Endocrine Abstracts

Objective: The definitive treatment of primary hyperparathyroidism (PPH) is the removal of the affected gland(s). However, its localization can be complicated. The usefulness of 18F-Choline PET-CT versus classical techniques is unknown. The aim of this study was to evaluate the results of 18F-Choline PET-CT in the detection of hyperfunctioning parathyroid tissue with respect to conventional imaging tests and to analyze the relationship between its findings and the levels of calcium and parathyroid hormone (PTH) prior to surgery.

Material and methods: Retrospective observational study of a sample of 30 patients with PPH candidates for surgery, assessed in consultation between 2020-2023, who underwent 18F-Choline PET-CT after negative or discordant conventional localization tests.

Results: Twenty-two females and 8 males were studied. Mean age: 55.6±12.1 years. Surgical criteria were: osteopenia/osteoporosis (73.3%), renal lithiasis (53.3%), serum calcium (50%), age (33.3%), elevated calciuria (20%) and glomerular filtration rate (3.5%). Eighty percent met 2 or more surgical criteria. Parathyroid ultrasound and/or MIBI scintigraphy had been performed in 96.7% of patients, with a concordance with 18F-choline PET-CT results of 40% and 17.2%, respectively. Parathyroid 4D-CT was performed in 19 patients, with a concordance with PET-CT results of 36.8%. In 100% of the sample the 18F-choline PET-CT was positive, with the most frequent localization being the right lower gland (36.7%). Ectopic gland was reported in 10%. The mean diameter of the lesions on PET-CT was 12.58 mm. 15 patients had already undergone surgery, and parathyroid adenoma was found in 13 of them and parathyroid hyperplasia in the remaining 2. There was 100% concordance between the PET-CT findings and the anatomical location of the hyperfunctioning gland in the pathological anatomy study. No association was found between serum PTH and/or calcium levels with the diameter of the lesion on PET-CT or with its weight on anatomic pathology.

Conclusions: 18F-Choline PET-CT was useful in cases where ultrasound, scintigraphy or CT-4D had negative or discordant results. It presents a high detection rate of parathyroid hyperfunction and concordance with the surgical location of the affected gland. In addition, it offers benefits in the planning of surgery in patients in whom a good preoperative localization of the lesion was not achieved and in patients with persistent or recurrent PPH.