In vivo study of intravoxel incoherent motion imaging in assessing obesity-related kidney injury

To assess the feasibility of intravoxel incoherent motion imaging (IVIM) for detecting renal injury in an obese rat model and monitoring renal function after weight-loss therapy. Forty-two male rats were randomly divided into high-fat diet (HF) and standard diet (St) groups (n = 21 per group). After 14 weeks of feeding, each group was further divided into weight-loss therapy using interleukin-27 (IL-27) and phosphate-buffered saline (PBS) groups (n = 6 per group). Six rats were randomly selected from each group and underwent IVIM with 14 different b values and T2WI scanning at weeks 6, 8, 10, 12, 14, and 17 using a 3.0 T MRI clinical scanner. Quantitative IVIM paraments, including D, D*, and f values, were obtained from the different renal anatomical regions. In addition, urine protein, glomerular filtration rate (GFR) and renal histopathological staining were analyzed at different time points. One-way analysis of variance (ANOVA) or Kruskal-Wallis H test was used to compare IVIM parameters at different time points. The correlation between IVIM parameters, glomerular diameter, GFR, and urinary protein levels was computed using Pearson correlation analysis. The D, D* and f values of the HF group generally decreased from weeks 6–14, whereas GFR showed an increasing trend during this period. After weight-loss treatment, D, D* and f in the HF (IL-27) group were significantly higher than those in the HF (PBS) group (p < 0.05). IVIM parameters at week 14 were negatively correlated with glomerular diameter. No correlations were found between the IVIM parameters, GFR, and urinary protein levels. IVIM is a potential tool for noninvasive and longitudinally detection of early obesity-related renal injury and renal function improvement after weight-loss therapy.