Sonographic imaging of the thyroid gland in congenital hypothyroidism.

We have attempted to facilitate differential diagnosis of etiological types of congenital hypothyroidism using real-time ultrasonography. Sonography of the thyroid gland was performed on 418 normal children, and 23 patients with congenital hypothyroidism and hyperthyrotropinemia. The thyroid gland was imaged by transverse scanning at the neck; the maximum thickness and the maximum width of the right and left lobe were measured. On the basis of the normal thyroid gland size obtained from normal children, the thyroid gland image of the patients were classified into 4 types: large image, normal image, small image, and no image of the thyroid gland at the neck: no image of the thyroid gland indicated agenesis or ectopia; large thyroid gland image indicated goitorous hypothyroidism. On the other hand, normal or small thyroid gland image probably included mild or transient forms of hypothyroidism, and transient hyperthyrotropinemia; these 2 types required further examination to complete the diagnosis. We concluded that real-time ultrasonography of the thyroid gland was a useful diagnostic imaging technic for patients who revealed elevated serum thyrotropin on neonatal mass-screening.