Wang Zhou, Ionita Ciprian, Rudin Stephen, Hoffmann Kenneth R, Paxton Adam B, Bednarek Daniel R
Department of Physiology and Biophysics, University at Buffalo (SUNY), 3435 Main Street, Buffalo, NY 14214.
Proc SPIE Int Soc Opt Eng. 2004 Apr;5369. doi: 10.1117/12.535347.
We have built new asymmetric stents for minimally invasive endovascular treatment of cerebral aneurysms. Each asymmetric stent consists of a commercial stent with a micro-welded circular mesh patch. The blood flow modification in aneurysm-vessel phantoms due to these stents was evaluated using x-ray angiographic analysis. However, the density difference between the radiographic contrast and the blood gives rise to a gravity effect, which was evaluated using an initial optical dye-dilution experiment. For the radiographic evaluations, curved-vessel phantoms instead of simple straight side-wall aneurysm phantoms were used in the characterization of meshes/stents. Six phantoms (one untreated, one treated with a commercial stent, and four treated with different asymmetric stents) with similar morphologies were used for comparison. We calculated time-density curves of the aneurysm region and then calculated the peak value (Pk) and washout rate (1/τ) after analytical curve fitting. Flow patterns in the angiograms showed reduction of vortex flow and slow washout in the dense mesh patch treated aneurysms. The meshes reduced Pk down to 21% and 1/τ down to 12% of the values for the untreated case. In summary, new asymmetric stents were constructed and their evaluation demonstrates that they may be useful in the endovascular treatment of aneurysms.
我们构建了用于脑动脉瘤微创血管内治疗的新型不对称支架。每个不对称支架由带有微焊接圆形网片的商用支架组成。使用X射线血管造影分析评估了这些支架在动脉瘤 - 血管模型中引起的血流改变。然而，造影剂与血液之间的密度差异会产生重力效应，这通过初始光学染料稀释实验进行了评估。对于放射学评估，在网片/支架的表征中使用了弯曲血管模型而非简单的直侧壁动脉瘤模型。使用六个形态相似的模型（一个未处理，一个用商用支架处理，四个用不同的不对称支架处理）进行比较。我们计算了动脉瘤区域的时间 - 密度曲线，然后在分析曲线拟合后计算了峰值（Pk）和洗脱率（1/τ）。血管造影中的血流模式显示，在经致密网片处理的动脉瘤中，涡流减少且洗脱缓慢。网片将Pk降低至未处理病例值的21%，将1/τ降低至12%。总之，构建了新型不对称支架，对其评估表明它们可能在动脉瘤的血管内治疗中有用。
