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Paz C, Suárez E, Cabarcos A, Pinto SIS. Numerical Study of a Thrombus Migration Risk in Aneurysm After Coil Embolization in Patient Cases: FSI Modelling. Cardiovasc Eng Technol 2023; 14:544-559. [PMID: 37468797 PMCID: PMC10465652 DOI: 10.1007/s13239-023-00672-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Accepted: 07/03/2023] [Indexed: 07/21/2023]
Abstract
PURPOSE There are still many challenges for modelling a thrombus migration process in aneurysms. The main novelty of the present research lies in the modelling of aneurysm clot migration process in a realistic cerebral aneurysm, and the analysis of forces suffered by clots inside an aneurysm, through transient FSI simulations. METHODS The blood flow has been modelled using a Womersley velocity profile, and following the Carreau viscosity model. Hyperelastic Ogden model has been used for clot and isotropic linear elastic model for the artery walls. The FSI coupled model was implemented in ANSYS® software. The hemodynamic forces suffered by the clot have been quantified using eight different clot sizes and positions inside a real aneurysm. RESULTS The obtained results have shown that it is almost impossible for clots adjacent to aneurysm walls, to leave the aneurysm. Nevertheless, in clots positioned in the centre of the aneurysm, there is a real risk of clot migration. The risk of migration of a typical post-coiling intervention clot in an aneurysm, in contact with the wall and occupying a significant percentage of its volume is very low in the case studied, even in the presence of abnormally intense events, associated with sneezes or impacts. CONCLUSIONS The proposed methodology allows evaluating the clot migration risk, vital for evaluating the progress after endovascular interventions, it is a step forward in the personalized medicine, patient follow-up, and helping the medical team deciding the optimal treatment.
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Affiliation(s)
- C. Paz
- CINTECX, Universidade de Vigo, Campus As Lagoas-Marcosende, 36310 Vigo, Spain
| | - E. Suárez
- CINTECX, Universidade de Vigo, Campus As Lagoas-Marcosende, 36310 Vigo, Spain
| | - A. Cabarcos
- CINTECX, Universidade de Vigo, Campus As Lagoas-Marcosende, 36310 Vigo, Spain
| | - S. I. S. Pinto
- Engineering Faculty of University of Porto, Institute of Science and Innovation in Mechanical and Industrial Engineering (LAETA-INEGI), Rua Dr. Roberto Frias, 4200-465 Porto, Portugal
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Jiang Y, Ge L, Huang L, Wan H, Lu G, Zhang X. Large postoperative inflow area predictive of recurrence for paraclinoid aneurysms treated by simple coiling. J Clin Neurosci 2022; 98:53-59. [DOI: 10.1016/j.jocn.2022.01.031] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2021] [Revised: 12/13/2021] [Accepted: 01/22/2022] [Indexed: 11/17/2022]
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Paz C, Suárez E, Cabarcos A, Pinto SIS. FSI modeling on the effect of artery-aneurysm thickness and coil embolization in patient cases. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2021; 206:106148. [PMID: 33992899 DOI: 10.1016/j.cmpb.2021.106148] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Accepted: 04/26/2021] [Indexed: 06/12/2023]
Abstract
BACKGROUND AND OBJECTIVE The attainment of a methodology to simulate the hemodynamic in patient-specific cerebral vessels with aneurysms is still a challenge. The novelty of this work is focused on the effect of coil embolization in a realistic cerebral aneurysm, according to the vessel wall thickness and aneurysm thickness, through transient FSI simulations. METHODS The quality of the mesh for simulations was checked with a specific mesh convergence study; and the numerical methodology was validated using numerical research data of the literature. The model was implemented in ANSYS® software. The total deformation and equivalent stress evolution in the studied cases, before and after coil embolization, were compared. More than 20 different models were employed due to different arterial wall thickness and aneurysm wall thickness combinations. RESULTS The obtained results have showed that deformation and stress values are highly influenced with the sac thickness. The thinner sac aneurysm thickness is, the greater deformation and stress are. The results after coil embolization process have highlighted that considering typical values of arterial wall thickness and aneurysm thickness 0.3 mm and 0.15 mm respectively, a deformation reduction around 50% and a stress reduction around 70% can be achieved. CONCLUSIONS The proposed methodology is a step forward in the personalized medicine, quantifying the aneurysm rupture risk reduction, and helping the medical team in the preoperative planning, or to deciding the optimal treatment.
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Affiliation(s)
- C Paz
- CINTECX, University of Vigo, Campus Universitario Lagoas-Marcosende, Vigo 36310, España.
| | - E Suárez
- CINTECX, University of Vigo, Campus Universitario Lagoas-Marcosende, Vigo 36310, España.
| | - A Cabarcos
- CINTECX, University of Vigo, Campus Universitario Lagoas-Marcosende, Vigo 36310, España.
| | - S I S Pinto
- Engineering Faculty of University of Porto, Institute of Science and Innovation in Mechanical and Industrial Engineering (LAETA-INEGI), Rua Dr. Roberto Frias, Porto 4200-465, Portugal.
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Wu WT, Aubry N, Antaki JF, Massoudi M. Simulation of blood flow in a sudden expansion channel and a coronary artery. JOURNAL OF COMPUTATIONAL AND APPLIED MATHEMATICS 2020; 376:112856. [PMID: 34703076 PMCID: PMC8545272 DOI: 10.1016/j.cam.2020.112856] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
In this paper, we numerically simulate the flow of blood in two benchmark problems: the flow in a sudden expansion channel and the flow through an idealized curved coronary artery with pulsatile inlet velocity. Blood is modeled as a suspension (a non-linear complex fluid) and the movement of the red blood cell (RBCs) is modeled by using a concentration flux equation. The viscosity of blood is obtained from experimental data. In the sudden expansion flow, the predicted velocity profiles for two different Reynolds numbers (based on the inlet velocity) agree well with the available experiments; furthermore, the numerical results also show that after the sudden expansion there exists a RBCs depletion region. For the second problem, the idealized curved coronary artery, it is found that the RBCs move towards and concentrate near the inner surface where the viscosity is higher and the shear stress lower; this phenomenon may be related to the atherosclerotic plaque formation which usually occurs on the inside surface of the arteries.
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Affiliation(s)
- Wei-Tao Wu
- School of Mechanical Engineering, Nanjing University of Science and Technology, Nanjing, J.S., 210094, China
| | - Nadine Aubry
- Department of Mechanical Engineering, Tufts University, Medford, MA, 02155, USA
| | - James F. Antaki
- Nancy E. and Peter C. Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY 14853, USA
| | - Mehrdad Massoudi
- U. S. Department of Energy, National Energy Technology Laboratory (NETL), Pittsburgh, PA, 15236, USA
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Sarrami-Foroushani A, Lassila T, Frangi AF. Virtual endovascular treatment of intracranial aneurysms: models and uncertainty. WILEY INTERDISCIPLINARY REVIEWS-SYSTEMS BIOLOGY AND MEDICINE 2017; 9. [PMID: 28488754 DOI: 10.1002/wsbm.1385] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Revised: 01/09/2017] [Accepted: 02/07/2017] [Indexed: 01/11/2023]
Abstract
Virtual endovascular treatment models (VETMs) have been developed with the view to aid interventional neuroradiologists and neurosurgeons to pre-operatively analyze the comparative efficacy and safety of endovascular treatments for intracranial aneurysms. Based on the current state of VETMs in aneurysm rupture risk stratification and in patient-specific prediction of treatment outcomes, we argue there is a need to go beyond personalized biomechanical flow modeling assuming deterministic parameters and error-free measurements. The mechanobiological effects associated with blood clot formation are important factors in therapeutic decision making and models of post-treatment intra-aneurysmal biology and biochemistry should be linked to the purely hemodynamic models to improve the predictive power of current VETMs. The influence of model and parameter uncertainties associated to each component of a VETM is, where feasible, quantified via a random-effects meta-analysis of the literature. This allows estimating the pooled effect size of these uncertainties on aneurysmal wall shear stress. From such meta-analyses, two main sources of uncertainty emerge where research efforts have so far been limited: (1) vascular wall distensibility, and (2) intra/intersubject systemic flow variations. In the future, we suggest that current deterministic computational simulations need to be extended with strategies for uncertainty mitigation, uncertainty exploration, and sensitivity reduction techniques. WIREs Syst Biol Med 2017, 9:e1385. doi: 10.1002/wsbm.1385 For further resources related to this article, please visit the WIREs website.
