Cantón Gador, Levy David I, Lasheras Juan C
Department of Mechanical and Aerospace Engineering, University of California, San Diego, USA.
J Neurosurg. 2005 Jul;103(1):146-55. doi: 10.3171/jns.2005.103.1.0146.
The aim of this study was to measure changes in intraaneurysm flow dynamics and mechanical stresses resulting from the placement of Neuroform stents in bifurcating intracranial aneurysm models.
A digital particle image velocimetry (DPIV) system was used to measure the pulsatile velocity and shear stress fields within the aneurysm and at the aneurysm neck-parent artery interface. The DPIV system provides an instantaneous two-dimensional measurement of the temporal and spatial variations of the velocity vector field of the flow inside the aneurysm pouch and the parent vessel, providing information on both the temporal and spatial variations of the velocity field during the entire cardiac cycle. The corresponding shear stress field was then computed from the velocity field data. A flexible silicone model of bifurcating intracranial aneurysms was used. Two Neuroform stents with a 60- to 65-microm strut thickness and an 11% metal/artery ratio were placed in a Y-configuration, and measurements were obtained after placing the stents.
Two three-dimensional vortices of different strengths persisted within the aneurysm during the entire cardiac cycle. The peak velocity and strength of these vortices were reduced after placing the two bifurcating stents. The effect of placing the Neuroform stent across the neck of a bifurcating intracranial aneurysm was shown to reduce the magnitude of the velocity of the jet entering the sac by as much as 11%. Nevertheless, the effect of the stents was particularly noticeable at the end of the cardiac cycle, when the residual vorticity and shear stresses inside the sac were decreased by more than 40%.
本研究的目的是测量在分叉颅内动脉瘤模型中植入Neuroform支架后动脉瘤内血流动力学和机械应力的变化。
使用数字粒子图像测速（DPIV）系统测量动脉瘤内以及动脉瘤颈部-母动脉界面处的脉动速度和剪应力场。DPIV系统可对动脉瘤囊袋和母血管内血流速度矢量场的时间和空间变化进行瞬时二维测量，提供整个心动周期内速度场的时间和空间变化信息。然后根据速度场数据计算相应的剪应力场。使用了分叉颅内动脉瘤的柔性硅胶模型。将两个支柱厚度为60至65微米、金属/动脉比率为11%的Neuroform支架呈Y形放置，并在放置支架后进行测量。
在整个心动周期内，动脉瘤内持续存在两个不同强度的三维涡流。放置两个分叉支架后，这些涡流的峰值速度和强度降低。结果表明，在分叉颅内动脉瘤颈部放置Neuroform支架可使进入瘤腔的射流速度降低多达11%。然而，在心动周期结束时，支架的效果尤为明显，此时瘤腔内的残余涡度和剪应力降低了40%以上。
