COMPUTATIONAL FLUID DYNAMICS SIMULATION OF THE BLOOD FLOW IN THE HUMAN AORTIC ARCH -EFFECTS OF THREE BRANCHES OF THE ARCH ON THE FLOW-

摘要

The vascular diseases occurred in large arteries are suggested to relate with the blood flow as well as the vessel structure, which significantly influences the flow. In order to investigate these interactions, we have to understand the detailed flow phenomena in the complex vessel configuration. The human aortic arch is known to have significant characteristic configuration. One of the characteristics is that the centerline of the arch is not laid in a plane (non-planarity). Another one is that there are major branches at the top of the arch. Yoshii et al. constructed 3-D images of human aortas by stacking a series of computed tomographical (CT) slices, and indicated that the angle between the ascending and descending legs of the arch in the cranial view tends to be sharper in aneurysm cases. However, no systematic investigations from a fluid dynamics point of view have been conducted. Kilner et al. observed a characteristic helical blood flow pattern in the human aortic arch using magnetic resonance (MR) measurement, and showed the qualitative flow structure in the arch. However, it is very difficult to obtain the precise hemodynamics information, such as Wall Shear Stress (WSS), correlating with various disorders, particularly atherosclerosis by such a clinical image measurement. Instead of the experimental methods, we studied more detailed flow in the human aortic arch by constructing the three-dimensional (3-D) realistic vessel models using computational fluid dynamics (CFD) methods, though the major branches at the top of the arch were not fully considered. In this study, we constructed an aortic arch model for CFD simulations that incorporates both non-planarity and the major branches, based on a set of MR images, and discuss their combined effects on blood flow.