In patients with autoimmune thyroiditis with mild subclinical hypothyroidism, the study period will include a screening period of not more than 30 days, and a 12-week treatment period compared to baseline. At completion of treatment, Thyroid Stimulating Hormone(TSH), free thyroxine (FT4)，free thyroxine (FT3) will be included. The changes of anti-thyroglobulin antibody, anti-thyroglobulin antibody, T1-mapping and metabolic indexes.
The purpose of this experiment is to compared the changes of thyroid function, anti-thyroid peroxidase antibody, anti-thyroglobulin antibody, thyroid magnetic resonance T1-mapping and various metabolic indexes from baseline to the end of treatment (after the thyroid function had been normal for more than three months)