MO457: Diffusion-MRI Predicts Decline of Renal Function in Chronic Kidney Diseases and Kidney Allograft Patients

Abstract BACKGROUND AND AIMS Kidney cortical interstitial fibrosis is highly predictive of renal prognosis and is currently assessed by the evaluation of a biopsy. Diffusion-weighted magnetic resonance imaging is a promising non-invasive tool to evaluate kidney fibrosis. We recently adapted a diffusion-weighted imaging sequence, allowing for the discrimination between the kidney cortex and medulla. The cortico-medullary difference in apparent diffusion coefficient (ΔADC) correlated to histological interstitial fibrosis. The aim of this study was to assess whether ΔADC as measured with diffusion-weighted magnetic resonance imaging is predictive of renal function decline and dialysis in chronic kidney diseases (CKD) and kidney allograft patients. METHOD We performed a prospective study including 197 patients. We measured ΔADC in 43 CKD patients [estimated glomerular filtration rate (eGFR) 55 mL/min/1.73m2] and 154 kidney allograft patients (eGFR 53 ml/min/1.73m2). Patients underwent a renal biopsy and diffusion-weighted magnetic resonance imaging, within 1 week of biopsy. Follow-up was 2.2 years in median. During follow-up, laboratory parameters were measured. Primary outcome was defined as rapid decline of renal function (eGFR decline > 30% or dialysis initiation) during follow-up. RESULTS Patients with low ΔADC (<0 x10-6mm2/s) had 5.4 times more risk of rapid decline of renal function or dialysis [95% confidence interval (CI): 2.29–12.58; P < 0.001]. After correction for renal function at baseline and proteinuria, low ADC still predict renal function loss with a hazard ratio (HR) of 4.62 (P < 0.001, 95% CI 1.56–13.67). CONCLUSION We demonstrate in this study that low ΔADC is a predictor of renal function decline and dialysis initiation in CKD and kidney allograft patients, independent of baseline renal function and proteinuria.