Compare the two series of pictures. Both images was made at the end of a methimazol therapy. Both patients were euthyroid.
The left patient with echonormal-minimally hypoechogenic, normally vascularized thyroid remained euthyroid 13 months later while the hyperthyroidism recurred in the right patient 6 months later. The sonographic pattern in the right case is also minimally-moderately hypoechogenic, but the vascularization is increased. 

Significantly more patient suffer relapse later in the course with hypoechogenic and more vascularized thyroid compared with echonormal and normally vascularized patients. On the other hand the significance of this observation has only limited role in the every day practice.