,1 kPa (2,5-97,5 percentiles, range: 3,6-81,3 kPa) for benign thyroid nodules, and 112,9 kPa (2,5-97,5 percentiles, range: 13,5-196,4 kPa) for malignant thyroid nodules. The cutoff value of 41,1 kPa was found to be optimal for discriminating between malignant and benign nodules with a sensitivity of 84% and a specificity of 81,8%. Statistical processing was performed using SPSS 13,0 Package.