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Liu Z, Zhang M, Wang C, Wang Z, Liao X, Ou C, Si W. Flow diverters treatment planning of small- and medium-sized intracranial saccular aneurysms on the internal carotid artery via constraint-based virtual deployment. Int J Comput Assist Radiol Surg 2024; 19:1175-1183. [PMID: 38619792 DOI: 10.1007/s11548-024-03124-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2024] [Accepted: 03/25/2024] [Indexed: 04/16/2024]
Abstract
PURPOSE The internal carotid artery (ICA) is a region with a high incidence for small- and medium-sized saccular aneurysms. However, the treatment relies heavily on the surgeon's experience to achieve optimal outcome. Although the finite element method (FEM) and computational fluid dynamics can predict the postoperative outcomes, due to the computational complexity of traditional methods, there is an urgent need for investigating the fast but versatile approaches related to numerical simulations of flow diverters (FDs) deployment coupled with the hemodynamic analysis to determine the treatment plan. METHODS We collected the preoperative and postoperative data from 34 patients (29 females, 5 males; mean age 55.74 ± 9.98 years) who were treated with a single flow diverter for small- to medium-sized intracranial saccular aneurysms on the ICA. The constraint-based virtual deployment (CVD) method is proposed to simulate the FDs expanding outward along the vessel centerline while be constrained by the inner wall of the vessel. RESULTS The results indicate that there were no significant differences in the reduction rates of wall shear stress and aneurysms neck velocity between the FEM and methods. However, the solution time of CVD was greatly reduced by 98%. CONCLUSION In the typical location of small- and medium-sized saccular aneurysms, namely the ICA, our virtual FDs deployment simulation effectively balances the computational accuracy and efficiency. Combined with hemodynamics analysis, our method can accurately represent the blood flow changes within the lesion region to assist surgeons in clinical decision-making.
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Affiliation(s)
- Zehua Liu
- Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Xueyuan street 1068, Shenzhen University Town, Nanshan District, Shenzhen, 518000, China
| | - Meng Zhang
- Department of Neurosurgery, Shenzhen Second People's Hospital, Sungang West Road 3002, Futian District, Guangdong, 510000, China
| | - Chao Wang
- Department of Interventional Neuroradiology, Beijing Neurosurgical Institute and Beijing Tian Tan Hospital, Capital Medical University, TiantanXili 6, Dongcheng District, Beijing, 100000, China
| | - Zhongxiao Wang
- Department of Interventional Neuroradiology, Beijing Neurosurgical Institute and Beijing Tian Tan Hospital, Capital Medical University, TiantanXili 6, Dongcheng District, Beijing, 100000, China
| | - Xiangyun Liao
- Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Xueyuan street 1068, Shenzhen University Town, Nanshan District, Shenzhen, 518000, China
| | - Chubin Ou
- Department of Radiology, Guangdong Provincial People's Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, Zhongshan 2nd Road 106, Yuexiu District, Guangdong, 510000, China.
| | - Weixin Si
- Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Xueyuan street 1068, Shenzhen University Town, Nanshan District, Shenzhen, 518000, China.
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Abdollahi R, Shahi A, Roy D, Lessard S, Mongrain R, Soulez G. Virtual and analytical self-expandable braided stent treatment models. Med Eng Phys 2024; 126:104145. [PMID: 38621838 DOI: 10.1016/j.medengphy.2024.104145] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2023] [Revised: 02/25/2024] [Accepted: 03/09/2024] [Indexed: 04/17/2024]
Abstract
The Flow Diverter is a self-expandable braided stent that has helped improve the effectiveness of cerebral aneurysm treatment during the last decade. The Flow Diverter's efficiency heavily relies on proper decision-making during the pre-operative phase, which is currently based on static measurements that fail to account for vessel or tissue deformation. In the context of providing realistic measurements, a biomechanical computational method is designed to aid physicians in predicting patient-specific treatment outcomes. The method integrates virtual and analytical treatment models, validated against experimental mechanical tests, and two patient treatment outcomes. In the case of both patients, deployed stent length was one of the validated result parameters, which displayed an error inferior to 1.5% for the virtual and analytical models. These results indicated both models' accuracy. However, the analytical model provided more accurate results with a 0.3% error while requiring a lower computational cost for length prediction. This computational method can offer designing and testing platforms for predicting possible intervention-related complications, patient-specific medical device designs, and pre-operative planning to automate interventional procedures.
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Affiliation(s)
- Reza Abdollahi
- Faculté de médecine, Université de Montréal, H3T 1J4, Montréal, Canada; Centre de Recherche du Centre Hospitalier de l'Université de Montréal, H2X 0A9, Montréal, Canada
| | - Amirali Shahi
- Faculté de médecine, Université de Montréal, H3T 1J4, Montréal, Canada; Centre de Recherche du Centre Hospitalier de l'Université de Montréal, H2X 0A9, Montréal, Canada
| | - Daniel Roy
- Faculté de médecine, Université de Montréal, H3T 1J4, Montréal, Canada; Département de Radiologie, Centre Hospitalier de l'Université de Montréal, H2X 0C1, Montréal, Canada
| | - Simon Lessard
- Centre de Recherche du Centre Hospitalier de l'Université de Montréal, H2X 0A9, Montréal, Canada; École de Technologie Supérieure, H3C 1K3, Montréal, Canada
| | - Rosaire Mongrain
- Mechanical Engineering Department, McGill University, H3A 0C3, Montréal, Canada
| | - Gilles Soulez
- Faculté de médecine, Université de Montréal, H3T 1J4, Montréal, Canada; Centre de Recherche du Centre Hospitalier de l'Université de Montréal, H2X 0A9, Montréal, Canada; Département de Radiologie, Centre Hospitalier de l'Université de Montréal, H2X 0C1, Montréal, Canada.
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Jahandardoost M, Ricci D, Milani AS, Jahandardoost M, Grecov D. A comprehensive simulation framework for predicting the eCLIPs implant crimping into a catheter and its deployment mechanisms. J Mech Behav Biomed Mater 2024; 150:106227. [PMID: 37995603 DOI: 10.1016/j.jmbbm.2023.106227] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Revised: 10/25/2023] [Accepted: 11/06/2023] [Indexed: 11/25/2023]
Abstract
Tubular flow diverters (FDs) represent an important subset of the endovascular treatment of cerebral aneurysms (CAs), acting to reduce aneurysm inflow, eventually resulting in aneurysm thrombosis and occlusion. eCLIPs (product of Evasc Neurovascular Enterprises, Vancouver, Canada), an innovative non-tubular implant causes flow diversion by bridging the neck of bifurcation CAs. However, in a small subset of challenging bifurcation aneurysms with fusiform pathology, the currently available eCLIPs models do not provide sufficient neck bridging resulting in a gap created between the device structure and the aneurysm/artery wall. To overcome this challenge, a new design of the eCLIPs (VR-eCLIPs) was developed by varying the rib length to cover such an inflow gap. To optimize the new product development process, and avoiding expensive and time-consuming iterative manufacture of prototype devices, we have developed a new finite element model to simulate the crimping and expansion processes of the VR-eCLIPs implant, and assess the possibility of plastic deformation. Results indicated that neither eCLIPs nor VR-eCLIPs experience plastic deformation during the crimping process. Upon full expansion, the ribs of VR-eCLIPs interact with the aneurysm and artery wall to cover the inflow gap that exists in certain challenging anatomies. This process serves as a basis to expedite design development prior to prototype manufacturing.
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Affiliation(s)
- Mehdi Jahandardoost
- Industrial and Biological Multiphysics Research Lab, Department of Mechanical Engineering, University of British Columbia, Vancouver, BC, Canada; Materials and Manufacturing Research Institute, University of British Columbia, Kelowna, BC, Canada.
| | - Donald Ricci
- eVasc Neurovascular Enterprise, Vancouver, BC, Canada; Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada.
| | - Abbas S Milani
- Materials and Manufacturing Research Institute, University of British Columbia, Kelowna, BC, Canada; Composites Research Network-Okanagan Laboratory, School of Engineering, University of British Columbia, Kelowna, BC, Canada.
| | - Mohsen Jahandardoost
- Department of Mechanical Engineering, University of Pittsburgh, Johnstown, PA, USA.
| | - Dana Grecov
- Industrial and Biological Multiphysics Research Lab, Department of Mechanical Engineering, University of British Columbia, Vancouver, BC, Canada.
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Bisighini B, Aguirre M, Biancolini ME, Trovalusci F, Perrin D, Avril S, Pierrat B. Machine learning and reduced order modelling for the simulation of braided stent deployment. Front Physiol 2023; 14:1148540. [PMID: 37064913 PMCID: PMC10090671 DOI: 10.3389/fphys.2023.1148540] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Accepted: 03/16/2023] [Indexed: 03/31/2023] Open
Abstract
Endoluminal reconstruction using flow diverters represents a novel paradigm for the minimally invasive treatment of intracranial aneurysms. The configuration assumed by these very dense braided stents once deployed within the parent vessel is not easily predictable and medical volumetric images alone may be insufficient to plan the treatment satisfactorily. Therefore, here we propose a fast and accurate machine learning and reduced order modelling framework, based on finite element simulations, to assist practitioners in the planning and interventional stages. It consists of a first classification step to determine a priori whether a simulation will be successful (good conformity between stent and vessel) or not from a clinical perspective, followed by a regression step that provides an approximated solution of the deployed stent configuration. The latter is achieved using a non-intrusive reduced order modelling scheme that combines the proper orthogonal decomposition algorithm and Gaussian process regression. The workflow was validated on an idealized intracranial artery with a saccular aneurysm and the effect of six geometrical and surgical parameters on the outcome of stent deployment was studied. We trained six machine learning models on a dataset of varying size and obtained classifiers with up to 95% accuracy in predicting the deployment outcome. The support vector machine model outperformed the others when considering a small dataset of 50 training cases, with an accuracy of 93% and a specificity of 97%. On the other hand, real-time predictions of the stent deployed configuration were achieved with an average validation error between predicted and high-fidelity results never greater than the spatial resolution of 3D rotational angiography, the imaging technique with the best spatial resolution (0.15 mm). Such accurate predictions can be reached even with a small database of 47 simulations: by increasing the training simulations to 147, the average prediction error is reduced to 0.07 mm. These results are promising as they demonstrate the ability of these techniques to achieve simulations within a few milliseconds while retaining the mechanical realism and predictability of the stent deployed configuration.
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Affiliation(s)
- Beatrice Bisighini
- Mines Saint-Étienne, University Lyon, University Jean Monnet, INSERM, Saint-Étienne, France
- Predisurge, Grande Usine Creative 2, Saint-Etienne, France
- Department of Enterprise Engineering, University Tor Vergata, Rome, Italy
| | - Miquel Aguirre
- Mines Saint-Étienne, University Lyon, University Jean Monnet, INSERM, Saint-Étienne, France
- Laboratori de Càlcul Numèric, Universitat Politècnica de Catalunya, Barcelona, Spain
- International Centre for Numerical Methods in Engineering (CIMNE), Gran Capità, Barcelona, Spain
| | | | | | - David Perrin
- Predisurge, Grande Usine Creative 2, Saint-Etienne, France
| | - Stéphane Avril
- Mines Saint-Étienne, University Lyon, University Jean Monnet, INSERM, Saint-Étienne, France
| | - Baptiste Pierrat
- Mines Saint-Étienne, University Lyon, University Jean Monnet, INSERM, Saint-Étienne, France
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Tong X, Han M, Wu Z, Feng X, Liu A. Effects of different stent size selection on pipeline embolization device treatment of intracranial aneurysms. Ther Adv Neurol Disord 2023; 16:17562864231151475. [PMID: 36776531 PMCID: PMC9909058 DOI: 10.1177/17562864231151475] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2022] [Accepted: 12/29/2022] [Indexed: 02/09/2023] Open
Abstract
Background Pipeline embolization device (PED) is becoming increasingly common in therapeutic practice. In idealized model studies, treatment effectiveness may vary with different stent sizes in the same vasculature. The true effect of stent size selection in the clinical setting remains unknown, however. Objective To determine the true effect of stent size selection in the clinical setting. Design It is a retrospective review. Methods A retrospective review was conducted on consecutive patients with aneurysms treated with a PED at our institution. The primary exposures were the difference between the diameter of the stent and the parent artery (DD) and the difference between the length of the stent and the aneurysm neck (DL). The outcomes were the clinical and angiographic results, perioperative complications, balloon application, and in-stent stenosis. The results were generated using univariable and multivariable logistic regression and restricted cubic spline (RCS) curves. Results A larger DD was significantly associated with incomplete occlusion [odds ratio (OR) = 2.37; 95% confidence interval (CI) = 1.43-3.98; p < 0.001], while a larger DL was significantly associated with balloon application (OR = 1.12; 95% CI = 1.02-1.23; p = 0.021) and in-stent stenosis (>25%) (OR = 1.07; 95% CI = 1.01-1.16; p = 0.042). The RCS curve indicated that the risk of incomplete occlusion increased as the DD became larger, the possibility of balloon application increased as the DL increased when the DL was >5.7 mm, and the risk of in-stent stenosis (>25%) increased as the DL increased. Conclusion In the clinical setting, stent selection was associated with treatment effectiveness and may add to the treatment burden. These occurrences should be considered for aneurysms treated with PED.
