Establishment Of Coronary Stenosis Digital Model And Computational Fluid Dynamics Analysis

Objective: With the development of society, the speedy work and livingrhythm, the increasing pressure, and aging society, the morbidity of coronaryheart disease increases gradually. It becomes a common disease that damageshuman’s health. Studies demonstrate that the age of patient with coronaryheart disease becomes younger.The research in this paper mainly focus on obtaining the real stenosisdata by scanning Ⅰ°-Ⅳ°left coronary artery occulsion proximal using MSCTand using three-dimensional reconstruction technique of digital imageprocessing to establish the true cardiovascular model. The combination ofthree-dimensional reconstruction and CFD technique makes hemodynamicparameters of cardiovascular model,such as wall stress, wall shear stress, flowrate, et al. It provides a visual plat for hemodynamic of coronary arterystenosis.Methods: Make a retrospective analysis of30patients with coronaryartery CTA scans from October2012to March2013, select each case from Ⅰ°-Ⅳ°typical coronary stenosis cases. Use PHILIPS BrillianceiCT, nonioniccontrast Iohexol injection (Iohexol),(100ml containing35g-37g Iohexol).Scanning range is from2cm under the tracheal bifurcation to the diaphragm.After the scan, the luminal diameters of anterior coronary artery stenosis,coronary artery stenosis and posterior coronary artery stenosis of differentdegrees are measured and the degree of stenosis is calculated in PACS imageworkstation. The CT scan data is stored into the read-write CD-ROM inDICOM files. Establish Ⅰ°-Ⅳ°coronary stenosis model with MIMICS14.0software, and optimize the three-dimensional model in the Geomagic9.0software and form fedb documents. Then the model file is imported intoWorkbench13.0to build flow-solid coupling procedures, and perform meshing and settings on the wall and blood for coupling calculation andanalysis.Result:1Get dimensional finite element analysis model of the real Ⅰ°-Ⅳ°leftcoronary artery occulsion proximal vessels. It is in line with real arteries thatseting vascular wall elastic blood vessels. So the model not only ensures theauthenticity and accuracy of the data, and we can make all kinds of fluiddynamics experiments.2Get visual graphics of intravascular blood flow changes in Ⅰ°-Ⅳ°leftcoronary artery occulsion proximal vessels and calculate its flow-solidcoupling to obtain a series of visual computational fluid data.3The flow line intensity of stenosis inⅠ°-Ⅳ°leftcoronary artery occulsion proximal vessels stenosis increases gradually and isless uniform.4The blood flow velocity within the lumen ofⅠ°-Ⅳ°leftcoronary artery occulsion proximal vessel stenosis increases gradually. Theblood flow velocity anterior stenosis is smaller than that posterior stenosis.5The vessels pressure declines rapidly from anterior stenosis to stenosisin Ⅰ°-Ⅳ°left coronary artery occulsion proximal vessel, and with increasingdegree of stenosis, the gradient of the pressure change increases. therecirculation zone exist at the rear of the stenosis.6The wall shear force inⅠ°-Ⅳ°left coronary artery occulsion proximalstenosis is highest, and with the increasing degree of stenosis, the gradient ofshear force change increases. The wall shear force lower after stenosis.7Hemodynamic changes in vascular stenosis is complicated. The impactof blood flow on stenosis will cause stress decline at the stenosis, change oflumen shear force is the most obvious. These are the reasons for the formationof atherosclerosis. The blood flow in the vessel of anterior stenosis is lowerthan that of posterior stenosis. The increased flow velocity, gradient ofpressure change and gradient of shear force change at the stenosis will resultin an increase in patches and increase the impact on plaque, increasing the risk of plaque off. The recirculation zone in posterior stenosis will also damage thevascular endothelial tissue and accelerate the development of thrombosis.Conclusion:1Establish digital models of each degree of stenosis with realmeasurement data of Ⅰ°-Ⅳ°left coronary artery occulsion proximal stenosis.2Establish finite element model ofⅠ°-Ⅳ°left coronary artery occulsionproximal stenosis.3Perform the fluid dynamics computation and analysis ofⅠ°-Ⅳ°leftcoronary artery occulsion proximal stenosis using computational fluiddynamics method.4Explore the establishment of a technical visualizing analysis method offluid state at coronary stenosis.