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Objective Hemodynamic factors are thought to play important roles in the pathogenesis, progression, and rupture of cerebral aneurysms. Previous hemodynamic studies have been based on comparisons between post-ruptured and unruptured aneurysms. Nevertheless, changes of aneurysm morphology after rupture render these results unreliable. Moreover, pressure, age, gender, and the morphology of the parent artery also influence these results. Therefore, in the present study, we identified hemodynamic and morphological characteristics of aneurysms prior to rupture using twelve mirror aneurysms. Materials and methods From our database, we retrospectively analyzed twelve mirror aneurysms (MANs) prior to rupture. Each mirror aneurysm was divided into the prior to rupture or the unruptured group. Patient-specific models were reconstructed from three-dimensional (3D) images of all patients. Hemodynamic and morphological factors were analyzed and compared. Results Compared with the unruptured side of MANs, aneurysms prior to rupture were significantly larger and significantly more irregular in shape; they also had significantly higher aspect ratio (AR), size ratio (SR), undulation index (UI), ellipticity index (EI), percentage of low wall shear stress area (LSA) and significantly lower normal wall shear stress (NWSS). The oscillatory shear index (OSI) and nonsphericity index (NSI) in the aneurysms prior to rupture were non-significantly higher than those of the unruptured group. Conclusion MANs prior to rupture may be extremely useful models to assess the risk of aneurysm rupture. Larger size, irregular shape, higher AR, SR, UI, NI, and lower WSS may be associated with aneurysms at risk for rupture.

Objective: Morphological and hemodynamic parameters might predict rupture of intracranial aneurysms (IAs). A practical model for the study is patients with ruptured mirror IAs in which one is ruptured and the other is unruptured. Although there have been analyses of the morphology and hemodynamics of ruptured mirror posterior communicating artery aneurysms (PComAAs), the sample sizes in these studies were small and only considered hemodynamics or morphological characters. Therefore, this study aimed to investigate the morphological and hemodynamic parameters associated with ruptured mirror PComAAs.Methods: We considered 72 patients with ruptured mirror PComAAs using computational fluid dynamics (CFDs). Ruptured mirror PComAAs were divided into ruptured and unruptured groups. Fourteen morphological and eight hemodynamic parameters were calculated and compared. Significant parameters were analyzed by the multivariate logistic regression to identify independent risk factors. Receiver operating characteristic (ROC) analysis was performed, and the area under the ROC curve (AUC) was calculated for all independent risk factors to determine the predictability and identify the optimal threshold.Results: Four hemodynamic and three morphological parameters were significantly different between ruptured and unruptured groups: normalized wall shear stress (NWSS), mean WSS, low wall shear WSS area (LSA%), size, aspect ratio (AR), size ratio (SR), and inflow angle (IA). Multivariate logistic regression analysis showed that AR, SR, NWSS, mean WSS, and LSA% were all independent factors significantly associated with PComAAs rupture. The ROC analysis for independent risk factors indicated that AR (0.751), NWSS (0.755), mean WSS (0.69), and LSA (0.778) had merely acceptable AUC values. Only SR (0.803) had a high acceptable AUC value. The threshold value of SR was 1.96.Conclusions: SR (>1.96) was the most significant parameter associated with IA rupture, whereas AR, NWSS, mean WSS, and LSA independently characterized the status of IA rupture.

