Value of dynamic MRI using the Ktrans technique for assessment of native kidneys in pre-emptive renal transplantation

Background: Different non-invasive imaging techniques such as Doppler ultrasonography and renal scintigraphy are commonly employed to assess allograft function and associated complications. However, all such methods lack sufficient specificity to discriminate between residual renal function of native kidneys. Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) evaluates signal dynamics during the passage of contrast material through the renal cortex, medulla, and collecting system. Purpose: To investigate the value of DCE 3T MRI using a quantitative pharmacokinetic parameter (Ktrans) for the assessment of native kidneys before and after pre-emptive renal transplantation. Material and Methods: Twenty-five consecutive patients with end-stage renal disease underwent DCE MRI before and 6 months after kidney transplantation. MRI was performed using a 3T scanner. Regions of interests were drawn over each kidney, encompassing the cortex and medulla but excluding the collecting system and any coexisting cysts. Parametric Ktrans values were automatically generated. Results: In the pre-transplantation group, mean Ktrans values for the right and left kidneys were 0.550.09 min(-1) and 0.44 +/- 0.15 min(-1), respectively. In the post-transplantation group, mean Ktrans values of the right and left kidneys were 0.27 +/- 0.07min(-1) and 0.25 +/- 0.10min(-1), respectively. There were statistically significant differences between right and left kidneys in terms of mean Ktrans values in the pre- and post-transplantation groups (P<0.001). Conclusion: Our preliminary results show that native kidneys were still functioning 6 months after transplantation. MR perfusion using Ktrans may constitute a non-invasive means of determination of the viability of native kidneys after renal transplantation.