ROLE OF COLOUR FLOW DOPPLER ULTRASONOGRAPHY TO DIFFERENTIATE GRAVES’ DISEASE AND GESTATIONAL THYROTOXICOSIS IN PREGNANCY

Objective: Accurate diagnosis of thyrotoxicosis in pregnancy is important to guide appropriate treatment. This study evaluated inferior thyroid artery (ITA)-peak systolic velocity (PSV) as a marker for differential diagnosis of thyrotoxicosis in pregnancy. Methods: This case-control study included sixty pregnant patients with thyrotoxicosis (35 with GTT and 25 with GD) along with 30 age-matched healthy euthyroid pregnant subjects. GD was documented by Thyrotropin receptor antibody (TRAb). The studies of the right and left ITAs were performed with Doppler, and the PSV and End diastolic velocity (EDV) values were obtained from the right and left ITA. TSH, T4 and T3 levels were measured by electrochemiluminescence immunoassay. Results: The mean age of patients was 34.3±11.2 years as compared to 32.8±11.2 years in controls. The mean total T4 value in GD and GTT were almost similar (25.04 ± 2.43 vs 23.25 ± 2.81, P value = 0.14). The ITA-PSV and EDV in patients with GD were significantly higher than GTT pregnant patients (right: 23.5±7.2 and 9.2±2.7; left: 24.7±7.6 and 9.6±2.5; P < 0.001). receiver-operating-characteristic (ROC) curve demonstrated an optimal cutoff value of mean right ITA-PSV of 30 cm/sec to differentiate GTT from GD during pregnancy, with 91% and 89% sensitivity and specificity. Conclusion: Thyroid artery velocities can help to differentiate between GD and GTT. The cutoff point of mean ITA-PSV at 30 cm/s had an excellent value in differentiating between the two, with good sensitivity and specificity.