The uptake of [¹⁸F]-fluorodeoxyglucose by the renal allograft correlates with the acute Banff scores of cortex inflammation but not with the 1-year graft outcomes

Introduction: [¹⁸F]FDG PET/CT noninvasively disproves acute kidney allograft rejection (AR) in kidney transplant recipients (KTRs) with suspected AR. However, the correlation of biopsy-based Banff vs. PET/CT-based scores of acute inflammation remains unknown, as does the prognostic performance of [¹⁸F]FDG PET/CT at one year post suspected AR.

Methods: From 2012 to 2019, 114 [¹⁸F]FDG-PET/CTs were prospectively performed in 105 adult KTRs who underwent per cause transplant biopsies. Ordinal logistic regression assessed the correlation between the extent of histological inflammation and the mean standardized [¹⁸F]FDG uptake values (mSUV_mean). Functional outcomes of kidney allografts were evaluated at one year post per cause biopsy and correlated to mSUVmean.

Results: A significant correlation between mSUV_mean and acute Banff score was found, with an adjusted R ² of 0.25. The mSUV_mean was significantly different between subgroups of "total i", with 2.30 ± 0.71 in score 3 vs. 1.68 ± 0.24 in score 0. Neither the function nor the survival of the graft at one year was statistically related to mSUV_mean.

Discussion: [¹⁸F]FDG-PET/CT may help noninvasively assess the severity of kidney allograft inflammation in KTRs with suspected AR, but it does not predict graft outcomes at one year.