An Immersed Porous Boundary Method for Computational Fluid Dynamics of Blood Flow in Aneurysms With Flow Diverters

2012 ◽  
Author(s):  
Viorel Mihalef ◽  
Puneet Sharma ◽  
Ali Kamen ◽  
Thomas Redel
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Blood Flow ◽  
Subarachnoid Hemorrhage ◽  
Cerebral Artery ◽  
Intracranial Aneurysms ◽  
Mortality Rates ◽  
Morbidity And Mortality ◽  
High Morbidity ◽  
Flow Diverters

Intracranial aneurysms are pathological dilatations of a cerebral artery that may suffer rupture and lead to subarachnoid hemorrhage. Such a condition presents high morbidity and mortality rates for the patients concerned.

Inter-patient variations in flow boundary conditions at middle cerebral artery from 7T PC-MRI and influence on Computational Fluid Dynamics of intracranial aneurysms

2020 ◽  
Vol 120 ◽  
pp. 103759
Author(s):  
Hamidreza Rajabzadeh-Oghaz ◽  
Pim van Ooij ◽  
Sricharan S. Veeturi ◽  
Vincent M. Tutino ◽  
Jaco JM. Zwanenburg ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Boundary Conditions ◽  
Middle Cerebral Artery ◽  
Cerebral Artery ◽  
Intracranial Aneurysms ◽  
Flow Boundary

Hemodynamic Features of Microsurgically Identified, Thin-Walled Regions of Unruptured Middle Cerebral Artery Aneurysms Characterized Using Computational Fluid Dynamics

Neurosurgery ◽  
2019 ◽  
Vol 86 (6) ◽  
pp. 851-859
Author(s):  
Jang Hun Kim ◽  
Huan Han ◽  
Young-June Moon ◽  
Sangil Suh ◽  
Taek-Hyun Kwon ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Middle Cerebral Artery ◽  
Cerebral Artery ◽  
Intracranial Aneurysms ◽  
Microscopic Surgery ◽  
Unruptured Intracranial Aneurysms ◽  
Thin Walled ◽  
Cfd Analyses ◽  
Middle Cerebral Artery Aneurysms

Abstract BACKGROUND Thin-walled regions (TWRs) of aneurysm surfaces observed in microscopic surgery are thought to be vulnerable areas for growth and rupture of unruptured intracranial aneurysms (UIAs). OBJECTIVE To identify hemodynamic features of TWRs of aneurysms by using computational fluid dynamics (CFD) analyses of unruptured middle cerebral artery bifurcation (MCAB) aneurysms. METHODS Nine patients with 11 MCAB aneurysms were enrolled, and their TWRs were identified. CFD analysis was performed using 3 parameters: pressure, wall shear stress (WSS), and WSS divergence (WSSD). Each parameter was evaluated for its correspondence with TWR. RESULTS Among 11 aneurysms, 15 TWRs were identified. Corresponding matches with CFD parameters (pressure, WSS, and WSSD) were 73.33, 46.67, and 86.67%, respectively. CONCLUSION WSSD, a hemodynamic parameter that accounts for both magnitude and directionality of WSS, showed the highest correspondence. High WSSD might correspond with TWR of intracranial aneurysms, which are likely high-risk areas for rupture.

Abstract 99: Computational Fluid Dynamics of CT Angiography in SAMMPRIS Reveal Blood Flow and Vessel Interactions in Middle Cerebral Artery Stenoses

Stroke ◽  
2016 ◽  
Vol 47 (suppl_1) ◽  
Author(s):  
David S Liebeskind ◽  
Fabien Scalzo ◽  
Graham W Woolf ◽  
Justin M Zubak ◽  
George A Cotsonis ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Blood Flow ◽  
Boundary Conditions ◽  
Middle Cerebral Artery ◽  
Ct Angiography ◽  
Cerebral Artery ◽  
Intraluminal Pressure ◽  
Intracranial Atherosclerosis ◽  
Fractional Flow

