Eur J Nucl Med Mol Imaging. 2025 May 8. doi: 10.1007/s00259-025-07307-x. Online ahead of print.
ABSTRACT
PURPOSE: Rejection, especially chronic rejection is a key factor influencing the prognosis of kidney transplantation patients. While 18F-fibroblast activation protein inhibitor (FAPI)-04 PET/CT has been widely utilized for diagnosing various diseases, its diagnostic efficacy in kidney transplant rejection remains unexplored.
METHODS: In this study, 24 kidney transplant recipients were prospectively enrolled and divided into a control cohort and a rejection cohort (KTR), which were further classified into acute rejection (AR), mixed rejection (MR), and chronic rejection (CR) subgroups. All patients underwent 18F-FAPI-04 PET/CT and 18F-FDG PET/CT scans, along with immunohistochemical FAP staining and Banff pathological scoring. The maximum and average standardized uptake values (SUVs) of the two imaging methods were calculated.
RESULTS: Compared with the control cohort, the KTR cohort showed significantly higher serum creatinine levels, lower estimated glomerular filtration rates, and lower hemoglobin levels. The SUVmax of 18F-FAPI-04 PET/CT in the allograft kidney cortex (AKC) and allograft kidney biopsy site (AKB) in the KTR cohort was significantly greater than that in the control cohort. The SUVmax of 18F-FDG PET/CT between the two cohorts was significantly different only in the AKC. For the KTR cohort, the SUVmax of 18F-FAPI-04 PET/CT in AKC and AKB was considerably greater than that of 18F-FDG PET/CT (5.5 vs. 2.8 and 3.6 vs. 2.5, respectively; both p < 0.01). In the CR cohort, the SUVmax of 18F-FAPI-04 PET/CT in the AKC, AKB, and allograft kidney medulla (AKM) was significantly greater (7.1, 5.3, and 3.2) than that of 18F-FDG PET/CT (2.5, 2.1 and 1.8) (p = 0.009, 0.009 and 0.016, respectively). The SUVmax of 18F-FAPI-04 PET/CT in AKB increased gradually in the AR, MR, and CR cohorts (2.8 vs. 3.6 vs. 5.3, p = 0.02). The above results were consistent with the SUVavg statistics. The number of FAP-positive stromal cells was different between the control and KTR groups and among the AR, MR, and CR subgroups.
CONCLUSION: 18F-FAPI-04 PET/CT outperforms 18F-FDG PET/CT in distinguishing kidney transplant rejection, especially chronic rejection.
PMID:40338305 | DOI:10.1007/s00259-025-07307-x