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Affiliation(s)
| | | | - Zhongxue Wu
- Neurointerventional Center, Beijing Neurosurgical Institute and Beijing Tiantan Hospital, Capital University, Beijing, China
| | - Xin Feng
- Neurosurgery Center, Department of Cerebrovascular Surgery, Engineering Technology Research Center of Education Ministry of China on Diagnosis and Treatment of Cerebrovascular Disease, Zhujiang Hospital, Southern Medical University, Guangzhou 510280, China,Guangdong Provincial Key Laboratory on Brain Function Repair and Regeneration, Guangzhou, China
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Zhang M, Tian Z, Zhang Y, Zhang Y, Wang K, Leng X, Yang X, Xiang J, Liu J. How to perform intra-aneurysmal coil embolization after Pipeline deployment: a study from a hemodynamic viewpoint. J Neurointerv Surg 2023; 15:157-162. [PMID: 35135848 DOI: 10.1136/neurintsurg-2021-018361] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Accepted: 01/23/2022] [Indexed: 01/14/2023]
Abstract
BACKGROUND Pipeline embolization device (PED) deployment combined with coil therapy for large complex intracranial aneurysms is effective and considered superior to PED deployment alone. However, the optimal strategy for use of coils remains unclear. We used patient-specific aneurysm models and finite element analysis to determine the ideal packing density of coils after PED placement. METHODS Finite element analysis was used to provide a higher-fidelity model for accurate post-treatment computational fluid dynamics analysis to simulate the real therapeutic process of PED and all coils. We then calculated and analyzed the reduction ratio of velocity to identify the hemodynamic change during PED deployment and each coil embolization. RESULTS Sixteen consecutive patients underwent PED plus coil procedures to treat internal carotid artery intracranial aneurysms. After PED deployment, the intra-aneurysmal flow velocity significantly decreased (15.3 vs 10.0 cm/s; p<0.001). When the first coil was inserted, the flow velocity in the aneurysm further decreased and the reduction was significant (10.0 vs 5.3 cm/s; p<0.001). Analysis of covariance showed that the effect of the reduction ratio of velocity of the second coil was significantly lower than that of the first coil (p<0.001)-that is, when the packing density increased to 7.06%, the addition of coils produced no further hemodynamic effect. CONCLUSION Adjunct coiling could improve the post-PED hemodynamic environment in treated intracranial aneurysms. However, dense packing is not necessary because the intra-aneurysmal hemodynamics tend to stabilize as the packing density reaches an average of 7.06% or after insertion of the second coil.
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Affiliation(s)
- Mingqi Zhang
- Department of Interventional Neuroradiology, Beijing Neurosurgical Institute and Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Zhongbin Tian
- Department of Neurosurgery, Zhujiang Hospital, Southern Medical University, Guangzhou, Guangdong, China
| | - Yisen Zhang
- Department of Interventional Neuroradiology, Beijing Neurosurgical Institute and Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Ying Zhang
- Department of Interventional Neuroradiology, Beijing Neurosurgical Institute and Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Kun Wang
- Department of Interventional Neuroradiology, Beijing Neurosurgical Institute and Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | | | - Xinjian Yang
- Department of Interventional Neuroradiology, Beijing Neurosurgical Institute and Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | | | - Jian Liu
- Department of Interventional Neuroradiology, Beijing Neurosurgical Institute and Beijing Tiantan Hospital, Capital Medical University, Beijing, China
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Rehearsals using patient-specific 3D-printed aneurysm models for simulation of endovascular embolization of complex intracranial aneurysms: 3D SIM study. J Neuroradiol 2023; 50:86-92. [PMID: 34914933 DOI: 10.1016/j.neurad.2021.11.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Revised: 11/29/2021] [Accepted: 11/30/2021] [Indexed: 01/31/2023]
Abstract
BACKGROUND In neurovascular treatment planning, endovascular devices to manage complex intracranial aneurysms requiring intervention are often selected based on conventional measurements and interventional neuroradiologist experience. A recently developed technology allows a patient-specific 3D-printed model to mimic the navigation experience. The goal of this study was to assess the effect of pre-procedure 3D simulation on procedural and clinical outcomes for wide-neck aneurysm embolization. MATERIALS & METHODS In this unblinded, non-randomized, prospective, multicenter study conducted from November 18 through December 20, patients with complex intracranial aneurysms (neck > 4 mm or ratio < 21) were treated by WEB or flow diverter stents (FDS). The primary endpoint was concordance between simulation and procedure, 3D-printed model accuracy as well as embolization outcomes including complications, procedure times, and radiation dose were also assessed. Secondary endpoint was to compare versus a retrospective WEB cohort. RESULTS Twenty-one patients were treated, 76% of cases by WEB and 24% by FDS. Concordance between post-simulation and real procedure efficiency was 0.85 [0.69 - 1.00] for size device selection and 0.93 [0.79 - 1.00] for wall-apposition/aneurysm neck closure. Geometrical accuracy of the 3D-printed model showed a mean absolute shift of 0.11 mm. Two complications without major clinical impact were reported with a post-operative mRS similar to pre-procedure mRS for all patients. CONCLUSIONS Rehearsal using accurate 3D-printed patient-specific aneurysm models enabled optimization of embolization strategy, resulting in reduced procedure duration and cumulative fluoroscopy time which translated to reduced radiation exposure compared to procedures performed without simulation.
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Tong X, Shan Y, Leng X, Chen J, Fiehler J, Siddiqui AH, Hu X, Liu A, Xiang J. Predicting flow diverter sizing using the AneuGuide TM software: a validation study. J Neurointerv Surg 2023; 15:57-62. [PMID: 35039401 DOI: 10.1136/neurintsurg-2021-018353] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2021] [Accepted: 12/23/2021] [Indexed: 12/16/2022]
Abstract
BACKGROUND Stent sizing remains a challenging task for flow diverter implantation because of stent foreshortening. In this study, we aimed to quantify the change in length after implantation and assess the error in length prediction using AneuGuideTM software. METHODS In a retrospective cohort of 101 patients with 102 aneurysms undergoing treatment with a pipeline embolization device (PED; Covidien, Irvine, California, USA), we used AneuGuideTM software to obtain measured lengths (ML) and calculated lengths (CL) after stent implantation. Stent elongation was defined as the ratio of ML-LL to the labeled length (LL). Simulation error was defined as the ratio of the absolute value of CL-ML to ML. The correlation and consistency between ML and LL and between ML and CL were analyzed using Pearson's correlation test and the Bland-Altman plot. Statistical significance was set at p<0.05. RESULTS The mean elongation of ML was 32.6% (range 26.3-109.2%). Moderate consistency was observed between LL and ML (ρ=0.74, p<0.001). With the AneuGuideTM software, the mean simulation error was 6.6% (range 0.32-21.2%). Pearson's correlation test and the Bland-Altman plot showed a high correlation and consistency between ML and CL (ρ=0.96, p<0.001). CONCLUSION Labeled length provides only a low reference value for predicting the actual length of the flow diverter after implantation. The high consistency between ML and CL obtained from AneuGuideTM software shows its great potential for the optimization of the flow diverter sizing process.
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Affiliation(s)
- Xin Tong
- Neurointervention Center, Beijing Neurosurgical Institute and Beijing Tiantan Hospital, Beijing, China
| | - Yejie Shan
- ArteryFlow Technology Co., Ltd, Hangzhou, China
| | | | - Jigang Chen
- Neurointervention Center, Beijing Neurosurgical Institute and Beijing Tiantan Hospital, Beijing, China
| | - Jens Fiehler
- Department of Neuroradiology, University Medical Center Hamburg Eppendorf, Hamburg, Germany
| | - Adnan H Siddiqui
- Neurosurgery and Radiology and Canon Stroke and Vascular Research Center, University at Buffalo Jacobs School of Medicine and Biomedical Sciences, Buffalo, New York, USA
| | - Xuebin Hu
- Department of Neurosurgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Aihua Liu
- Neurointervention Center, Beijing Neurosurgical Institute and Beijing Tiantan Hospital, Beijing, China
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Jiang Y, Lu G, Ge L, Zou R, Li G, Wan H, Leng X, Xiang J, Zhang X. Hemodynamic Comparison of Treatment Strategies for Intracranial Vertebral Artery Fusiform Aneurysms. Front Neurol 2022; 13:927135. [PMID: 35873788 PMCID: PMC9296783 DOI: 10.3389/fneur.2022.927135] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2022] [Accepted: 06/06/2022] [Indexed: 11/23/2022] Open
Abstract
Objective This study comparatively analyzed the hemodynamic changes resulting from various simulated stent-assisted embolization treatments to explore an optimal treatment strategy for intracranial vertebral artery fusiform aneurysms. An actual vertebral fusiform aneurysm case treated by large coil post-stenting (PLCS) was used as a control. Materials and Methods A single case of an intracranial vertebral artery fusiform aneurysm underwent a preoperative and eight postoperative finite element treatment simulations: PLCS [single and dual Low-profile Visualized Intraluminal Support (LVIS)], Jailing technique (single and dual LVIS both simulated twice, Pipeline Embolization Device (PED) with or without large coils (LCs). Qualitative and quantitative assessments were performed to analyze the most common hemodynamic risk factors for recurrence. Results Jailing technique and PED-only had a high residual flow volume (RFV) and wall shear stress (WSS) on the large curvature of the blood flow impingement region. Quantitative analysis determined that PLSC and PED had a lower RFV compared to preoperative than did the jailing technique [PED+LC 2.46% < PLCS 1.2 (dual LVIS) 4.75% < PLCS 1.1 (single LVIS) 6.34% < PED 6.58% < Jailing 2.2 12.45% < Jailing 1.2 12.71% < Jailing 1.1 14.28% < Jailing 2.1 16.44%]. The sac-averaged flow velocity treated by PLCS, PED and PED+LC compared to preoperatively was significantly lower than the jailing technique [PED+LC = PLCS 1.2 (dual LVIS) 17.5% < PLCS 1.1 (single LVIS) = PED 27.5% < Jailing 1.2 = Jailing 2.2 32.5% < Jailing 1.1 37.5% < Jailing 2.1 40%]. The sac-averaged WSS for the PLCS 1.2 (dual LVIS) model was lower than the PED+LC, while the high WSS area of the Jailing 1 model was larger than for Jailing 2 [PLCS 1.2 38.94% (dual LVIS) < PED+LC 41% < PLCS 1.1 43.36% (single LVIS) < PED 45.23% < Jailing 2.1 47.49% < Jailing 2.2 47.79% < Jailing 1.1 48.97% < Jailing 1.2 49.85%]. Conclusions For fusiform aneurysms, post large coil stenting can provide a uniform coil configuration potentially reducing the hemodynamic risk factors of recurrence. Flow diverters also may reduce the recurrence risk, with long-term follow-up required, especially to monitor branch blood flow to prevent postoperative ischemia.
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Affiliation(s)
- Yeqing Jiang
- Huashan Hospital, Fudan University, Shanghai, China
| | - Gang Lu
- Huashan Hospital, Fudan University, Shanghai, China
| | - Liang Ge
- Huashan Hospital, Fudan University, Shanghai, China
| | - Rong Zou
- ArteryFlow Technology Co., Ltd, Hangzhou, China
| | - Gaohui Li
- ArteryFlow Technology Co., Ltd, Hangzhou, China
| | - Hailin Wan
- Huashan Hospital, Fudan University, Shanghai, China
| | | | - Jianping Xiang
- ArteryFlow Technology Co., Ltd, Hangzhou, China
- *Correspondence: Jianping Xiang
| | - Xiaolong Zhang
- Huashan Hospital, Fudan University, Shanghai, China
- Xiaolong Zhang
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Shiozaki S, Otani T, Fujimura S, Takao H, Wada S. Computational modeling of braided-stent deployment for interpreting the mechanism of stent flattening. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2021; 37:e3335. [PMID: 32212324 DOI: 10.1002/cnm.3335] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2019] [Revised: 02/20/2020] [Accepted: 03/16/2020] [Indexed: 06/10/2023]
Abstract
This study develops a computational model of the braided stent for interpreting the mechanism of stent flattening during deployment into curved arteries. Stent wires are expressed using Kirchhoff's rod theory and their mechanical behavior is treated using a corotational beam formulation. The equation of motion of the braided stent is solved in a step-by-step manner using the resultant elastic force and mechanical interactions of wires with friction. Examples of braided-stent deployment into idealized arteries with various curvatures are numerically simulated. In cases of low curvature, the braided stent expands from a catheter by releasing the bending energy stored in stent wires, while incomplete expansion is found at both stent ends (ie, the fish-mouth phenomenon), where relatively little bending energy is stored. In cases of high curvature, much torsional energy is stored in stent wires locally in the midsection of the curvature and the bending energy for stent self-expansion is not fully released even after deployment, leading to stent flattening. These findings suggest that the mechanical state of the braided stent and its transition during deployment play an important role in the underlying mechanism of stent flattening. NOVELTY STATEMENT: This study developed a computational mechanical model of the braided stent for interpreting stent flattening, which is a critical issue observed during deployment into highly curved arteries. Mechanical behaviors of the stent wires are appropriately treated by corotational beam element formulation with considering multiple contacts. We conducted numerical examples of the stent deployment into curved arteries and found that the mechanical state of the braided stent during deployment associated with occurrences of the stent flattening. We believe this finding gives new insight into the mechanism of stent flattening and would advance the design of the stent and its deployment protocol.
