Thyroid vascularity--documentation of the iodide effect in thyrotoxicosis.

Thyroid vascularity was measured in 101 thyrotoxic patients by analysis of 99mTc pertechnetate thyroid flow studies obtained with a gamma camera--minicomputer system. The diffusely hyperplastic goitres tended to have higher vascularity than the toxic multinodular goitres, and many of the solitary toxic nodules had vascularity results within normal limits. Potassium iodide therapy, 60 mg b.d. for 10-14 days results in a dramatic reduction in thyroid vascularity in diffuse thyroid hyperplasia and toxic multinodular goitre but the effect on toxic nodules was marginal.