T1 mapping magnetic resonance imaging predicts decline of kidney function

Abstract Background Renal cortical interstitial fibrosis, typically assessed by biopsy, is crucial for kidney function prognosis. MRI is a promising method to assess fibrosis non-invasively. Diffusion-Weighted (DW) MRI correlates with renal fibrosis and predicts kidney function decline in chronic kidney disease (CKD) and kidney allograft patients. This study evaluates whether T1 and T2 mapping predict kidney function decline and if their simultaneous use enhances the predictive power of a DW-MRI-based model. Methods We prospectively included 197 patients (42 CKD, 155 allograft kidneys). Each underwent a biopsy followed by multiparametric MRI without contrast within a week. Over a median follow-up of 2.2 years, laboratory parameters were recorded. Primary endpoint was a rapid decline in kidney function (GFR reduction > 30%) or replacement therapy initiation. T1 and T2 mapping sequences’ ability to predict poor renal outcome was examined using multivariable Cox regression models, incorporating MRI-derived parameters, eGFR, and proteinuria. Results Renal outcome occurred in 54 patients after a median of 1.1 years (IQR 0.9–2.1). Univariable survival analysis showed cortical T1 was associated with poor renal outcome (HR: 3.02 [1.44–6.33]), while T2 sequences had no significant predictive value. Adding cortical T1 to the established model (ΔADC, eGFR, proteinuria) did not improve the hazard ratio (from 4.62 [1.56–13.67] to 4.36 [1.46–13.02]) and marginally increased Harrell's C-index (0.77 to 0.79). Adjusting the regression model for ΔT2 yielded no enhancement in predictive power. Conclusions Cortical T1 is strongly associated with poor renal outcome but did not enhance prognostic power of the DW-MRI-based model.