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Affiliation(s)
- Ali Sarrami-Foroushani
- Center for Computational Imaging and Simulation Technologies in Biomedicine (CISTIB), The University of Sheffield, Sheffield, UK
| | - Toni Lassila
- Center for Computational Imaging and Simulation Technologies in Biomedicine (CISTIB), The University of Sheffield, Sheffield, UK
| | - Alejandro F Frangi
- Center for Computational Imaging and Simulation Technologies in Biomedicine (CISTIB), The University of Sheffield, Sheffield, UK
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Otani T, Ii S, Shigematsu T, Fujinaka T, Hirata M, Ozaki T, Wada S. Computational study for the effects of coil configuration on blood flow characteristics in coil-embolized cerebral aneurysm. Med Biol Eng Comput 2016; 55:697-710. [DOI: 10.1007/s11517-016-1541-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2015] [Accepted: 06/29/2016] [Indexed: 11/28/2022]
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Wang C, Tian Z, Liu J, Jing L, Paliwal N, Wang S, Zhang Y, Xiang J, Siddiqui AH, Meng H, Yang X. Flow diverter effect of LVIS stent on cerebral aneurysm hemodynamics: a comparison with Enterprise stents and the Pipeline device. J Transl Med 2016; 14:199. [PMID: 27370946 PMCID: PMC4930570 DOI: 10.1186/s12967-016-0959-9] [Citation(s) in RCA: 122] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2016] [Accepted: 06/23/2016] [Indexed: 11/14/2022] Open
Abstract
Background The aim of this study was to quantify the effect of the new Low-profile Visualized Intraluminal Support (LVIS®D) device and the difference of fluid diverting effect compared with the Pipeline device and the Enterprise stent using computational fluid dynamics (CFD). Methods In this research, we simulated three aneurysms constructed from 3D digital subtraction angiography (DSA). The Enterprise, LVIS and the Pipeline device were virtually conformed to fit into the vessel lumen and placed across the aneurysm orifice. Computational fluid dynamics analysis was performed to compare the hemodynamic differences such as WSS, Velocity and Pressure among these stents. Results Control referred to the unstented model, the percentage of hemodynamic changes were all compared to Control. A single LVIS stent caused more wall shear stress reduction than double Enterprise stents (39.96 vs. 30.51 %) and velocity (23.13 vs. 18.64 %). Significant reduction in wall shear stress (63.88 %) and velocity (46.05 %) was observed in the double-LVIS stents. A single Pipeline showed less reduction in WSS (51.08 %) and velocity (37.87 %) compared with double-LVIS stent. The double-Pipeline stents resulted in the most reduction in WSS (72.37 %) and velocity (54.26 %). Moreover, the pressure increased with minuscule extent after stenting, compared with the unstented model. Conclusions This is the first study analyzing flow modifications associated with LVIS stents. We found that the LVIS stent has certain hemodynamic effects on cerebral aneurysms: a single LVIS stent caused more flow reductions than the double-Enterprise stent but less than a Pipeline device. Nevertheless, the double-LVIS stent resulted in a better flow diverting effect than a Pipeline device.
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Affiliation(s)
- Chao Wang
- Department of Interventional Neuroradiology, Beijing Neurosurgical Institute and Beijing Tian Tan Hospital, Capital Medical University, TiantanXili 6, Dongcheng District, Beijing, China.,Department of Neurosurgery, The Affiliated Hospital, Binzhou Medical University, Binzhou, Shandong, China
| | - Zhongbin Tian
- Department of Interventional Neuroradiology, Beijing Neurosurgical Institute and Beijing Tian Tan Hospital, Capital Medical University, TiantanXili 6, Dongcheng District, Beijing, China
| | - Jian Liu
- Department of Interventional Neuroradiology, Beijing Neurosurgical Institute and Beijing Tian Tan Hospital, Capital Medical University, TiantanXili 6, Dongcheng District, Beijing, China
| | - Linkai Jing
- Department of Interventional Neuroradiology, Beijing Neurosurgical Institute and Beijing Tian Tan Hospital, Capital Medical University, TiantanXili 6, Dongcheng District, Beijing, China
| | - Nikhil Paliwal
- Toshiba Stroke and Vascular Research Center, University at Buffalo, The State University of New York, Buffalo, NY, USA.,Department of Mechanical and Aerospace Engineering, University at Buffalo, The State University of New York, Buffalo, NY, USA
| | - Shengzhang Wang
- Department of Mechanics and Engineering Science, Fudan University, Shanghai, China
| | - Ying Zhang
- Department of Interventional Neuroradiology, Beijing Neurosurgical Institute and Beijing Tian Tan Hospital, Capital Medical University, TiantanXili 6, Dongcheng District, Beijing, China
| | - Jianping Xiang
- Toshiba Stroke and Vascular Research Center, University at Buffalo, The State University of New York, Buffalo, NY, USA.,Department of Mechanical and Aerospace Engineering, University at Buffalo, The State University of New York, Buffalo, NY, USA
| | - Adnan H Siddiqui
- Toshiba Stroke and Vascular Research Center, University at Buffalo, The State University of New York, Buffalo, NY, USA.,Department of Neurosurgery, University at Buffalo, The State University of New York, Buffalo, NY, USA
| | - Hui Meng
- Toshiba Stroke and Vascular Research Center, University at Buffalo, The State University of New York, Buffalo, NY, USA.,Department of Mechanical and Aerospace Engineering, University at Buffalo, The State University of New York, Buffalo, NY, USA
| | - Xinjian Yang
- Department of Interventional Neuroradiology, Beijing Neurosurgical Institute and Beijing Tian Tan Hospital, Capital Medical University, TiantanXili 6, Dongcheng District, Beijing, China.
