Ultrasonographic features of normal human parathyroids and related validating strategies / 第二军医大学学报

ABSTRACT

Objective To screen for and validate the principal ultrasonographic features of normal human parathyroid glands, so as to provide guidance for diagnostic ultrasound in parathyroid pathologies and protection of normal parathyroid during total thyroidectomy. Methods From Apr. 2008 to Dec. 2012, the neck ultrasonograms focusing on the thyroids and adjacent structures were obtained from 600 healthy subjects. One-by-one identification and exclusion was performed based on anatomical evidences, and the most probable parathyroid images (termed as presumed parathyroid sonogram) of normal human parathyroid were obtained. Based on those presumed parathyroid sonograms, we compared the detection rates of parathyroid in subjects with or without hypoparathyroidism following total thyroidectomy, and we also analyzed the ultrasonic features of patients with hyperparathyroidism. Moreover, we assessed the influence of intraoperative ultrasonography on the occurrence of hypoparathyroidism following total thyroidectomy. The accuracy and reliability of the presumed parathyroid sonogram were discussed. Results It was verified that the normal parathyroid appeared as a small well-circumscribed nodule with fine and homogenous internal hyperechoes. Their configuration varied, with oval shape as the commonest one; the texture was softer than that of adjacent thyroid parenchyma, with the quantitative strain ratio below 1 on elastography. About 62. 5% of the normal parathyroids were filled with color Doppler flow signals. The gland was small, with the mean length, width, and thickness being (6.38 + 1.46), (3.76 + 1.02), and (2.75 + 1.99) mm, respectively, and the mean volume was (0.13 + 0.06)mL by VOCAL method. The inferior glands were much better displayed than the superior ones. As for the patients who had experienced a total thyroidectomy, among five cases complicated with postoperative hypoparathyroidism, 4 (80%) developed the absence of parathyroid on ultrasonography, which was not seen in 35 patients with normal parathyroid function. As for the patients with hyperparathyroidism, normal parathyroid glands were invisible in the area of adenomatous or hyperplastic parathyroids. One patient (3. 3%) with intraoperative ultrasonography and six patients (20%) without intraoperative ultrasonography developed postoperative hypoparathyroidism (P<0. 01). Two patients with thyroid agenesis showed 2 normal ipsilateral normal parathyroids. Conclusion In the present study we have successfully obtained the ultrasonic features of normal parathyroids using non-invasive research strategies, which have been preliminarily validated in clinical application.