The value of the mean peak systolic velocity of the superior thyroidal artery in the differential diagnosis of thyrotoxicosis

PURPOSE The aim of this study was to validate the superior thyroidal artery mean peak systolic velocity (STA-mPSV) as an alternative to other diagnostic parameters in the differentiation of the causes of thyrotoxicosis in Korean patients. METHODS This study was conducted with newly diagnosed and untreated thyrotoxic patients. Forty patients were diagnosed with Graves disease (GD) and 20 patients with destructive thyroiditis (DT). Another 60 healthy subjects without thyroid disease participated as the control group. Blood samples were taken to evaluate the thyroid function and thyroid autoantibodies (TRAb). Twenty-four hour radioactive iodine uptake (RAIU) scanning was performed to confirm GD or DT. The STA-mPSV was measured using color Doppler ultrasonography. RESULTS The STA-mPSV was significantly higher in the untreated GD group than in the DT group (GD, 78.96±29.04 cm/sec; DT, 29.97±14.67 cm/sec; control, 17.55±4.99 cm/sec; P<0.001). The area under the curve (AUC) of the STA-mPSV for the differential diagnosis of untreated GD and DT was 0.9506 (optimal cutoff value, 41.3 cm/sec; sensitivity, 95%, 38/40; specificity, 85%, 17/20) in the receiver operating characteristic analysis. The AUC values of the STA-mPSV, RAIU, and TRAb were 0.9506, 1, and 0.9988, respectively (P=0.159). CONCLUSION In clinical practice, the STA-mPSV has a diagnostic value similar to that of the TRAb and 24-hour RAIU in the differential diagnosis of newly diagnosed Korean thyrotoxic patients.