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Park W, Song Y, Park KJ, Koo HW, Yang K, Suh DC. Hemodynamic Characteristics Regarding Recanalization of Completely Coiled Aneurysms: Computational Fluid Dynamic Analysis Using Virtual Models Comparison. Neurointervention 2016; 11:30-6. [PMID: 26958410 PMCID: PMC4781914 DOI: 10.5469/neuroint.2016.11.1.30] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2016] [Accepted: 02/25/2016] [Indexed: 11/24/2022] Open
Abstract
Purpose Hemodynamic factors are considered to play an important role in initiation and progression of the recurrence after endosaccular coiling of the intracranial aneurysms. We made paired virtual models of completely coiled aneurysms which were subsequently recanalized and compared to identify hemodynamic characteristics related to the recurred aneurysmal sac. Materials and Methods We created paired virtual models of computational fluid dynamics (CFD) in five aneurysms which were initially regarded as having achieved complete occlusion and then recurred during follow-up. Paired virtual models consisted of the CFD model of 3D rotational angiography obtained in the recurred aneurysm and the control model of the initial, parent artery after artificial removal of the coiled and recanalized aneurysm. Using the CFD analysis of the virtual model, we analyzed the hemodynamic characteristics on the neck of each aneurysm before and after its recurrence. Results High wall shear stress (WSS) was identified at the cross-sectionally identified aneurysm neck at which recurrence developed in all cases. A small vortex formation with relatively low velocity in front of the neck was also identified in four cases. The aneurysm recurrence locations corresponded to the location of high WSS and/or small vortex formation. Conclusion Recanalized aneurysms revealed increased WSS and small vortex formation at the cross-sectional neck of the aneurysm. This observation may partially explain the hemodynamic causes of future recanalization after coil embolization.
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Affiliation(s)
- Wonhyoung Park
- Department of Radiology, University of Ulsan College of Medicine, Asan Medical Center, Seoul, Korea.; Department of Neurosurgery, University of Ulsan College of Medicine, Asan Medical Center, Seoul, Korea
| | - Yunsun Song
- Department of Radiology, University of Ulsan College of Medicine, Asan Medical Center, Seoul, Korea
| | - Kye Jin Park
- Department of Radiology, University of Ulsan College of Medicine, Asan Medical Center, Seoul, Korea
| | - Hae-Won Koo
- Department of Radiology, University of Ulsan College of Medicine, Asan Medical Center, Seoul, Korea
| | - Kuhyun Yang
- Department of Radiology, University of Ulsan College of Medicine, Asan Medical Center, Seoul, Korea
| | - Dae Chul Suh
- Department of Radiology, University of Ulsan College of Medicine, Asan Medical Center, Seoul, Korea
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Liu J, Jing L, Wang C, Paliwal N, Wang S, Zhang Y, Xiang J, Siddiqui AH, Meng H, Yang X. Effect of hemodynamics on outcome of subtotally occluded paraclinoid aneurysms after stent-assisted coil embolization. J Neurointerv Surg 2015; 8:1140-1147. [PMID: 26610731 DOI: 10.1136/neurintsurg-2015-012050] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2015] [Accepted: 11/09/2015] [Indexed: 11/03/2022]
Abstract
BACKGROUND Endovascular treatment of paraclinoid aneurysms is preferred in clinical practice. Flow alterations caused by stents and coils may affect treatment outcome. OBJECTIVE To assess hemodynamic changes following stent-assisted coil embolization (SACE) in subtotally embolized paraclinoid aneurysms with residual necks that were predisposed to recanalization. METHODS We studied 27 paraclinoid aneurysms (seven recanalized and 20 stable) treated with coils and Enterprise stents. Computational fluid dynamic simulations were performed on patient-specific aneurysm geometries using virtual stenting and porous media technology. RESULTS After stent placement in 27 cases, aneurysm flow velocity decreased significantly, the reduction gradually increasing from the neck plane (11.9%), to the residual neck (12.3%), to the aneurysm dome (16.3%). Subsequent coil embolization was performed after stent placement and the hemodynamic factors decreased further and significantly at all aneurysm regions except the neck plane. In a comparison of recanalized and stable cases, univariate analysis showed no significant differences in any parameter before treatment. After stent-assisted coiling, only the reduction in area-averaged velocity at the neck plane differed significantly between recanalized (8.1%) and stable cases (20.5%) (p=0.016). CONCLUSIONS Aneurysm flow velocity can be significantly decreased by stent placement and coil embolization. However, hemodynamics at the aneurysm neck plane is less sensitive to coils. Significant reduction in flow velocity at the neck plane may be an important factor in preventing recanalization of paraclinoid aneurysms after subtotal SACE.
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Affiliation(s)
- Jian Liu
- Department of Interventional Neuroradiology, Beijing Neurosurgical Institute and Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Linkai Jing
- Department of Interventional Neuroradiology, Beijing Neurosurgical Institute and Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Chao Wang
- Department of Interventional Neuroradiology, Beijing Neurosurgical Institute and Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Nikhil Paliwal
- Toshiba Stroke and Vascular Research Center, University at Buffalo, The State University of New York, Buffalo, New York, USA Department of Mechanical and Aerospace Engineering, University at Buffalo, The State University of New York, Buffalo, New York, USA
| | - Shengzhang Wang
- Department of Mechanics and Engineering Science, Fudan University, Shanghai, China
| | - Ying Zhang
- Department of Interventional Neuroradiology, Beijing Neurosurgical Institute and Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Jianping Xiang
- Toshiba Stroke and Vascular Research Center, University at Buffalo, The State University of New York, Buffalo, New York, USA Department of Mechanical and Aerospace Engineering, University at Buffalo, The State University of New York, Buffalo, New York, USA Department of Neurosurgery, University at Buffalo, The State University of New York, Buffalo, New York, USA
| | - Adnan H Siddiqui
- Toshiba Stroke and Vascular Research Center, University at Buffalo, The State University of New York, Buffalo, New York, USA Department of Neurosurgery, University at Buffalo, The State University of New York, Buffalo, New York, USA Department of Radiology, University at Buffalo, The State University of New York, Buffalo, New York, USA
| | - Hui Meng
- Toshiba Stroke and Vascular Research Center, University at Buffalo, The State University of New York, Buffalo, New York, USA Department of Mechanical and Aerospace Engineering, University at Buffalo, The State University of New York, Buffalo, New York, USA Department of Neurosurgery, University at Buffalo, The State University of New York, Buffalo, New York, USA
| | - Xinjian Yang
- Department of Interventional Neuroradiology, Beijing Neurosurgical Institute and Beijing Tiantan Hospital, Capital Medical University, Beijing, China
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Damiano RJ, Ma D, Xiang J, Siddiqui AH, Snyder KV, Meng H. Finite element modeling of endovascular coiling and flow diversion enables hemodynamic prediction of complex treatment strategies for intracranial aneurysm. J Biomech 2015; 48:3332-40. [PMID: 26169778 DOI: 10.1016/j.jbiomech.2015.06.018] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2014] [Revised: 04/13/2015] [Accepted: 06/15/2015] [Indexed: 11/29/2022]
Abstract
Endovascular interventions using coil embolization and flow diversion are becoming the mainstream treatment for intracranial aneurysms (IAs). To help assess the effect of intervention strategies on aneurysm hemodynamics and treatment outcome, we have developed a finite-element-method (FEM)-based technique for coil deployment along with our HiFiVS technique for flow diverter (FD) deployment in patient-specific IAs. We tested four clinical intervention strategies: coiling (1-8 coils), single FD, FD with adjunctive coils (1-8 coils), and overlapping FDs. By evaluating post-treatment hemodynamics using computational fluid dynamics (CFD), we compared the flow-modification performance of these strategies. Results show that a single FD provides more reduction in inflow rate than low packing density (PD) coiling, but less reduction in average velocity inside the aneurysm. Adjunctive coils add no additional reduction of inflow rate beyond a single FD until coil PD exceeds 11%. This suggests that the main role of FDs is to divert inflow, while that of coils is to create stasis in the aneurysm. Overlapping FDs decreases inflow rate, average velocity, and average wall shear stress (WSS) in the aneurysm sac, but adding a third FD produces minimal additional reduction. In conclusion, our FEM-based techniques for virtual coiling and flow diversion enable recapitulation of complex endovascular intervention strategies and detailed hemodynamics to identify hemodynamic factors that affect treatment outcome.
