Study on Flow Pattern in Stent Neighborhood and Hemodynamics in Cerebral Aneurysm

Cerebral aneurysms (CA) are pathological dilations of the cerebral artery walls, which mostly occur at the circle of Willis. The incidence of CA has been estimated to be between 1% and 8 % among western populations. CA has rupture mortality and morbidity rates are exceedingly high. In the medical field, the stent placement in intracranial artery is call as endovascular treatment. Recently, stent placement as a low invasive therapy is paid to attention for treatment of aneurysm. The role of stent is to prevent blood flow into the aneurysm and to decrease the risk of rupture. Moreover, the effect of only stent on the flow reduction in CA has been reported in Computed Fluid Dynamics (CFD), recently. Moreover, the comparable effect is also reported in experiment. Some results suggested that the blood flow into aneurysm can reduce by only stent placement. Moreover, in generally, he stent porosities investigated under physiologically flow conditions were limited to the rage of 60-86%. And the stent of high porosity such as silk stent and pipeline stent is used for treatment of CA. However, the rupture of CA is reported in the case to use silk stent for CA. Although low or high porosity, it is important to understand flow of stent neighborhood and effect to aneurysm in stent placement. We reconstructed idealize cerebral aneurysm geometry to examine flow pattern and effect to aneurysm by stent placement and analyzed without- and with-stent. As results, the flow cannot divert by stent placement. The flow of wall neighborhood flows into aneurysm. Moreover, average and maximum of pressure distribution and wall shear stress distribution with stent is higher than that of without stent. We examine flow pattern and effect to aneurysm. Although treating by stent placement, there is a possibility of increasing the influence on the aneurysm.