Contribution of Diffusion MRI in Renal Graft Transplantation

While renal graft outcomes were really improved for the last decade, long time outcomes remains stable. Indeed, at 10 years after transplantation, the renal graft survival rate reaches 50%. The chronic allograft nephropathy is the main cause of renal graft loss. Other features such as acute allograft rejection, delayed renal recovery and anti-human leukocyte antigen (anti-HLA) antibodies are associated with poor renal graft survival prognosis. Renal graft protocol biopsies at 3 and 12 months after transplantation are valuable to detect precociously renal injuries at a reversible stage before clinical manifestation. However, renal biopsy is an invasive examination with hemorrhagic risk. Diffusion MRI could be a non-invasive diagnostic tool allowing the early detection of renal injuries, especially allograft rejection without hemorrhagic risk. This tool could be applied routinely to the renal allograft recipient in replacement of protocol biopsies. Here, aim of this study is to correlate the results from diffusion MRI of renal graft with pathologic findings from protocol renal graft biopsies. In this view, the investigators include prospectively all recipients of renal transplantation who beneficiate of a protocol renal graft biopsy without barrier to peform MRI examination. Thus, the investigators exclude patients who are not be able to beneficiate of a MRI examination and patient obstacle to renal graft biopsy. Expected results are the Banff classification from the histopathologic analysis of biopsies. The expected results for MRI examination are signal intensity, diffusive coefficient, anisotropy fraction and change of the diffusion way. Next, the investigators search an association between these features by statistical analysis (Wilcoxon test, Chi², Fisher, Pearson or Spearman). The investigators performed this study since 01/06/2014 and projected end-time to 01/06/2017.