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Affiliation(s)
- Robert J Damiano
- Department of Mechanical and Aerospace Engineering, University at Buffalo, State University of New York, Buffalo, NY 14203, USA; Toshiba Stroke and Vascular Research Center, University at Buffalo, State University of New York, Buffalo, NY 14203, USA
| | - Ding Ma
- Department of Mechanical and Aerospace Engineering, University at Buffalo, State University of New York, Buffalo, NY 14203, USA; Toshiba Stroke and Vascular Research Center, University at Buffalo, State University of New York, Buffalo, NY 14203, USA
| | - Jianping Xiang
- Toshiba Stroke and Vascular Research Center, University at Buffalo, State University of New York, Buffalo, NY 14203, USA; Department of Neurosurgery, University at Buffalo, State University of New York, Buffalo, NY 14203, USA
| | - Adnan H Siddiqui
- Toshiba Stroke and Vascular Research Center, University at Buffalo, State University of New York, Buffalo, NY 14203, USA; Department of Neurosurgery, University at Buffalo, State University of New York, Buffalo, NY 14203, USA; Department of Radiology, University at Buffalo, State University of New York, Buffalo, NY 14203, USA
| | - Kenneth V Snyder
- Toshiba Stroke and Vascular Research Center, University at Buffalo, State University of New York, Buffalo, NY 14203, USA; Department of Neurosurgery, University at Buffalo, State University of New York, Buffalo, NY 14203, USA; Department of Radiology, University at Buffalo, State University of New York, Buffalo, NY 14203, USA
| | - Hui Meng
- Department of Mechanical and Aerospace Engineering, University at Buffalo, State University of New York, Buffalo, NY 14203, USA; Toshiba Stroke and Vascular Research Center, University at Buffalo, State University of New York, Buffalo, NY 14203, USA; Department of Neurosurgery, University at Buffalo, State University of New York, Buffalo, NY 14203, USA; Department of Biomedical Engineering, University at Buffalo,State University of New York, Buffalo, NY 14203, USA.
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Futami K, Sano H, Kitabayashi T, Misaki K, Nakada M, Uchiyama N, Ueda F. Parent artery curvature influences inflow zone location of unruptured sidewall internal carotid artery aneurysms. AJNR Am J Neuroradiol 2014; 36:342-8. [PMID: 25234030 DOI: 10.3174/ajnr.a4122] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE Future aneurysmal behaviors or treatment outcomes of cerebral aneurysms may be related to the hemodynamics around the inflow zone. Here we investigated the influence of parent artery curvature on the inflow zone location of unruptured sidewall internal carotid artery aneurysms. MATERIALS AND METHODS In 32 aneurysms, the inflow zone location was decided by 4D flow MR imaging, and the radius of the parent artery curvature was measured in 2D on an en face image of the section plane corresponding to the aneurysm orifice. RESULTS The inflow zone was on the distal neck in 10 (group 1, 31.3%), on the lateral side in 19 (group 2, 59.4%), and on the proximal neck in 3 (group 3, 9.4%) aneurysms. The radius in group 1 was significantly larger than that in group 2 (8.3 mm [4.5 mm] versus 4.5 mm [1.9 mm]; median [interquartile range]; P < .0001). All 7 aneurysms with a radius of >8.0 mm were in group 1. All 18 aneurysms with a radius of <6.0 mm were in group 2 or 3. In two group 3 aneurysms, the inflow zone was located in a part of the neck extending beyond the central axis of the parent artery. CONCLUSIONS The inflow zone locations of sidewall aneurysms can be influenced by the parent artery curvature evaluated in 2D on an en face image of the section plane corresponding to the aneurysm orifice.
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Affiliation(s)
- K Futami
- From the Department of Neurosurgery (K.F.), Mattoh-Ishikawa Central Hospital, Ishikawa, Japan
| | - H Sano
- Departments of Neurosurgery (H.S., T.K., K.M., M.N., N.U.)
| | - T Kitabayashi
- Departments of Neurosurgery (H.S., T.K., K.M., M.N., N.U.)
| | - K Misaki
- Departments of Neurosurgery (H.S., T.K., K.M., M.N., N.U.)
| | - M Nakada
- Departments of Neurosurgery (H.S., T.K., K.M., M.N., N.U.)
| | - N Uchiyama
- Departments of Neurosurgery (H.S., T.K., K.M., M.N., N.U.)
| | - F Ueda
- Radiology (F.U.), Kanazawa University School of Medicine, Ishikawa, Japan
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Chung B, Cebral JR. CFD for Evaluation and Treatment Planning of Aneurysms: Review of Proposed Clinical Uses and Their Challenges. Ann Biomed Eng 2014; 43:122-38. [DOI: 10.1007/s10439-014-1093-6] [Citation(s) in RCA: 81] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2014] [Accepted: 08/08/2014] [Indexed: 11/29/2022]
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Futami K, Sano H, Misaki K, Nakada M, Ueda F, Hamada J. Identification of the inflow zone of unruptured cerebral aneurysms: comparison of 4D flow MRI and 3D TOF MRA data. AJNR Am J Neuroradiol 2014; 35:1363-70. [PMID: 24610906 DOI: 10.3174/ajnr.a3877] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE The hemodynamics of the inflow zone of cerebral aneurysms may be a key factor in coil compaction and recanalization after endovascular coil embolization. We performed 4D flow MR imaging in conjunction with 3D TOF MRA and compared their ability to identify the inflow zone of unruptured cerebral aneurysms. MATERIALS AND METHODS This series comprised 50 unruptured saccular cerebral aneurysms in 44 patients. Transluminal color-coded 3D MRA images were created by selecting the signal-intensity ranges on 3D TOF MRA images that corresponded with both the luminal margin and the putative inflow. RESULTS 4D flow MR imaging demonstrated the inflow zone and yielded inflow velocity profiles for all 50 aneurysms. In 18 of 24 lateral-projection aneurysms (75%), the inflow zone was located distally on the aneurysmal neck. The maximum inflow velocity ranged from 285 to 922 mm/s. On 4D flow MR imaging and transluminal color-coded 3D MRA studies, the inflow zone of 32 aneurysms (64%) was at a similar location. In 91% of aneurysms whose neck section plane angle was <30° with respect to the imaging section direction on 3D TOF MRA, depiction of the inflow zone was similar on transluminal color-coded 3D MRA and 4D flow MR images. CONCLUSIONS 4D flow MR imaging can demonstrate the inflow zone and provide inflow velocity profiles. In aneurysms whose angle of the neck-section plane is obtuse vis-a-vis the imaging section on 3D TOF MRA scans, transluminal color-coded 3D MRA may depict the inflow zone reliably.