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Affiliation(s)
- Shunya Shiozaki
- Department of Mechanical Science and Bioengineering, Graduate School of Engineering Science, Osaka University, Toyonaka, Japan
| | - Tomohiro Otani
- Department of Mechanical Science and Bioengineering, Graduate School of Engineering Science, Osaka University, Toyonaka, Japan
| | - Soichiro Fujimura
- Department of Innovation for Medical Information Technology, The Jikei University School of Medicine, Minato-ku, Japan
- Graduate School of Mechanical Engineering, Tokyo University of Science, Katsushika-ku, Japan
| | - Hiroyuki Takao
- Department of Innovation for Medical Information Technology, The Jikei University School of Medicine, Minato-ku, Japan
- Graduate School of Mechanical Engineering, Tokyo University of Science, Katsushika-ku, Japan
- Department of Neurosurgery, The Jikei University School of Medicine, Minato-ku, Japan
| | - Shigeo Wada
- Department of Mechanical Science and Bioengineering, Graduate School of Engineering Science, Osaka University, Toyonaka, Japan
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Gyürki D, Csippa B, Paál G, Szikora I. Impact of Design and Deployment Technique on the Hydrodynamic Resistance of Flow Diverters : An in Vitro Experimental Study. Clin Neuroradiol 2021; 32:107-115. [PMID: 34686884 PMCID: PMC8894302 DOI: 10.1007/s00062-021-01106-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2021] [Accepted: 09/22/2021] [Indexed: 11/27/2022]
Abstract
PURPOSE Despite the high efficacy of flow diverters (FD) in treating sidewall intracranial aneurysms, failures are reported. One of the physical factors determining efficacy is the flow reducing capacity of the FD that is currently unknown to the operator. Our aim was to measure the flow reducing capacity expressed as the hydrodynamic resistance (HR), the metallic surface area (MSA) and pore density (PD) of two different FD designs and quantitatively investigate the impact of sizing and the deployment technique on these parameters. METHODS Altogether 38 Pipeline (Medtronic) and P64 (Phenox) FD‑s were implanted in holder tubes by a neurointerventionist in nominally sized, oversized and longitudinally compressed or elongated manners. The tubes were placed in a flow model with the flow directed across the FD through a side hole on the tube. HR was expressed by the measured pressure drop as the function of the flow rate. Deployed length, MSA and PD were also measured and correlated with the HR. RESULTS Both PD and MSA changed with varying deployment length, which correlates well with the change in HR. Oversizing the device by 1 mm in diameter has reduced the HR on average to one fifth of the original value for both manufacturers. CONCLUSION This study demonstrates experimentally that different FD designs have different flow diverting capacities (HR). Parameters are greatly influenced by radial sizing and longitudinal compression or elongation during implantation. Our results might be useful in procedure planning, predicting clinical outcome, and in patient-specific numerical flow simulations.
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Affiliation(s)
- Dániel Gyürki
- Department of Hydrodynamic Systems, Faculty of Mechanical Engineering, Budapest University of Technology and Economics, Műegyetem rkp. 3., D building, 3rd floor, 1111, Budapest, Hungary.
| | - Benjamin Csippa
- Department of Hydrodynamic Systems, Faculty of Mechanical Engineering, Budapest University of Technology and Economics, Műegyetem rkp. 3., D building, 3rd floor, 1111, Budapest, Hungary
| | - György Paál
- Department of Hydrodynamic Systems, Faculty of Mechanical Engineering, Budapest University of Technology and Economics, Műegyetem rkp. 3., D building, 3rd floor, 1111, Budapest, Hungary
| | - István Szikora
- Department of Neurointerventions, National Institute of Clinical Neurosciences, Budapest, Hungary
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12
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Lamooki SR, Tutino VM, Paliwal N, Damiano RJ, Waqas M, Nagesh SSV, Rajabzadeh-Oghaz H, Vakharia K, Siddiqui AH, Meng H. Evaluation of Two Fast Virtual Stenting Algorithms for Intracranial Aneurysm Flow Diversion. Curr Neurovasc Res 2021; 17:58-70. [PMID: 31987021 DOI: 10.2174/1567202617666200120141608] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2019] [Revised: 11/13/2019] [Accepted: 11/25/2019] [Indexed: 11/22/2022]
Abstract
BACKGROUND Endovascular treatment of intracranial aneurysms (IAs) by flow diverter (FD) stents depends on flow modification. Patient-specific modeling of FD deployment and computational fluid dynamics (CFD) could enable a priori endovascular strategy optimization. We developed a fast, simplistic, expansion-free balls-weeping algorithm to model FDs in patientspecific aneurysm geometry. However, since such strong simplification could result in less accurate simulations, we also developed a fast virtual stenting workflow (VSW) that explicitly models stent expansion using pseudo-physical forces. METHODS To test which of these two fast algorithms more accurately simulates real FDs, we applied them to virtually treat three representative patient-specific IAs. We deployed Pipeline Embolization Device into 3 patient-specific silicone aneurysm phantoms and simulated the treatments using both balls-weeping and VSW algorithms in computational aneurysm models. We then compared the virtually deployed FD stents against experimental results in terms of geometry and post-treatment flow fields. For stent geometry, we evaluated gross configurations and porosity. For post-treatment aneurysmal flow, we compared CFD results against experimental measurements by particle image velocimetry. RESULTS We found that VSW created more realistic FD deployments than balls-weeping in terms of stent geometry, porosity and pore density. In particular, balls-weeping produced unrealistic FD bulging at the aneurysm neck, and this artifact drastically increased with neck size. Both FD deployment methods resulted in similar flow patterns, but the VSW had less error in flow velocity and inflow rate. CONCLUSION In conclusion, modeling stent expansion is critical for preventing unrealistic bulging effects and thus should be considered in virtual FD deployment algorithms. Also endowed with its high computational efficiency and superior accuracy, the VSW algorithm is a better candidate for implementation into a bedside clinical tool for FD deployment simulation.
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Affiliation(s)
- Saeb R Lamooki
- Canon Stroke and Vascular Research Center, University at Buffalo, Buffalo, NY, United States.,Department of Mechanical & Aerospace Engineering, University at Buffalo, Buffalo, NY, United States
| | - Vincent M Tutino
- Canon Stroke and Vascular Research Center, University at Buffalo, Buffalo, NY, United States.,Department of Biomedical Engineering, University at Buffalo, Buffalo, NY, United States.,Department of Neurosurgery, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY, United States.,Department of Pathology and Anatomical Sciences, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY, United States
| | - Nikhil Paliwal
- Canon Stroke and Vascular Research Center, University at Buffalo, Buffalo, NY, United States.,Department of Mechanical & Aerospace Engineering, University at Buffalo, Buffalo, NY, United States
| | - Robert J Damiano
- Canon Stroke and Vascular Research Center, University at Buffalo, Buffalo, NY, United States.,Department of Mechanical & Aerospace Engineering, University at Buffalo, Buffalo, NY, United States
| | - Muhammad Waqas
- Canon Stroke and Vascular Research Center, University at Buffalo, Buffalo, NY, United States.,Department of Neurosurgery, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY, United States
| | - Setlur S V Nagesh
- Canon Stroke and Vascular Research Center, University at Buffalo, Buffalo, NY, United States.,Department of Neurosurgery, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY, United States.,Department of Radiology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY, United States
| | - Hamidreza Rajabzadeh-Oghaz
- Canon Stroke and Vascular Research Center, University at Buffalo, Buffalo, NY, United States.,Department of Mechanical & Aerospace Engineering, University at Buffalo, Buffalo, NY, United States
| | - Kunal Vakharia
- Department of Neurosurgery, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY, United States
| | - Adnan H Siddiqui
- Canon Stroke and Vascular Research Center, University at Buffalo, Buffalo, NY, United States.,Department of Neurosurgery, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY, United States.,Department of Neurology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY, United States
| | - Hui Meng
- Canon Stroke and Vascular Research Center, University at Buffalo, Buffalo, NY, United States.,Department of Mechanical & Aerospace Engineering, University at Buffalo, Buffalo, NY, United States.,Department of Biomedical Engineering, University at Buffalo, Buffalo, NY, United States.,Department of Neurosurgery, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY, United States
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13
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Fast virtual coiling algorithm for intracranial aneurysms using pre-shape path planning. Comput Biol Med 2021; 134:104496. [PMID: 34077817 DOI: 10.1016/j.compbiomed.2021.104496] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Revised: 05/11/2021] [Accepted: 05/12/2021] [Indexed: 09/30/2022]
Abstract
To aid in predicting and improving treatment outcome of endovascular coiling of intracranial aneurysms, simulation of patient-specific coil deployment should be both accurate and fast. We developed a fast virtual coiling algorithm called Pre-shape Path Planning (P3). It captures the mechanical propensity of a released coil to restore its pre-shape for bending energy minimization, producing coils without unrealistic kinks and bends. A coil is discretized into finite-length segments and extruded from the delivery catheter segment-by-segment following a generic coil pre-shape. With the release of each segment, coil-wall and coil-coil collisions are detected and resolved. Modeling of each case took seconds to minutes. To test the algorithm, we evaluated its output against the literature, experiments, and patient angiograms. The periphery-to-core ratio of coils deployed by P3 decreased with increasing coil packing density, consistent with observations in the literature. Coils deployed by P3 compared well with in vitro experiments, free from unphysical kinks and loops that arose from previous virtual coiling algorithms. Simulations of coiling in four patient-specific aneurysms agreed well with the patient angiograms. To test the influence of coil pre-shape on P3, we performed hemodynamic simulations in aneurysms with coils deployed by P3 using the generic pre-shape, P3 using a coil-specific pre-shape, and full finite-element-method simulation. We found that the generic pre-shape was sufficient to produce results comparable to virtual coiling by finite element modeling. Based on these findings, P3 can rapidly simulate coiling in patient-specific aneurysms with good accuracy and is thus a potential candidate for clinical treatment planning.
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14
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Leng X, Wan H, Li G, Jiang Y, Huang L, Siddiqui AH, Zhang X, Xiang J. Hemodynamic effects of intracranial aneurysms from stent-induced straightening of parent vessels by stent-assisted coiling embolization. Interv Neuroradiol 2021; 27:181-190. [PMID: 33641496 DOI: 10.1177/1591019921995334] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
BACKGROUND Straightening of parent vessels happens for stent-assisted coiling embolization (SACE) treatment of intracranial aneurysms. This study aims to investigate aneurysmal hemodynamic modifications caused by stent-induced vessel straightening. METHODS Stent and coil deployments of a SACE-treated distal bifurcation aneurysm by finite element method were performed first with the preoperative (not straightened, NS) and postoperative (straightened, S) vessel models respectively. Computational fluid dynamics were then performed for eight models, including (I) NS only model, (II) NS+stent model, (III) NS+coils model, (IV) NS+stent+coils model, (V) S only model, (VI) S+stent model, (VII) S+coils model, and (VIII) S+stent+coils model. Finally, changes in aneurysmal flow velocity, isovelocity surface and wall shear stress (WSS) were analyzed qualitatively and quantitatively. RESULTS The flow was less in the S models than that in the corresponding NS models. Coils blocked most of the flow into the aneurysm sac in both NS models and S models and vessel straightening had more profound effect on the high aneurysmal flow volume reduction than coiling, while stenting generated adverse effect on flow reduction. Taking the NS only model as baseline (100%), the sac-averaged velocities of models II to VIII were 112%, 36%, 42%, 45%, 39%, 12%, 13%, and high flow volumes were 119%, 21%, 30%, 10%, 8%, 3%, 3%, while the sac-averaged WSSs were 106%, 37%, 44%, 41%, 35%, 17% and 24%, respectively. CONCLUSIONS Stent-induced vessel straightening combined coil embolization has the best performance in hemodynamic modifications and may reduce the recurrence rate, whereas stenting may generate adverse effect on hemodynamic alterations.
