Inverse finite element characterization of soft tissues

Area of Science:

• Biomechanics
• Biomaterials Science
• Computational Mechanics

Background:

• Accurate characterization of biological soft tissue material properties is crucial for surgical planning and medical device design.
• Existing methods may lack precision or in vivo applicability.
• Understanding tissue viscoelasticity is key to modeling its mechanical behavior.

Purpose of the Study:

• To present a novel tissue aspiration method for in vivo determination of biological soft tissue material parameters.
• To model soft biological tissue as a viscoelastic, non-linear, nearly incompressible, isotropic continuum.
• To validate the developed aspiration method experimentally.

Main Methods:

• An explicit axisymmetric finite element simulation of the aspiration experiment was employed.
• A Levenberg-Marquardt algorithm was used for inverse parameter determination.
• The method was validated using a synthetic material and in vivo/ex vivo experiments on human uteri.

Main Results:

• The study successfully developed and validated a tissue aspiration method for in vivo material parameter determination.
• Finite element simulations coupled with inverse parameter estimation provided accurate material property assessment.
• Experimental validation with synthetic and human uterine tissues demonstrated the method's efficacy.

Conclusions:

• The presented tissue aspiration method offers a reliable approach for in vivo characterization of soft tissue mechanics.
• This technique holds potential for improving intra-operative assessments and the design of tissue-interfacing devices.
• The quasi-linear viscoelastic model effectively captures the complex behavior of soft biological tissues.