Finite element models of cardiovascular system components (such as the heart valve or blood vessels) are based on in vivo organ geometries obtained from 3D imaging systems such as computed tomography (CT) or magnetic resonance imaging (MRI).
Although medical imaging techniques offer accurate in vivo visualization of 3D patient-specific geometries, the geometries are under a loaded state (for example, in the presence of blood pressure) and lack in vivo stress/strain field information. Therefore, a nonlinear analysis performed directly on the geometry to simulate additional loading leads to inaccurate results.
In such cases, an inverse-solving analysis uses input geometry consisting of images where the models are already in a deformed shape under applied loads. The material properties and applied loads are known. The analysis can then determine the following:
The organ geometries at zero-pressure state (zero-pressure configuration)
The stress and strain fields on the in vivo organ geometries (the input geometries)
The behavior and response of the organ geometries when increasing the loading and taking accounting for prestressed effects