Prediction of relapse after antithyroid drug therapy of Graves' disease: value of color Doppler sonography.

Opinions differ regarding the indications for antithyroid drugs, radioiodine and surgery in patients with Graves' disease because the likelihood of long-term remission after medical treatment cannot be predicted. The aim of this study was to assess the value of quantifying thyroid blood flow in an attempt to predict outcome following withdrawal of antithyroid drug therapy. Spectral Doppler recordings were obtained from the thyroid arteries in 24 patients with Graves' disease at the time of diagnosis. Thyroid blood flow levels measured at the time of diagnosis of Graves' disease were correlated with outcome following withdrawal of medical treatment (mean duration of treatment: 14 months). Clinical follow-up for at least 18 months (range: 18 - 39 months) after antithyroid drug withdrawal was possible in 13 patients (12 women). Mean peak systolic velocity and volume flow rate values as well as thyroid volume measured at the time of diagnosis were significantly higher (139 cm/s, SD 46; 195 ml/min, SD 170; 52 ml, SD 18) in patients who relapsed after drug treatment compared with patients in remission (71 cm/s, SD 27; 67 ml/min, SD 61; 25 ml, SD 13). The correlation between thyroid blood flow measurements and thyroid volume was high (r = 0.79 - 0.96). Recurrence of disease could be predicted with a sensitivity of 71 % and a specificity of 100 % based on thyroid blood flow measurements. This preliminary data suggest that quantification of thyroid blood flow by means of Doppler sonography might be a useful tool to predict the outcome of Graves' disease following withdrawal of medical treatment and could be helpful in finding the adequate kind of therapy.