中文摘要：

目的 探讨应用计算流体力学方法（CFD）结合MR血管成像（MRA），是否可以观察在体颈动脉分叉处血管狭窄的血液动力学状况。方法 选取7例颈动脉球部或颈内动脉近端狭窄患者，采用Siemens Trio型3．0TMR仪，行颈动脉MR增强血管成像（CEMRA）检查，所得原始图像经计算机后处理及网格化后，采用CFD方法进行计算。结果 随着血管狭窄的出现和程度加重，该狭窄段血管的血流模式变化很大，在狭窄区域血流速度和管壁切应力明显升高，轻度狭窄和中、重度狭窄的最大管壁切应力值范围分别为68—235Pa和201—563Pa，而在狭窄下游区域可观察到不同范围的低管壁切应力区，其分布与局部血液涡流、回流区域相符合。结论 应用CFD方法结合MRA能显示颈动脉分叉血管狭窄的血流模式。

英文摘要：

Objective To analyze flow pattern and hemodynamic variables in stenotic carotid bifurcation in vivo by combining computational fluid dynamics（CFD） and MR angiography imaging. Methods Seven patients with carotid atherosclerosis underwent contrast-enhanced MR angiography of carotid bifurcation by Siemens 3.0 T MR scanner. Hemodynamic variables and flow patterns of the carotid bifurcation were calculated and visualized by combining vascular imaging post-processing and CFD. Results As the extent of stenosis were commencing and aggravating, the stronger jets formed at the portion of narrowing and more prominent flow separation in the internal carotid artery with regions of slow retrograde fluid eddies in the lee of the stenosis. Regions of elevated wall shear stress （WSS） were predicted at the portion of stenosis and at the path of the downstream jet. The maximum value range of WSS was 68-235 Pa and 201-563 Pa in mild stenotic cases and moderate to severe stenotic cases, respectively. Areas of low WSS were predicted on the leeward side of the stenosis, corresponding with the location of slowly recirculating turbulent flow. Conclusion CFD combined with MPd can used to simulate flow patterns and calculate hemodynamic variables in the stenotic carotid bifurcation as well as normal carotid bifurcation.