New applications of thyroid and parathyroid ultrasound.

In the past decade ultrasound has become an essential part of the examination of the thyroid patient. Sonography of the thyroid has been integrated with the history and physical exam and other thyroid tests (especially needle biopsy) to provide valuable information that has improved patient care. Advances in technology and engineering including high-resolution phased-array transducers, color flow and power Doppler have provided much more detail and information regarding thyroid and neck morphology making diagnosis more accurate. This has expanded the use of ultrasound and resulted in development of new ultrasound applications for both the diagnosis and therapy of thyroid and parathyroid disorders. Ultrasound guidance for needle biopsy of thyroid nodules has become routine. It is now being used to confirm the ultrasound diagnosis of parathyroid adenoma by measuring parathyroid hormone obtained with the needle placed in the lesion under ultrasound guidance. Likewise, non-palpable lymph nodes in the neck discovered by ultrasound and suspected of having metastatic carcinoma can be easily biopsied using ultrasound. The material can be submitted for both cytology and peptide analysis to confirm the diagnosis replacing more expensive imaging. Using these same ultrasound guidance techniques, several groups of investigators have developed methods of therapeutic ablation of tissue by chemical or physical means. This may result in an alternative to surgery for certain thyroid, parathyroid, and lymph node lesions.