Interstitial fibrosis (IF) is the common pathway of chronic kidney injury in various conditions. Magnetic resonance imaging (MRI) may be a promising tool for the noninvasive assessment of IF in renal allografts.
Methods: This prospective trial was primarily designed to investigate whether the results of T1-weighted MRI associate with the degree of IF. Thirty-two kidney transplant recipients were subjected to 1.5-Tesla MRI scans shortly before or after routine allograft biopsies. MRI parameters [T1 and T2 relaxation times; apparent diffusion coefficient (ADC)] were assessed for cortical and medullary sections.
Results: Advanced IF (Banff ci score >1) was associated with higher cortical T1 (but not T2) values [1451 (median; interquartile range: 1331-1506) versus 1306 (1197-1321) ms in subjects with ci scores ≤1; P = 0.011; receiver operating characteristic area under the curve for prediction of ci > 1: 0.76]. In parallel, T1 values were associated with kidney function and proteinuria. There was also a relationship between IF and corticomedullary differences on ADC maps (receiver operating characteristic area under the curve for prediction of ci ≤ 1: 0.79).
Conclusions: Our results support the use of MRI for noninvasive assessment of allograft scarring. Future studies will have to clarify the role of T1 (and ADC) mapping as a surrogate endpoint reflecting the progression of chronic graft damage.
Copyright © 2020 The Author(s). Transplantation Direct. Published by Wolters Kluwer Health, Inc.