Color Doppler sonography in Graves' disease: Value in assessing activity of disease and predicting outcome

OBJECTIVE. The aims of the study were to establish the usefulness of color Doppler sonography in assessing changes in thyroid blood flow during the course of Graves' disease and to investigate which of several variables (thyroid volume, number of intraparenchymal vessels, and blood flow in the thyroid artery) were best related to thyroid hyperfunction and therefore could be used to evaluate the course of the disease. SUBJECTS AND METHODS. Fifty-six patients with Graves' disease were selected and divided on the basis of clinical and laboratory data into four groups: patients untreated at first diagnosis, patients undergoing antithyroid drug treatment, patients in remission after withdrawal of therapy, and patients having a relapse of hyperthyroidism. Ten healthy subjects served as controls. RESULTS. Patients with active hyperthyroidism (at first diagnosis, during treatment, or at relapse) had a significantly enlarged thyroid (p =.005); intrathyroid vascularization, evaluated as number of vessels per square centimeter (p <.0001); and blood flow in the thyroid artery (p <.0001) compared with control subjects and with patients in remission after withdrawal of therapy. During treatment, sonographic values were slightly lower but not significantly different from those registered in patients at the onset of hyperthyroidism, indicating that normalization of vascularity does not parallel the drug-induced decrease of hormonal synthesis, Among 21 patients in remission, the nine patients who had a relapse shortly after the examination had a higher number of vessels per square centimeter (2.18 +/- 0.34 versus 1.03 +/- 0.16, p = .03) and higher flow in the thyroid artery (80.3 +/- 19.1 versus 10.6 +/- 2.3 ml/min, p =.01) than did the other 12 patients who remained in stable remission, despite normal hormonal levels in both groups. CONCLUSION. Our results suggest that color Doppler sonography can be used to assess activity of Graves' disease and to predict the outcome of the disease after withdrawal of medical therapy.