Endocrine Abstracts

JOINT2410

Background/Aim: [¹⁸F]fluorocholine-PET has emerged to a diagnostic tool of first choice in the localization of a culprit parathyroid gland in primary hyperparathyroidism. The aim of this analysis was to retrospectively compare quantitative radioligand uptake of parathyroid adenomas and non-target organs, target to background ratios and the diagnostic accuracy of [¹⁸F]fluorocholine-PET at different scan times.

Methodology: All operated patients with primary hyperparathyroidism who preoperatively underwent [¹⁸F]fluorocholine-PET scan at LMU Hospital between November 2020 and December 2024 were included. A visual qualitative and a semiquantitative (SUV_mean and SUV_max) analysis of histopathologically proven parathyroid adenomas and non-target organs were applied. Quantitative values are reported with median and interquartile range. The radioligand uptake and target to background ratios were then compared between three acquisition times (early: 15-24 min, intermediate: 25-54 min, late: 55-94 min) using the Kruskal-Wallis test.

Results: A total of 101 patients were included in the study. Histopathological reports revealed a single parathyroid adenoma in 89 patients. Sixteen hyperplastic glands were identified in six patients (one of whom carried a MEN1 germline variant). One patient presented with a parathyroid carcinoma. In 3 cases, no parathyroid tissue was found in the histopathological examination. 50 patients were scanned at an early, 33 at an intermediate and 19 at a late acquisition time. Overall, the visual analysis showed a very good detection rate of 91. 08% with no significant difference between the groups (P = 0. 953). In the quantitative analysis, the median SUV_max of the 108 histologically proven lesions was highest in the late acquisition group, although statistical significance was not reached (4. 0(2. 2) vs. 4. 0(1. 9) and 5. 1(2. 7); P = 0. 163). Similarly, the median adenoma to mediastinal blood pool ratio was highest in the late acquisition group (3. 63(2. 47) vs. 4. 14(2. 58) vs. 5. 89(5. 91)), with significant differences between the early and late acquisition (P = 0. 002) and the intermediate and late acquisition (P = 0. 012).

Conclusion: [¹⁸F]fluorocholine-PET is a reliable diagnostic tool in the detection of adenoma in patients with primary hyperparathyroidism. The [¹⁸F]fluorocholine uptake of the parathyroid adenomas was strongest at late acquisition times. However, the present study found no significant difference in detection rate between the early and late acquisition groups.