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Affiliation(s)
- K Futami
- From the Department of Neurosurgery (K.F.), Mattoh-Ishikawa Central Hospital, Ishikawa, Japan
| | - H Sano
- Departments of Neurosurgery (H.S., K.M., M.N., J.H.) and Radiology (F.U.), Kanazawa University School of Medicine, Ishikawa, Japan
| | - K Misaki
- Departments of Neurosurgery (H.S., K.M., M.N., J.H.) and Radiology (F.U.), Kanazawa University School of Medicine, Ishikawa, Japan
| | - M Nakada
- Departments of Neurosurgery (H.S., K.M., M.N., J.H.) and Radiology (F.U.), Kanazawa University School of Medicine, Ishikawa, Japan
| | - F Ueda
- From the Department of Neurosurgery (K.F.), Mattoh-Ishikawa Central Hospital, Ishikawa, Japan
| | - J Hamada
- Departments of Neurosurgery (H.S., K.M., M.N., J.H.) and Radiology (F.U.), Kanazawa University School of Medicine, Ishikawa, Japan
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14
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Emergence of the white-collar sign after coil embolization of cerebral aneurysms. Acta Neurochir (Wien) 2014; 156:11-6. [PMID: 24114076 DOI: 10.1007/s00701-013-1898-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2013] [Accepted: 09/23/2013] [Indexed: 10/26/2022]
Abstract
BACKGROUND The white-collar sign (WCS) is represented by the formation of neointimal tissue at the level of the aneurysm neck as the successful outcome on follow-up angiography after coil embolization. WCS has been reported only in aneurysms treated with Matrix® coils. This is the first study to report WCS emergence in aneurysms treated with bare platinum coils, and potential factors associated with WCS emergence were evaluated. METHOD Total 130 unruptured (female: male ratio, 100: 30; mean age, 60 years) cerebral aneurysms were treated with coil embolization. Embolization status was assessed immediately and 1 year after treatment, and emergence of WCS in follow-up angiography was assessed. We evaluated the association between WCS emergence and aneurysm location, dome diameter, neck diameter, dome-neck ratio, and type of coil used (bare platinum or bioactive). RESULTS WCS appeared in nine aneurysms (6.9%), of which six were treated only with bare platinum coils. Neck diameter was significantly smaller in the WCS-positive group than in the WCS-negative group. The proportion of aneurysms treated with bioactive coils was not significantly different between the groups. Immediate embolization status in the WCS-positive group tended to be slightly better than that in the WCS-negative group. No aneurysmal morphological characteristics other than small neck diameter were associated with WCS emergence. CONCLUSIONS WCS is not specific to bioactive coil usage. Small neck diameter was significantly associated with WCS emergence in our series. Further investigations to clarify the predictors of WCS will contribute to progress of aneurysmal embolization.
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15
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Babiker MH, Chong B, Gonzalez LF, Cheema S, Frakes DH. Finite element modeling of embolic coil deployment: multifactor characterization of treatment effects on cerebral aneurysm hemodynamics. J Biomech 2013; 46:2809-16. [PMID: 24119679 DOI: 10.1016/j.jbiomech.2013.08.021] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2012] [Revised: 08/27/2013] [Accepted: 08/31/2013] [Indexed: 10/26/2022]
Abstract
Endovascular coiling is the most common treatment for cerebral aneurysms. During the treatment, a sequence of embolic coils with different stiffness, shapes, sizes, and lengths is deployed to fill the aneurysmal sac. Although coil packing density has been clinically correlated with treatment success, many studies have also reported success at low packing densities, as well as recurrence at high packing densities. Such reports indicate that other factors may influence treatment success. In this study, we used a novel finite element approach and computational fluid dynamics (CFD) to investigate the effects of packing density, coil shape, aneurysmal neck size, and parent vessel flow rate on aneurysmal hemodynamics. The study examines a testbed of 80 unique CFD simulations of post-treatment flows in idealized basilar tip aneurysm models. Simulated coil deployments were validated against in vitro and in vivo deployments. Among the investigated factors, packing density had the largest effect on intra-aneurysmal velocities. However, multifactor analysis of variance showed that coil shape can also have considerable effects, depending on packing density and neck size. Further, linear regression analysis showed an inverse relationship between mean void diameter in the aneurysm and mean intra-aneurysmal velocities, which underscores the importance of coil distribution and thus coil shape. Our study suggests that while packing density plays a key role in determining post-treatment hemodynamics, other factors such as coil shape, aneurysmal geometry, and parent vessel flow may also be very important.
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Affiliation(s)
- M Haithem Babiker
- School of Biological and Health Systems Engineering, Arizona State University, 501 E. Tyler, ECG 334, P.O. Box 879709, Tempe, AZ 85287-9709, United States.
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16
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Jeong W, Han MH, Rhee K. Effects of framing coil shape, orientation, and thickness on intra-aneurysmal flow. Med Biol Eng Comput 2013; 51:981-90. [DOI: 10.1007/s11517-013-1073-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2012] [Accepted: 03/29/2013] [Indexed: 11/30/2022]
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17
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Babiker MH, Gonzalez LF, Albuquerque F, Collins D, Elvikis A, Zwart C, Roszelle B, Frakes DH. An In Vitro Study of Pulsatile Fluid Dynamics in Intracranial Aneurysm Models Treated with Embolic Coils and Flow Diverters. IEEE Trans Biomed Eng 2013. [DOI: 10.1109/tbme.2012.2228002] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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18
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Otani T, Nakamura M, Fujinaka T, Hirata M, Kuroda J, Shibano K, Wada S. Computational fluid dynamics of blood flow in coil-embolized aneurysms: effect of packing density on flow stagnation in an idealized geometry. Med Biol Eng Comput 2013; 51:901-10. [PMID: 23529587 DOI: 10.1007/s11517-013-1062-5] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2012] [Accepted: 03/10/2013] [Indexed: 11/30/2022]
Abstract
Coil embolization is performed to induce flow stagnation in cerebral aneurysms and enhance blood clot formation, thus preventing rupture and further growth. We investigated hemodynamics in differently positioned aneurysms coiled at various packing densities to determine the effective packing density in terms of flow stagnation. As a first step, hemodynamic simulations were conducted for idealized geometries of both terminal- and sidewall-type aneurysms. Porous media modeling was employed to describe blood flow in coil-embolized aneurysms. The stagnant volume ratio (SVR) was analyzed to quantify the efficacy of coil embolization. Regardless of aneurysm type and angle, SVR increased with increasing packing density, but the increase in SVR varied depending on type. For sidewall-type aneurysms, the packing density required to achieve 60 % SVR was 20 %, roughly independent of aneurysm angle; flow stagnation was achieved at low packing density. In contrast, in terminal-type aneurysms, the packing density required to achieve 60 % SVR was highly dependent on aneurysm angle, accomplishing a 20 % packing density only for lower angles. Indications are that a relatively high packing density would be required, particularly when these aneurysms are angled against the parent artery. The packing density required for flow stagnation varies depending on aneurysm type and relative position.
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Affiliation(s)
- Tomohiro Otani
- Graduate School of Engineering Science, Osaka University, Machikaneyama-chou 1-3, Toyonaka, Osaka 560-8531, Japan
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19
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Computer Simulations in Stroke Prevention: Design Tools and Virtual Strategies Towards Procedure Planning. Cardiovasc Eng Technol 2013. [DOI: 10.1007/s13239-013-0134-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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20
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Irie K, Anzai H, Kojima M, Honjo N, Ohta M, Hirose Y, Negoro M. Computational fluid dynamic analysis following recurrence of cerebral aneurysm after coil embolization. Asian J Neurosurg 2013; 7:109-15. [PMID: 23293665 PMCID: PMC3532756 DOI: 10.4103/1793-5482.103706] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Hemodynamic factors are thought to play important role in the initiation, growth, and rupture of cerebral aneurysms. However, hemodynamic features in the residual neck of incompletely occluded aneurysms and their influences on recanalization are rarely reported. This study characterized the hemodynamics of incompletely occluded aneurysms that had been confirmed to undergo recanalization during long-term follow-up using computational fluid dynamic analysis. A ruptured left basilar-SCA aneurysm was incompletely occluded and showed recanalization during 11 years follow-up period. We retrospectively characterized on three-dimensional MR angiography. After subtotal occlusion, the flow pattern, wall shear stress (WSS), and velocity at the remnant neck changed during long-term follow-up period. Specifically, high WSS region and high blood flow velocity were found near the neck. Interestingly, these area of the remnant neck coincided with the location of aneurysm recanalization. High WSS and blood flow velocity were consistently observed near the remnant neck of incompletely occluded aneurysm, prone to future recanalization. It will suggest that hemodynamic factors may play important roles in aneurismal recurrence after endovascular treatment.
