Mechanical soft tissue property validation in tissue engineering using magnetic resonance imaging experimental research.

RATIONALE AND OBJECTIVES To perform magnetic resonance imaging (MRI) scans regarding material parameter and model validation in computational simulations of mechanical interaction of human soft-tissue with body-supporting devices, enhanced medical prognosis in pressure sore prophylaxis, and comfort optimization in automotive and aircraft seating. MATERIALS AND METHODS In vivo human gluteal fat and passive muscle tissue material parameters of a volunteer evaluated via combined MRI numerical method and body-supporting foam material parameters employed in finite element (FE) simulations of tissue-support interaction were verified by a defined loading scenario using MRI. MRI of the loaded configurations were performed and compared with simulation results for displacement field information. RESULTS Deformation of gluteal skin/fat and passive muscle-tissue and support material under interacting loading using numerical simulation complied with the MRI results. Accordance was found for deformed skin surface and internal fat-muscle tissue boundaries by superimposing experimental and numerical outputs. Further evidence of established through in vivo gluteal tissue parameters was thus provided and tissue material isotropy assumption was shown for use in simulated buttock loading interactions. Additionally, a new concept of FE model validation regarding non-MRI-sensitive materials such as polyurethane foam was introduced comprising peripheral surface visualization. CONCLUSION Imaging techniques are essential in biomechanical modeling and provide key information regarding model validation and validity assessment.