Abstract:Objective: To evaluate the detecting rate, scanning techniques, locations and sonographic features of normal parathyroid gland by high frequency ultrasonography. Methods: High-frequency ultrasonography was used to detect parathyroid glands in 300 cases of healthy volunteers. The size, shape, position, number, internal echo and blood flow of normal parathyroid glands were carefully documented and analyzed. Results: Altogether 465 parathyroid glands were found in 300 cases of healthy volunteers. Among them, 4 glands were detected in 12 cases, 3 glands in 27 cases, 2 glands in 139 cases, 1 gland in 58 cases and no gland was detected in 64 cases, with the detecting rate of 78.7%(236/300). Normal parathyroid glands have three shapes: oval(73.5%), spindle(18.1%), irregular(8.4%), and there are three kinds of echoes: hyperechoic(78.3%), hypoechoic(16.5%) and isoechoic(5.2%). Color Doppler flow imaging(CDFI) showed no blood flow(81.9%), little blood flow(17.9%) and abundant blood flow(only one case). On longitudinal scanning section, parathyroid glands mostly locate near the posterior border of the lateral thyroid lobe and inferior pole; on horizontal scanning section, they mostly locate at the posterior border of lateral lobe of thyroid, which stand between the trachea and the common carotid artery. Conclusions: Normal parathyroid glands can be detected by high-frequency ultrasonography and they commonly appear as oval hyperechoic lesions with no or little blood flow.