Abstract: The purpose of this study was to investigate the effect of shear wave elastography (SWE) elastic modulus quantification parameters on the differentiation of TI-RADS4 Hashimoto's thyroiditis (HT) with thyroid nodules and its relationship with the biological behavior of malignant nodules. Selected 312 patients (356 nodules) who found suspicious nodules in TI-RADS 4 HT combined with thyroid nodules before thyroid surgery, 215 benign nodules, and malignant nodules 141, malignant nodules Emean, Emax, Esd and angiogenesis genes (VEGF, COX-2, Gal-3), proliferation genes (BRAF, TPX2, MCM7), invasion genes (Sixl) mRNA are higher than benign nodules (P<0.05). The AUC value of Emean, Emax and Esd in differentiating malignant nodules was higher than that of single diagnosis. The mRNA of VEGF, COX-2, Gal-3, BRAF, TPX2, MCM7 and Sixl in malignant nodules were positively correlated with Emean, Emax and Esd, while the mRNA of BRMSI, TSHR, CCNG2, P53 and PTEN were negatively correlated with Emean, Emax and Esd (P<0.05). The elastic modulus parameters Emean, Emax and Esd of SWE technology have a good differential diagnosis value for benign and malignant thyroid nodules, and the specific level can reflect the angiogenesis, cancer cell proliferation and invasive activity of malignant nodules, which can provide reference for clinical diagnosis and treatment and prognosis evaluation of patients.

Key words: shear wave elastography, elastic modulus, Hashimoto thyroiditis, thyroid nodules, TI-RADS grade 4, biological behavior