C-Choline PET/CT vs. Tc-MIBI/Iodide Subtraction SPECT/CT for Preoperative Detection of Abnormal Parathyroid Glands in Primary Hyperparathyroidism: A Prospective, Single-Centre Clinical Trial in 60 Patients.

Background: In patients with primary hyperparathyroidism (PHPT) locating hyperfunctioning glands (HPGs) is crucial when planning minimally invasive surgery. Dual-isotope subtraction scintigraphy with Tc-MIBI/Iodide using SPECT/CT and planar pinhole imaging (Method A) has previously shown a sensitivity >93%. However, the method is costly and time consuming and entails a high radiation dose. C-Choline PET/CT (Method B) is an appealing candidate method unencumbered by these disadvantages.

Methods: Sixty patients with newly diagnosed PHPT participated and were scanned using both methods prior to parathyroidectomy. We investigated whether sensitivities of Method A and Method B are similar in a method-to-method comparison when using surgical findings as the true location.

Results: At the patient level, sensitivities were (A) 0.98 (95% CI: 0.90-1.00) and (B) 1.00 (95% CI: 0.93-1.00). At the gland level, sensitivities were (A) 0.88 (95% CI: 0.78-0.94) and (B) 0.87 (95% CI: 0.76-0.92). With a non-inferiority margin of ∆ = -0.1, we found a 1-sided -value < 0.001.

Conclusion: Our methods comparison study found that sensitivity of Method B was not inferior to Method A. We suggest that C-Choline PET/CT is a clinically relevant first-choice candidate for preoperative imaging of PHPT and that Method B can likely replace Method A in the near future.