Association Between Morphological Factors And The Distribution Of WSS Of Posterior Communicating Artery Aneurysm

BACKGROUND Unruptured intracranial aneurysms(UIAs)are increasingly detected because of improved quality and more frequent of cranial vascular imaging.Rupture of intracranial aneurysms can cause catastrophic consequence,with a very high rate of mortality or mobordity.Current studies find that most UIAs can saty quiet in a very long time.How to distinguish these aneurysms with higher risk of rupture from the ohters is a more and more common task for neurosurgeries.Recently,computer fluid dynamics are implied in the analysis of intracranial hemodynamics,and wall shear stress(WSS)has been defined as a key role which associates with the progress of aneurysm development and rupture.Though the pathophysiology of the function of WSS on the wall of intracranial aneurysm has not been thoroughly understood,researchers found that low WSS often occurs at the area of rupture,while the high WSS often make the formation of aneurysm.OBJECTIVES Study the relationships between the morphological characters and the distribution of WSS on aneruysm,which may help the clinic neurosurgeon to distinguish these aneurysms which need interventions by their morphologies.METHODS This study retrospectively studied 25 patients diagnosed as posterior communicating artery aneurysm by DSA.Their 3D-DSA vascular models were reconstructed and the morphologic characters and WSS distribution were measured respectively.We mainly studied these following characters,the diameters of ICA and PcomA,the angle and tortuosity of ICA and PcomA,the width of the neck of aneurysm,the length of aneurysm,volume,superficial area,aspect ratio,size ratio,the in-flow angle,the mean WSS of aneurysm,the area of low WSS,the area of normal and high WSS.Then we used SPSS to calculate the correlation between those morphological characters and distribution of WSS.RESULTS The height and aspect ratio of aneurysm have a positive correlation with the low WSS area,while have a negative correlation with the high WSS area.The volume and superficial area of aneurysm have a positive correlation with low WSS area,while has a negative correlation with the percentage of Area(WSS?1.5Pa)%.The width and size ratio also have positive correlation with Area(WSS ? 1.5Pa).CONCLUTIONS This study found that not only large aneurysms with large volume and superficial are,but also higher aneurysms appear to have larger area under the impact of low WSS.These low WSS area often lack blood flow,which may trigger the inflammation process of vessel wall and lead to rupture.