Three-dimensional in-vivo intra-cardiac vortex flow from 4D Flow MRI : quantification, automatic identification and association with energy loss

Abstract

Despite one might intuitively think that blood inflows inside the human heart in a straight path, direct imaging of cardiac blood flow showed that, actually, cardiac blood inflows in a swirling motion forming what is called vortex flow pattern. In fact, blood inflow forms a pair of counter-rotating vortices distal to the mitral valve inside the heart. In three-dimensions, this pair of vortices forms a ring-like vortex: a vortex ring. This thesis revealed the three-dimensional form and time evolution of such vortex ring flow in the human heart in health and disease. This was achieved using cutting-edge 4D Flow MRI in-vivo imaging technology and developments of novel advanced methods integrating image and applied fluid mechanics concepts enabling characterization, quantification and automatic identification of heart’s vortex flow. In this thesis, a novel framework was developed allowing for the first noninvasive assessment of intra-cardiac viscous energy loss. This thesis showed that alteration in cardiac vortex ring flow properties, due to heart disease, can result in 2-4 fold increase in viscous energy loss in the left ventricle. As such, heart’s vortex flow could be an efficient mechanism of energy loss minimization in healthy hearts and might act as a biomarker of cardiac health.