A Comparative Study Based on Patient-Specific Fluid-Structure Interaction Modeling of Cerebral Aneurysms

2011 ◽  
Vol 79 (1) ◽  
Author(s):  
Kenji Takizawa ◽  
Tyler Brummer ◽  
Tayfun E. Tezduyar ◽  
Peng R. Chen

We present an extensive comparative study based on patient-specific fluid-structure interaction (FSI) modeling of cerebral aneurysms. We consider a total of ten cases, at three different locations, half of which ruptured. We use the stabilized space-time FSI technique developed by the Team for Advanced Flow Simulation and Modeling (T⋆AFSM), together with a number of special techniques targeting arterial FSI modeling, which were also developed by the T⋆AFSM. What we look at in our comparisons includes the wall shear stress, oscillatory shear index and the arterial-wall stress and stretch. We also investigate how simpler approaches to computer modeling of cerebral aneurysms perform compared to FSI modeling.

2010 ◽  
Vol 65 (1-3) ◽  
pp. 308-323 ◽  
Author(s):  
Kenji Takizawa ◽  
Creighton Moorman ◽  
Samuel Wright ◽  
John Purdue ◽  
Travis McPhail ◽  
...  

Trauma ◽  
2020 ◽  
pp. 146040862092172
Author(s):  
Reza Razaghi ◽  
Hasan Biglari ◽  
Alireza Karimi

Background There is a lack of knowledge on the magnitudes of the biomechanical stresses and deformations occurring in the cerebral arterial wall after traumatic brain injury (TBI). Experimental techniques are unable to calculate the stresses and deformations in the cerebral arterial wall after TBI; therefore, the application of numerical simulations, such as finite element modeling, is preferred. Methods This study was aimed to calculate the stresses and deformations as well as the alteration in the pressure and velocity of the blood in the cerebrovascular artery using a fluid–structure interaction model. Results The results revealed considerable increase in the pressure and velocity of the blood which might lead to cerebrovascular damage followed by hemorrhage. The arterial wall showed the highest deformation of 0.047 mm in the X direction which was higher than that in the Y (0.035–0.050 mm) and Z (0.019–0.030 mm) directions. Conclusions These results have implications not only for the understanding of the stresses and deformations in the cerebral artery because of TBI, but also for providing a comprehensive knowledge for biomechanical and medical experts in regard to thresholds of cerebrovascular damage for use in establishing preventive and/or treatment methods.


2009 ◽  
Vol 01 (01) ◽  
pp. 179-199 ◽  
Author(s):  
F. P. P. TAN ◽  
R. TORII ◽  
A. BORGHI ◽  
R. H. MOHIADDIN ◽  
N. B. WOOD ◽  
...  

In this study, fluid-structure interaction (FSI) simulation was carried out to predict wall shear stress (WSS) and blood flow patterns in a thoracic aortic aneurysm (TAA) where haemodynamic stresses on the diseased aortic wall are thought to lead to the growth, progression and rupture of the aneurysm. Based on MR images, a patient-specific TAA model was reconstructed. A newly developed two-equation laminar-turbulent transitional model was employed and realistic velocity and pressure waveforms were used as boundary conditions. Analysis of results include turbulence intensity, wall displacement, WSS, wall tensile stress and comparison of velocity profiles between MRI data, rigid and FSI simulations. Velocity profiles demonstrated that the FSI simulation gave better agreement with the MRI data while results for the time-averaged WSS (TAWSS) and oscillatory shear index (OSI) distributions showed no qualitative differences between the simulations. With the FSI model, the maximum TAWSS value was 13% lower, whereas the turbulence intensity was significantly higher than the rigid model. The FSI simulation also provided results for wall mechanical stress in terms of von Mises stress, allowing regions of high wall stress to be identified.


Author(s):  
Christine M. Scotti ◽  
Ender A. Finol

Primary among the mechanical factors linked with abdominal aortic aneurysm (AAA) rupture is peak wall stress, frequently quantified as either the maximum principal or Von Mises stress exerted along the diseased arterial wall. Intraluminal pressure, as an impinging normal force on the wall, has been hypothesized as the dominant influence on this stress and thus the majority of numerical modeling studies of AAA mechanics have focused on static computational solid stress (CSS) predictions [1,2]. Unfortunately, retrospective studies comparing the magnitude of wall stress with the failure strength of the aneurysmal wall have yet to consistently predict the outcome for patient-specific AAAs [3,4]. Previous studies have shown that hemodynamics also plays a significant role in both the biological and mechanical factors that exist within AAAs. In the present investigation, partially and fully coupled fluid-structure interaction (p-FSI and f-FSI, respectively) computations of patient-specific AAA models are presented and compared to identify the effect of fluid flow in the biomechanical environment of these aneurysms.


Author(s):  
Michalis Xenos ◽  
Suraj Rambhia ◽  
Yared Alemu ◽  
Shmuel Einav ◽  
John J. Ricotta ◽  
...  

Fluid structure interaction (FSI) simulations were conducted to assess the risk of rupture in reconstructed AAA from patients who had contained ruptured AAAs. The goal was to test to ability of our FSI methodology to predict the location of rupture, by correlating the high wall stress regions with the actual rupture location. We also present a parametric study in which the relationship of iliac bifurcation angle and the role of embedded calcifications were studied in respect to the aneurismal wall stress. The patient specific AAA FSI simulations were carried out with advanced constitutive material models of the various components of AAA, including models that describe the wall anisotropy, structural strength based on collagen fibers orientation within the arterial wall, AAA intraluminal thrombus (ILT), and embedded calcifications. The anisotropic material model used to describe the wall properties closely correlated with experimental results of AAA specimens [1]. The results demonstrate that the region of rupture can be predicted by the region of the highest wall stress distribution. Embedded wall calcifications increase the local wall stress surrounding calcified spots, and eventually increases the risk of rupture. FSI results in streamlined AAA geometries show that the maximum stress on the aneurismal wall increases as the iliac bifurcation angle increases.


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