The Role Of Tc99m Mibi Spect/Ct In Detection And Localization Of Ectopic Parathyroid Adenoma

Abstract

Introduction: The main regulator of calcium homeostasis in human’s body is parathyroid hormone. Hypercalcemia is a symptom of primary hyperparathyroidism (PHPT) and is caused by an inappropriate overproduction of parathyroid hormone by one or more parathyroid glands. Aim: Accurate pre-operative localization of ectopic parathyroid adenoma via TC99m MIBI and comparison to dual phase planar images. Patients and methods: This prospective study was performed at NEMROCK center, Cairo University. It wa:s done on one hundred and five patients. The common eligibility criteria were a preoperative diagnosis of primary parathyroid hyper-functioning diseases in patients with elevated parathormone (PTH). Results: Planar images detected parathyroid lesions (adenoma/hyperplasia) in 38/105 (36.2%) in the early images, and 56 (53.3%) in the late images 23/105 patients showed ectopic parathyroid adenomas.16/23 (69.9%) were originating from inferior the inferior glands where 7/16 (43.8%) were inferior to the lower thyroid border, 6/16 (37.5%) were retro-clavicular and 3/16(18.7%) were at the anterior mediastinum. 7/23 (30.4%) were originating from the superior glands where 5/7(71.4%) were in the trachea-esophageal groove and 2/7(28.6%) were in the posterior mediastinum. Dual phase planar images detected ectopic adenomas in 5 (4.8%) and 6 (5.7%) patients in early and late image respectively. On the other hand, SPECT/CT could detect 23 (21.9%) and 18 (17.1%) respectively. It should be noted that 5 cases could not be diagnosed in early SPECT/CT images but diagnosed in the late images. Conclusion: TC99m MIBI SPECT/CT has a significant role in preoperative localization of ectopic parathyroid adenoma.