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Affiliation(s)
- Keiko Irie
- Department of Neurosurgery, Fujita Health University, Toyoake city Aichi 470-1192, Japan
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21
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Tang AYS, Chan HN, Tsang ACO, Leung GKK, Leung KM, Yu ACH, Chow KW. The effects of stent porosity on the endovascular treatment of intracranial aneurysms located near a bifurcation. ACTA ACUST UNITED AC 2013. [DOI: 10.4236/jbise.2013.68099] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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22
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Morales HG, Larrabide I, Geers AJ, San Román L, Blasco J, Macho JM, Frangi AF. A virtual coiling technique for image-based aneurysm models by dynamic path planning. IEEE TRANSACTIONS ON MEDICAL IMAGING 2013; 32:119-129. [PMID: 23008248 DOI: 10.1109/tmi.2012.2219626] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Computational algorithms modeling the insertion of endovascular devices, such as coil or stents, have gained an increasing interest in recent years. This scientific enthusiasm is due to the potential impact that these techniques have to support clinicians by understanding the intravascular hemodynamics and predicting treatment outcomes. In this work, a virtual coiling technique for treating image-based aneurysm models is proposed. A dynamic path planning was used to mimic the structure and distribution of coils inside aneurysm cavities, and to reach high packing densities, which is desirable by clinicians when treating with coils. Several tests were done to evaluate the performance on idealized and image-based aneurysm models. The proposed technique was validated using clinical information of real coiled aneurysms. The virtual coiling technique reproduces the macroscopic behavior of inserted coils and properly captures the densities, shapes and coil distributions inside aneurysm cavities. A practical application was performed by assessing the local hemodynamic after coiling using computational fluid dynamics (CFD). Wall shear stress and intra-aneurysmal velocities were reduced after coiling. Additionally, CFD simulations show that coils decrease the amount of contrast entering the aneurysm and increase its residence time.
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Affiliation(s)
- Hernán G Morales
- Center for Computational Imaging and Simulation Technologies in Biomedicine (CISTIB), Information and Communications Technologies Department, Universitat Pompeu Fabra (UPF), Barcelona, Spain.
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23
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Morales HG, Larrabide I, Geers AJ, Dai D, Kallmes DF, Frangi AF. Analysis and quantification of endovascular coil distribution inside saccular aneurysms using histological images. J Neurointerv Surg 2012; 5 Suppl 3:iii33-7. [PMID: 22914746 DOI: 10.1136/neurintsurg-2012-010456] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
OBJECTIVE Endovascular coiling is often performed by first placing coils along the aneurysm wall to create a frame and then by filling up the aneurysm core. However, little attention has been paid to quantifying this filling strategy and to see how it changes for different packing densities. The purpose of this work is to analyze and quantify endovascular coil distribution inside aneurysms based on serial histological images of experimental aneurysms. METHOD Seventeen histological images from 10 elastase-induced saccular aneurysms in rabbits treated with coils were studied. In-slice coil density, defined as the area taken up by coil winds, was calculated on each histological image. Images were analyzed by partitioning the aneurysm along its longitudinal and radial axes. Coil distribution was quantified by measuring and comparing the in-slice coil density of each partition. RESULTS Mean total in-slice coil density was 22.0 ± 6.2% (range 10.1-30.2%). The density was non-significantly different (p = 0.465) along the longitudinal axis. A significant difference (p < 0.001) between peripheral and core densities was found. Additionally, the peripheral-core density ratio was observed to be inversely proportional to the total in-slice coil density (R(2)=0.57, p <0.001). This ratio was near unity for high in-slice coil density (around 30%). CONCLUSIONS These findings demonstrate and confirm that coils tend to be located near the aneurysm periphery when few are inserted. However, when more coils are added, the radial distribution becomes more homogeneous. Coils are homogeneously distributed along the longitudinal axis.
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Affiliation(s)
- Hernán G Morales
- Center for Computational Imaging and Simulation Technologies in Biomedicine (CISTIB), Information and Communication Technologies Department, Universitat Pompeu Fabra, Barcelona, Spain
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24
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Li C, Wang S, Chen J, Yu H, Zhang Y, Jiang F, Mu S, Li H, Yang X. Influence of hemodynamics on recanalization of totally occluded intracranial aneurysms: a patient-specific computational fluid dynamic simulation study. J Neurosurg 2012; 117:276-83. [PMID: 22680247 DOI: 10.3171/2012.5.jns111558] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Object
Some totally occluded intracranial aneurysms may recur. The role of hemodynamic mechanisms in this process remains to be elucidated. The authors used computational fluid dynamic analysis and investigated the local hemodynamic characteristics at the aneurysm neck before and after total embolization, attempting to identify hemodynamic risk factors leading to recurrence of totally embolized aneurysms.
Methods
Between May 2008 and June 2010, the authors recruited 17 consecutive patients with totally occluded intracranial aneurysms (7 recanalized and 10 stable lesions). Using patient-specific 3D digital subtraction angiography data, the hemodynamic features before and after embolization were retrospectively characterized.
Results
The overall preembolization blood flow patterns were nearly the same in the recanalized and stable groups, with no significant difference in either the maximum wall shear stress (WSS) (p = 0.914) or the spatially averaged WSS (p = 0.322) at peak systole at the aneurysm neck. After occlusion, the overall flow pattern changed, and the WSS distribution at the treated aneurysm neck differed in the 2 groups. In all of the 7 recanalized cases, both the maximum WSS and spatially averaged WSS at peak systole at the treated aneurysm neck were higher than those at the aneurysm neck before embolization. In contrast, both parameters were decreased in 70%–80% of the stable cases. After embolization, both the maximum WSS (p = 0.021) and spatially averaged WSS (p = 0.041) at peak systole at the treated aneurysm neck were higher in the recanalized group than in the stable group.
Conclusions
Higher WSS at the treated aneurysm neck after total embolization can be an important hemodynamic factor that contributes to aneurysm recurrence after endovascular treatment.
