Kidney allograft fibrosis is a marker of chronic kidney disease (CKD) and predicts functional decline, and eventual allograft failure. This study evaluates if spectral diffusion MRI can help detect early development and mild/moderate fibrosis in kidney allografts. In a prospective two-center study of kidney allografts, interstitial fibrosis and tubular atrophy (IFTA) was scored and eGFR was calculated from serum creatinine. Multi-b-value DWI (bvalues=0, 10, 30, 50, 80, 120, 200, 400, 800mm2/s) was post-processed with spectral diffusion, intravoxel incoherent motion (IVIM), and apparent diffusion coefficient (ADC). Connection between imaging parameters and biological processes was measured by Mann-Whitney U-test and Spearman's rank; diagnostic ability was measured by five-fold cross-validation univariate and multi-variate logistic regression. Quality control analyses included volunteer MRI (n=4) and inter-observer analysis (n=19). 99 patients were included (5013yo, 64M/35F, 39 IFTA=0, 22 IFTA=2, 20 IFTA=4, 18 IFTA=6, 46 eGFR0) in patients with normal/stable eGFR>45ml/min/1. 73m2 AUC (95\%CI) =0. 72 (0. 56, 0. 87), p=0. 007. Spectral diffusion detected mild/moderate fibrosis (IFTA=2-4) AUC (95\%CI) =0. 65 (0. 52, 0. 71), p=0. 023, as did ADC AUC (95\%CI) =0. 71 (0. 54, 0. 87), p=0. 013). eGFR, time-from-transplant, and allograft size could not. Interobserver correlation was >0. 50 in 24 out of 40 diffusion parameters. Spectral diffusion MRI showed detection of mild/moderate fibrosis and fibrosis before decline in function. It is a promising method to detect early development of fibrosis and CKD before progression.
Liu et al. (Fri,) studied this question.