MR validation of soft tissue deformation as modeled by nonlinear finite element analysis

Finite element analysis (FEA) can potentially be used to predict soft tissue motion for the purpose of elasticity reconstruction and data fusion applications. For a simple phantom that simulated a soft tissue, FEA accurately predicted motion for surface deformations on the order of 11%. A computer controlled Magnetic Resonance (MR) compatible compression apparatus provided precise, time varying compression to a phantom. The motion of the phantom was measured with MR by acquiring velocity images throughout the cycle of compression. The phantom geometry was modeled with a finite element mesh and the mechanical properties of the phantom material were measured and incorporated in the finite element model. A static deformation was applied to the finite element model of the phantom and the internal motion was calculated. The motion as calculated by the finite element analysis was compared to the motion measured with MR and there was good agreement.