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Affiliation(s)
- Chuanhui Li
- 1Beijing Tiantan Hospital, Beijing Neurosurgical Institute, and
| | - Shengzhang Wang
- 3Department of Mechanics and Engineering Science, Fudan University, Shanghai; and
| | - Jialiang Chen
- 3Department of Mechanics and Engineering Science, Fudan University, Shanghai; and
| | - Hongyu Yu
- 2Department of Biomedical Engineering, Capital Medical University, Beijing
| | - Ying Zhang
- 1Beijing Tiantan Hospital, Beijing Neurosurgical Institute, and
| | - Fan Jiang
- 4Key Laboratory of Cardiovascular Remodeling and Function Research, Medical School and Qilu Hospital, Shandong University, Jinan, Shandong Province, China
| | - Shiqing Mu
- 1Beijing Tiantan Hospital, Beijing Neurosurgical Institute, and
| | - Haiyun Li
- 2Department of Biomedical Engineering, Capital Medical University, Beijing
| | - Xinjian Yang
- 1Beijing Tiantan Hospital, Beijing Neurosurgical Institute, and
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25
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Hemodynamics of cerebral aneurysms: computational analyses of aneurysm progress and treatment. COMPUTATIONAL AND MATHEMATICAL METHODS IN MEDICINE 2012; 2012:782801. [PMID: 22454695 PMCID: PMC3290806 DOI: 10.1155/2012/782801] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/22/2011] [Accepted: 11/10/2011] [Indexed: 12/02/2022]
Abstract
The progression of a cerebral aneurysm involves degenerative arterial wall remodeling. Various hemodynamic parameters are suspected to be major mechanical factors related to the genesis and progression of vascular diseases. Flow alterations caused by the insertion of coils and stents for interventional aneurysm treatment may affect the aneurysm embolization process. Therefore, knowledge of hemodynamic parameters may provide physicians with an advanced understanding of aneurysm progression and rupture, as well as the effectiveness of endovascular treatments. Progress in medical imaging and information technology has enabled the prediction of flow fields in the patient-specific blood vessels using computational analysis. In this paper, recent computational hemodynamic studies on cerebral aneurysm initiation, progress, and rupture are reviewed. State-of-the-art computational aneurysmal flow analyses after coiling and stenting are also summarized. We expect the computational analysis of hemodynamics in cerebral aneurysms to provide valuable information for planning and follow-up decisions for treatment.
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26
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Morales HG, Kim M, Vivas EE, Villa-Uriol MC, Larrabide I, Sola T, Guimaraens L, Frangi AF. How do coil configuration and packing density influence intra-aneurysmal hemodynamics? AJNR Am J Neuroradiol 2011; 32:1935-41. [PMID: 21885712 DOI: 10.3174/ajnr.a2635] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE Endovascular coiling is a well-established therapy for treating intracranial aneurysms. Nonetheless, postoperative hemodynamic changes induced by this therapy remain not fully understood. The purpose of this work is to assess the influence of coil configuration and packing density on intra-aneurysmal hemodynamics. MATERIALS AND METHODS Three 3D rotational angiography images of 3 intracranial aneurysms before and after endovascular coiling were used. For each aneurysm, a 3D representation of the vasculature was obtained after the segmentation of the images. Afterward, a virtual coiling technique was used to treat the aneurysm geometries with coil models. The aneurysms were coiled with 5 packing densities, and each was generated by using 3 coil configurations. Computational fluid dynamics analyses were carried out in both untreated and treated aneurysm geometries. Statistical tests were performed to evaluate the relative effect of coil configuration on local hemodynamics. RESULTS The intra-aneurysmal blood flow velocity and wall shear stress were diminished as packing density increased. Aneurysmal flow velocity was reduced >50% due to the first inserted coils (packing density <12%) but with a high dependency on coil configuration. Nonsignificant differences (P > .01) were found in the hemodynamics due to coil configuration for high packing densities (near 30%). A damping effect was observed on the intra-aneurysmal blood flow waveform after coiling. CONCLUSIONS Intra-aneurysmal hemodynamics are altered by coils. Coil configuration might reduce its influence on intra-aneurysmal hemodynamics as the packing density increases until an insignificant influence could be achieved for high packing densities.
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Affiliation(s)
- H G Morales
- Center for Computational Imaging & Simulation Technologies in Biomedicine, Information & Communication Technologies Department, Universitat Pompeu Fabra, Barcelona, Spain.
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27
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Luo B, Yang X, Wang S, Li H, Chen J, Yu H, Zhang Y, Zhang Y, Mu S, Liu Z, Ding G. High shear stress and flow velocity in partially occluded aneurysms prone to recanalization. Stroke 2011; 42:745-53. [PMID: 21233477 DOI: 10.1161/strokeaha.110.593517] [Citation(s) in RCA: 97] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND AND PURPOSE Hemodynamic factors are thought to play an important role in the initiation, growth, and rupture of cerebral aneurysms. However, the hemodynamic features in the residual neck of the partially embolized aneurysms and their influences on recanalization are rarely reported. In this study, we characterized the hemodynamics of partially occluded aneurysms, which were proven to undergo recanalization during follow-up using computational fluid dynamic analysis. METHODS From May 2007 to June 2009, we identified 11 partial aneurysms during follow-up, including 5 recanalized cases and 6 stable cases with 3-dimensional digital subtraction angiography. We retrospectively characterized the hemodynamic features around the residual aneurysmal pouch using the available postprocedural digital subtraction angiography image data. The occluded part of the aneurysm was regarded as completely separated from the circulation. RESULTS The overall blood flow patterns before embolization were almost the same in the recanalized and stable groups. After occlusion, the flow pattern changes, wall shear stress (WSS), and velocity at the remnant neck demonstrated different changes between the 2 groups. Specifically, in the recanalized group, high WSS regions were found near the neck in all 5 cases, with 4 of them being even higher than those before occlusion. Interestingly, in all cases, the high WSS area of the remnant neck coincided with the location where the aneurysm recanalization occurred. In the stable group, 5 out of 6 cases demonstrated lower WSS and velocity at the remnant neck after occlusion. CONCLUSIONS High WSS and blood flow velocity were consistently observed near the remnant neck of partially embolized aneurysms prone to future recanalization, suggesting that hemodynamic factors may have an important role in aneurysmal recurrence after endovascular treatment. The difference in flow pattern could be caused by the incomplete occlusion of the aneurysms.
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Affiliation(s)
- Bin Luo
- Department of Interventional Neuroradiology, Beijing Neurosurgical Institute, Beijing Tiantan Hospital, Tiantan Xili 6, Chongwen District, Beijing 100050, China
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28
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Goubergrits L, Thamsen B, Berthe A, Poethke J, Kertzscher U, Affeld K, Petz C, Hege HC, Hoch H, Spuler A. In vitro study of near-wall flow in a cerebral aneurysm model with and without coils. AJNR Am J Neuroradiol 2010; 31:1521-8. [PMID: 20488901 DOI: 10.3174/ajnr.a2121] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE Coil embolization procedures change the flow conditions in the cerebral aneurysm and, therefore, in the near-wall region. Knowledge of these flow changes may be helpful to optimize therapy. The goal of this study was to investigate the effect of the coil-packing attenuation on the near-wall flow and its variability due to differences in the coil structure. MATERIALS AND METHODS An enlarged transparent model of an ACA aneurysm was fabricated on the basis of CT angiography. The near-wall flow was visualized by using a recently proposed technique called Wall-PIV. Coil-packing attenuation of 10%, 15%, and 20% were investigated and compared with an aneurysmal flow without coils. Then the flow variability due to the coil introduction was analyzed in 10 experiments by using a packing attenuation of 15%. RESULTS A small packing attenuation of 10% already alters the near-wall flow significantly in a large part of the aneurysmal sac. These flow changes are characterized by a slow flow with short (interrupted) path lines. An increased packing attenuation expands the wall area exposed to the altered flow conditions. This area, however, depends on the coil position and/or on the 3D coil structure in the aneurysm. CONCLUSIONS To our knowledge, this is the first time the near-wall flow changes caused by coils in an aneurysm model have been visualized. It can be concluded that future hydrodynamic studies of coil therapy should include an investigation of the coil structure in addition to the coil-packing attenuation.
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Affiliation(s)
- L Goubergrits
- Biofluid Mechanics Laboratory Charité-Universitätsmedizin Berlin, Berlin, Germany.