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Affiliation(s)
- Xiaochang Leng
- ArteryFlow Technology Co., Ltd., Hangzhou, China.,School of Civil Engineering and Architecture, Nanchang University, Nanchang, China
| | - Hailin Wan
- Department of Radiology, Huashan Hospital Affiliated to Fudan University, Shanghai, China
| | - Gaohui Li
- ArteryFlow Technology Co., Ltd., Hangzhou, China
| | - Yeqing Jiang
- Department of Radiology, Huashan Hospital Affiliated to Fudan University, Shanghai, China
| | - Lei Huang
- Department of Radiology, Huashan Hospital Affiliated to Fudan University, Shanghai, China
| | - Adnan H Siddiqui
- Department of Neurosurgery and Radiology, University at Buffalo, The State University of New York, Buffalo, NY, USA
| | - Xiaolong Zhang
- Department of Radiology, Huashan Hospital Affiliated to Fudan University, Shanghai, China
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15
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Sunohara T, Imamura H, Goto M, Fukumitsu R, Matsumoto S, Fukui N, Oomura Y, Akiyama T, Fukuda T, Go K, Kajiura S, Shigeyasu M, Asakura K, Horii R, Sakai C, Sakai N. Neck Location on the Outer Convexity is a Predictor of Incomplete Occlusion in Treatment with the Pipeline Embolization Device: Clinical and Angiographic Outcomes. AJNR Am J Neuroradiol 2021; 42:119-125. [PMID: 33184073 DOI: 10.3174/ajnr.a6859] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Accepted: 08/11/2020] [Indexed: 12/11/2022]
Abstract
BACKGROUND AND PURPOSE With the increasing use of the Pipeline Embolization Device for the treatment of aneurysms, predictors of clinical and angiographic outcomes are needed. This study aimed to identify predictors of incomplete occlusion at last angiographic follow-up. MATERIALS AND METHODS In our retrospective, single-center cohort study, 105 ICA aneurysms in 89 subjects were treated with Pipeline Embolization Devices. Patients were followed per standardized protocol. Clinical and angiographic outcomes were analyzed. We introduced a new morphologic classification based on the included angle of the parent artery against the neck location: outer convexity type (included angle, <160°), inner convexity type (included angle, >200°), and lateral wall type (160° ≤ included angle ≤200°). This classification reflects the metal coverage rate and flow dynamics. RESULTS Imaging data were acquired in 95.3% of aneurysms persistent at 6 months. Complete occlusion was achieved in 70.5%, and incomplete occlusion, in 29.5% at last follow-up. Multivariable regression analysis revealed that 60 years of age or older (OR, 5.70; P = .001), aneurysms with the branching artery from the dome (OR, 10.56; P = .002), fusiform aneurysms (OR, 10.2; P = .009), and outer convexity-type saccular aneurysms (versus inner convexity type: OR, 30.3; P < .001; versus lateral wall type: OR, 9.71; P = .001) were independently associated with a higher rate of incomplete occlusion at the last follow-up. No permanent neurologic deficits or rupture were observed in the follow-up period. CONCLUSIONS The aneurysm neck located on the outer convexity is a new, incomplete occlusion predictor, joining older age, fusiform aneurysms, and aneurysms with the branching artery from the dome. No permanent neurologic deficits or rupture was observed in the follow-up, even with incomplete occlusion.
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Affiliation(s)
- T Sunohara
- From the Department of Neurosurgery, Kobe City Medical Center General Hospital, Kobe, Japan.
| | - H Imamura
- From the Department of Neurosurgery, Kobe City Medical Center General Hospital, Kobe, Japan
| | - M Goto
- From the Department of Neurosurgery, Kobe City Medical Center General Hospital, Kobe, Japan
| | - R Fukumitsu
- From the Department of Neurosurgery, Kobe City Medical Center General Hospital, Kobe, Japan
| | - S Matsumoto
- From the Department of Neurosurgery, Kobe City Medical Center General Hospital, Kobe, Japan
| | - N Fukui
- From the Department of Neurosurgery, Kobe City Medical Center General Hospital, Kobe, Japan
| | - Y Oomura
- From the Department of Neurosurgery, Kobe City Medical Center General Hospital, Kobe, Japan
| | - T Akiyama
- From the Department of Neurosurgery, Kobe City Medical Center General Hospital, Kobe, Japan
| | - T Fukuda
- From the Department of Neurosurgery, Kobe City Medical Center General Hospital, Kobe, Japan
| | - K Go
- From the Department of Neurosurgery, Kobe City Medical Center General Hospital, Kobe, Japan
| | - S Kajiura
- From the Department of Neurosurgery, Kobe City Medical Center General Hospital, Kobe, Japan
| | - M Shigeyasu
- From the Department of Neurosurgery, Kobe City Medical Center General Hospital, Kobe, Japan
| | - K Asakura
- From the Department of Neurosurgery, Kobe City Medical Center General Hospital, Kobe, Japan
| | - R Horii
- From the Department of Neurosurgery, Kobe City Medical Center General Hospital, Kobe, Japan
| | - C Sakai
- From the Department of Neurosurgery, Kobe City Medical Center General Hospital, Kobe, Japan
| | - N Sakai
- From the Department of Neurosurgery, Kobe City Medical Center General Hospital, Kobe, Japan
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16
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A Brush-Spin-Coating Method for Fabricating In Vitro Patient-Specific Vascular Models by Coupling 3D-Printing. Cardiovasc Eng Technol 2020; 12:200-214. [PMID: 33263929 DOI: 10.1007/s13239-020-00504-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Accepted: 11/18/2020] [Indexed: 12/31/2022]
Abstract
PURPOSE In vitro patient-specific flexible vascular models are helpful for understanding the haemodynamic changes before and after endovascular treatment and for effective training of neuroendovascular interventionalists. However, it is difficult to fabricate models of overall unified or controllable thickness using existing manufacturing methods. In this study, we developed an improved and easily implemented method by combining 3D printing and brush-spin-coating processes to produce a transparent silicone model of uniform or varied thickness. METHODS First, a water-soluble inner-skeleton model, based on clinical data, was printed on a 3D printer. The skeleton model was subsequently fixed in a single-axis-rotation machine to enable continuous coating of silicone, the thickness of which was manually controlled by adsorption and removal of excess silicone in a brush-spinning operation. After the silicone layer was solidified, the inner skeleton was further dissolved in a hot water bath, affording a transparent vascular model with real geometry. To verify the controllability of the coating thickness by using this method, a straight tube, an idealised aneurysm model, a patient-specific aortic arch model, and an abdominal aortic aneurysm model were manufactured. RESULTS The different thicknesses of the manufactured tubes could be well controlled, with the relative standard deviations being 5.6 and 8.1% for the straight and aneurysm tubes, respectively. Despite of the diameter changing from 33 to 20 mm in the patient-specific aorta, the thickness of the fabricated aortic model remains almost the same along the longitudinal direction with a lower standard deviation of 3.1%. In the more complex patient-specific abdominal aneurysm model, varied thicknesses were realized to mimic the measured data from the CT images, where the middle of the aneurysm was with 2 mm and abdominal aorta as well as the iliac arteries had the normal thickness of 2.3 mm. CONCLUSION Through the brush-spin-coating method, models of different sizes and complexity with prescribed thickness can be manufactured, which will be helpful for developing surgical treatment strategies or training neuroendovascular interventionalists.
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17
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Maragkos GA, Dmytriw AA, Salem MM, Tutino VM, Meng H, Cognard C, Machi P, Krings T, Mendes Pereira V. Overview of Different Flow Diverters and Flow Dynamics. Neurosurgery 2020; 86:S21-S34. [PMID: 31838536 DOI: 10.1093/neuros/nyz323] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Accepted: 04/30/2019] [Indexed: 12/16/2022] Open
Abstract
Over the past decade, flow diverter technology for endocranial aneurysms has seen rapid evolution, with the development of new devices quickly outpacing the clinical evidence base. However, flow diversion has not yet been directly compared to surgical aneurysm clipping or other endovascular procedures. The oldest and most well-studied device is the Pipeline Embolization Device (PED; Medtronic), recently transitioned to the Pipeline Flex (Medtronic), which still has sparse data regarding outcomes. To date, other flow diverting devices have not been shown to outperform the PED, although information comes primarily from retrospective studies with short follow-up, which are not always comparable. Because of this lack of high-quality outcome data, no reliable recommendations can be made for choosing among flow diversion devices yet. Moreover, the decision to proceed with flow diversion should be individualized to each patient. In this work, we wish to provide a comprehensive overview of the technical specifications of all flow diverter devices currently available, accompanied by a succinct description of the evidence base surrounding each device.
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Affiliation(s)
- Georgios A Maragkos
- Neurosurgical Service, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts
| | - Adam A Dmytriw
- Neurosurgical Service, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts.,Department of Medical Imaging, Toronto Western Hospital and St. Michael's Hospital, University of Toronto, Toronto, Canada
| | - Mohamed M Salem
- Neurosurgical Service, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts
| | - Vincent M Tutino
- Canon Stroke and Vascular Research Center, University at Buffalo, Clinical and Translational Research Center, New York
| | - Hui Meng
- Canon Stroke and Vascular Research Center, University at Buffalo, Clinical and Translational Research Center, New York
| | - Christophe Cognard
- Department of Diagnostic and Therapeutic Neuroradiology, Centre Hopitalier de Toulouse, Toulouse, France
| | - Paolo Machi
- Department of Neuroradiology, Montpellier University Hospital, Montpellier, France
| | - Timo Krings
- Department of Medical Imaging, Toronto Western Hospital and St. Michael's Hospital, University of Toronto, Toronto, Canada
| | - Vitor Mendes Pereira
- Department of Medical Imaging, Toronto Western Hospital and St. Michael's Hospital, University of Toronto, Toronto, Canada
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18
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Zhang M, Tupin S, Anzai H, Kohata Y, Shojima M, Suzuki K, Okamoto Y, Tanaka K, Yagi T, Fujimura S, Ohta M. Implementation of computer simulation to assess flow diversion treatment outcomes: systematic review and meta-analysis. J Neurointerv Surg 2020; 13:164-170. [PMID: 33097626 PMCID: PMC7848055 DOI: 10.1136/neurintsurg-2020-016724] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Revised: 09/11/2020] [Accepted: 09/17/2020] [Indexed: 12/31/2022]
Abstract
Introduction Despite a decade of research into virtual stent deployment and the post-stenting aneurysmal hemodynamics, the hemodynamic factors which correlate with successful treatment remain inconclusive. We aimed to examine the differences in various post-treatment hemodynamic parameters between successfully and unsuccessfully treated cases, and to quantify the additional flow diversion achievable through stent compaction or insertion of a second stent. Methods A systematic review and meta-analysis were performed on eligible studies published from 2000 to 2019. We first classified cases according to treatment success (aneurysm occlusion) and then calculated the pooled standardized mean differences (SMD) of each available parameter to examine their association with clinical outcomes. Any additional flow diversion arising from the two common strategies for improving the stent wire density was quantified by pooling the results of such studies. Results We found that differences in the aneurysmal inflow rate (SMD −6.05, 95% CI −10.87 to −1.23, p=0.01) and energy loss (SMD −5.28, 95% CI −7.09 to −3.46, p<0.001) between the successfully and unsuccessfully treated groups were indicative of statistical significance, in contrast to wall shear stress (p=0.37), intra-aneurysmal average velocity (p=0.09), vortex core-line length (p=0.46), and shear rate (p=0.09). Compacting a single stent could achieve additional flow diversion comparable to that by dual-stent implantation. Conclusions Inflow rate and energy loss have shown promise as identifiers to discriminate between successful and unsuccessful treatment, pending future research into their diagnostic performance to establish optimal cut-off values.
