Avid thyroid uptake of [Tc-99m] sodium pertechnetate in children with goitrous cretinism.

Three children with goitrous hypothyroidism had thyroid scans with [Tc-99m] sodium pertechnetate, which showed symmetrically enlarged thyroid glands with uniformly increased activities compared to little activities in the salivary glands and low body background activities. These scan findings, simulating those of Graves' disease, reflect acid trapping of this tracer, analogous to that seen with I-131. Perchlorate discharge test was positive in two patients, indicating an organification defect.