A computational model combined ultrasonographic data and computational fluid dynamics (CFD) was developed and applied to an anatomically realistic model of the human left ventricle. The proposed methodology employs but not limited to ultrasonographic scans of a human left ventricle to obtain a set of time-varying images of morphology and dynamics of the left ventricle, which are utilized in generating a dynamic geometrical model for blood flow simulation. A so-called Two-Chamber-View modeling method has been proposed to obtain digitized anatomical images on two mutually orthogonal planes that cut through the left ventricle chamber along the long axis from base to apex, and from which two endocardial borderlines in the two planes are extracted for each time frame. Endocardial contours in the short-axis plane is approximated as an ellipse with two radii determined from the extracted endocardial borderlines in the two long-axis planes and stacked up from base to apex to generate a fully three-dimensional geometric model. Physiological conditions of inflow/outflow at orifices notionally representing the mitral and aortic vales are obtained also based on the ultrasonographic images by deriving flow rates at the orifices directly through calculating time-variation-rate of the left ventricle volume. Computational modeling of left ventricle hemodynamics is accomplished by using an in-house NS solver with specific modification for blood flow in heart chamber. The reconstructed CFD model well captures the three-dimensional dynamics of endocardial wall in terms of contraction and expansion phases in the left ventricle; and the dominant fluid dynamics involving vortices and swirls are simulated reasonably. Our computed results indicate that realistic modeling of both geometry and physiological conditions of left ventricle is of great importance in correctly predicting the behavior of the dominant vortex flow and their influence on the heart function.
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