Diagnostic value of ACR TI-RADS combined with three-dimensional shear wave elastography in ACR TI-RADS 4 and 5 thyroid nodules

BACKGROUND: Three-dimensional shear wave elastography (3D-SWE) is a promising method in distinguishing benign and malignant thyroid nodules. By combining with conventional method, it may further improve the diagnostic value. The study aimed to assess the diagnostic value of American College of Radiology (ACR) thyroid imaging reporting and data system (TI-RADS) combined with 3D-SWE in ACR TI-RADS 4 and 5 thyroid nodules. METHODS: All nodules were examined by conventional ultrasonography, ACR TI-RADS classification, and 3D-SWE examination. Conventional ultrasonography was used to observe the location, size, shape, margin, echogenicity, taller-than-wide sign, microcalcification, and blood flow of thyroid nodules, and then ACR TI-RADS classification was performed. The Young's modulus values (3D-C-Emax, 3D-C-Emean, and elastography standard deviation [3D-C-Esd]) were measured on the reconstructed coronal plane images. According to the receiver operating characteristic (ROC) curve, the best diagnostic efficiency among 3D-C-Emax, 3D-C-Emean, and 3D-C-Esd was selected and the cut-off threshold was calculated. According to the surgical pathology, they were divided into benign group and malignant group. And appropriate statistical methods such as t-test and Mann–Whitney U test were used to compare the difference between the two groups. On this basis, 3D-SWE combined with conventional ACR TI-RADS was reclassified as combined ACR TI-RADS to determine benign or malignant thyroid nodules. RESULTS: Of the 112 thyroid nodules, 62 were malignant and 50 were benign. The optimal cut-off value of three-dimensional maximum Young's modulus in coronal plane (3D-C-Emax) was 51.5 kPa and the area under the curve (AUC) was 0.798. The AUC, sensitivity, specificity, and accuracy of conventional ACR TI-RADS were 0.828, 83.9%, 66.0%, and 75.9%, respectively. The AUC, sensitivity, specificity, and accuracy of combined ACR TI-RADS were 0.845, 90.3%, 66.0%, and 79.5%, respectively. The difference between the two AUC values was statistically significant. CONCLUSIONS: Combined ACR TI-RADS has higher diagnostic efficiency than conventional ACR TI-RADS. The sensitivity and accuracy of combined ACR TI-RADS showed significant improvements. It can be used as an effective method in the diagnosis of thyroid nodules.