Compare the two series of pictures. At the first investigation (left column,) the patient had hypothyroidism (TSH 47.7 mIU/L) which has spontaneously resolved 3 months later (right column).

Three relevant changes can be found comparing the images of the two investigations. First, the hypoechogenicity has decreased. Second, the size of the thyroid has also decreased and third, the vascularization was more pronounced at first compared with the follow-up investigation.