High Resolution Simulation of Diastolic Left Ventricular Hemodynamics Guided by Four-Dimensional Flow Magnetic Resonance Imaging Data

We investigate the diastolic hemodynamics in a patient-specific left ventricle (LV) of a healthy subject using four dimensional flow magnetic resonance imaging (4D-Flow MRI) measurement and numerical simulation. From four dimensional Cardiac Magnetic Resonance (CMR) Imaging data, the kinematics of the endocardium is reconstructed. The endocardial kinematics and the time varying velocity distribution from 4D-Flow MRI at the mitral orifice are prescribed as boundary conditions for the numerical simulation. Both 4D-Flow MRI data and numerical results show the classical formation of the mitral vortex ring (MVR) during E-wave filling. The in-vivo data reveals that a large three-dimensional vortex structure forms near in the mid-level region of LV during diastasis (mid-level vortex). This mid-level vortex is formed simultaneously with the MVR and has not been reported in the literature. Quantitative comparison shows that the computed kinetic energy (KE) evolves in a similar manner to one derived from 4D-Flow MRI data during early E-wave filling. Both computational and measurement data show that the peak KE at E-wave is approximately 8 mJ. Our results suggest that numerical simulation can be used to provide useful hemodynamic data given the inputs from 4D-Flow MRI, which is now available in clinical practice. However, further investigation is needed to understand the formation mechanism of the mid-level vortex and its implication on the end-diastolic flow pattern.