Parathyroid imaging by (18)F-fluorocholine PET/CT in patients with primary hyperparathyroidism and inconclusive conventional methods: clinico-pathological correlations.

(18)F-fluorocholine positron emission tomography/computed tomography (FCH) was performed after inconclusive neck ultrasound and (99)Tc-sestaMIBI SPECT (MIBI) scintigraphy in patients with primary hyperparathyroidism (PHPT) to localize abnormal parathyroid glands before surgery. The results were retrospectively evaluated and compared to postoperative histopathological findings. 13 patients with PHPT were enrolled (mean age 64.3 years, preoperative calcium 2.74 mmol/l and parathyroid hormone 114.6 ng/l). FCH localized hyperfunctioning parathyroid glands in 12 patients of 13 (per patient sensitivity 92 % and positive predictive value (PPV) 100 %). Fourteen parathyroid lesions (11 adenomas, 3 hyperplastic glands) were resected with a mean size of 11.9 mm (per lesion sensitivity 93 % and PPV 81 %). Four adenomas and one hyperplastic gland were composed of only chief cells, whereas five lesions contained both chief and oxyphil cells. In three patients an exclusively oxyphil adenoma was found, surprisingly with negative MIBI scintigraphy in spite of a high mitochondria content in the oxyphil parathyroid cells. 12 of 13 patients had thyroid disease. In our limited study sample, FCH correctly identified parathyroid adenomas and/or hyperplastic glands in 92 % of patients with previously inconclusive conventional imaging. Unlike MIBI, FCH successfully localized small, hyperplastic and multiple hyperfunctioning parathyroid glands, irrespective of their histopathological composition.