Efficacy of Ultrasonography and Tc-99m MIBI SPECT/CT in Preoperative Localization of Parathyroid Adenomas Causing Primary Hyperthyroidism

Abstract

Background: Primary hyperparathyroidism (PHPT) results from an excess of parathyroid hormone (PTH) produced from an overactive parathyroid gland. The study aimed to explore the sonographic features of parathyroid adenomas and assess the diagnostic performance of ultrasonography (US) and Tc-99m MIBI SPECT/CT for preoperative localization of parathyroid adenomas. Methods: A total of 107 patients were enrolled in this retrospective study who had PHPT and underwent parathyroidectomy. Of the 107 patients, 97 performed US and Tc-99m MIBI SPECT/CT examinations for preoperative localization of parathyroid nodules. The sensitivity and accuracy of each modality were calculated. Results: In this study, residual parathyroid sign and polar vascular sign were identified as characteristic US features of parathyroid adenomas and these manifestations are closely related to the size of the abnormal parathyroid lesions. Using 108 parathyroid nodules from 97 patients with PHPT, the sensitivity and accuracy of US in locating parathyroid nodules were significantly higher than those of Tc-99m MIBI SPECT/CT (93.0% vs. 63.0% and 88.0% vs. 63.0%), and the difference was statistically significant (c²=26.224, 18.227, P<0.001). The difference between US combined with Tc-99m MIBI SPECT/CT and Tc-99m MIBI SPECT/CT-alone was statistically significant (c²=33.410, 21.587, P<0.001), yet there was no significant difference compared with US alone (c²=0.866, 0.187, P=0.352 and 0.665). Conclusions: US shows significantly better sensitivity and accuracy for localization of parathyroid adenomas than Tc-99m MIBI SPECT/CT. However, US combined with Tc-99m MIBI SPECT/CT is of great clinical value in the preoperative localization of parathyroid nodules in patients with PHPT.