Renal perfusion in acute kidney injury with DCE-MRI: Deconvolution analysis versus two-compartment filtration model

Purpose: To investigate the results of different pharmacokinetic models of a quantitative analysis of renal blood flow (RBF) in acute kidney injury using deconvolution analysis and a two-compartment renal filtration model.Materials and methods: MRI data of ten male Lewis rats were analyzed retrospectively. Six animals were subjected to unilateral acute kidney injury and underwent perfusion imaging by dynamic contrast-enhanced MRI (DCE-MRI). Renal blood flow was estimated from regions-of-interest depicting the cortex in the DCE-MRI perfusion maps. The perfusion models were compared by a paired t-test and Bland-Altman plots.Results: No significant difference was found between the two compartment model and the deconvolution analysis (P = 0.2807). Differences between healthy and diseased kidney in the AKI model were significant for both methods (P < 0.05). A Bland-Altman plot showed no systematic errors, and values were equally distributed around the mean difference between the methods lying within the range of 1.96 standard deviations.Conclusion: Both quantification strategies could detect the kidneys that were impaired by AKI. When just aiming at RBF as a marker, a deconvolution analysis can provide similar values as the 2CFM. If functional parameters beyond RBF like glomerular filtration rate are needed, the 2CFM should be employed. (C) 2014 Elsevier Inc. All rights reserved

Quantitative renal perfusion measurements in a rat model of acute kidney injury at 3T: Testing inter- and intramethodical significance of ASL and DCE-MRI

Objectives: To establish arterial spin labelling (ASL) for quantitative renal perfusion measurements in a rat model at 3 Tesla and to test the diagnostic significance of ASL and dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) in a model of acute kidney injury (AKI).Material and Methods: ASL and DCE-MRI were consecutively employed on six Lewis rats, five of which had a unilateral ischaemic AKI. All measurements in this study were performed on a 3 Tesla MR scanner using a FAIR True-FISP approach and a TWIST sequence for ASL and DCE-MRI, respectively. Perfusion maps were calculated for both methods and the cortical perfusion of healthy and diseased kidneys was inter-and intramethodically compared using a region-of-interest based analysis.Results/Significance: Both methods produce significantly different values for the healthy and the diseased kidneys (

CORMs protect endothelial cells during cold preservation, resulting in inhibition of intimal hyperplasia after aorta transplantation in rats

P>Allograft vasculopathy is the leading cause for chronic transplant loss. We investigated if the addition of carbon monoxide releasing molecules (CORMs) to the preservation solution would protect the endothelium from cold preservation injury in an aortic transplantation model. In particular, we tested if CORM preserve vascular functioning and limit neo-intima formation following cold preservation (Cp). Abdominal aortas from Lewis or Fisher rats were subjected to Cp in University of Wisconsin (UW) solution to which 50 mu m of CORM-3 was added or not. Hereafter, whole mount staining, acetylcholine mediated vasorelaxation (AMV) and aortic transplantation was performed. In vitro CORM-3 protected human umbilical vein endothelial cells from Cp injury and prevented denudation and intercellular gap formation in aortic grafts. Cp resulted in loss of AMV of aorta segments. By contrast, AMV was preserved after the addition of CORM-3 during Cp. Two months after transplantation Cp of aorta grafts resulted in an increased adventitial remodelling and neo-intima formation. This was significantly blunted by CORM-3 in syngeneic recipients. Our study demonstrates that addition of CORM-3 to UW solution prevents endothelial damage, thereby maintaining vascular function directly after cold preservation. Hence, our findings might offer a novel strategy to prevent vascular damage during CP

Time course of contrast uptake in DCE-MRI.

<p>The lower panel shows two exemplary DCE-MRI time courses of the tissue signal intensities (<b>B</b>), i.e. the contrast uptake in two cortical ROIs. In the upper panel (<b>A</b>) the position of the according ROIs is depicted. One ROI was placed in the healthy kidney (green), one in the diseased kidney (red). Please note that choice and shape of the ROIs in this figure are different from the ones drawn for the data evaluation.</p

Donor dopamine treatment in brain dead rats is associated with an improvement in renal function early after transplantation and a reduction in renal inflammation

Brain death (BD) is associated with tissue inflammation. As dopamine treatment of BD donor rats reduces renal monocyte infiltration, we tested if this treatment affects renal function and inflammation in recipients. BD was induced in F344 rats and was maintained for 6 h in all experiments. Dopamine was given for 6 (DA6) or 3 h (DA3) from the onset of BD. Ventilated non-BD (NBD) and BD animals served as controls. Kidneys were transplanted into bilaterally nephrectomized Lewis recipients. Serum creatinine (s-crea) was measured and leukocyte infiltration was assessed 10 days after transplantation. One day after transplantation, s-crea was significantly reduced in recipients who received a renal allograft from dopamine treated BD or from NBD rats compared to BD vehicle (P <0.05). Ten days after transplantation, the number of infiltrating monocytes was significantly lower in grafts obtained from dopamine treated and from NBD rats (P <0.05). A reduced infiltration in these grafts was confirmed by Banff 97 classification. Cytokine-induced neutrophil-chemoattractant 1 and interleukin (IL)-6 mRNA expression were reduced in DA rats compared to BD controls. No difference for macrophage chemoattractant protein 1 and IL-10 were found. These findings may explain the salutary effect of donor dopamine treatment in renal transplantation