Background: Noninvasive fractional flow measures with CT angiography (CTA) have revolutionized cardiology, yet the complex anatomy of the cerebral circulation and boundary conditions challenge the study of intracranial atherosclerosis. We developed a framework for systematic computational fluid dynamics (CFD) of middle cerebral artery (MCA) stenosis with CTA in SAMMPRIS. Methods: A 3D geometric mesh was generated from CTA source images, followed by CFD processing in Ansys (ICEM, CFX) on a Cray supercomputer. Reference boundary conditions were applied with an ICA inlet and outlets at the ACA and distal MCA to yield quantitative maps of intraluminal pressure drops (ΔP or fractional flow), blood flow velocity (V) and turbulent kinetic energy (TKE) with wall shear stress (WSS) mapped along the arteries. CFD parameters were then compared with SAMMPRIS angiography variables. Results: Of 451 SAMMPRIS (70-99% symptomatic stenosis) subjects, CTA was acquired at enrollment in 41 MCA cases. CFD results were successfully attained in 30, limited by anatomy (e.g. across branch points) in 7/11 and poor CTA resolution in 4/11. Fractional flow (ΔP) across stenosis was mean 0.64 ± SD 0.33, with maximal stenosis velocity of mean 192 ± SD 101 cm/s and maximal WSS 0.36 ± SD 0.25 mm Hg. SAMMPRIS angiography percent stenosis was unrelated to ΔP -0.163 (p=0.399), velocity 0.126 (p=0.514) or WSS 0.078 (p=0.689). Worse collateral blood flow grades were associated with larger ΔP (p=0.137), higher velocity (p=0.059), higher WSS (p=0.112). Asymmetric WSS with high and low regions on opposing arterial walls was measured in the post-stenotic segment in 25/30 (83%). TKE maps revealed focal increases in the post-stenotic region, yet not above abnormal thresholds based on arterial diameter. Conclusions: CTA CFD of intracranial atherosclerosis provides detailed noninvasive measures of hemodynamics.

One-Year Morbidity and Mortality Rates Associated with Clipping Unruptured Intracranial Aneurysms

2019 ◽  
Author(s):  
Khodayar Goshtasbi ◽  
Ronald Sahyouni ◽  
Alice Wang ◽  
Edward Choi ◽  
Gilbert Cadena ◽  
...  
Keyword(s):  
Intracranial Aneurysms ◽  
Mortality Rates ◽  
Morbidity And Mortality ◽  
Unruptured Intracranial Aneurysms ◽  
One Year

Computational fluid dynamics based hemodynamics in the management of intracranial aneurysms: state-of-the-art

2021 ◽  
Author(s):  
Bin Hu ◽  
Zhao Shi ◽  
U. Joseph Schoepf ◽  
Akos Varga-Szemes ◽  
W. Evans Few ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Intracranial Aneurysms ◽  
State Of The Art

scholarly journals Porous Media Computational Fluid Dynamics and the Role of the First Coil in the Embolization of Ruptured Intracranial Aneurysms

2021 ◽  
Vol 10 (7) ◽  
pp. 1348
Author(s):  
Karol Wiśniewski ◽  
Bartłomiej Tomasik ◽  
Zbigniew Tyfa ◽  
Piotr Reorowicz ◽  
Ernest Bobeff ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Porous Media ◽  
Packing Density ◽  
Coil Embolization ◽  
Intracranial Aneurysms ◽  
Patient Specific ◽  
Computational Fluid Dynamics Analysis ◽  
Ruptured Intracranial Aneurysms ◽  
Statistical Results

