Application of intravoxel incoherent motion diffusion weighted imaging for assessment of early chronic allograft nephropathy

OBJECTIVE: To investigate the feasibility and clinical application of intravoxel incoherent motion diffusion weighted imaging (IVIM-DWI) technique in non-invasive assessment for early chronic allograft nephropathy (CAN).
 Methods: A total of 23 renal allograft recipients were recruited from inpatients or outpatients according to the inclusion and exclusion criteria for this study. Recipients were divided into a CAN group (n=12, pathologically confirmed early CAN patients) and a control group (n=11, volunteers with long-term stable renal function). Abdominal MRI was performed on patients of renal allograft with a multi-b value DWI sequence. IVIM2b-new software was used for obtaining the IVIM-DWI quantitative parameter pseudo-color maps and the values of IVIM-DWI of renal parenchyma, including the pure diffusion coefficient (D), perfusion correlation diffusion coefficient (D*) and perfusion fraction (f). The IVIM quantitative parameters between the two groups were compared using independent sample t test. ROC analysis was performed when the differences in parameter were statistically significant and the area under curve (AUC) was calculated.
 Results: In IVIM bi-exponential analysis, The D value was significantly decreased in the CAN group compared with the control group (P 0.05). The AUC of D value for distinguishing the early CAN from the control were 0.784 with sensitivity and specificity at 58.3% and 90.9%, respectively.
 Conclusion: The IVIM-DWI quantitative parameter D can non-invasively assess early CAN to some extent. IVIM-DWI technique is expected to be an effective, easy and non-invasive method to detect early CAN, and assist early diagnose as well as dynamically monitor CAN.