Noninvasive assessment of early kidney allograft dysfunction by blood oxygen level-dependent magnetic resonance imaging

Transplantation. 2006 Sep 15;82(5):621-8. doi: 10.1097/


Background: Blood oxygen level-dependent (BOLD) magnetic resonance imaging (MRI) is a noninvasive method to assess tissue oxygen bioavailability, using deoxyhemoglobin as an endogenous contrast agent. We hypothesized that BOLD-MRI could accurately discriminate different types of rejection early after kidney transplantation.

Methods: Twenty-three patients underwent imaging in the first four months posttransplant. Five had normal functioning transplants and 18 had biopsy-proven acute allograft dysfunction (acute tubular necrosis [ATN, n=5] and acute rejection [n=13] including borderline rejection: n=3; IA rejection: n=4; IIA rejection: n=6: C4d(+) rejection: n=9).

Results: Mean medullary R2* (MR2*) levels (a measure directly proportional to tissue deoxyhemoglobin levels) were significantly higher in normal functioning allografts (R2*=24.3/s+/-2.3) versus acute rejection (R2*=16.6/s+/-2.1) and ATN (R2*=20.9/s+/-1.8) (P<0.05). The lowest MR2* levels were observed in acute rejection episodes with vascular injury i.e. IIA and C4d (+). Similarly, the lowest medullary to cortical R2* ratios (MCR2*) were present in allografts with IIA (1.24+/-0.05) and C4d(+) rejection (1.26+/-0.06). ROC curve analyses suggested that MR2* and MCR2* values could accurately discriminate acute rejection in the early posttransplant period.

Conclusions: BOLD-MRI demonstrated significant changes in medullary oxygen bioavailability in allografts with biopsy-proven ATN and acute rejection, suggesting that there may be a role for this noninvasive tool to evaluate kidney function early after transplantation.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Biopsy
  • Female
  • Graft Rejection / epidemiology
  • Graft Survival / physiology
  • Humans
  • Kidney Function Tests
  • Kidney Transplantation / adverse effects*
  • Kidney Transplantation / pathology
  • Kidney Transplantation / physiology*
  • Magnetic Resonance Imaging
  • Male
  • Middle Aged
  • Oxygen / blood*
  • Postoperative Complications / blood
  • Postoperative Complications / pathology
  • Postoperative Complications / physiopathology*
  • Transplantation, Homologous


  • Oxygen