Diagnostic Value of Preoperative Imaging Modalities and Their Association with Clinical Parameters in Lesion Localization in Primary Hyperparathyroidism

Objective: The aim of the study was to assess the diagnostic value of preoperative imaging modalities for identifying primary hyperparathyroidism (PHPT) and to examine the clinical and biochemical characteristics associated with successful lesion localization. Materials and Methods: Data from 216 patients who underwent parathyroidectomy for PHPT and had successful preoperative localization from neck ultrasonography (USG) and Tc-99m sestamibi scintigraphy were analyzed retrospectively. Cases that were not initially localized by imaging were evaluated based on 4D-CT or 18F-fluorocholine PET/CT reports. The associations between accurate localization with imaging modalities and the clinical and biochemical characteristics were investigated. Results: The combined use of neck USG and Tc-99m sestamibi scintigraphy had a sensitivity of 55.1% and a positive predictive value of 96.3% for detecting hyperfunctional lesions. Multivariable analysis revealed that a parathyroid gland size greater than 1 cm (odds ratio [OR]=2.521, p=0.002), serum intact parathyroid hormone (iPTH) concentration greater than 134 ng/L (OR=2.270, p=0.007), and the presence of normocalcemic PHPT (OR=2.546, p=0.023) were independently associated with successful localization when using USG and sestamibi scintigraphy together. Conclusions: Combined neck USG and Tc-99m sestamibi scintigraphy are particularly effective for localizing of PHPT in patients with larger glands, higher iPTH levels, and normocalcemic PHPT, potentially obviating the need for advanced imaging in selected cases.