Abstract: BACKGROUND: The global prevalence of thyroid cancer has increased significantly in recent years. Ultrasonography is the preferred method for differentiating benign and malignant thyroid nodules preoperatively and is recommended by guidelines. OBJECTIVE: To assess the application value of gray-scale ultrasound and shear wave elastography in distinguishing small thyroid nodules. METHODS: A retrospective analysis of 228 thyroid nodules, all of which were confirmed by pathology after surgery or FNA from January 2019 to January 2020, was carried out. All nodules were divided into a ⩽ 5 mm group and a > 5 mm group according to their maximum size. We compared the differences in the gray scale and elastography of the nodules between the two groups and the accuracy of different diagnostic methods. RESULTS: The accuracies of gray-scale ultrasound and shear wave elastography in the ⩽ 5 mm group were found to be lower than those in the > 5 mm group, and the gray-scale accuracy was slightly higher than that of shear wave elastography in both groups (p< 0.05). The largest AUC (area under the curve) of elastic parameters in the ⩽ 5 mm and > 5 mm groups was found for Emax and Esd, respectively. Based on a combination of these two parameters, the accuracies of the two groups were significantly higher than those of the parameters or gray scale alone (p< 0.05) and were 84.62% and 85.48%, respectively. CONCLUSION: Shear wave elastography is valuable in the diagnosis of benign and malignant thyroid nodules using ultrasonography. When combining gray-scale ultrasound and shear wave elastography, the diagnostic accuracy is obviously improved, especially for ⩽ 5 mm small thyroid nodules.