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29
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Quantitative Effects of Coil Packing Density on Cerebral Aneurysm Fluid Dynamics: An In Vitro Steady Flow Study. Ann Biomed Eng 2010; 38:2293-301. [DOI: 10.1007/s10439-010-9995-4] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2009] [Accepted: 03/02/2010] [Indexed: 11/25/2022]
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30
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Ventikos Y, Holland EC, Bowker TJ, Watton PN, Kakalis NMP, Megahed M, Zhu F, Summers PE, Byrne JV. Computational modelling for cerebral aneurysms: risk evaluation and interventional planning. Br J Radiol 2009; 82 Spec No 1:S62-71. [DOI: 10.1259/bjr/14303482] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
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31
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Ortega J, Hartman J, Rodriguez J, Maitland D. Post-treatment hemodynamics of a basilar aneurysm and bifurcation. Ann Biomed Eng 2008; 36:1531-46. [PMID: 18629647 PMCID: PMC2704058 DOI: 10.1007/s10439-008-9535-7] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2008] [Accepted: 06/30/2008] [Indexed: 11/29/2022]
Abstract
To investigate whether or not a successful aneurysm treatment procedure can subject a parent artery to harmful hemodynamic stresses, computational fluid dynamics simulations are performed on a patient-specific basilar aneurysm and bifurcation before and after a virtual endovascular treatment. Prior to treatment, the aneurysm at systole is filled with a periodic train of vortex tubes, which form at the aneurysm neck and advect upwards into the dome. Following the treatment procedure however, the motion of the vortex train is inhibited by the aneurysm filling material, which confines the vortex tubes to the region beneath the aneurysm neck. Analysis of the post-treatment flow field indicates that the impingement of the basilar artery flow upon the treated aneurysm neck and the close proximity of a vortex tube to the parent artery wall increase the maximum wall shear stresses to values approximately equal to 50 Pa at systole. Calculation of the time-averaged wall shear stresses indicates that there is a 1.4 x 10(-7) m(2) area on the parent artery exposed to wall shear stresses greater than 37.9 Pa, a value shown by Fry [Circ. Res. 22(2):165-197, 1968] to cause severe damage to the endothelial cells that line the artery wall. The results of this study demonstrate that it is possible for a treatment procedure, which successfully isolates the aneurysm from the circulation and leaves no aneurysm neck remnant, to elevate the hemodynamic stresses to levels that are injurious to the artery wall.
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Affiliation(s)
- J Ortega
- Lawrence Livermore National Laboratory, P.O. Box 808, L-645, Livermore, CA 94550, USA.
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Ford MD, Nikolov HN, Milner JS, Lownie SP, Demont EM, Kalata W, Loth F, Holdsworth DW, Steinman DA. PIV-measured versus CFD-predicted flow dynamics in anatomically realistic cerebral aneurysm models. J Biomech Eng 2008; 130:021015. [PMID: 18412502 DOI: 10.1115/1.2900724] [Citation(s) in RCA: 152] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Computational fluid dynamics (CFD) modeling of nominally patient-specific cerebral aneurysms is increasingly being used as a research tool to further understand the development, prognosis, and treatment of brain aneurysms. We have previously developed virtual angiography to indirectly validate CFD-predicted gross flow dynamics against the routinely acquired digital subtraction angiograms. Toward a more direct validation, here we compare detailed, CFD-predicted velocity fields against those measured using particle imaging velocimetry (PIV). Two anatomically realistic flow-through phantoms, one a giant internal carotid artery (ICA) aneurysm and the other a basilar artery (BA) tip aneurysm, were constructed of a clear silicone elastomer. The phantoms were placed within a computer-controlled flow loop, programed with representative flow rate waveforms. PIV images were collected on several anterior-posterior (AP) and lateral (LAT) planes. CFD simulations were then carried out using a well-validated, in-house solver, based on micro-CT reconstructions of the geometries of the flow-through phantoms and inlet/outlet boundary conditions derived from flow rates measured during the PIV experiments. PIV and CFD results from the central AP plane of the ICA aneurysm showed a large stable vortex throughout the cardiac cycle. Complex vortex dynamics, captured by PIV and CFD, persisted throughout the cardiac cycle on the central LAT plane. Velocity vector fields showed good overall agreement. For the BA, aneurysm agreement was more compelling, with both PIV and CFD similarly resolving the dynamics of counter-rotating vortices on both AP and LAT planes. Despite the imposition of periodic flow boundary conditions for the CFD simulations, cycle-to-cycle fluctuations were evident in the BA aneurysm simulations, which agreed well, in terms of both amplitudes and spatial distributions, with cycle-to-cycle fluctuations measured by PIV in the same geometry. The overall good agreement between PIV and CFD suggests that CFD can reliably predict the details of the intra-aneurysmal flow dynamics observed in anatomically realistic in vitro models. Nevertheless, given the various modeling assumptions, this does not prove that they are mimicking the actual in vivo hemodynamics, and so validations against in vivo data are encouraged whenever possible.
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Affiliation(s)
- Matthew D Ford
- Imaging Research Laboratories, Robarts Research Institute, London, Canada N6A 5K8
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Inflow into Saccular Cerebral Aneurysms at Arterial Bends. Ann Biomed Eng 2008; 36:1489-95. [DOI: 10.1007/s10439-008-9522-z] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2007] [Accepted: 06/11/2008] [Indexed: 10/21/2022]
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Haemodynamic simulation of aneurysm coiling in an anatomically accurate computational fluid dynamics model: technical note. Neuroradiology 2007; 50:341-7. [DOI: 10.1007/s00234-007-0334-x] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2007] [Accepted: 10/17/2007] [Indexed: 11/26/2022]
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Sorteberg A, Farhoudi D. The Influence of Aneurysm Configuration on Intra-Aneurysmal Pressure and Flow. Interv Neuroradiol 2006; 12:203-14. [DOI: 10.1177/159101990601200302] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2006] [Accepted: 08/15/2006] [Indexed: 11/17/2022] Open
Abstract
Aneurysm rupture may occur in conjunction with swift pressure increases like heavy lifting. We therefore investigated the transmission of pressure waves as well as local flow rates in various types of experimental aneurysms and their parent arteries. 0.014-inch guidewires containing a combined pressure and thermistor sensor were inserted into both the dome and the parent artery of idealized silicone aneurysms mounted in a pulsatile flow phantom. Intravascular pressure and thermodilution responses to injections of room-temperatured normal saline at a rate of 5cc.s−1 over two seconds were recorded simultaneously at both sites. Flow was evaluated semiquantitatively applying the thermodilution principle. We found that the propagation of pressure was attenuated at the dome of the aneurysms compared to their respective parent arteries. This difference was more distinct in side-wall aneurysms than in bifurcational aneurysms. The attenuation of traveling pressure in the aneurysm was most effective at low systemic pressures. The intraaneurysmal flow rate was unique, always lower than in the respective parent arteries and highly dependent on the configuration of the aneurysm. We observed considerably higher flow rates in bifurcational aneurysms compared to side-wall aneurysms. Bifurcational aneurysms were hence characterized by a relatively high pressure transmission and high flow rates which may represent a stimulus for enlargement of untreated aneurysms and promote coil compaction in endovascularly treated lesions.
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Affiliation(s)
- A. Sorteberg
- Department of Neurosurgery, Rikshospitalet, The National Hospital, 0027 Oslo, Norway
| | - D. Farhoudi
- Department of Neurosurgery, Rikshospitalet, The National Hospital, 0027 Oslo, Norway
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