Purpose

Intracranial aneurysms are malformations forming bulges on the walls of brain arteries. A flow diverter device is a fine braided wire structure used for the endovascular treatment of brain aneurysms. This work presents a rig and a protocol for the measurement of the hydrodynamic resistance of flow diverter stents. Hydrodynamic resistance is interpreted here as the pressure loss versus volumetric flow rate function through the mesh structure. The difficulty of the measurement is the very low flow rate range and the extreme sensitivity to contamination and disturbances.

Methods

Rigorous attention was paid to reproducibility, hence a strict protocol was designed to ensure controlled circumstances and accuracy. Somewhat unusually, the history of the development of the rig, including the pitfalls was included in the paper. In addition to the hydrodynamic resistance measurements, the geometrical properties—metallic surface area, pore density, deployed and unconstrained length and diameter—of the stent deployment were measured.

Results

Based on our evaluation method a confidence band can be determined for a given deployment scenario. Collectively analysing the hydrodynamic resistance and the geometric indices, a deeper understanding of an implantation can be obtained. Our results suggest that to correctly interpret the hydrodynamic resistance of a scenario, the deployment length has to be considered. To demonstrate the applicability of the measurement, as a pilot study the results of four intracranial flow diverter stents of two types and sizes have been reported in this work. The results of these measurements even on this small sample size provide valuable information on differences between stent types and deployment scenarios.

中文翻译：

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颅内分流支架的流体动力阻力：测量说明和数据评估。

目的

颅内动脉瘤是畸形，在脑动脉壁上形成凸起。分流器装置是用于脑动脉瘤的血管内治疗的细编织线结构。这项工作提出了用于测量分流支架的水动力阻力的装置和协议。流体动力阻力在这里被解释为通过网孔结构的压力损失与体积流量的函数关系。测量的困难在于非常低的流量范围以及对污染和干扰的极高灵敏度。

方法

高度重视可重复性，因此设计了严格的协议以确保受控的情况和准确性。某些不同寻常的是，该钻机的发展历史（包括陷阱）也包括在本文中。除了测量流体动力阻力外，还测量了支架展开的几何特性（金属表面积，孔密度，展开和不受约束的长度和直径）。

结果

根据我们的评估方法，可以确定给定部署方案的置信度。共同分析流体动力阻力和几何指数，可以获得对植入物的更深入的了解。我们的结果表明，要正确解释方案的水动力阻力，必须考虑部署长度。为了证明该测量方法的适用性，作为一项初步研究，已在这项工作中报告了两种类型和大小的四个颅内分流支架的结果。即使在这么小的样本量下，这些测量结果也提供了有关支架类型和部署方案之间差异的有价值的信息。