Objectives: To evaluate effect of intravoxel incoherent motion (IVIM) imaging MRI on monitoring chronic allograft Dysfunction (CAD) in rat models.

Materials and Methods: For experimental group, twenty Fisher donor kidneys were transplanted into Lewis recipients. For control group, twenty Lewis kidneys were transplanted into Lewis recipients. Serum creatinine (sCr) was monitored every two weeks. All the rats underwent IVIM examination at 4, 12, 20 weeks after modeling. IVIM parameters were obtained using region of interests (ROI) drawn over the renal parenchyma. Five rats from both groups were chosen randomly for histological analysis at different time points. Histological changes in the kidney were evaluated by chronic allograft damage index (CADI) scores. Differences between groups were analyzed by Mann-Whitney U test, and the correlation of IVIM parameters with CADI was determined by Spearman correlation analysis.

Results: All the rats in the experimental group developed into CAD which was confirmed by histological analysis at 4 weeks after transplantation. However, sCr showed no significant difference between two groups until 10 weeks after modeling. IVIM revealed impairment of renal perfusion and diffusion in experimental group at 4 weeks after transplantation compared with the control group. And these changes became severe over time. IVIM parameters were significantly correlated with CADI (P<0.05)

Conclusions: Intravoxel incoherent motion imaging MRI is an effective technique for detecting early signs of CAD and monitoring progress of CAD in rat model.