Multiscale fluid-structure interaction simulation of patient-specific left ventricle fluid dynamics with fictitious elastic structure regularization

We propose a new approach for the data assimilation and simulation of patient-specific left ventricle fluid dynamics based on cardiac magnetic resonance images. The movement of the ventricle is captured by a set of tracking points on the endocardium identified from a time series of magnetic resonance images. The displacement of the endocardium is interpolated using radial basis functions to produce a smooth global deformation field in both space and time. To regularize the motion of the fluid inside the ventricle we impose the displacement on a fictitious elastic structure surrounding the fluid domain, and then solve the problem in a fluid-structure interaction formulation. This allows our simulation to provide physiological flow and pressure levels inside the left ventricle. In order to have physically reasonable outflow conditions, we couple the left ventricle to a geometrical multiscale model of a network of one-dimensional models, where we can simulate the pressure and flow rate waveforms in the major arteries. The end result is a baseline model for the left ventricle that captures the basic fluidic phenomena and that can in the future be extended to consider clinical patient-specific studies by integrating more complex models into the multiscale framework.