Background: The objective of our project was to identify a late recanalization predictor in ruptured intracranial aneurysms treated with coil embolization. This goal was achieved by means of a statistical analysis followed by a computational fluid dynamics (CFD) with porous media modelling approach. Porous media CFD simulated the hemodynamics within the aneurysmal dome after coiling. Methods: Firstly, a retrospective single center analysis of 66 aneurysmal subarachnoid hemorrhage patients was conducted. The authors assessed morphometric parameters, packing density, first coil volume packing density (1st VPD) and recanalization rate on digital subtraction angiograms (DSA). The effectiveness of initial endovascular treatment was visually determined using the modified Raymond–Roy classification directly after the embolization and in a 6- and 12-month follow-up DSA. In the next step, a comparison between porous media CFD analyses and our statistical results was performed. A geometry used during numerical simulations based on a patient-specific anatomy, where the aneurysm dome was modelled as a separate, porous domain. To evaluate hemodynamic changes, CFD was utilized for a control case (without any porosity) and for a wide range of porosities that resembled 1–30% of VPD. Numerical analyses were performed in Ansys CFX solver. Results: A multivariate analysis showed that 1st VPD affected the late recanalization rate (p < 0.001). Its value was significantly greater in all patients without recanalization (p < 0.001). Receiver operating characteristic curves governed by the univariate analysis showed that the model for late recanalization prediction based on 1st VPD (AUC 0.94 (95%CI: 0.86–1.00) is the most important predictor of late recanalization (p < 0.001). A cut-off point of 10.56% (sensitivity—0.722; specificity—0.979) was confirmed as optimal in a computational fluid dynamics analysis. The CFD results indicate that pressure at the aneurysm wall and residual flow volume (blood volume with mean fluid velocity > 0.01 m/s) within the aneurysmal dome tended to asymptotically decrease when VPD exceeded 10%. Conclusions: High 1st VPD decreases the late recanalization rate in ruptured intracranial aneurysms treated with coil embolization (according to our statistical results > 10.56%). We present an easy intraoperatively calculable predictor which has the potential to be used in clinical practice as a tip to improve clinical outcomes.

Outcomes following aneurysmal coil embolization with intentionally shortened low-profile visible intraluminal support stent deployment

2021 ◽  
pp. 197140092110269
Author(s):  
Kenji Yatomi ◽  
Yumiko Mitome-Mishima ◽  
Takashi Fujii ◽  
Kohsuke Teranishi ◽  
Hidenori Oishi ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Coil Embolization ◽  
Intracranial Aneurysms ◽  
Perioperative Complications ◽  
Flow Diversion ◽  
Stent Deployment ◽  
Coverage Ratio ◽  
Low Profile ◽  
Unruptured Intracranial Aneurysms

Purpose Among all stents available for neuroendovascular therapy, the low-profile visible intraluminal support stent bears the highest metal coverage ratio. We deployed a low-profile visible intraluminal support stent with a delivery wire or/and microcatheter system push action to shorten the low-profile visible intraluminal support stent and thus achieve a flow diversion effect. We report our single-institution experience with the use of low-profile visible intraluminal support stents for intentionally shortened deployment (shortening group) and non-shortened deployment (non-shortening group) for unruptured intracranial aneurysms. Methods We retrospectively reviewed the medical records of 130 patients with 131 intracranial aneurysms who were treated with low-profile visible intraluminal support stent-assisted coil embolization from February 2016–January 2019. All perioperative complications were noted. Every 6 months, we re-examined the patients with cerebral angiography or magnetic resonance angiography. The outcomes of aneurysm occlusion were evaluated by the modified Raymond–Roy occlusion classification. We used the finite element method and computational fluid dynamics to investigate the hemodynamics after shortened low-profile visible intraluminal support stent deployment. Results Immediately after treatment, the modified Raymond-Roy occlusion classification was significantly better in the shortening group than in the non-shortening group ( p<0.05). The latest angiographic outcomes showed the same tendency. Hemodynamic analysis by computational fluid dynamics suggested an adequate flow diversion effect with the use of our intentional shortening method. Conclusions Stent-assisted coil embolization using this technique showed good results of a high complete occlusion rate and low complication rate. These findings suggest that shortened low-profile visible intraluminal support stent deployment yields a flow diversion effect and may lead to early intra-aneurysmal thrombus formation.

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