[Relationship between thyroid echogram and thyroid function in Hashimoto's thyroiditis]

Seventeen cases of untreated Hashimoto's thyroiditis were selected from the files of the Taipei Municipal Jen-Ai Hospital during the period from Jan. 1985 to Jan. 1986. All the cases were confirmed by a physical examination, determination of thyroid antibodies and fine needle aspiration cytology. Thyroid function was also determined. According to the echogenicity of the thyroid, they were divided into 2 groups, group A (8 cases) and group B (9 cases). In group A, homogeneous hypoechogenicity of the thyroid was noted and was lower than that of the adjacent muscles. In group B, heterogeneous echogenicity of the thyroid with equal or higher echogenicity than that of the adjacent muscles was noted. Group A showed a significantly lower serum T4, T3 and a higher serum TSH in comparison with group B. Five cases in group A presented hypothyroidism clinically while only 1 in group B presented. In conclusion, in the cases of Hashimoto's thyroiditis, the homogeneous hypoechogenicity of the thyroid echogram suggested the possibility of hypothyroidism. Statistically, the sensitivity was 83.3%, specificity 72.8%, positive prediction value 62.5% and the negative prediction value was 88.9%.