Noninvasive assessment of metabolic syndrome–related renal injury using magnetic resonance imaging fat fraction and apparent diffusion coefficient: A cross-sectional study

Objective To investigate the value of mDIXON-Quant imaging–based proton density fat fraction and diffusion-weighted imaging in detecting metabolic syndrome–related renal injury. Methods A total of 24 patients with metabolic syndrome and 21 age-matched healthy volunteers were prospectively enrolled in this study and underwent mDIXON-Quant imaging and diffusion-weighted imaging. The participants were divided into those with metabolic syndrome–normal estimated glomerular filtration rate (eGFR; expressed in mL/min/1.73 m 2 ) (n = 10, eGFR ≥ 90; metabolic syndrome group 1), those with metabolic syndrome–mildly decreased eGFR (n = 14, 60 ≤ eGFR < 90; metabolic syndrome group 2), and controls (n = 21). Observer A measured radiological data, including renal fat fraction, renal apparent diffusion coefficient, liver fat fraction, and perirenal fat fraction. Statistical analyses were performed to compare the imaging parameters among groups, assess correlations with eGFR, determine the diagnostic performance of renal fat fraction using receiver operating characteristic analysis, identify eGFR predictors via multivariate analysis, and evaluate inter- and intra-observer consistency. Results Renal fat fraction was significantly elevated in metabolic syndrome groups compared with that in the control group (control: 3.83% ± 0.52%; metabolic syndrome group 1: 4.61% ± 0.59%; and metabolic syndrome group 2: 5.32% ± 0.47%; p < 0.001). No significant difference was observed in the apparent diffusion coefficient among the three groups ( p = 0.938). Renal fat fraction exhibited an inverse correlation with eGFR ( r = −0.688) across the study cohort. No significant correlation was observed between apparent diffusion coefficient values and eGFR ( r = −0.104, p = 0.495). The area under the curve value was 0.94 (95% confidence interval: 0.87–1.00) for distinguishing controls from patients with metabolic syndrome. A multivariable-adjusted analysis revealed a significant negative association between the renal fat fraction and eGFR (standardized B = −12.59). The interclass correlation coefficient between observers A and B for renal fat fraction measurements was 0.86. Conclusion mDIXON-Quant imaging exhibits greater clinical utility than diffusion-weighted imaging in detecting metabolic syndrome–related renal injury and may serve as a promising imaging tool for monitoring renal lipid deposition and therapeutic efficacy in lipid-mediated renal injury.