Use of choline PET and ultrasound for preoperative localization of hyperfunctioning parathyroid glands: a single-institution retrospective cohort study.

Background: Positron emission tomography (PET) with fluorine-18 or carbon-11 labeled choline (choline PET) has been found to have higher diagnostic accuracy for localizing hyperfunctioning parathyroid glands than other imaging methods. To evaluate if ultrasound (US) still has value in the diagnostic workup, we compared the findings on choline PET with US findings in patients with hyperparathyroidism (HPT).

Methods: We retrospectively reviewed all patients with HPT who underwent a choline PET in the University Hospital of North Norway between 2019-2022. The indications for choline PET were negative or inconclusive localization with [^99mTc]Tc-sestamibi scintigraphy and US, previous parathyroid surgery, or suspicion of multiglandular disease. Additionally, a focused parathyroid US was performed either before (67% of patients) or after the choline PET, without any blinding between modalities.

Results: Sixty-two patients were included, of which 50 had been operated on at the time of analysis. Parathyroid tissue was removed in all patients, and multiglandular disease was found intraoperatively in 15 patients (30%). 96% of patients became normocalcemic after surgery. Diagnostic accuracy for choline PET and US was 98% and 89%, respectively, and 100% combined. Multiglandular disease was detected in 28% of patients by both modalities. Two patients with negative choline PET had a true positive US finding.

Conclusions: Choline PET in combination with US performed by a radiologist specialized in neck US, successfully localized parathyroid disease in all operated patients. Both modalities detected 28% multiglandular disease. Findings on choline PET had better correspondence with intraoperative findings than US.