Clinical Value and Limitations of [11C]-Methionine PET for Detection and Localization of Suspected Parathyroid Adenomas

Abstract

Purpose: The aim of this study was to assess the clinical value of [11C]methionine-PET (MET-PET) for detection and localization of parathyroid adenomas in patients without prior thyroidectomy. Methods: A retrospective analysis of patients with suspected hyperparathyroidism undergoing imaging with MET-PET was performed. Prior thyroidectomy was an exclusion criterion. 41 patients with a total of 49 MET-PET scans were included. MET-PET consisted of whole-body images obtained 15 - 20 min after injection of 430 ± 81 MBq of MET using a dedicated PET scanner. Imaging findings were validated by histology or other imaging studies and clinical follow-up on a lesion, side and location basis. Comparison of PET results to other imaging modalities including ultrasound, MIBI scintigraphy and morphological imaging (CT and/or MRI) and subgroup analysis of primary vs. secondary hyperparathyroidism was performed. Results: 23/49 PET scans revealed pathologic findings, whereas 26/49 scans were negative. Validation of PET findings for detection and localization of hyperthyroidism resulted in an overall sensitivity of MET-PET of 54%, 49% and 35% on a lesion, side and location basis, respectively. Sensitivity of MET-PET was inferior compared to ultrasonography (50% vs. 93%), MIBI scintigraphy (53% vs. 74%) and morphological imaging (52% vs. 74%). Subgroup analysis revealed higher sensitivity for MET-PET in sHPT than pHPT (62% vs. 43%; side basis). Conclusions: In patients with initial diagnosis of hyperparathyroidism and no prior thyroidectomy, the sensitivity of MET-PET for detection and localization of hyperparathyroidism is markedly lower compared to previous reports. While performance was better in sHPT, MET-PET can not be recommended for pHPT localization in this clinically relevant subcollective