The study of normal parathyroid echogenicity

Background: Some of the normal parathyroid can be shown on an ultrasound image. To our knowledge, however, either high or low echoic level of the normal parathyroid has been described without the confirmation of an experiment. Therefore, the echogenicity of the normal parathyroid was studied using intraoperative ultrasound.

Materials and methods: Between October 2015 and January 2016, the parathyroid was examined in thyroidectomy procedures of 16 contiguous patients with thyroidal disease using an intraoperative array 8 – 18 MHz probe sheathed with a sterilized covering. There were 12 female and 4 male patients with an age range of 29 – 74 years old (mean, 47 ± 15). After one thyroid lobe or whole thyroid gland was removed, the parathyroid was found out by the surgeon. Then the parathyroid was scanned directly and through frontally-padded muscle of the neck, respectively.

Results: The pathology results were thyroid papillary carcinoma (n = 11), thyroid medullary carcinoma (n = 2), thyroid adenoma (n = 1), retrosternal nodular goiter (n = 1), and thyroid nodular goiter (n = 1). Totally, twenty-five parathyroids were scanned in operation, including 8 right superior, 6 right inferior, 6 left superior, and 5 left inferior glands. All the parathyroids were visualized as hyperechoic structures, being homogeneous in texture (n = 22, 88%) and oval (n = 20, 80%), round (n = 3, 12%), or strip-like (n = 2, 8%) in shape. The length, width, and thickness averaged 6.8 ± 2.9 mm (range, 4 – 18 mm), 4.3 ± 1.6 mm (range, 3 – 10 mm), and 3.5 ± 1.3 mm (range, 1 – 7 mm).

Conclusion: The normal parathyroid was confirmed to have a hyperechoic echogenicity, with most of them being homogenous and round-shaped, and measuring an average size of 6.8 × 4.3 × 3.5 mm through intraoperative ultrasound.