Bennet Johannes Ulrich Hensen, Presenter: Nothing to Disclose

Song Rong MD, Abstract Co-Author: Nothing to Disclose

Marcel Gutberlet DiplPhys, Abstract Co-Author: Nothing to Disclose

Matti Peperhove MD, Abstract Co-Author: Nothing to Disclose

Susanne Tewes MD, Abstract Co-Author: Nothing to Disclose

Martin Meier PhD, Abstract Co-Author: Nothing to Disclose

Sibylle von Vietinghoff, Abstract Co-Author: Nothing to Disclose

Michael Mengel, Abstract Co-Author: Nothing to Disclose

Frank K. Wacker MD, Abstract Co-Author: Research Grant, Siemens AG Research Grant, Pro Medicus Limited

Dagmar Hartung MD, Abstract Co-Author: Nothing to Disclose

Faikah Gueler MD, Abstract Co-Author: Nothing to Disclose

Katja Hueper, Abstract Co-Author: Nothing to Disclose

To investigate whether multiparametric MRI allows detection of acute renal allograft rejection (AR) and to compare MRI parameters with renal histopathology.

AR was induced by allogenic kidney transplantation (ktx) of C57Bl/6-kidneys to Balb/c-mice (n=6). Animals after isogenic ktx (C57Bl/6-kidneys to C57Bl/6-mice) served as controls. Mice were examined 3 weeks after ktx using a 7T MRI. The multiparametric MRI protocol consisted of perfusion imaging (FAIR EPI ASL), T1- (IR EPI) and T2-mapping (multi echo TSE) and diffusion weighted imaging (7 b-values=0-700 s/mm2). Animals were sacrificed after the MRI. Renal histology (Banff) and macrophage and T-cell infiltration (immunohistochemistry&FACS) were examined. Differences between groups were evaluated using unpaired t-tests and MRI parameters were compared with amount and composition of cell infiltrates. Values are given as mean±SEM.

Animals after allogenic ktx developed an acute T-cell-mediated rejection (Banff IIB/III), whereas renal histology after isogenic ktx was unremarkable. Renal perfusion was impaired in animals with allogenic compared to isogenic ktx (56±7 vs 293±44 ml/(min*100g); p<0.001). After allogenic ktx T1- and T2-times of the outer stripe of the outer medulla were increased compared to isogenic ktx (T1: 1938±53 ms vs 1350±27 ms, p<0.001; T2: 60.1±1.9 ms vs 45.7±1.1 ms, p<0.001). ADC-values were significantly lower in animals with AR (1.38±0.14*10-3 mm2/s) compared to controls (1.82±0.05*10-3 mm2/s, p<0.05). Correspondingly,  in allogenic animals infiltration of macrophages (score 3.8±0.2 vs 1.1±0.2; p<0.001) and T-cells (score 3.4±0.2 vs. 1.0±0; p<0.001) was significantly more pronounced than in controls. FACS-analysis revealed an increased percentage of infiltrating T-cells (38.8±4.0% vs 5.5±2.2%; p<0.001).  

Multiparametric functional MRI allows detection of acute renal AR. AR was characterized by renal perfusion impairment, increase of T1- and T2-values, interpreted as tissue edema, and reduced ADC due to cellular infiltration. These changes correspond well to renal histology and amount of infiltrating cells.

Multiparametric functional MRI allows non-invasive diagnosis of acute renal allograft rejection. It may additionally help to differentiate renal allograft pathologies such as acute rejection (allogenic ktx) and ischemia/reperfusion injury (isogenic ktx) and to facilitate therapy decisions in an early state.

Hensen, B, Rong, S, Gutberlet, M, Peperhove, M, Tewes, S, Meier, M, von Vietinghoff, S, Mengel, M, Wacker, F, Hartung, D, Gueler, F, Hueper, K, Multiparametric Functional MRI for Assessment of Acute Renal Allograft Rejection in Mice—Comparison with Renal Histology.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14014414.html