To investigate the value of three-dimensional shear wave elastography (3D-SWE) in the differential diagnosis of benign and malignant thyroid nodules.

From December 2018 to October 2019, a total of 75 patients with 94 thyroid nodules at Sichuan Cancer Hospital were included. Ultrasound, 2D-SWE, and 3D-SWE were performed, and the maximum Young's modulus (Emax), average Young's modulus (Emean), and elastic data dispersion (Esd) were measured. All nodules were confirmed by operation and pathology. According to the pathology results, the receiver operating characteristic (ROC) curves of 2D-SWE and 3D-SWE parameters were plotted to assess their value in distinguishing benign and malignant thyroid nodules.

There were 24 benign nodules and 70 malignant nodules confirmed by pathology in this study. On all sections of 2D-SWE/3D-SWE, the Emax, Emean, and Esd of malignant nodules were significantly larger than those of benign nodules (P<0.05 for all). On the sagittal and transverse planes of 2D-SWE/3D-SWE and coronal plane of 3D-SWE, the areas under the ROC curves (AUCs) of Emax in diagnosing thyroid nodules were 0.753, 0.797, 0.79, 0.811, and 0.806, respectively, and there were no significant differences between them (P>0.05 for all); the AUCs of Emean were 0.740, 0.745, 0.771, 0.780, and 0.802, respectively, and there were no significant differences between them (P>0.05 for all). The AUC of Esd was significantly lower on the transverse plane of 2D-SWE than on the sagittal plane of 2D-SWE/3D-SWE and coronal plane of 3D-SWE (0.675 vs 0.803, 0.805, and 0.774, Z=2.540, 1.971, and 1.963, P<0.05 for all).

3D-SWE can be used to identify benign and malignant thyroid nodules by quantitative evaluation of the hardness of thyroid nodules. The diagnostic performance of Esd on the sagittal and coronal planes of 3D-SWE is significantly better than that on the transverse plane of 2D-SWE, and Esd is a useful method for differential diagnosis of benign and malignant thyroid nodules.