Virtual MR Elastography with Diffusion-Weighted Imaging to Evaluate Chronic Kidney Disease Fibrosis and Dysfunction

Background Renal stiffness declines with chronic kidney disease (CKD) progression. MR elastography (MRE) enables quantitative assessment of tissue stiffness but requires external hardware, limiting routine clinical use. Purpose To develop a diffusion-derived virtual shear modulus (µdiff) for vibration-free renal virtual MR elastography (vMRE) and evaluate its ability to assess dysfunction and fibrosis across CKD stages. Materials and Methods This prospective single-center study included 53 healthy volunteers and 114 CKD patients, stratified by estimated glomerular filtration rate (eGFR) into early-stage CKD (CKD1–2, eGFR 60–120 mL/min/1.73 m2) and moderate-to-advanced CKD (CKD3–5, eGFR < 60 mL/min/1.73m2). Renal biopsy results performed for clinical care were collected. MRE and multi–b-value DWI (b = 0–2000 s/mm2) were performed on a 3T MRI (MAGNETOM Prisma, Siemens). Cortical shifted apparent diffusion coefficient (csADC) across b-value combinations correlated with cortical MR elastographic shear modulus (cµMRE) to identify the optimal combination and derive µdiff. Age-adjusted ANCOVA compared MRI parameters. Partial correlations with eGFR and Spearman correlations with interstitial fibrosis (IF) were performed. Diagnostic performance was evaluated by ROC analysis. Results A significant correlation (R2 = 0.94, P < 0.001) was observed between cµMRE and csADC derived from DWI at b-values of 200 (S200) and 800 (S800) s/mm2 (csADC200–800), yielding μdiffkPa=4.91 ln(S200/S800) +0.92.Cortical µdiff (cμdiff) correlated with eGFR (r = 0.602, P < 0.001) and IF (r = −0.809, P < 0.001). In biopsied patients (n = 51), cμdiff showed comparable diagnostic performance to cµMRE in differentiating mild from moderate-to-severe IF (AUC, 0.910 [95% CI: 0.822–0.998] vs 0.901 [95% CI: 0.813–0.989]; P > 0.05). Conclusion DWI-derived µdiff enables vibration-free renal vMRE, offering a stiffness-related surrogate that correlates with renal dysfunction and fibrosis. Diagnostic performance is comparable to MRE, including in early-stage CKD. If validated externally, this may provide a scalable alternative for CKD evaluation.