Department of Mechanical Engineering, Michigan State University, East Lansing, MI.
J Neuroimaging. 2013 Oct;23(4):495-501. doi: 10.1111/jon.12044. Epub 2013 Aug 27.
Flow diversion techniques are increasingly used to treat cerebral aneurysms. The optimal stent porosity to achieve aneurysm obliteration would allow clinicians to treat aneurysms more effectively. We sought to determine the optimal porosity threshold in an in vitro flow model that would lead to stagnation of flow in an aneurysm.
Using a 3-dimensional (3-D) sidewall aneurysm glass model and a 2-dimensional (2-D) cavity model, we measured the total kinetic energy (TKE) in the cavity and aneurysm using digital particle image velocimetry by adjusting for the surface area of a metal mesh across the cavity. Additionally, we assessed how a gap between the mesh and 2-D cavity impacted circulatory patterns within a cavity.
In the 3-D aneurysm model, we noted a 90.4% reduction in TKE after placement of a stent. In the 2-D cavity model, we adjusted the porosity between 39.1% and 64.8% and noted a reduction in the TKE by 99.75% and 93.9%, respectively. When there was a gap between the mesh and entry into the cavity, unfavorable circulatory conditions occurred with the development of counterclockwise flow that had increased TKE within the cavity.
The current model demonstrates a method to evaluate the optimal porosity threshold to achieve thrombosis of an aneurysm as a primary modality. Moreover, a gap may occur between the stent and the aneurysm that may create unfavorable circulatory conditions by increasing flow into the aneurysm.
血流导向技术越来越多地用于治疗脑动脉瘤。最佳的支架孔隙率将有助于实现动脉瘤闭塞，从而使临床医生能够更有效地治疗动脉瘤。我们试图确定在体外血流模型中导致动脉瘤内血流停滞的最佳孔隙率阈值。
使用三维（3D）侧壁动脉瘤玻璃模型和二维（2D）腔模型，我们通过调整穿过腔的金属网的表面积，使用数字粒子图像测速法测量腔内和动脉瘤内的总动能（TKE）。此外，我们评估了网眼和 2D 腔之间的间隙如何影响腔内的循环模式。
在 3D 动脉瘤模型中，我们注意到放置支架后 TKE 降低了 90.4%。在 2D 腔模型中，我们调整了孔隙率在 39.1%至 64.8%之间，TKE 分别降低了 99.75%和 93.9%。当网眼和进入腔之间存在间隙时，会出现不利于循环的情况，形成逆时针流动，从而增加腔内的 TKE。
目前的模型展示了一种评估实现动脉瘤血栓形成的最佳孔隙率阈值的方法，作为主要方式。此外，支架和动脉瘤之间可能存在间隙，通过增加流入动脉瘤的血流，可能会产生不利于循环的情况。
