Assessment of Tissue Impedance Postmortem Using Needle Measurement and Computation Modelling

Area of Science:

• Biomedical Engineering
• Organ Transplantation
• Tissue Engineering

Background:

• Global organ transplant shortages necessitate improved preservation and diagnostic methods.
• Understanding tissue degradation post-procurement is crucial for successful long-term transplant outcomes.
• Current methods like biopsies are invasive and do not provide continuous real-time data.

Purpose of the Study:

• To investigate the potential of electric bioimpedance measurement as a tool for assessing organ quality.
• To develop a computational model for translating in-tissue impedance measurements into electrical properties.
• To characterize time-, temperature-, and depth-dependent changes in kidney tissue electrical properties.

Main Methods:

• Developed a homogeneous 3D computational model in COMSOL Multiphysics.
• Collected in-tissue impedance measurement time series from porcine kidneys (procurement to 72h post-procurement).
• Translated impedance data into tissue conductivity, relative permittivity, and capacitance time series.

Main Results:

• The computational model successfully translated experimental impedance data into electrical property time series.
• Identified time-, temperature-, and tissue depth-dependent changes in electrical properties.
• Established value ranges and trends indicative of kidney function and degradation processes.

Conclusions:

• Needle-based bioimpedance measurement provides a minimally invasive, real-time method for assessing kidney tissue condition.
• Computational modeling of bioimpedance data facilitates the characterization of tissue degradation during organ preservation.
• The findings offer valuable insights for improving kidney transplant quality assessment and preservation strategies.