Diagnostic Ability and Correlation of Digital ¹¹C-Methionine PET/CT in Primary Hyperparathyroidism with Inconclusive Standard Imaging

¹¹C-Methionine PET/CT is a promising method for detecting parathyroid lesions in patients with primary hyperparathyroidism (PHPT). We aimed to determine the diagnostic ability and correlation of digital ¹¹C-Methionine PET/CT for parathyroid lesions in patients with PHPT, particularly in cases where standard imaging methods yielded inconclusive results.

This retrospective analysis was conducted on patients diagnosed with PHPT who underwent digital ¹¹C-Methionine PET/CT imaging because of ambiguous results on standard imaging work-up (^99mTc-MIBI parathyroid scan and/or neck ultrasonography). Quantitative ¹¹C-Methionine PET/CT parameters, including maximum standardized uptake value (SUVmax), mean SUV (SUVmean), peak SUV (SUVpeak), parathyroid methionine volume (PMV), and whole methionine uptake (WMU: PMV multiplied by SUVmean) were calculated with various thresholds, and their correlations with biochemical and pathologic parameters were investigated.

This study included 22 consecutive patients (10 men and 12 women) with a median age of 64.0 years. The lesion detection rate and sensitivity of digital ¹¹C-Methionine PET/CT were 81.8% (18/22) and 100.0% (18/18), respectively. Quantitative analysis revealed that serum PTH (r = 0.490, P = 0.039) and serum calcium (r = 0.583, P = 0.011) were significantly correlated with PMV50%.

Digital ¹¹C-Methionine PET/CT offers good performance in the detection of parathyroid lesions in PHPT patients with inconclusive standard imaging work-up. The volume parameter of PMV50% significantly correlated biochemical parameters and can serve as a complementary diagnostic tool.