Performance of rupture-related morphological parameters in posterior communicating artery aneurysms with fetal-type variant

Background: The aim of the study was to investigate the impact of fetal-type posterior cerebral artery (fPCA) variant on morphological parameters of posterior communicating artery (PComA) aneurysms for rupture risk assessment. Materials and methods: A total of 98 PComA aneurysms (62 ruptured and 36 unruptured) in 98 consecutive patients were reviewed. Morphological parameters were calculated including aneurysm size, aspect ratio (AR), size ratio (SR), dome-to-neck ratio, bottleneck factor and inflow angle. Performances of morphological parameters to discriminate rupture status were compared between aneurysms with or without fPCA. Results: Fetal-type posterior cerebral artery variant was determined in 39 (39.8%, 25 ruptured and 14 unruptured) lesions. The ruptured group revealed a significantly larger size (p = 0.004), AR (p = 0.003), SR (p = 0.001), and inflow angle (p < 0.001). For the aneurysms without fPCA, all morphological parameters were significantly different between ruptured and unruptured aneurysms (p < 0.05); for the aneurysms with fPCA, only inflow angle (p = 0.001) was significantly related with the rupture status. Multivariate analysis showed that SR (p = 0.035 and p = 0.011) and inflow angle (p = 0.001 and p = 0.028) were independent rupture risk factors for the total cohort and the aneurysms without fPCA; while only inflow angle (p = 0.004) revealed to be independently related with rupture status of aneurysms without fPCA. Conclusions: The performances of morphological parameters to discriminate rupture status were different between PComA aneurysms with and without fPCA variants. Inflow angle might be a reliable predictor for rupture risk of PComA aneurysms.