To evaluate the clinical value of the superior thyroid artery peak systolic velocity (STA-PSV) for the differential diagnosis of autoimmune thyrotoxicosis.

A total of 301 patients with newly diagnosed thyrotoxicosis and without any anti-thyroid drug intervention were collected from the Department of Endocrinology and Metabolism, Peking University People′s Hospital from Jan. 2015 to Oct. 2018. Among them, 241 patients were with Graves′ disease (GD) and 60 patients were with autoimmune thyroiditis (AIT). STA-PSV, thyroid function and thyrotropin receptor antibody (TRAb) were determined. A multiple linear regression was used to identify factors associated with STA-PSV. A receiver operating characteristic (ROC) curve and area under the curve (AUC) were used to evaluate the discriminating ability of STA-PSV to GD.

STA-PSV leves in GD group were significantly higher than those in AIT group [61.00 (41.00, 86.50) cm/s vs. 34.50 (25.25, 46.00) cm/s, P<0.001]. The ROC curve analysis showed that the AUC was 0.790 (95%CI 0.734-0.845), and 49.5cm/s was the optimal cutoff point for the diagnosis of GD, in which the sensitivity was 64.3% and the specificity was 83.3%. In all patients with thyrotoxicosis, multiple linear regression analyses showed free thyroxine (FT₄) (β=0.371, 95%CI 0.005-0.010, P<0.001) and TRAb (β=0.138, 95%CI 0.001-0.014, P=0.035) were positively associated with STA-PSV.

The STA-PSV is positively associated with FT₄ and TRAb levels, and it is a helpful marker in differential diagnosis between GD and AIT.

Graves disease; Thyroiditis, autoimmune; Thyrotoxicosis; Blood flow velocity