Morphological Characteristics Of Posterior Communicating Artery Aneurysms Associated With Fetal-type Posterior Cerebral Artery

Background and Objective:Recent study have confirmed that the presence of ipsilateral fetal-type posterior cerebral artery(FTP)were associated with the occurrence of posterior communicating artery aneurysms(PCoAAs).However,there are few reports have been published on the relationships between FTP and PCoAAs' morphological characteristics and rupture statuses.The purpose of this study was to determine the morphological characteristics of PCoAAs associated with ipsilateral FTP.Methods:We retrospectively reviewed the clinical and imaging datas of patients with PCoAAs managed at our institution from January 2015 to June 2017.Clinical datas were included age,gender,current smoker or not,alcohol consumption status,history of hypertension,whether or not oculomotor nerve palsy and aneurysm rupture occurred.According to the results of CT and DSA,all of PCoAAs were divided into group A(PCoAAs with FTP),group B(PCoAAs without FTP),group C(ruptured PCoAAs with FTP)and group D(ruptured PCoAAs without FTP).The aneurysms and vascular model were established by the patient's individualized 3D-DSA image.Morphological parameters of the aneurysms were calculated and included the maximum height,the perpendicular height,the bottleneck diameter,the neck diameter,aspect ratio(AR),size ratio(SR),bottleneck factor(BF),ellipticity index(EI),undulation index(UI)and nonsphericity index(NSI).The univariate analysis was performed on the clinical datas and morphological parameters of the group A and group B,as well as the group C and group D.The multivariate logistic regression analysis was performed on the variates with a P value <0.1 in the univariate analysis.Results:A total of 214 PCoAAs were enrolled in the study,including 81 in group A,133 in group B,59 in group C,and 83 in group D.In the univariate analysis,there was no statistical differences of clinical datas between group A and group B,as well as group C and group D(P>0.05).The comparisons of morphological parameters showed thatPCoAAs in group A with smaller maximum height,AR,BF and UI than group B(P<0.05),and PCoAAs in group C with smaller maximum height,perpendicular height,AR,BF,UI and NSI than group D(P<0.05).Multivariate logistic regression analysis showed that there was no statistically significant parameters between group A and group B.However,NSI(OR 0.000,95% CI 0.000-0.151,P=0.030)was showed significant differences between group C and group D.Conclusion:1.There were differences characteristics between PCoAAs with FTP and PCoAAs without FTP.PCoAAs with FTP with smaller size and more regular shape.2.Compared to the ruptured PCoAAs without FTP,the ruptured PCoAAs with FTP also appear to smaller size and more regular shape.It was showed that PCoAAs with FTP would ruptured when they are smaller and more regular in shape.This suggests that PCoAAs with FTP have a higher risk of rupture.