Background: Positron emission tomography (PET) has not been evaluated for preoperative localization and functional characterization of the parathyroid tissue in hyperparathyroidism.
Methods: Images of the neck and upper mediastinum of 23 patients with hyperparathyroidism were obtained by PET after intravenous administration of 400 to 800 MBq L-[methyl-11C]-methionine. The investigation was repeated in six patients after Na2-ethylenediamine tetraacetic acid infusion, whereby stable 65% to 157% rise in intact serum parathyroid hormone values was attained.
Results: Parathyroid surgical procedure revealed single (21 patients) or two enlarged parathyroid glands (two patients) that were characterized as chief cell adenoma (n = 13), hyperplasia (n = 10), or carcinoma (n = 2) and weighed 80 to 6000 mg. Twenty (80%) of these glands were localized by PET. The remaining examinations (20%) were false negative and mainly encompassed small parathyroids in juxtathyroid position. Among 15 patients undergoing parathyroid reoperation true-positive localizations were obtained for 87% of the glands. The images displayed lower tracer uptake in residual thyroid lobes (n = 40), esophagus, and cervical vertebrae. Na2-ethylenediamine tetraacetic acid infusion failed to enhance parathyroid uptake values. Ultrasonography, computed tomography, technetium-thallium scintigraphy, and venous sampling revealed 25% to 53% of the pathologic parathyroid tissues of the patients undergoing reoperation and was largely complementary to PET.
Conclusions: The results suggest that PET may provide novel possibilities for the imaging of pathologic parathyroid glands in hyperparathyroidism.