[Ultrasound of the thyroid]

Thyroid nodules and thyroid abnormalities are common findings in the general population. Ultrasonography is the most important imaging tool for diagnosing thyroid disease. In the majority of cases a correct diagnosis can already be made in synopsis of the sonographic together with clinical findings and basal thyroid hormone parameters and an appropriate therapy can be initiated thereafter. A differentiation of hormonally active versus inactive nodes, and in particular benign versus malignant nodules is sonographically, however, not reliably possible. In this context, radioscanning has its clinical significance predominantly in diagnosing hormonal activity of thyroid nodules. Efforts of the past years aimed to improve sonographic risk stratification to predict malignancy of thyroid nodules through standardized diagnostic assessment of evaluated risk factors in order to select patients, who need further diagnostic work up. According to the "Breast Imaging Reporting and Data System" (BI-RADS), "Thyroid Imaging Reporting and Data Systems" (TI-RADS) giving standardized categories with rates of malignancy were evaluated as a basis for further clinical management. Recent technological developments, such as elastography, also show promising data and could gain entrance into clinical practice. The ultrasound-guided fine-needle aspiration is the key element in the diagnosis of sonographically suspicious thyroid nodules and significantly contributes to the diagnosis of malignancy versus benignity.