The Role Of ¹⁸F-FCH PET/CT In Patients With Uremic Hyperparathyroidism Compared With ^99mTc-MIBI SPECT/CT And Ultrasonography

Objective:The aim of this study was to evaluate the diagnostic efficacy of ¹⁸F-fluorocholine(¹⁸F-FCH)PET/CT for uremic hyperparathyroidism（uHPT）compared to ^99mTc-MIBI SPECT/CT and ultrasonography（US）,and test the correlation between the necessary PET parameters and the laboratory parameters of patients.Materials and Methods:A total of 17 uHPT patients with stage 5chronic kidney disease（CKD）were prospectively enrolled.All patients underwent US,^99mTc-MIBI SPECT/CT,and ¹⁸F-FCH within 2 months and received surgical treatment.Visual and quantitative methods were used for image analyses.Intraoperative localization and postoperative histological results of the reference standard as well as the sensitivity,specificity,accuracy,positive predictive value（PPV）,and negative predictive value（NPV）of the three modalities were analyzed using Pearson’sχ²-tests.In addition,the diagnostic efficacy of ¹⁸F-FCH PET/CT for uHPT was evaluated.Furthermore,the independent sample T test was used to compare the difference in the lesion size between the positive group and the negative group.The relationships between PET parameters and laboratory parameters were assessed using the Spearman correlation coefficient.Results:A total of 63 parathyroid hyperplasia lesions were resected in17 uHPT patients and 53 lesions were detected using ¹⁸F-FCH PET/CT with no false-positive results.The sensitivity,specificity,accuracy,PPV,and NPV were 84.13%,100%,86.49%,100%,and 52.38%,respectively.In comparison,the corresponding values for ^99mTc-MIBI SPECT/CT and US were 63.49%,90.91%,67.57%,97.56%,and 30.30%and 61.90%,81.82%,64.86%,95.12%,and 27.27%,respectively.The volume of hyper-functioning parathyroid glands was significantly different between lesions positive in ¹⁸F-FCH PET/CT and negative in ¹⁸F-FCH PET/CT（mean volume 1.36±0.55 cm³ vs.0.83±0.26 cm³;P=0.019）.There were also significant differences in lesion volume between the ^99mTc-MIBI SPECT/CT positive groups and negative groups（mean volume 1.34±0.57cm³ vs.0.87±0.39 cm³;P=0.001）.US misidentified intrathyroidal parathyroid hyperplasia as thyroid nodules in three patients,while ¹⁸F-FCH PET correctly identified the anatomy.No significant associations were observed between total maximum standard uptake value(SUV_max),total metabolic tumor volume（MTV）and preoperative parathyroid hormone（PTH）,alkaline phosphataseALP),bone alkaline phosphatase（BAP）in uHPT patients.Conclusion:¹⁸F-FCH PET/CT was more sensitive and accurate for uHPT than ^99mTc-MIBI SPECT/CT and US,and had better preoperative diagnostic efficacy.The volume of hyper-functioning parathyroid glands was significantly different between lesions positive in ¹⁸F-FCH PET/CT and negative in ¹⁸F-FCH PET/CT.¹⁸F-FCH PET/CT is superior to ultrasound in the diagnosis of intrathyroidal parathyroid adenoma or hyperplasia,but it needs to be combined with PTH,SUVmax and the tracer uptake of other parathyroids.In addition,there was no significant correlation between PET parameters and laboratory parameters of uHPT patients.