Ultrasound of the Parathyroid Glands and Neck Masses

Abstract

Ultrasound is successfully applied for imaging abnormal parathyroid glands in orthotopic location. One or two inferior parathyroid glands can be revealed with ultrasound in 60–70% of patients. Adenoma of the superior parathyroid is usually detected along the back margin of the middle segment of the thyroid lobe. Adenoma of the inferior parathyroid is most often located below the inferior pole of the thyroid lobe. The shape of a lesion serves as a criterion for differential diagnosis between thyroid and parathyroid tumors. The pulsing afferent artery of the parathyroid gland is identified with CDI and PDI in 83% of patients. In doubtful cases, US-guided fine needle aspiration with a test for PTH in the needle washout is of benefit. Parathyroid hyperplasia is commonly characterized by the enlargement of two or more glands. Similar morphologic changes in the parathyroid glands of patients with hyperplasia and adenoma practically exclude the possibility of ultrasound differentiation between these conditions. Parathyroid cancer is a rare disease accounting for only 1–2% of all cases of primary hyperparathyroidism. It demonstrates higher echodensity, retains its round or oval shape with irregular, rough, indistinct margins, absence of a hyperechoic capsule, irregular asymmetric vascularity with CDI and PDI, hard pattern with compression ultrasound elastography, and high share-wave velocities with elastometry. This chapter also discusses the typical features of median and lateral neck cysts, paragangliomas, malignant pathology of the larynx, Hodgkin’s lymphoma, cervical esophageal diverticulum, inflammatory processes in the soft tissues, and other abnormalities.