Optimal scan time for evaluation of parathyroid adenoma with 18F-choline PET/CT
Introduction: Parathyroid adenomas are the most common cause of primary hyperparathyroidism (PHP).18F-choline (FCH) is one of the PET markers of cellular proliferation. The aim of this study was to assess the possibility of preoperative localization of parathyroid glands in patients with PHP with FCH PET/CT and to optimize the FCH PET/CT scanning protocol.
Methods: 27 patients with PHP were enrolled in this study. A triple-phase static PET/CT imaging was performed five minutes, one and two hours after the administration of FCH. Regions of interest (ROI) were placed in parathyroid and thyroid tissue. SUVmean, retention index (RI) and lesion contrast (LC) for parathyroid and thyroid tissue were calculated.
Results: Sensitivity and specificity of FCH PET/CT were 93% and 100%.SUVmean in abnormal parathyroid tissue was significantly higher in the second (p=0.0008) and in the third phase (p<0.0001) in comparison to the thyroid tissue. Average RI, decreased between first and second phase and slightly increased between second and third phase in abnormal parathyroid tissue and decreased over all phases in thyroid tissue. The difference in LC of abnormal parathyroid and thyroid tissue was statistically significant between all three phases.
Conclusion: FCH PET/CT imaging provides a reliable preoperative localization of parathyroid glands in patients with PTH. The optimal time to performed FCH PET/CT scan is the one hour after administration of the FCH.