Ultrasonic imaging of the thyroid gland

Since the introduction in the 1970s of ultrasonography (US) for diagnostic and therapeutic purposes in clinical thyroidology, US has become widely accepted, increasingly employed, and mastered not only by specialist in diagnostic imaging. It is recommended by the thyroid specialist societies as the initial imaging method for individuals with thyroid disorders, especially when there is suspicion of thyroid malignancy. The technology is increasingly mastered by physicians who are in charge of such patients, whether for the initial workup or for follow-up. This chapter focuses, in detail, on basic aspects of B-mode US, as well as color- and power Doppler US, and discusses elastosonography. Strengths and weaknesses of these modalities are covered and characteristic findings are highlighted pictorially. Much emphasis is on the technique of US-guided fine-needle aspiration as a diagnostic tool, since this is also the prerequisite for the increasing use of US-guided therapy and the decrease in diagnostic thyroidectomies. The use of percutaneous ethanol injection (PEI) therapy, interstitial laser photocoagulation (ILP), and radiofrequency ablation (RFA) is covered, although their use in thyroid malignancy is still in its infancy.