Abstract: Objective To compare the role of 99mTc-MIBI SPECT-CT image and ultrasonography in reoperation therapy for persistent secondary hyperparathyroidism patients. Methods Eight persistent secondary hyperparathyroidism patients underwent parathyroidectomy. The sensitivity and accuracy of 99mTc-MIBI image and ultrasonography before operation were compared. Results Nine of the 14 surgically resected tissues from the 8 persistent secondary hyperparathyroidism patients were confirmed to be parathyroid hyperplasia. The sensitivity was 77.8% and 100% for ultrasonography and 99mTc-MIBI SPECT-CT image, respectively, and the accuracy was 50% and 78.6% for ultrasonography and 99mTc-MIBI dual time planar image and SPECT-CT, respectively. These differences were statistically significant (P=0.021). The glands located in superior and inferior poles could be detected by either ultrasonography or the scintigraphy, and two ectopic parathyroid nodules were found only by 99mTc-MIBI SPECT-CT but not by ultrasonography. However, the two methods for the detection of nodules were statistically similar (P=0.300). Despite the absence of pathological findings, the nodules located in the paraesophagus sulcus and ascending aorta were detected by 99mTc-MIBI SPECT-CT in two cases who had high iPTH of 800 and 1,429 pg/ml, respectively, higher than the iPTH of <
400 pg/ml in other 4 cases. Conclusion Re-operation for parathyroidectomy is a safe and effective treatment for patients with persistent secondary hyperparathyroidism. 99mTc-MIBI planar and SPECT-CT imaging based on fusion of anatomical and functional images is better than ultrasonography in localization of hyperparathyroidism glands. This method can display ectopic parathyroid glands and help clinicians accurately localize the hyperparathyroidism glands.

Key words: Secondary hyperparathyroidism, Parathyroidectomy with auto transplantation, ^99mTc-MIBI, SPECT-CT, Persistent hyperparathyroidism