Dynamics of thermoelastic expansion for native and coagulated ex-vivo bovine liver tissues

Dynamics of the thermoelastic expansion of native and coagulated ex-vivo bovine liver tissues after their irradiation by short laser pulses were studied. The differences in optical and thermo-mechanical properties of the native and coagulated samples such as their Gruneisen coefficient and optical attenuation depth were quantitatively determined. It was found that for coagulated ex-vivo bovine liver samples, the optical attenuation depth decrease by an average of 47%. Also significant differences were observed in the dynamics of thermoelastic expansion of the tissue surface. These differences can be potentially linked to differences in thermo-mechanical properties between native and coagulated samples. The changes in these properties may be used to understand the mechanisms of contrast between coagulated and non-coagulated tissues in optoacoustic imaging.