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Affiliation(s)
- Mingzi Zhang
- Biomedical Flow Dynamics Laboratory, Tohoku University Institute of Fluid Science, Sendai, Miyagi, Japan
| | - Simon Tupin
- Biomedical Flow Dynamics Laboratory, Tohoku University Institute of Fluid Science, Sendai, Miyagi, Japan
| | - Hitomi Anzai
- Biomedical Flow Dynamics Laboratory, Tohoku University Institute of Fluid Science, Sendai, Miyagi, Japan
| | - Yutaro Kohata
- Biomedical Flow Dynamics Laboratory, Tohoku University Institute of Fluid Science, Sendai, Miyagi, Japan
| | - Masaaki Shojima
- Department of Neurosurgery, Saitama Medical University Saitama Medical Center, Kawagoe, Saitama, Japan
| | - Kosuke Suzuki
- Department of Mechanical and Electrical Engineering, Nagoya Institute of Technology, Nagoya, Aichi, Japan
| | - Yoshihiro Okamoto
- Division of Medical Devices, National Institute of Health Sciences, Kawasaki, Kanagawa, Japan
| | - Katsuhiro Tanaka
- Department of Neurosurgery, Mie Central Medical Center, Tsu, Mie, Japan
| | - Takanobu Yagi
- Center for Advanced Biomedical Sciences (TWIns), Waseda University, Shinjuku, Tokyo, Japan
| | - Soichiro Fujimura
- Department of Innovation for Medical Information Technology, Jikei University School of Medicine, Minato, Tokyo, Japan.,Graduate School of Mechanical Engineering, Tokyo University of Science, Shinjuku, Tokyo, Japan
| | - Makoto Ohta
- Biomedical Flow Dynamics Laboratory, Tohoku University Institute of Fluid Science, Sendai, Miyagi, Japan .,ElyTMaX, CNRS - Université de Lyon - Tohoku University, International Joint Unit, Tohoku University, Sendai, Miyagi, Japan
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19
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Tian Z, Zhang M, Li G, Jin R, Leng X, Zhang Y, Wang K, Zhang Y, Yang X, Xiang J, Liu J. Hemodynamic differences by increasing low profile visualized intraluminal support (LVIS) stent local compaction across intracranial aneurysm orifice. Interv Neuroradiol 2020; 26:557-565. [PMID: 32830566 DOI: 10.1177/1591019920952903] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
BACKGROUND The Low-profile Visualized Intraluminal Support device (LVIS) has been successfully used to treat cerebral aneurysm, and the push-pull technique has been used clinically to compact the stent across aneurysm orifice. Our aim was to exhibit the hemodynamic effect of the compacted LVIS stent. METHODS Two patient-specific aneurysm models were constructed from three-dimensional angiographic images. The uniform LVIS stent, compacted LVIS and Pipeline Embolization Device (PED) with or without coil embolization were virtually deployed into aneurysm models to perform hemodynamic analysis. Intra-aneurysmal flow parameters were calculated to assess hemodynamic differences among different models. RESULTS The compacted LVIS had the highest metal coverage across the aneurysm orifice (case 1, 46.37%; case 2, 67.01%). However, the PED achieved the highest pore density (case 1, 19.56 pores/mm2; case 2, 18.07 pores/mm2). The compacted LVIS produced a much higher intra-aneurysmal flow reduction than the uniform LVIS. The PED showed a higher intra-aneurysmal flow reduction than the compacted LVIS in case 1, but the results were comparable in case 2. After stent placement, the intra-aneurysmal flow was further reduced as subsequent coil embolization. The compacted LVIS stent with coils produced a similar reduction in intra-aneurysmal flow to that of the PED. CONCLUSIONS The combined characteristics of stent metal coverage and pore density should be considered when assessing the flow diversion effects of stents. More intra-aneurysmal flow reductions could be introduced by compacted LVIS stent than the uniform one. Compared with PED, compacted LVIS stent may exhibit a flow-diverting effect comparable to that of the PED.
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Affiliation(s)
- Zhongbin Tian
- Department of Interventional Neuroradiology, Beijing Neurosurgical Institute and Beijing Tian Tan Hospital, Capital Medical University, Beijing, China
| | - Mingqi Zhang
- Department of Interventional Neuroradiology, Beijing Neurosurgical Institute and Beijing Tian Tan Hospital, Capital Medical University, Beijing, China
| | - Gaohui Li
- ArteryFlow Technology Co., Ltd, Hangzhou, China
| | - Rongbo Jin
- ArteryFlow Technology Co., Ltd, Hangzhou, China
| | | | - Ying Zhang
- Department of Interventional Neuroradiology, Beijing Neurosurgical Institute and Beijing Tian Tan Hospital, Capital Medical University, Beijing, China
| | - Kun Wang
- Department of Interventional Neuroradiology, Beijing Neurosurgical Institute and Beijing Tian Tan Hospital, Capital Medical University, Beijing, China
| | - Yisen Zhang
- Department of Interventional Neuroradiology, Beijing Neurosurgical Institute and Beijing Tian Tan Hospital, Capital Medical University, Beijing, China
| | - Xinjian Yang
- Department of Interventional Neuroradiology, Beijing Neurosurgical Institute and Beijing Tian Tan Hospital, Capital Medical University, Beijing, China
| | | | - Jian Liu
- Department of Interventional Neuroradiology, Beijing Neurosurgical Institute and Beijing Tian Tan Hospital, Capital Medical University, Beijing, China
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20
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Závodszky G, Csippa B, Paál G, Szikora I. A novel virtual flow diverter implantation method with realistic deployment mechanics and validated force response. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2020; 36:e3340. [PMID: 32279440 PMCID: PMC7317397 DOI: 10.1002/cnm.3340] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/17/2019] [Revised: 04/01/2020] [Accepted: 04/02/2020] [Indexed: 06/11/2023]
Abstract
Virtual flow diverter deployment techniques underwent significant development during the last couple of years. Each existing technique displays advantageous features, as well as significant limitations. One common drawback is the lack of quantitative validation of the mechanics of the device. In the following work, we present a new spring-mass-based method with validated mechanical responses that combines many of the useful capabilities of previous techniques. The structure of the virtual braids naturally incorporates the axial length changes as a function of the local expansion diameter. The force response of the model was calibrated using the measured response of real FDs. The mechanics of the model allows to replicate the expansion process during deployment, including additional effects such as the push-pull technique that is required for the deployment of braided FDs to achieve full opening and proper wall apposition. Furthermore, it is a computationally highly efficient solution that requires little pre-processing and has a run-time of a few seconds on a general laptop and thus allows for exploratory analyses. The model was applied in a patient-specific geometry, where corresponding accurate control measurements in a 3D-printed model were also available. The analysis shows the effects of FD oversizing and push-pull application on the radial expansion, surface density, and on the wall contact pressure.
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Affiliation(s)
- Gábor Závodszky
- Computational Science Lab, Faculty of Science, Institute for InformaticsUniversity of AmsterdamAmsterdamNetherlands
- Department of Hydrodynamic SystemsBudapest University of Technology and EconomicsBudapestHungary
| | - Benjámin Csippa
- Department of Hydrodynamic SystemsBudapest University of Technology and EconomicsBudapestHungary
| | - György Paál
- Department of Hydrodynamic SystemsBudapest University of Technology and EconomicsBudapestHungary
| | - István Szikora
- Department of NeurointerventionsNational Institute of Clinical NeurosciencesBudapestHungary
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21
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Saqr KM, Rashad S, Tupin S, Niizuma K, Hassan T, Tominaga T, Ohta M. What does computational fluid dynamics tell us about intracranial aneurysms? A meta-analysis and critical review. J Cereb Blood Flow Metab 2020; 40:1021-1039. [PMID: 31213162 PMCID: PMC7181089 DOI: 10.1177/0271678x19854640] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Despite the plethora of published studies on intracranial aneurysms (IAs) hemodynamic using computational fluid dynamics (CFD), limited progress has been made towards understanding the complex physics and biology underlying IA pathophysiology. Guided by 1733 published papers, we review and discuss the contemporary IA hemodynamics paradigm established through two decades of IA CFD simulations. We have traced the historical origins of simplified CFD models which impede the progress of comprehending IA pathology. We also delve into the debate concerning the Newtonian fluid assumption used to represent blood flow computationally. We evidently demonstrate that the Newtonian assumption, used in almost 90% of studies, might be insufficient to describe IA hemodynamics. In addition, some fundamental properties of the Navier-Stokes equation are revisited in supplementary material to highlight some widely spread misconceptions regarding wall shear stress (WSS) and its derivatives. Conclusively, our study draws a roadmap for next-generation IA CFD models to help researchers investigate the pathophysiology of IAs.
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Affiliation(s)
- Khalid M Saqr
- Biomedical Flow Dynamics Laboratory, Institute of Fluid Science, Tohoku University, Sendai, Miyagi, Japan.,Department of Mechanical Engineering, College of Engineering and Technology, Arab Academy for Science, Technology and Maritime Transport, Alexandria, Egypt
| | - Sherif Rashad
- Department of Neurosurgical Engineering and Translational Neuroscience, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan.,Department of Neurosurgery, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan
| | - Simon Tupin
- Biomedical Flow Dynamics Laboratory, Institute of Fluid Science, Tohoku University, Sendai, Miyagi, Japan
| | - Kuniyasu Niizuma
- Department of Neurosurgical Engineering and Translational Neuroscience, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan.,Department of Neurosurgery, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan.,Department of Neurosurgical Engineering and Translational Neuroscience, Graduate School of Biomedical Engineering, Tohoku University, Sendai, Japan
| | - Tamer Hassan
- Department of Neurosurgery, Alexandria University School of Medicine, Azarita Medical Campus, Alexandria, Egypt
| | - Teiji Tominaga
- Department of Neurosurgery, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan
| | - Makoto Ohta
- Biomedical Flow Dynamics Laboratory, Institute of Fluid Science, Tohoku University, Sendai, Miyagi, Japan
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22
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Cai Y, Meng Z, Jiang Y, Zhang X, Yang X, Wang S. Finite element modeling and simulation of the implantation of braided stent to treat cerebral aneurysm. MEDICINE IN NOVEL TECHNOLOGY AND DEVICES 2020. [DOI: 10.1016/j.medntd.2020.100031] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
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23
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Computational methods applied to analyze the hemodynamic effects of flow-diverter devices in the treatment of cerebral aneurysms: Current status and future directions. MEDICINE IN NOVEL TECHNOLOGY AND DEVICES 2019. [DOI: 10.1016/j.medntd.2019.100018] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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24
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Voß S, Beuing O, Janiga G, Berg P. Stent-induced vessel deformation after intracranial aneurysm treatment – A hemodynamic pilot study. Comput Biol Med 2019; 111:103338. [DOI: 10.1016/j.compbiomed.2019.103338] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Revised: 06/18/2019] [Accepted: 06/18/2019] [Indexed: 12/13/2022]
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25
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Ospel JM, Gascou G, Costalat V, Piergallini L, Blackham KA, Zumofen DW. Comparison of Pipeline Embolization Device Sizing Based on Conventional 2D Measurements and Virtual Simulation Using the Sim&Size Software: An Agreement Study. AJNR Am J Neuroradiol 2019; 40:524-530. [PMID: 30733254 DOI: 10.3174/ajnr.a5973] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Accepted: 01/04/2019] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE The Sim&Size software simulates case-specific intraluminal Pipeline Embolization Device behavior, wall apposition, and device length in real-time on the basis of rotational angiography DICOM data. The purpose of this multicenter study was to evaluate whether preimplantation device simulation with the Sim&Size software results in selection of different device dimensions than manual sizing. MATERIALS AND METHODS In a multicenter cohort of 74 patients undergoing aneurysm treatment with the Pipeline Embolization Device, we compared apparent optimal device dimensions determined by neurointerventionalists with considerable Pipeline Embolization Device experience based on manual 2D measurements taken from rotational angiography with computed optimal dimensions determined by Sim&Size experts blinded to the neurointerventionalists' decision. Agreement between manually determined and computed optimal dimensions was evaluated with the Cohen κ. The significance of the difference was analyzed with the Wilcoxon signed rank test. RESULTS The agreement index between manual selection and computed optimal dimensions was low (κ for diameter = 0.219; κ for length = 0.149, P < .01). Computed optimal device lengths were significantly shorter (median, 14 versus 16 mm, T = 402, r = -0.28, P < .01). No significant difference was observed for device diameters. CONCLUSIONS Low agreement between manually determined and computed optimal device dimensions is not proof, per se, that virtual simulation performs better than manual selection. Nevertheless, it ultimately reflects the potential for optimization of the device-sizing process, and use of the Sim&Size software reduces, in particular, device length. Nevertheless, further evaluation is required to clarify the impact of device-dimension modifications on outcome.