Jinlong Yuan,1,&ast; Chenlei Huang,2,&ast; Zhenbao Li,1 Xiaochun Jiang,1 Xintong Zhao,1 Niansheng Lai,1 Dayong Xia,1 Degang Wu,1 Bingbing Zhang,1 Xuanzhi Wang,3 Xinggen Fang1 1Department of Neurosurgery, The First Affiliated Hospital of Wannan Medical College (Yijishan Hospital of Wannan Medical College), Wuhu, People’s Republic of China; 2Department of Clinical Laboratory, The First Affiliated Hospital of Wannan Medical College (Yijishan Hospital of Wannan Medical College), Wuhu, People’s Republic of China; 3Department of Neurosurgery, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, People’s Republic of China&ast;These authors contributed equally to this workCorrespondence: Xinggen FangDepartment of Neurosurgery, The First Affiliated Hospital of Wannan Medical College (Yijishan Hospital of Wannan Medical College), Zheshan West Road 2, Wuhu, 241001, People’s Republic of ChinaEmail 18805536056@163.comObjective: Hemodynamic parameters are associated with the recurrence of intracranial aneurysms (IAs). Studies showed that high velocity and wall shear stress (WSS) were associated with IAs recurrence after endovascular treatment; nevertheless, factors such as small sample size, locations of IAs, and types of IAs (ie, sidewall or bifurcation) were neglected. The purpose of this study was to identify the hemodynamic characteristics associated with recurrence of middle cerebral artery bifurcation aneurysms (MCABAs) after total embolization by the method of computer fluid dynamics (CFD).Methods: Following inclusion criteria, we included 92 MCABAs treated with coils only after total embolization from January 2014 to January 2019. We segmented into recurrent and non-recurrent groups according to follow-up digital subtraction angiography (DSA). The MCABA models, including pre-operatively and immediate post-operatively, were reconstructed using 3D-DSAs. The hemodynamic parameters pre-operatively and immediately post-operatively between the groups were calculated and analyzed.Results: There were no significant differences between the recurrent and non-recurrent groups for spatially averaged wall shear stress (SAWSS), maximum wall shear stress (MWSS), velocity, or oscillatory shear index (OSI) at the neck pre-operatively. In the recurrent group, the WSS (22.02± 5.11 vs 37.43± 8.27 pa, p < 0.001), MWSS (42.59± 17.02 vs 66.98± 18.61 pa, p=0.014), velocity (0.86± 0.19 vs 1.44± 0.61 m/s, p=0.01) preoperatively were significantly higher than postoperative values. By contrast, in the non-recurrent group, the WSS (26.53± 8.18 vs 22.29± 8.64pa, p=0.002), MWSS (42.71± 14.01 vs 37.15± 15.56 pa, p=0.013), velocity (1.08± 0.43 vs 0.23 (0.52, 0.57) m/s, p < 0.001) postoperatively were significantly lower than preoperative values. The OSI, whether in the recurrent group or the non-recurrent group, did not differ significantly between groups (p=0.79 and p=0.19).Conclusion: Higher WSS (SAWSS, MWSS) and flow velocity at the aneurysm neck after embolization might be related to recurrence of bifurcation IAs. These might be applied to clinical post-embolization management for the evaluation of bifurcation IAs recanalization.Keywords: computational fluid dynamic, hemodynamics, middle cerebral artery bifurcation aneurysms, recurrence

Objective: Posterior communicating artery bifurcation aneurysms (PcomA-BAs) and infundibular dilations (PcomA-IDs) are found at the junction between the internal carotid artery (ICA) and the posterior communicating artery (PcomA). Several studies found that PcomA-IDs potentially progress to aneurysms and can even rupture. In our clinical practice, digital subtraction angiography (DSA) helps differentiate PcomA-IDs from unruptured PcomA-BAs. However, when PcomA-IDs are >3 mm in diameter or PcomA are absent on DSA, it is challenging to use DSA to differentiate PcomA-IDs from unruptured PcomA-BAs. Hemodynamic and morphological factors are thought to play important roles in the pathogenesis, progression, and rupture of cerebral aneurysms. We compared hemodynamic and morphological differences in unruptured PcomA-BAs and PcomA-IDs to better manage PcomA-IDs.Methods: We included 83 PcomA-IDs and 115 unruptured PcomA-BAs dignosed and measured using DSA from January 2015 to January 2019. Computational fluid dynamics was performed on these patient-specific models reconstructed using axial slices in DICOM format. Clinical, hemodynamic, and morphological factors were compared between the PcomA-IDs and PcomA-BAs. Significant parameters were analyzed using binary logistic regression analysis to identify independent risk factors. Receiver operating characteristic (ROC) analysis was performed on the independent risk factors to acquire cutoff values.Results: One hemodynamic and four morphyological parameters were significantly different between PcomA-IDs and PcomA-BAs: normalized wall shear stress (NWSS), size, the angle between the ophthalmic segment of the ICA and the PcomA (APcomA), the angle between the ophthalmic and the communicating segment of the ICA (AICA) and the diameter of the PcomA (DPcomA). Binary logistic regression analysis showed that small size and DPcomA as well as APcomA were all independent significant factors characterizing the status of PcomA-IDs and the ROC analysis for independent risk factors indicated the cutoff values of size, APcomA, and DPcomA were 3.45 mm, 66.27°, and 1.24 mm, respectively.Conclusions: Size, DpcomA, and ApcomA could independently characterize the status of PcomA-IDs. These might help us better differentiate them from real aneurysms and guide its management.