Association of Hemodynamic Characteristics and Cerebral Aneurysm Rupture

Abstract

Background and purpose Hemodynamic factors are thought to play an important role in the initiation, growth and rupture of cerebral aneurysms. This report describes a study of the associations between qualitative intra-aneurysmal hemodynamics and the rupture of cerebral aneurysms. Methods 210 consecutive aneurysms were analyzed using patient-specific CFD simulations under pulsatile flow conditions. The aneurysms were classified into categories depending on the complexity and stability of the flow pattern, size of the impingement region, and inflow concentration by two blinded observers. A statistical analysis was then performed with respect to history of previous rupture. Inter-observer variability analysis was performed. Results Ruptured aneurysms were more likely to have complex flow patterns (83%, p<0.001), stable flow patterns (75%, p=0.0018), 66% concentrated inflow (66%, p=<0.0001), and small impingement regions (76%, p=0.0006) compared to unruptured aneurysms. Inter-observer variability analyses indicate that all the classifications performed are in very good agreement, i.e. well within the 95% confidence interval. Conclusions A qualitative hemodynamic analysis of cerebral aneurysms using image based patient-specific geometries has shown that concentrated inflow jets, small impingement regions, complex flow patterns, and unstable flow patterns are correlated with a clinical history of prior aneurysm rupture. These qualitative measures provide a starting point for more sophisticated quantitative analysis aimed at assigning aneurysm risk of future rupture. These analyses highlight the potential for CFD to play an important role in the clinical determination of aneurysm risks.

From imaging to hemodynamics – how reconstruction kernels influence the blood flow predictions in intracranial aneurysms

“…Studies of large cohorts of patient-specific dilatations mainly try to understand initiation, remodelling as well as rupture processes in order to assist physicians during therapy planning [1,2]. However, due to several assumptions, which are required to receive numerical results in a feasible time frame, the acceptance of CFD remains limited in the clinical context.…”

Morphologic and Hemodynamic Risk Factors in Ruptured Aneurysms Imaged before and after Rupture

“…4,[6][7][8][14][15][16][17] Our objective was to investigate morphology and flow properties of aneurysms before and after rupture and find whether previously identified risk factors were present in aneurysms before rupture. We sought to identify risk factors that consistently existed in ruptured aneurysms in both unruptured and ruptured states to guide early determination of aneurysm rupture risk.…”

Fluid dynamic characterization of a novel branching anastomosis design

“…Based on previous literature, the global flow and stress profiles generated by compliant wall simulations are similar to those from the rigid simulation case (Zhao et al 2000;Dempere-Marco et al 2006). Accordingly, rather than using our computational resources to accomplish a handful of compliant model simulations, we chose to explore a more extensive range of boundary conditions, which (such as geometry) generally have greater impact on fluid dynamic outcomes (Cebral et al 2011). Using compliant models would of course decrease WSS levels; however, we expect that relative trends across the two different anastomosis designs would not change considerably.…”