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Affiliation(s)
- J M Ospel
- From the Diagnostic and Interventional Neuroradiology Section (J.M.O., K.A.B., D.W.Z.), Department of Radiology and Nuclear Medicine
| | - G Gascou
- Department of Neuroradiology (G.G., V.C., L.P.), Hôpital Gui de Chauliac, Centre Hospitalier Universitaire de Montpellier, University of Montpellier, Montpellier, France
| | - V Costalat
- Department of Neuroradiology (G.G., V.C., L.P.), Hôpital Gui de Chauliac, Centre Hospitalier Universitaire de Montpellier, University of Montpellier, Montpellier, France
| | - L Piergallini
- Department of Neuroradiology (G.G., V.C., L.P.), Hôpital Gui de Chauliac, Centre Hospitalier Universitaire de Montpellier, University of Montpellier, Montpellier, France.,Postgraduation School of Radiodiagnostics (L.P.), Università degli Studi di Milano, Milan, Italy
| | - K A Blackham
- From the Diagnostic and Interventional Neuroradiology Section (J.M.O., K.A.B., D.W.Z.), Department of Radiology and Nuclear Medicine
| | - D W Zumofen
- From the Diagnostic and Interventional Neuroradiology Section (J.M.O., K.A.B., D.W.Z.), Department of Radiology and Nuclear Medicine.,Department of Neurosurgery (D.W.Z.), University Hospital Basel, University of Basel, Basel, Switzerland
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26
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Zhu Y, Zhang H, Zhang Y, Wu H, Wei L, Zhou G, Zhang Y, Deng L, Cheng Y, Li M, Santos HA, Cui W. Endovascular Metal Devices for the Treatment of Cerebrovascular Diseases. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2019; 31:e1805452. [PMID: 30589125 DOI: 10.1002/adma.201805452] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Revised: 09/20/2018] [Indexed: 06/09/2023]
Abstract
Cerebrovascular disease involves various medical disorders that obstruct brain blood vessels or deteriorate cerebral circulation, resulting in ischemic or hemorrhagic stroke. Nowadays, platinum coils with or without biological modification have become routine embolization devices to reduce the risk of cerebral aneurysm bleeding. Additionally, many intracranial stents, flow diverters, and stent retrievers have been invented with uniquely designed structures. To accelerate the translation of these devices into clinical usage, an in-depth understanding of the mechanical and material performance of these metal-based devices is critical. However, considering the more distal location and tortuous anatomic characteristics of cerebral arteries, present devices still risk failing to arrive at target lesions. Consequently, more flexible endovascular devices and novel designs are under urgent demand to overcome the deficiencies of existing devices. Herein, the pros and cons of the current structural designs are discussed when these devices are applied to the treatment of diseases ranging broadly from hemorrhages to ischemic strokes, in order to encourage further development of such kind of devices and investigation of their use in the clinic. Moreover, novel biodegradable materials and drug elution techniques, and the design, safety, and efficacy of personalized devices for further clinical applications in cerebral vasculature are discussed.
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Affiliation(s)
- Yueqi Zhu
- Department of Radiology, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, No. 600, Yishan Road, Shanghai, 200233, P. R. China
| | - Hongbo Zhang
- Shanghai Key Laboratory for Prevention and Treatment of Bone and Joint Diseases, Shanghai Institute of Traumatology and Orthopaedics, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, 197 Ruijin 2nd Road, Shanghai, 200025, P. R. China
- Department of Pharmaceutical Sciences Laboratory, Åbo Akademi University, Turku, FI-20520, Finland
- Turku Center for Biotechnology, University of Turku and Åbo Akademi University, Turku, FI-20520, Finland
| | - Yiran Zhang
- Department of Radiology, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, No. 600, Yishan Road, Shanghai, 200233, P. R. China
| | - Huayin Wu
- Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, 02138, USA
| | - Liming Wei
- Department of Radiology, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, No. 600, Yishan Road, Shanghai, 200233, P. R. China
| | - Gen Zhou
- Department of Radiology, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, No. 600, Yishan Road, Shanghai, 200233, P. R. China
| | - Yuezhou Zhang
- Department of Pharmaceutical Sciences Laboratory, Åbo Akademi University, Turku, FI-20520, Finland
- Turku Center for Biotechnology, University of Turku and Åbo Akademi University, Turku, FI-20520, Finland
| | - Lianfu Deng
- Shanghai Key Laboratory for Prevention and Treatment of Bone and Joint Diseases, Shanghai Institute of Traumatology and Orthopaedics, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, 197 Ruijin 2nd Road, Shanghai, 200025, P. R. China
| | - Yingsheng Cheng
- Department of Radiology, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, No. 600, Yishan Road, Shanghai, 200233, P. R. China
| | - Minghua Li
- Department of Radiology, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, No. 600, Yishan Road, Shanghai, 200233, P. R. China
| | - Hélder A Santos
- Drug Research Program, Division of Pharmaceutical Chemistry and Technology, Faculty of Pharmacy, University of Helsinki, FI-00014, Helsinki, Finland
- Helsinki Institute of Life Science, University of Helsinki, FI-00014, Helsinki, Finland
| | - Wenguo Cui
- Shanghai Key Laboratory for Prevention and Treatment of Bone and Joint Diseases, Shanghai Institute of Traumatology and Orthopaedics, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, 197 Ruijin 2nd Road, Shanghai, 200025, P. R. China
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27
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Leng X, Wang Y, Xu J, Jiang Y, Zhang X, Xiang J. Numerical simulation of patient-specific endovascular stenting and coiling for intracranial aneurysm surgical planning. J Transl Med 2018; 16:208. [PMID: 30031395 PMCID: PMC6054731 DOI: 10.1186/s12967-018-1573-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Accepted: 07/07/2018] [Indexed: 11/17/2022] Open
Abstract
Background In this study, we develop reliable and practical virtual coiling and stenting methods for intracranial aneurysm surgical planning. Since the purpose of deploying coils and stents is to provide device geometries for subsequent accurate post-treatment computational fluid dynamics analysis, we do not need to accurately capture all the details such as the stress and force distribution for the devices and vessel walls. Our philosophy for developing these methods is to balance accuracy and practicality. Methods We consider the mechanical properties of the devices and recapitulate the clinical practice using a finite element method (FEM) approach. At the same time, we apply some simplifications for FEM modeling to make our methods efficient. For the virtual coiling, the coils are modeled as 3D Euler–Bernoulli beam elements, which is computationally efficient and provides good geometry representation. During the stent deployment process, the stent–catheter system is transformed according to the centerline of the parent vessel since the final configuration of the stent is not dependent of the deployment history. The aneurysm and vessel walls are assumed to be rigid and are fully constrained during the simulation. All stent–catheter system and coil–catheter system are prepared and packaged as a library which contains all types of stents, coils and catheters, which improves the efficiency of surgical planning process. Results The stent was delivered to the suitable position during the clinical treatment, achieving good expansion and apposition of the stent to the arterial wall. The coil was deployed into the aneurysm sac and deformed to different shapes because of the stored strain energy during coil package process and the direction of the microcatheter. Conclusions The method which we develop here could become surgical planning for intracranial aneurysm treatment in the clinical workflow.
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Affiliation(s)
- Xiaochang Leng
- ArteryFlow Technology Co., Ltd, 459 Qianmo Road, Suite C1-501, Binjiang District, Hangzhou, 310000, Zhejiang Province, China
| | - Yang Wang
- Department of Neurosurgery, The First Affiliated Hospital of Nanchang University, Nanchang University, Nanchang, China
| | - Jing Xu
- Department of Neurosurgery, The Second Affiliated Hospital of Zhejiang University, Zhejiang University, Hangzhou, China
| | - Yeqing Jiang
- Department of Radiology, Huashan Hospital Affiliated to Fudan University, No. 12 Wulumuqi Zhong Road, Shanghai, 200040, China
| | - Xiaolong Zhang
- Department of Radiology, Huashan Hospital Affiliated to Fudan University, No. 12 Wulumuqi Zhong Road, Shanghai, 200040, China.
| | - Jianping Xiang
- ArteryFlow Technology Co., Ltd, 459 Qianmo Road, Suite C1-501, Binjiang District, Hangzhou, 310000, Zhejiang Province, China.
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28
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Berg P, Saalfeld S, Janiga G, Brina O, Cancelliere NM, Machi P, Pereira VM. Virtual stenting of intracranial aneurysms: A pilot study for the prediction of treatment success based on hemodynamic simulations. Int J Artif Organs 2018; 41:698-705. [PMID: 29783867 DOI: 10.1177/0391398818775521] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Endovascular treatment of intracranial aneurysms using flow-diverting devices has revolutionized the treatment of large and complex lesions due to its minimally invasive nature and potential clinical outcomes. However, incomplete or delayed occlusion and persistent intracranial aneurysm growth are still an issue for up to one-third of the patients. We evaluated two patients with intracranial aneurysm located at the internal carotid artery who were treated with flow-diverting devices and had opposite outcomes. Both patients presented with similar aneurysms and were treated with the same device, but after a 1-year follow-up, one case presented with complete occlusion (Case 1) and the other required further treatment (Case 2). To reproduce the interventions, virtual stents were deployed and blood flow simulations were carried out using the respective patient-specific geometries. Afterward, hemodynamic metrics such as aneurysmal inflow reduction, wall shear stresses, oscillatory shear, and inflow concentration indices were quantified. The hemodynamic simulations reveal that for both cases, the neck inflow was clearly reduced due to the therapy (Case 1: 19%, Case 2: 35%). In addition, relevant hemodynamic parameters such as time-averaged wall shear stress (Case 1: 35.6%, Case 2: 57%) and oscillatory shear (Case 1: 33.1%, Case 2: 26.7%) were decreased considerably. However, although stronger relative reductions occurred in the unsuccessful case, the absolute flow values in the successful case were approximately halved. The findings demonstrate that a high relative effect of endovascular devices is not necessarily associated with the desired treatment outcome. Instead, it appears that a successful intracranial aneurysm therapy requires a certain patient-specific inflow threshold.
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Affiliation(s)
- Philipp Berg
- 1 Department of Fluid Dynamics and Technical Flows, University of Magdeburg, Magdeburg, Germany.,2 Forschungscampus STIMULATE, Magdeburg, Germany
| | - Sylvia Saalfeld
- 2 Forschungscampus STIMULATE, Magdeburg, Germany.,3 Department of Simulation and Graphics, University of Magdeburg, Magdeburg, Germany
| | - Gábor Janiga
- 1 Department of Fluid Dynamics and Technical Flows, University of Magdeburg, Magdeburg, Germany.,2 Forschungscampus STIMULATE, Magdeburg, Germany
| | - Olivier Brina
- 4 Interventional Neuroradiology Unit, University Hospital of Geneva, Geneva, Switzerland
| | - Nicole M Cancelliere
- 5 Joint Department of Medical Imaging, Toronto Western Hospital, University Health Network, Toronto, ON, Canada
| | - Paolo Machi
- 4 Interventional Neuroradiology Unit, University Hospital of Geneva, Geneva, Switzerland
| | - Vitor M Pereira
- 5 Joint Department of Medical Imaging, Toronto Western Hospital, University Health Network, Toronto, ON, Canada.,6 Division of Neurosurgery, Department of Surgery, Toronto Western Hospital, University Health Network, Toronto, ON, Canada
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29
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Fu W, Xia Q, Yan R, Qiao A. Numerical investigations of the mechanical properties of braided vascular stents. Biomed Mater Eng 2017; 29:81-94. [DOI: 10.3233/bme-171714] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Affiliation(s)
- Wenyu Fu
- College of Mechanical and Electrical Engineering, Beijing Union University, Beijing 100020, China
- College of Architecture and Civil Engineering, Beijing University of Technology, Beijing 100124, China
| | - Qixiao Xia
- College of Mechanical and Electrical Engineering, Beijing Union University, Beijing 100020, China
| | - Ruobing Yan
- Department of Civil Engineering, University of Ottawa, Ottawa, K1N 6N5, Canada
| | - Aike Qiao
- College of Life Science and Bioengineering, Beijing University of Technology, Beijing 100124, China. E-mail:
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30
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Interaction between Flow Diverter and Parent Artery of Intracranial Aneurysm: A Computational Study. Appl Bionics Biomech 2017; 2017:3751202. [PMID: 29209136 PMCID: PMC5676342 DOI: 10.1155/2017/3751202] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2017] [Revised: 09/16/2017] [Accepted: 09/26/2017] [Indexed: 11/18/2022] Open
Abstract
To evaluate the influence of deployment strategy on the mechanical interaction between braided stent and parent artery of intracranial aneurysm (the elasticity of the arterial wall is considered), finite-element analyses are carried out by referring to computational models of flow-diverter device and arterial wall. Two implantation strategies are used to virtually implant the braided stent into the ideal intracranial aneurysm model. One is the noncompacted implantation method, and the other is the implantation method of using push-pull technique. During the process of the implantation, the changes of the arterial shape around the aneurysm and the changes of the wall pressure at the contact area between the braided stent and the inner wall of the artery are analyzed. The results indicate that the average contact pressure in the area of low porosity is 57 mmHg using the push-pull technique, and the average contact pressure of the parent artery is 10.45 mmHg using the non-push-pull technique. The diameter of the parent artery at the aneurismal orifice increased about 0.2 mm when using the push-pull technique, so the elasticity of the vessel should be considered in the mechanical analysis of interaction between stent and vessel.
