NDT Advance Access originally published online on February 28, 2008
Nephrology Dialysis Transplantation 2008 23(8):2666-2672; doi:10.1093/ndt/gfn064
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The significance of BOLD MRI in differentiation between renal transplant rejection and acute tubular necrosis
1 Kidney Disease Center 2 Department of Radiology, The First Affiliated Hospital, College of Medicine, Zhejiang University, People's Republic of China
Correspondence and offprint requests to: Jianghua Chen, 79 Qingchun Road, Hangzhou, Zhejiang Province, 310003, People's Republic of China. Tel: +86-571-87236992; E-mail: chenjianghua{at}zju.edu.cn
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Abstract |
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Background. Blood oxygen level-dependent MRI (BOLD MRI) can be used to assess intra-renal oxygen bioavailability by measuring the R2* level, which reflects tissue deoxyhaemoglobin levels. This study was designed to identify the significance of BOLD MRI in differentiation of acute rejection (AR) and acute tubular necrosis (ATN) in patients within 6 months after kidney transplantation.
Methods. Eighty-two patients with normal graft function and 28 patients with biopsy-proven AR (n = 21) or ATN (n = 7) were enrolled. Patients with normal functioning allograft underwent BOLD MRI within 2 to 3 weeks post-transplantation, while patients with AR and ATN underwent BOLD MRI within 6 days before or after kidney transplant biopsy. Cortical R2* (CR2*) and medullary R2* (MR2*) levels were measured.
Results. The mean CR2* level was significantly higher in the ATN group (15.25 ± 1.03/s) compared to the normal group (13.35 ± 2.31/s, P = 0.028) and AR group (12.02 ± 1.72/s, P = 0.001). There was a significant difference also between the AR group and normal group on CR2* levels (P = 0.013). The mean MR2* level was significantly lower in the AR group (14.02 ± 2.68/s) compared to the normal group (16.66 ± 2.82/s, P < 0.001) and ATN group (19.47 ± 1.62/s, P < 0.001). There was also a significant difference between the ATN group and normal group on MR2* levels (P = 0.011). There were no correlations between characteristics such as patient age, post-operation time, post-biopsy time, Scr level, HB level, urine output volume, MAP level, CNI trough concentration and R2* levels, except between MAP level and CR2* level (P = 0.029).
Conclusions. BOLD MRI could be a valuable method to discriminate between AR and ATN by measuring tissue oxygen bioavailability in early kidney allograft dysfunction.
Keywords: acute rejection; acute tubular necrosis; kidney transplantation; magnetic resonance imaging (MRI); oxygen bioavailability
* Fei Han and Wenbo Xiao contributed equally in this study.
Received for publication: 28. 9.07
Accepted in revised form: 25. 1.08