Morphological differences between internal carotid-posterior communicating artery bifurcation aneurysm and vessels around the infundibulum

Objective To analyze the morp hological features of internal carotid artery-posterior communicating artery(ICA-PComA) aneurysms and the vessels around the infundibulums.Methods Twenty two ICA-PComA aneurysms and 20 infundibulums were observed.The morphological parameters obtained from three-dimensional digital subtraction angiography(3D-DSA) were evaluated, including the diameters of the ICA segment and origin of PComA(Dica and Dpcom), the included angle between ICA and the origin of the PComA(Apcom), and the angle between the ophthalmic segment and clinoid segment reversal site of the ICA(Aica).Parameters were analyzed with two-tailed independent-samples t test and logistic regression analysis.ROC analysis was performed for the parameters related to aneurysmogenesis.Results Statistically significant differences were found in the value of Dpcom, Aica and Apcom between the two groups(P0.05).Decrease of Apcom could lead to the increase of aneurysmogenesis probability.The area under the ROC curve of Apcom was 0.913;threshold for optimal diagnosis was 52.25 degree.Conclusion Apcom is a promising morphological parameter in the differential diagnosis of aneurysm and infundibulum,and also for the prediction of aneurysm formation.