A Comparison Study of Real-Time Ultrasound Elastography and Electron Microscopy for the Assessment of Liver Damage Induced by Brain Death

Abstract

The aim of this study was to investigate the specificity and sensitivity of real-time ultrasound elastography (RTE) in the evaluation of liver damage induced by brain death and the correlation with ultrastructural changes in liver tissue. Eleven RTE parameters before brain death and at 0, 3, 6 and 9 h after brain death in 12 miniature pigs were collected and analyzed, and the correlation of these parameters with electron microscopy results was explored. Six of the RTE parameters, namely, mean relative strain value within the region of interest, standard deviation of the relative strain value within the region of interest, area of low strain within the region of interest, complexity of low strain area within the region of interest, skewness and correlation, significantly differed among the time periods. Categorical data were analyzed using the χ2-test. Spearman's correlation analysis was used for evaluating correlations between RTE parameters and electron microscopy results, and the correlation coefficients (r) were calculated. Electron microscopy results revealed that liver damage gradually increased after brain death, with significant differences between 0 and 9 h (χ2 = 14.143, p value = 0.027). In addition, the six aforementioned RTE parameters significantly correlated with electron microscopy results, with the mean relative strain value within the region of interest being the strongest (r = –0.59, p value < 0.001) correlated parameter. RTE could provide preliminary assessment of liver damage induced by brain death, and correlates to ultrastructural changes in liver tissue.