Preoperative ¹¹C-methionine PET/CT enables focused parathyroidectomy in MIBI-SPECT negative parathyroid adenoma.

Background: Precise preoperative localization is essential for focussed parathyroidectomy. The imaging standard consists of cervical ultrasonography (cUS) and (99m)Tc-MIBI-SPECT (MIBI-SPECT). (11)C-methionine positron emission tomography/computed tomography (Met-PET/CT) is a promising method for localizing parathyroid adenomas. The objective of our study was to elucidate whether additional Met-PET/CT increases the rate of focussed parathyroidectomy.

Methods: Fourteen patients with primary hyperparathyroidism (HPT) and three patients with tertiary HPT underwent cUS and MIBI-SPECT. Met-PET/CT was carried out in patients with negative MIBI results. Subsequent surgical strategy was adapted according to imaging results.

Results: cUS localized a single parathyroid adenoma in 10/17 patients (59 %), while MIBI-SPECT/CT identified 11/17 single adenomas (65 %). In the remaining six patients, Met-PET/CT identified five single adenomas. This step-up approach correctly identified single adenomas in 16/17 patients (94 %).

Conclusion: Met-PET/CT raises the rate of correctly localized single parathyroid adenomas in patients with negative cUS and MIBI-SPECT/CT and increases the number of focussed surgical approaches.