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31
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Suzuki T, Takao H, Fujimura S, Dahmani C, Ishibashi T, Mamori H, Fukushima N, Murayama Y, Yamamoto M. Relationships between geometrical parameters and mechanical properties for a helical braided flow diverter stent. Technol Health Care 2017; 25:611-623. [DOI: 10.3233/thc-160535] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Affiliation(s)
- Takashi Suzuki
- Graduate School of Mechanical Engineering, Tokyo University of Science, Tokyo 125-8585, Japan
| | - Hiroyuki Takao
- Graduate School of Mechanical Engineering, Tokyo University of Science, Tokyo 125-8585, Japan
- Division of Endovascular Neurosurgery, Department of Neurosurgery, The Jikei University School of Medicine, Tokyo 105-8461, Japan
- Department of Innovation for Medical Information Technology, The Jikei University School of Medicine, Tokyo 105-8461, Japan
| | - Soichiro Fujimura
- Graduate School of Mechanical Engineering, Tokyo University of Science, Tokyo 125-8585, Japan
| | - Chihebeddine Dahmani
- Division of Endovascular Neurosurgery, Department of Neurosurgery, The Jikei University School of Medicine, Tokyo 105-8461, Japan
| | - Toshihiro Ishibashi
- Division of Endovascular Neurosurgery, Department of Neurosurgery, The Jikei University School of Medicine, Tokyo 105-8461, Japan
| | - Hiroya Mamori
- Department of Mechanical Engineering, Tokyo University of Science, Tokyo 125-8585, Japan
| | - Naoya Fukushima
- Department of Mechanical Engineering, Tokyo University of Science, Tokyo 125-8585, Japan
| | - Yuichi Murayama
- Division of Endovascular Neurosurgery, Department of Neurosurgery, The Jikei University School of Medicine, Tokyo 105-8461, Japan
| | - Makoto Yamamoto
- Department of Mechanical Engineering, Tokyo University of Science, Tokyo 125-8585, Japan
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32
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FU WENYU, CHENG GUANG, YAN RUOBING, QIAO AIKE. NUMERICAL INVESTIGATIONS OF THE FLEXIBILITY OF INTRAVASCULAR BRAIDED STENT. J MECH MED BIOL 2017. [DOI: 10.1142/s0219519417500750] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Braided stents are commonly used to treat cerebral aneurysm, but there is little information about the bending characteristic of braided stent used for cerebral aneurysm. This paper investigates how geometrical parameters of braided stent influence its flexibility. Eight groups of braided stent models with different geometries (i.e., nominal diameter, length, braiding angle, number of wires, diameter of wire, frictional coefficient among wires and porosity) were constructed. Parametric analyses of these models were carried out by using Abaqus/Explicit. When the nominal diameter varied from 2[Formula: see text]mm to 5.5[Formula: see text]mm, the forces required for flexural deformation decrease from [Formula: see text][Formula: see text]N to [Formula: see text][Formula: see text]N; when the axial length varied from 10[Formula: see text]mm to 40[Formula: see text]mm, the forces required for flexural deformation decrease from [Formula: see text][Formula: see text]N to [Formula: see text][Formula: see text]N; when the braiding angle increases from 30[Formula: see text] to 75[Formula: see text] (the number of wires is 48 and the diameter of the wire is 0.026[Formula: see text]mm), the forces required for bending deformation decrease from [Formula: see text][Formula: see text]N to [Formula: see text][Formula: see text]N; when the diameter of wires increases from 0.026[Formula: see text]mm to 0.052[Formula: see text]mm (the number of wires is 24 and the braiding angle is 60[Formula: see text]), the forces required for flexural deformation increase from [Formula: see text][Formula: see text]N to [Formula: see text][Formula: see text]N; and when the number of wires increases from 14 to 48 (the braiding angle is 75[Formula: see text] and the diameter of the wire is 0.026[Formula: see text]mm), the forces required for flexural deformation increase from [Formula: see text][Formula: see text]N to [Formula: see text][Formula: see text]N. From the data above it can be seen that the diameter of wires, the number of wires and braiding angle have a larger impact on bending characteristics of braided stent; and the axial length and nominal diameter have a smaller impact on bending characteristics of braided stent. Results of the present study may provide theoretical guidance for the design of self-expanding braided stent and its clinical practice.
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Affiliation(s)
- WENYU FU
- College of Mechanical and Electrical Engineering, Beijing Union University, Beijing 100020, P. R. China
- Beijing Engineering Research Center of Smart Mechanical, Innovation Design Service, Beijing 100020, P. R. China
| | - GUANG CHENG
- College of Mechanical and Electrical Engineering, Beijing Union University, Beijing 100020, P. R. China
- Beijing Engineering Research Center of Smart Mechanical, Innovation Design Service, Beijing 100020, P. R. China
| | - RUOBING YAN
- Department of Civil Engineering, University of Ottawa, Ottawa, ON, Canada K1N 6N5, Canada
| | - AIKE QIAO
- College of Life Science and Bioengineering, Beijing University of Technology, Beijing 100124, P. R. China
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Zhang M, Li Y, Zhao X, Verrelli DI, Chong W, Ohta M, Qian Y. Haemodynamic effects of stent diameter and compaction ratio on flow-diversion treatment of intracranial aneurysms: A numerical study of a successful and an unsuccessful case. J Biomech 2017; 58:179-186. [PMID: 28576622 DOI: 10.1016/j.jbiomech.2017.05.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2017] [Revised: 04/02/2017] [Accepted: 05/05/2017] [Indexed: 10/19/2022]
Abstract
BACKGROUND Compacting a flow-diverting (FD) stent is an emerging technique to create a denser configuration of wires across the aneurysm ostium. However, quantitative analyses of post-stenting haemodynamics affected by the compaction level of different stent sizes remain inconclusive. OBJECTIVE To compare the aneurysmal haemodynamic alterations after virtual FD treatments with different device diameters at different compaction ratios. METHODS We virtually implanted three sizes of FD stent, with each size deployed at four compaction ratios, into two patient aneurysms previously treated with the Silk+FD-one successful case and the other unsuccessful. Wire configurations of the FD in the 24 treatment scenarios were examined, and aneurysmal haemodynamic alterations were resolved by computational fluid dynamics (CFD) simulations. We investigated the aneurysmal flow patterns, aneurysmal average velocity (AAV), mass flowrate (MF), and energy loss (EL) in each scenario. RESULTS Compactions of the stent in the successful case resulted in a greater metal coverage rate than that achieved in the unsuccessful one. A 25% increment in compaction ratio further decreased the AAV (12%), MF (11%), and EL (9%) in both cases (average values). The averaged maximum differences attributable to device size were 10% (AAV), 8% (MF), and 9% (EL). CONCLUSIONS Both stent size and compaction level could markedly affect the FD treatment outcomes. It is therefore important to individualise the treatment plan by selecting the optimal stent size and deployment procedure. CFD simulation can be used to investigate the treatment outcomes, thereby assisting doctors in choosing a favourable treatment plan.
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Affiliation(s)
- Mingzi Zhang
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, New South Wales, Australia; Graduate School of Engineering, Tohoku University, Sendai, Miyagi, Japan
| | - Yujie Li
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, New South Wales, Australia; Graduate School of Engineering, Tohoku University, Sendai, Miyagi, Japan
| | - Xi Zhao
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, New South Wales, Australia
| | - David I Verrelli
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, New South Wales, Australia
| | - Winston Chong
- Neuroradiology Department, Monash Medical Centre, Melbourne, Victoria, Australia; Department of Surgery, School of Clinical Sciences, Faculty of Medicine, Nursing and Health Sciences, Monash University, Clayton, Victoria, Australia
| | - Makoto Ohta
- Institute of Fluid Science, Tohoku University, Sendai, Miyagi, Japan
| | - Yi Qian
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, New South Wales, Australia.
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Damiano RJ, Tutino VM, Paliwal N, Ma D, Davies JM, Siddiqui AH, Meng H. Compacting a Single Flow Diverter versus Overlapping Flow Diverters for Intracranial Aneurysms: A Computational Study. AJNR Am J Neuroradiol 2017; 38:603-610. [PMID: 28057633 DOI: 10.3174/ajnr.a5062] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2016] [Accepted: 10/27/2016] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE Locally compacting the mesh of a flow diverter by a dynamic push-pull technique can accelerate intracranial aneurysm healing. We asked how this deployment strategy compares with overlapping 2 flow diverters for aneurysmal flow reduction. MATERIALS AND METHODS Using a high-fidelity virtual stent placement method, we simulated 3 flow-diverter strategies (single noncompacted, 2 overlapped, and single compacted) in 3 aneurysms (fusiform, large saccular, and medium saccular). Computational fluid dynamics analysis provided posttreatment hemodynamic parameters, including time-averaged inflow rate, aneurysm-averaged velocity, wall shear stress, total absolute circulation, and turnover time. We examined the relationship between the achieved degree of compaction and aneurysm orifice area. RESULTS Flow-diverter compaction resulted in a compaction coverage of 57%, 47%, and 22% over the orifice of the fusiform, large, and medium saccular aneurysm, respectively. Compaction coverage increased linearly with orifice area. In the fusiform aneurysm, the single compacted flow diverter accomplished more aneurysmal flow reduction than the other 2 strategies, as indicated by all 5 hemodynamic parameters. In the 2 saccular aneurysms, the overlapped flow diverters achieved the most flow reduction, followed by the single compacted and the noncompacted flow diverter. CONCLUSIONS Compacting a single flow diverter can outperform overlapping 2 flow diverters in aneurysmal flow reduction, provided that the compaction produces a mesh denser than 2 overlapped flow diverters and this denser mesh covers a sufficient portion of the aneurysm orifice area, for which we suggest a minimum of 50%. This strategy is most effective for aneurysms with large orifices, especially fusiform aneurysms.
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Affiliation(s)
- R J Damiano
- From the Department of Mechanical and Aerospace Engineering (R.J.D., N.P., D.M., H.M.).,Toshiba Stroke and Vascular Research Center (R.J.D., V.M.T., N.P., D.M., J.M.D., A.H.S., H.M.)
| | - V M Tutino
- Toshiba Stroke and Vascular Research Center (R.J.D., V.M.T., N.P., D.M., J.M.D., A.H.S., H.M.).,Department of Biomedical Engineering (V.M.T., H.M.)
| | - N Paliwal
- From the Department of Mechanical and Aerospace Engineering (R.J.D., N.P., D.M., H.M.).,Toshiba Stroke and Vascular Research Center (R.J.D., V.M.T., N.P., D.M., J.M.D., A.H.S., H.M.)
| | - D Ma
- From the Department of Mechanical and Aerospace Engineering (R.J.D., N.P., D.M., H.M.).,Toshiba Stroke and Vascular Research Center (R.J.D., V.M.T., N.P., D.M., J.M.D., A.H.S., H.M.)
| | - J M Davies
- Toshiba Stroke and Vascular Research Center (R.J.D., V.M.T., N.P., D.M., J.M.D., A.H.S., H.M.).,Department of Neurosurgery (J.M.D., A.H.S., H.M.), University at Buffalo, State University of New York, Buffalo, New York
| | - A H Siddiqui
- Toshiba Stroke and Vascular Research Center (R.J.D., V.M.T., N.P., D.M., J.M.D., A.H.S., H.M.).,Department of Neurosurgery (J.M.D., A.H.S., H.M.), University at Buffalo, State University of New York, Buffalo, New York
| | - H Meng
- From the Department of Mechanical and Aerospace Engineering (R.J.D., N.P., D.M., H.M.) .,Toshiba Stroke and Vascular Research Center (R.J.D., V.M.T., N.P., D.M., J.M.D., A.H.S., H.M.).,Department of Biomedical Engineering (V.M.T., H.M.).,Department of Neurosurgery (J.M.D., A.H.S., H.M.), University at Buffalo, State University of New York, Buffalo, New York
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35
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Zhang Q, Meng Z, Zhang Y, Yao K, Liu J, Zhang Y, Jing L, Yang X, Paliwal N, Meng H, Wang S. Phantom-based experimental validation of fast virtual deployment of self-expandable stents for cerebral aneurysms. Biomed Eng Online 2016; 15:125. [PMID: 28155680 PMCID: PMC5260011 DOI: 10.1186/s12938-016-0250-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Endovascular intervention using a stent is a mainstream treatment for cerebral aneurysms. To assess the effect of intervention strategies on aneurysm hemodynamics, we have developed a fast virtual stenting (FVS) technique to simulate stent deployment in patient-specific aneurysms. However, quantitative validation of the FVS against experimental data has not been fully addressed. In this study, we performed in vitro analysis of a patient-specific model to illustrate the realism and usability of this novel FVS technique. METHODS We selected a patient-specific aneurysm and reproduced it in a manufactured realistic aneurismal phantom. Three numerical simulation models of the aneurysm with an Enterprise stent were constructed. Three models were constructed to obtain the stented aneurysms: a physical phantom scanned by micro-CT, fast virtual stenting technique and finite element method. The flow in the three models was simulated using a computational fluid dynamics software package, and the hemodynamics parameters for the three models were calculated and analyzed. RESULTS The computational hemodynamics in the patient-specific aneurysm of the three models resembled the very well. A qualitative comparison revealed high similarity in the wall shear stress, streamline, and velocity plane among the three different methods. Quantitative comparisons revealed that the difference ratios of the hemodynamic parameters were less than 10%, with the difference ratios for area average of wall shear stress in the aneurysm being very low. CONCLUSIONS In conclusion, the results of the computational hemodynamics indicate that FVS is suitable for evaluation of the hemodynamic factors that affect treatment outcomes.
