Parathyroid ultrasonography: the evolving role of the radiologist

Abstract

Previously, radiologists played a limited role in the treatment of parathyroid disease, primary focusing on the preoperative localization of parathyroid lesions responsible for hyperparathyroidism. But, the widespread use of high-resolution ultrasound has lead to the increasing detection of parathyroid incidentalomas (PTIs). Consequently, radiologists may be required to differentiate PTIs from thyroid lesions, which is most reliably accomplished through the fine needle aspiration-parathyroid hormone analysis. Various nonsurgical treatment modalities for hyperfunctioning parathyroid lesions have been developed with some efficacy. Especially for symptomatic nonfunctioning parathyroid cysts, simple aspiration is a first-line procedure for diagnosis and treatment, while ethanol ablation is a subsequent treatment modality for recurrent cases.

Keywords: Ablation techniques; Hyperparathyroidism; Incidental findings; Parathyroid glands; Ultrasonography.

Fig. 1.. A 55-year-old woman with parathyroid adenoma.

A, B. Coronal images from a technetium-99m sestamibi parathyroid scan (A, early phase; B, delayed phase) demonstrate a single area of increased uptake in the right lower neck. C, D. Gray-scale sonograms (C, axial scan; D, longitudinal scan) demonstrate a large well-defined hypoechoic solid mass posteroinferior to the right lobe of the thyroid gland.

Fig. 2.. A 73-year-old woman with parathyroid adenoma with characteristic feeding vessels.

A longitudinal sonogram shows a hypoechoic solid mass with multiple feeding vessels from the lower pole margin of the thyroid gland.

Fig. 3.. A 63-year-old man (A) and a 34-year-old woman (B) with suspicious parathyroid incidentalomas (PTIs).

A. An axial sonogram depicts an oval, well-defined hypoechoic solid PTI (arrow). The lesion was proven to be a parathyroid lesion by a fine needle aspiration-parathyroid hormone (FNA-PTH) assay. B. An axial sonogram shows an enlarged thyroid gland with heterogeneous parenchymal echogenicity and a flat hypoechoic nodular lesion (arrow) located posterior to the gland. Many lymphocytes were found up on cytologic examination and an FNA-PTH assay found low level of parathyroid hormone. A flat nodular lesion, suspected to be a PTI, was proven to be an enlarged perithyroidal lymph node associated with chronic thyroiditis.

Fig. 4.. A 51-year-old woman with very large nonfunctioning parathyroid cyst.

A. An axial sonogram shows the parathyroid cyst (PC) (6.2 cm, 58.1 mL) below the right lower pole of the thyroid gland. The PC recurred two 2 months after simple aspiration. B. An axial sonogram shows the transisthmic approach of an 18-gauge needle (arrow) into the PC. C. An axial sonogram shows the PC after it was filled with instilled ethanol via an 18-gauge needle (arrow) after the complete evacuation of the cystic fluid. D. An axial sonogram shows the PC with a much smaller size (2.5 cm, 3.3 mL) 1 month after ethanol ablation. T, trachea; C, common carotid artery.