Folyadékok mechanikája, hidraulikus-, turbó, és dugattyús motorok
Klinikai orvostan
Orvostechnikai műszaki tudományok
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.
