| Summary: | 碩士 === 國立臺灣科技大學 === 機械工程系 === 98 === Atherosclerosis is a common cardiovascular disease. It may be related to blood
flows in arteries, so understanding hemodynamics in arteries play a vital role in prediction of atherosclerosis. Also, the distribution of wall shear stress (WSS) and calcium ion (Ca2+) concentration is thought to be one of important factor of atherogenesis. In order to investigate the possibility of atherogenesis, computer tomography (CT) images of right coronary arteries (RCA) and computational fluid dynamics (CFD) are utilized to simulate blood flows and predict distributions of wall shear stress and Ca2+ concentration.
The periphery of RCA is obtained from CT images of 5 healthy adults. First
of all, we retrieve 2D contours of RCA from CT images and then reconstruct
a 3D RCA model. Those reconstructed RCA models are used in the numerical
simulation of blood flows. As a result, predicted flow patterns, WSS, and Ca2+
distributions on arteries walls are presented to explore the influence of periphery.
From the numerical results, the Dean flow is observed in the proximal part
of RCA. The low AWSS and Ca2+ concentration are found at the inner wall of
the proximal part of RCA. Subsequently, when the blood flow passes through the
first branch between the main RCA and acute marginal (AM) artery, the blood flow is influenced by the bifurcation angle and diameter ratio of the bifurcation. When the angle is small, a recirculation appears at the entrance of AM and causes low WSS and low Ca2+ concentration. In the bifurcation between posterior descending artery (PDA) and posterior lateral (PL) artery, two recirculations are found as the bifurcation angle is large. average wall shear stress (AWSS) and Ca2+ decrease in those recirculation regions. This study provides the information of influences of periphery of RCA on flow behavior, AWSS, and Ca2+ concentration. Those influences can be used to predict the possibilities for atherosclerosis in RCA.
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