18 F-Fluorocholine PET/CT in primary hyperparathyroidism: superior diagnostic performance to conventional scintigraphic imaging for localization of hyperfunctioning parathyroid glands.

Primary hyperparathyroidism (PHPT) is a common endocrine disorder, definitive treatment usually requiring surgical removal of the offending parathyroid glands. In order to perform focused surgical approaches, it is necessary to localize all hyperfunctioning glands. The aim of the study was to compare the efficiency of established conventional scintigraphic imaging modalities with emerging 18 F-Fluorocholine PET/CT imaging in preoperative localization of hyperfunctioning parathyroid glands in a larger series of PHPT patients. Methods: 103 patients with PHPT were imaged preoperatively with 18 F-Fluorocholine PET/CT and conventional scintigraphic imaging methods, consisting of 99m Tc-sestaMIBI SPECT/CT, 99m Tc-sestaMIBI/pertechnetate subtraction imaging and 99m Tc-sestaMIBI dual-phase imaging. The results of histological analysis as well as intact parathormone and serum calcium values obtained one day after surgery and on the follow-up served as the standard of truth for evaluation of imaging results. Results: Diagnostic performance of 18 F-Fluorocholine PET/CT surpassed conventional scintigraphic methods (separately or combined), with calculated sensitivity of 92% for PET/CT and 39-56% for conventional imaging (65% for conventional methods combined) in the entire patient group. Subgroup analysis, differentiating single and multiple hyperfunctioning parathyroid glands, showed PET/CT to be most valuable in multiple hyperfunctioning gland group with sensitivity of 88%, while conventional imaging with sensitivity of 22-34% (44% combined) was significantly inferior. Conclusion: 18 F-Fluorocholine PET/CT is the superior diagnostic modality in comparison to the conventional imaging methods, allowing for accurate preoperative localization in patients with PHPT.