Rejection evaluation after renal transplantation using MR diffusion tensor imaging

Area of Science:

• Radiology
• Nephrology
• Transplant Surgery

Background:

• Current monitoring of renal allograft dysfunction relies on serum creatinine, Doppler ultrasound, or biopsy.
• Diffusion-based magnetic resonance imaging (MRI) methods offer a potential non-invasive approach for assessing post-transplant renal function.

Purpose of the Study:

• To evaluate the utility of fractional anisotropy (FA) measurements derived from MRI diffusion tensor imaging (DTI) in identifying acute rejection in renal transplant recipients.

Main Methods:

• Diffusion tensor imaging (DTI) MRI was performed on 42 renal transplant patients (21 with graft dysfunction, 21 with normal function).
• Fractional anisotropy (FA) values were measured in the renal cortex and medulla at multiple poles.
• MR examinations utilized a 1.5-T MRI scanner with b-values of 0 and 800 s/mm².

Main Results:

• Medulla FA values were significantly different between patients with acute rejection (0.19 ± 0.02) and those with normal graft function (0.22 ± 0.05, P = 0.017).
• Renal cortex FA values showed no significant difference between the two groups (0.18 ± 0.04 vs. 0.18 ± 0.04, P = 0.97).

Conclusions:

• MR DTI-derived fractional anisotropy (FA) measurements in the renal medulla show potential for non-invasive functional assessment of transplanted kidneys.
• Renal medulla FA values correlate with allograft function, suggesting utility in monitoring transplant status.
• Renal cortex FA values did not correlate with allograft function in this study.