Publications of Faculty of Medicine:Evaluation Of Preoperative Localization Of Parathyroid Adenoma Using 99mTc-sestamibi Scintigraphy As A Single Diagnostic Modality For Patients With Primary Hyperparathyroidism: Abstract

Objective : This study was designed to evaluate the diagnostic yield of Technetium-99m hexakis methoxyisobutylisonitrile (Tc-99m-M1131) scintigraphy in patients with primary hyperparathyroidism (PHPT) for identification oft/it site of parathyroid adenoma compared versus operative and histopathologi cal findings. Patients & Methods : The study included 13 cases with PHPT, 5 males and 8 females with mean age of 56.5±10.3; range: 39-69 years. Preoperative scanning using 991lTc-sestandbi was done. All patients underwent surgical exploration after methylene blue transfusion. Imaging data were compared with intraoperative finding. Ad identified and excised glands were sent for his topathological examination. Results : Preoperative sestamibi scan defined a case with mediastinal parathyroid gland and another active cervical gland in 2 patients with persistent and recurrent hypercalcaemia, respectively. Preoperative sestamibi scan defined 6 cases with single parathyroid adenoma in each case, while surgical exploration defined 7 parathyroid adenomata; 5 cases had solitary adenoma and one case had adenoma in 2 parathyroid glands both stained blue after methylene blue infusion. Thus, sestamibi scan defined solitary parathyroid adenomas with an accuracy rate of 83.3%. However, sestamibi scan defined 3 cases with adenoma in 2 parathyroid glands and 2 cases had adenoma in 3 glands. Surgical exploration defined adenoma that confirmed histopathologically in 9 glands of the 12 identified by sestamibi scan; 4 cases had 2 adenomas and one case had one solitary adenoma, the other 3 glands showed only hyperplasia without adenoma formation. Thus, sestamibi scan defined multiple parathyroid adenoinas with an accuracy rate of 75%. Conclusion : It Could be concluded that preoperative localization of parathyroid gland depending on preoperative sestamibi scan could identify ectopic active glands with accuracy 100% and active cervical glands with an overall accuracy rate of 79.2% and concomitant intraoperahte methylene blue localization allowed detection of active glands missed by preoperative sestamibi scan. Keywords: 99^,Tc-sestamibi, preoperative localization, primary hyperparathyroidism.