A severely hypoechogenic thyroid with decreased vascularization. The most important role of color mode is the differential diagnostic of hyperthyroid states. In an active hormone-producing disease (Graves-Basedow) the vascularization is significantly increased in more than 95% of cases. Such increased blood flow can be observed even in hyperthyroid states caused by destruction (Hashimoto's disease) but less frequently, in around 30% of cases. The decreased vascularization is the sign which has practical relevance. Such pattern in a hyperthyroid patient is very specific for thyroiditis.