Dielectric spectrogram for evaluating ischemic microstructural changes of the liver in simple cold preservation.

Abstract

Monitoring ischemic liver injury is important in liver transplantation. We previously reported that dielectric properties were correlated with tissue adenosine triphosphate during liver preservation; however, it is unknown what the changes in dielectric properties are based on. Using rats, we studied the relationship between dielectric parameters and microstructural changes in liver tissues during preservation. We serially measured the percent decrease in conductivity and the percent increase in relative permittivity in rat livers, and determined the areas of cellular and extracellular components using a charge-coupled device microscope and an NIH image. Thereafter, we evaluated the relationship between dielectric parameters and microstructural changes in the liver tissues. A positive linear and exponential correlation was found between the percent decrease in conductivity and the percent decrease in extracellular components ( P < 0.01). A positive linear and exponential correlation was also found between the percent increase in relative permittivity and the percent increase in cellular components ( P < 0.01). Our results suggest that the serial changes in tissue conductivity and the relative permittivity reflect changes in liver tissue microstructures during cold preservation.