Diagnostic Reliability and Clinical Impact of [¹¹C]Choline PET/CT for Detecting Hyperfunctioning Parathyroid Glands

[¹¹C]choline PET/CT could become the preferred method for detecting hyperfunctioning parathyroid glands in patients with clinical hyperparathyroidism (cHPT), given its growing accessibility and superior diagnostic performance compared with conventional imaging. This study aimed to evaluate the robustness of [¹¹C]choline PET/CT in identifying and localizing hyperfunctioning parathyroid glands in preoperative settings. Methods: This retrospective study included patients with biochemically proven cHPT who underwent [¹¹C]choline PET/CT for preoperative localization of parathyroid adenomas. Parathyroid hormone levels, calcium metabolism, and previous scintigraphy and ultrasound results were collected for each patient, along with available histopathology results. Three reviewers evaluated the presence and anatomic localization of adenomas, and interobserver agreement was assessed. The diagnostic performance of [¹¹C]choline PET/CT was assessed exclusively in patients who underwent surgical resection or fine-needle aspiration biopsy of the suspected hyperfunctioning glands, using histopathologic results as the reference standard. Results: This study included 174 patients. Moderate interobserver agreement was reached regarding examination positivity (Fleiss κ, 0.636; 95% CI, 0.633-0.638) and gland localization (Fleiss κ, 0.656; 95% CI, 0.655-0.657). In the patient-based analysis, [¹¹C]choline PET/CT had a sensitivity of 92.2% and a positive predictive value of 98.3%; in the lesion-based analysis, the sensitivity reached 88.2%, with a positive predictive value of 96.8%. The cure rate of cHPT after [¹¹C]choline PET/CT-guided surgery was 84.1% (95% CI, 73.5%-91.3%). Conclusion: Our findings support the diagnostic efficacy of [¹¹C]choline PET/CT in patients with cHPT. Although the diagnostic performance is promising, the moderate interobserver agreement, particularly related to the accuracy of localizing ectopic parathyroid glands, calls for a refinement of interpretation criteria to improve the use of this imaging technique.