Evaluation of the Stiffness of Tissues Surrounding Thyroid Nodules with Shear Wave Elastography

This study evaluated the stiffness of tissue surrounding thyroid nodules using shear wave elastography (SWE).A total of 128 thyroid nodules in 108 patients were examined with conventional ultrasound imaging and SWE. The maximum Young modulus value was measured to evaluate the stiffness of the thyroid nodules (E) and the 2-mm perinodular region (Eshell ). The number of thyroid fibrocytes was evaluated by Masson trichrome staining and image-processing software. The arrangement of the fibrous structure was also classified.The mean age ± SD of the 108 patients was 33.12 ± 13.34 years (range, 18-80 years). Thirty-nine thyroid nodules were classified as benign and 89 as malignant. Eshell was significantly higher for malignant nodules (95.0 ± 21.9 kPa) compared with benign nodules (48.1 ± 17.0 kPa; P < .001). Eshell yielded an area under the receiver operator characteristic curve value of 0.951, which was used for the diagnosis of nodules. There was a high positive correlation between E and Eshell in the malignant group (R = 0.722; P < .001) and a moderate positive correlation in the benign group (R = 0.601; P < .001). Percentages of fibrocytes correlated highly with Eshell in all samples as well as in malignant samples (R = 0.867 and R = 0.729, respectively; P < .001). The degree of disorder of the tissue surrounding thyroid nodules was positively correlated with Eshell (R = 0.833).Perinodular stiffness has potential to improve diagnosis of thyroid nodules.