An inverse approach to determining myocardial material properties

Area of Science:

• Biomedical Engineering
• Computational Mechanics
• Cardiovascular Physiology

Background:

• Passive myocardial material properties are crucial for understanding heart function.
• Previous methods relied on in vitro testing or pressure-volume relationships in intact hearts.
• Accurate in vivo measurement of these properties remains a challenge.

Purpose of the Study:

• To develop and validate a new inverse method for determining passive myocardial material properties in vivo.
• To couple a p-version finite element model with magnetic resonance imaging (MRI) derived strain data.
• To solve an inverse boundary value problem for nonlinear, nonhomogeneous material parameters.

Main Methods:

• Utilized a p-version finite element model of the heart.
• Integrated a nonlinear optimization algorithm with dense transmural strain data from MRI radiofrequency tissue tagging.
• Employed a novel optimization algorithm calculating derivatives via forward finite element solutions.

Main Results:

• Successfully determined known true material parameters within a small tolerance in validation tests.
• Demonstrated that random noise does not significantly affect the stability of the inverse solution.
• Validated the efficacy of the inverse material identification approach for in vivo conditions.

Conclusions:

• The developed inverse method can accurately determine unknown material parameters for in vivo myocardial behavior.
• This approach offers a promising non-invasive technique for assessing passive cardiac material properties.
• The findings pave the way for improved diagnostic and therapeutic strategies in cardiovascular medicine.