In vivo liver tissue mechanical properties by Transient Elastography: comparison with Dynamic Mechanical Analysis

Area of Science:

• Biomedical Engineering
• Biophysics
• Materials Science

Background:

• Accurate liver mechanical properties are crucial for medical modeling and impact biomechanics.
• In vitro data often differs from in vivo properties due to post-mortem changes.
• Quantitative comparison between in vivo and in vitro liver elasticity is lacking.

Purpose of the Study:

• To compare in vivo and in vitro porcine liver mechanical properties.
• To evaluate Transient Elastography (TE) and Dynamic Mechanical Analysis (DMA) methods.
• To investigate the influence of post-mortem time and boundary conditions on liver viscoelasticity.

Main Methods:

• Shear modulus (G) measured using TE and DMA on porcine liver.
• Measurements performed both in vivo and in vitro.
• Analysis of liver tissue behavior in the 0.1–4 Hz frequency range.

Main Results:

• TE and DMA methods showed agreement for in vitro liver elastic properties.
• Porcine liver tissue can be modeled by a two-mode relaxation model.
• Liver tissue is homogeneous, isotropic, and predominantly elastic.
• Viscoelastic properties significantly altered by post-mortem time and boundary conditions.

Conclusions:

• TE and DMA are reliable methods for measuring liver elasticity.
• Liver mechanical properties are time- and condition-dependent.
• Findings are critical for accurate computational modeling of the liver.