DCD Pigsʼ Kidneys Analyzed By MRI to Assess Ex-Vivo Their Viability.

Abstract

Background: MRI Gadolinium-perfusion was applied in simulated Donation after Cardiac Death in porcine kidneys to measure intra-renal perfusion. ATP resynthesis during Oxygenated Hypothermic Perfusion was compared to evaluate the “ex-vivo organ viability”. Adenine Nucleotide (AN) was measured by 31P Nuclear Magnetic Resonance spectroscopy. Whereas this latter technique requires sophisticated hardware, Gadolinium-perfusion can be realized using any standard proton-MRI scanner. The aim of this work was to establish a correlation between the two methods. Methods: 22 porcine kidneys presenting up to 90 min Warm Ischemia were perfused with oxygenation at 4°C using our Magnetic Resonance-compatible machine. During the perfusion, 31P NMR spectroscopy and Gadolinium-perfusion sequences were performed. Measures obtained from the Gadolinium-perfusion were the speed of elimination of the cortical Gadolinium and the presence or absence of a corticomedullar shunt. For ATP resynthesis analysis, 31P Chemical Shift Imaging (CSI) was acquired and analyzed. All the kidneys have been submitted to histologic examination. Results: ATP resynthesis was observed in all organs presenting a cortical Gadolinium elimination slope of (-)23 ° or greater. In organs with lower Gadolinium elimination, no AN, or only precursors were detected. This study reveals a link between the two methods, and demonstrates “ex vivo viability” in 93% of the analyzed kidneys. Benefits and side effects of both methods are discussed. Conclusion: Oxygenated hypothermic perfusion enables the evaluation of kidneys in DCD simulated situation; Gadolinium-perfusion can be introduced into any center equipped with a proton MRI scanner allowing results superposable with ATP measurement.