[Role of Doppler color ultrasonography and of flowmetric analysis in the diagnosis and follow-up of Grave's disease].

Hyperthyroidism in Graves' disease is caused by the presence of circulating autoantibodies to the THS receptors on the thyroid cells. Thyroid-suppression therapy prevents hormone production directly, without affecting the pathogenetic process. We performed color Doppler US of the thyroid gland and pulsed Doppler analysis of thyroid artery flow in 21 patients with Graves' disease before and during medical treatment. US results were compared with those of a control group of 40 healthy subjects and correlated with the values of thyroid hormones, TSH, and thyroid microsomal and thyroglobulin antibodies. The thyroid gland was hypovascularized in the control group. Pulsed Doppler examination of the thyroid arteries exhibited peak systolic velocity of PSV 20 +/- 4 cm/s, diastolic velocity of 8 +/- 1 cm/s, and resistive index of 0.60 +/- 0.04. The thyroid gland of Graves' disease patients was hypervascularized. Pulsed Doppler examination of the thyroid arteries exhibited peak systolic velocity (PSV = 51 +/- 12 cm/s), end diastolic velocity (VD = 15 +/- 4 cm/s), and resistive index (RI = 0.71 +/- 0.04) significantly higher than in normal subjects (p < 0.001). Circulating thyroid hormones and flow parameters normalized after 6-8 months of medical therapy (PSV = 20 +/- 6 cm/s, VD = 9 +/- 3 cm/s, RI = 0.58 +/- 0.07). Conversely, the color Doppler patterns normalized only in a patient with normal TSH and antibodies. Sampling of the thyroid arteries proved more repeatable than sampling of parenchymal vessels.