L.M. Skrip, L. Boerger, K.A. Walter, A. Arnold, L.A. Böhne, E. Keshi, A.S. Pietsch, N. Raschzok, T.A. Auer, U. Fehrenbach, F. Krenzien, J. Pratschke, I.M. Sauer, J. Guo, J. Braun, M. Tzschätzsch, I. Sack, K.H. Hillebrandt, and S. Moosburner evaluated whether magnetic resonance elastography (MRE) can assess liver graft quality after normothermic machine perfusion (NMP) in the context of liver transplantation. Because of organ shortages, extended criteria donor livers are increasingly used, but factors such as older donor age and prolonged cold ischemia time (CIT) can impair graft quality.
Using a rat liver NMP model, 24 livers underwent 6 or 12 hours of cold ischemia followed by 6 hours of NMP. Ex vivo multifrequency MRE was used to measure liver viscoelastic properties, including the power-law exponent (α) and shear modulus (μ).
Results showed that all liver samples displayed predominantly viscous-fluid characteristics (α > 0.5). The highest α values were found in young livers with short CIT, indicating better tissue properties, while older livers with prolonged CIT had significantly lower α values, suggesting impaired viscoelasticity. Additionally, shear modulus was lowest in young livers with short CIT, distinguishing them from the other groups.
Overall, the findings indicate that extended cold ischemia and older donor age impair liver tissue mechanics even after NMP. MRE may serve as a complementary imaging tool alongside MRI and histological analysis to evaluate liver graft quality during machine perfusion.
The paper "Assessing age and cold ischemia effects on liver tissue viscoelastic properties: Implications for graft quality assessment with MRE during machine perfusion" is available in Journal of the Mechanical Behavior of Biomedical Materials 2026; 175: 107291.