Accuracy of preoperative localizing imaging techniques is a prerequisite for successful focused and minimally invasive surgical approaches in primary hyperparathyroidism (pHPT). New imaging techniques have been recently proposed. This study was aimed to determine the impact of 18-F-choline PET CT/MRI (FCh) in patients with negative or controversial 99mTc-sestamibi Scintiscan (sMIBI).

One-hundred-eighty-five consecutive patients undergoing surgery for pHPT between 2021 and 2023 were analyzed. In 117 patients neck ultrasonography and sMIBI localization studies were performed (sMIBI Group); FCh was also performed in 68 patients (FCh Group) with previous inconclusive or controversial localization at sMIBI.

Cure was achieved in 184 patients; persistent pHPT occurred only in 1 case in sMIBI group. The overall sensitivity of localizing studies was 65.2% (95%IC: 57.8-72.1) for sMIBI), while it was significantly higher in FCh group (92.3%; 95%IC: 82.9- 97.4). FCh revealed an unequivocal single localization allowing a focused successful parathyroidectomy and avoiding an unnecessary bilateral neck exploration in 48/68 patients (70.6%); while it was theoretically possible only in 104/185 patients (56.2%) after sMIBI. Patients in FCh+ group had lower preoperative calcium than sMIBI group (2.71 vs 2.78mmol/L, p=0.01), lower preoperative PTH levels (172 vs 236 pg/ml, p=0.03) and smaller size of the removed gland (17 vs 21 mm; p=0.001).

FCh allows a successful focused parathyroidectomy in pHPT patients with inconclusive sMIBI, avoiding unnecessary bilateral neck exploration. FCh might allow successful earlier surgery in patients with milder pHPT, with lower preoperative calcium and PTH levels and smaller pathological parathyroids.