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Affiliation(s)
- Qianqian Zhang
- Beijing Neurosurgical Institute, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Zhuangyuan Meng
- Department of Mechanics and Engineering Science, Fudan University, 220 Handan Rd., Yangpu District, Shanghai, 200433, China
| | - Ying Zhang
- Beijing Neurosurgical Institute, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Kai Yao
- Department of Mechanics and Engineering Science, Fudan University, 220 Handan Rd., Yangpu District, Shanghai, 200433, China
| | - Jian Liu
- Beijing Neurosurgical Institute, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Yisen Zhang
- Beijing Neurosurgical Institute, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Linkai Jing
- Beijing Neurosurgical Institute, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Xinjian Yang
- Beijing Neurosurgical Institute, 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, NY, USA
| | - Hui Meng
- Toshiba Stroke and Vascular Research Center, University at Buffalo, The State University of New York, Buffalo, NY, USA
| | - Shengzhang Wang
- Department of Mechanics and Engineering Science, Fudan University, 220 Handan Rd., Yangpu District, Shanghai, 200433, China.
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36
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Suzuki T, Takao H, Fujimura S, Dahmani C, Ishibashi T, Mamori H, Fukushima N, Yamamoto M, Murayama Y. Selection of helical braided flow diverter stents based on hemodynamic performance and mechanical properties. J Neurointerv Surg 2016; 9:999-1005. [PMID: 27646987 PMCID: PMC5629929 DOI: 10.1136/neurintsurg-2016-012561] [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: 06/05/2016] [Revised: 08/24/2016] [Accepted: 08/29/2016] [Indexed: 11/04/2022]
Abstract
BACKGROUND Although flow diversion is a promising procedure for the treatment of aneurysms, complications have been reported and it remains poorly understood. The occurrence of adverse outcomes is known to depend on both the mechanical properties and flow reduction effects of the flow diverter stent. OBJECTIVE To clarify the possibility of designing a flow diverter stent considering both hemodynamic performance and mechanical properties. MATERIALS AND METHODS Computational fluid dynamics (CFD) simulations were conducted based on an ideal aneurysm model with flow diverters. Structural analyses of two flow diverter models exhibiting similar flow reduction effects were performed, and the radial stiffness and longitudinal flexibility were compared. RESULTS In CFD simulations, two stents-Pore2-d35 (26.77° weave angle when fully expanded, 35 μm wire thickness) and Pore3-d50 (36.65°, 50 μm respectively)-demonstrated similar flow reduction rates (68.5% spatial-averaged velocity reduction rate, 85.0% area-averaged wall shear stress reduction rate for Pore2-d35, and 68.6%, 85.4%, respectively, for Pore3-d50). However, Pore3-d50 exhibited greater radial stiffness than Pore2-d35 (40.0 vs 21.0 mN/m at a 3.5 mm outer diameter) and less longitudinal flexibility (0.903 vs 0.104 N·mm bending moments at 90°). These measurements indicate that changing the wire thickness and weave angle allows adjustment of the mechanical properties while maintaining the same degree of flow reduction effects. CONCLUSIONS The combination of CFD and structural analysis can provide promising solutions for an optimized stent. Stents exhibiting different mechanical properties but the same flow reduction effects could be designed by varying both the weave angle and wire thickness.
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Affiliation(s)
- Takashi Suzuki
- Graduate School of Mechanical Engineering, Tokyo University of Science, Tokyo, Japan
| | - Hiroyuki Takao
- Graduate School of Mechanical Engineering, Tokyo University of Science, Tokyo, Japan.,Department of Neurosurgery, Jikei University School of Medicine, Tokyo, Japan.,Department of Innovation for Medical Information Technology, Jikei University School of Medicine, Tokyo, Japan
| | - Soichiro Fujimura
- Graduate School of Mechanical Engineering, Tokyo University of Science, Tokyo, Japan
| | - Chihebeddine Dahmani
- Department of Neurosurgery, Jikei University School of Medicine, Tokyo, Japan.,Siemens Healthcare K.K., Tokyo, Japan
| | - Toshihiro Ishibashi
- Department of Neurosurgery, Jikei University School of Medicine, Tokyo, Japan
| | - Hiroya Mamori
- Department of Mechanical Engineering, Tokyo University of Science, Tokyo, Japan
| | - Naoya Fukushima
- Department of Mechanical Engineering, Tokyo University of Science, Tokyo, Japan
| | - Makoto Yamamoto
- Department of Mechanical Engineering, Tokyo University of Science, Tokyo, Japan
| | - Yuichi Murayama
- Department of Neurosurgery, Jikei University School of Medicine, Tokyo, Japan
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37
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Alherz AI, Tanweer O, Flamini V. A numerical framework for the mechanical analysis of dual-layer stents in intracranial aneurysm treatment. J Biomech 2016; 49:2420-7. [DOI: 10.1016/j.jbiomech.2016.02.026] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2016] [Accepted: 02/08/2016] [Indexed: 11/28/2022]
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38
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Bouillot P, Brina O, Yilmaz H, Farhat M, Erceg G, Lovblad KO, Vargas MI, Kulcsar Z, Pereira VM. Virtual-versus-Real Implantation of Flow Diverters: Clinical Potential and Influence of Vascular Geometry. AJNR Am J Neuroradiol 2016; 37:2079-2086. [PMID: 27365325 DOI: 10.3174/ajnr.a4845] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Accepted: 04/24/2016] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE Intracranial stents have become extremely important in the endovascular management of complex intracranial aneurysms. Sizing and landing zone predictions are still very challenging steps in the procedure. Virtual stent deployment may help therapeutic planning, device choice, and hemodynamic simulations. We aimed to assess the predictability of our recently developed virtual deployment model by comparing in vivo and virtual stents implanted in a consecutive series of patients presenting with intracranial aneurysms. MATERIALS AND METHODS Virtual stents were implanted in patient-specific geometries of intracranial aneurysms treated with the Pipeline Embolization Device. The length and cross-section of virtual and real stents measured with conebeam CT were compared. The influence of vessel geometry modifications occurring during the intervention was analyzed. RESULTS The virtual deployment based on pre- and poststent implantation 3D rotational angiography overestimated (underestimated) the device length by 13% ± 11% (-9% ± 5%). These differences were highly correlated (R2 = 0.67) with the virtual-versus-real stent radius differences of -6% ± 7% (5% ± 4%) for predictions based on pre- and poststent implantation 3D rotational angiography. These mismatches were due principally to implantation concerns and vessel-shape modifications. CONCLUSIONS The recently proposed geometric model was shown to predict accurately the deployment of Pipeline Embolization Devices when the stent radius was well-assessed. However, unpredictable delivery manipulations and variations of vessel geometry occurring during the intervention might impact the stent implantation.
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Affiliation(s)
- P Bouillot
- From the Division of Neuroradiology (P.B., O.B., H.Y., G.E., K.-O.L., M.I.V., Z.K.), University Hospitals of Geneva, Geneva, Switzerland.,Laboratory for Hydraulic Machines (P.B., M.F.), École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - O Brina
- From the Division of Neuroradiology (P.B., O.B., H.Y., G.E., K.-O.L., M.I.V., Z.K.), University Hospitals of Geneva, Geneva, Switzerland
| | - H Yilmaz
- From the Division of Neuroradiology (P.B., O.B., H.Y., G.E., K.-O.L., M.I.V., Z.K.), University Hospitals of Geneva, Geneva, Switzerland
| | - M Farhat
- Laboratory for Hydraulic Machines (P.B., M.F.), École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - G Erceg
- From the Division of Neuroradiology (P.B., O.B., H.Y., G.E., K.-O.L., M.I.V., Z.K.), University Hospitals of Geneva, Geneva, Switzerland
| | - K-O Lovblad
- From the Division of Neuroradiology (P.B., O.B., H.Y., G.E., K.-O.L., M.I.V., Z.K.), University Hospitals of Geneva, Geneva, Switzerland
| | - M I Vargas
- From the Division of Neuroradiology (P.B., O.B., H.Y., G.E., K.-O.L., M.I.V., Z.K.), University Hospitals of Geneva, Geneva, Switzerland
| | - Z Kulcsar
- From the Division of Neuroradiology (P.B., O.B., H.Y., G.E., K.-O.L., M.I.V., Z.K.), University Hospitals of Geneva, Geneva, Switzerland
| | - V M Pereira
- Division of Neuroradiology (V.M.P.), Department of Medical Imaging .,Division of Neurosurgery (V.M.P.), Department of Surgery, Toronto Western Hospital, University Health Network, Toronto, Ontario, Canada
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39
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Geometrical deployment for braided stent. Med Image Anal 2016; 30:85-94. [DOI: 10.1016/j.media.2016.01.006] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2015] [Revised: 11/20/2015] [Accepted: 01/20/2016] [Indexed: 11/21/2022]
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40
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Paliwal N, Yu H, Xu J, Xiang J, Siddiqui A, Yang X, Li H, Meng H. Virtual stenting workflow with vessel-specific initialization and adaptive expansion for neurovascular stents and flow diverters. Comput Methods Biomech Biomed Engin 2016; 19:1423-1431. [PMID: 26899135 DOI: 10.1080/10255842.2016.1149573] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Endovascular intervention using traditional neurovascular stents and densely braided flow diverters (FDs) have become the preferred treatment strategies for traditionally challenging intracranial aneurysms. Modeling stent and FD deployment in patient-specific aneurysms and its flow modification results prior to the actual intervention can potentially predict the patient outcome and treatment optimization. We present a clinically focused, streamlined virtual stenting workflow that efficiently simulates stent and FD treatment in patient-specific aneurysms based on expanding a simplex mesh structure. The simplex mesh is generated using an innovative vessel-specific initialization technique, which uses the patient's parent artery diameter to identify the initial position of the simplex mesh inside the artery. A novel adaptive expansion algorithm enables the acceleration of deployment process by adjusting the expansion forces based on the distance of the simplex mesh from the parent vessel. The virtual stenting workflow was tested by modeling the treatment of two patient-specific aneurysms using the Enterprise stent and the Pipeline Embolization Device (commercial FD). Both devices were deployed in the aneurysm models in a few seconds. Computational fluid dynamics analyses of pre- and post-treatment aneurysmal hemodynamics show flow reduction in the aneurysmal sac in treated aneurysms, with the FD diverting more flow than the Enterprise stent. The test results show that this workflow can rapidly simulate clinical deployment of stents and FDs, hence paving the way for its future clinical implementation.
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Affiliation(s)
- Nikhil Paliwal
- Department of Mechanical & Aerospace Engineering, University at Buffalo, State University of New York, Buffalo, NY.,Toshiba Stroke and Vascular Research Center, University at Buffalo, State University of New York, Buffalo, NY
| | - Hongyu Yu
- School of Biomedical Engineering, Capital Medical University, Beijing, China
| | - Jinhui Xu
- Department of Computer Science & Engineering, University at Buffalo, State University of New York, Buffalo, NY
| | - Jianping Xiang
- Department of Neurosurgery, University at Buffalo, State University of New York, Buffalo, NY.,Toshiba Stroke and Vascular Research Center, University at Buffalo, State University of New York, Buffalo, NY
| | - Adnan Siddiqui
- Department of Neurosurgery, University at Buffalo, State University of New York, Buffalo, NY.,Toshiba Stroke and Vascular Research Center, University at Buffalo, State University of New York, Buffalo, NY
| | - Xinjian Yang
- Beijing Neurosurgical Institute, Beijing Tiantan Hospital, Beijing, China
| | - Haiyun Li
- School of Biomedical Engineering, Capital Medical University, Beijing, China
| | - Hui Meng
- Department of Mechanical & Aerospace Engineering, University at Buffalo, State University of New York, Buffalo, NY.,Department of Neurosurgery, University at Buffalo, State University of New York, Buffalo, NY.,Department of Biomedical Engineering, University at Buffalo, State University of New York, Buffalo, NY.,Toshiba Stroke and Vascular Research Center, University at Buffalo, State University of New York, Buffalo, NY
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41
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Zhong J, Long Y, Yan H, Meng Q, Zhao J, Zhang Y, Yang X, Li H. Fast Virtual Stenting with Active Contour Models in Intracranical Aneurysm. Sci Rep 2016; 6:21724. [PMID: 26876026 PMCID: PMC4753686 DOI: 10.1038/srep21724] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2015] [Accepted: 01/28/2016] [Indexed: 11/09/2022] Open
Abstract
Intracranial stents are becoming increasingly a useful option in the treatment of intracranial aneurysms (IAs). Image simulation of the releasing stent configuration together with computational fluid dynamics (CFD) simulation prior to intervention will help surgeons optimize intervention scheme. This paper proposed a fast virtual stenting of IAs based on active contour model (ACM) which was able to virtually release stents within any patient-specific shaped vessel and aneurysm models built on real medical image data. In this method, an initial stent mesh was generated along the centerline of the parent artery without the need for registration between the stent contour and the vessel. Additionally, the diameter of the initial stent volumetric mesh was set to the maximum inscribed sphere diameter of the parent artery to improve the stenting accuracy and save computational cost. At last, a novel criterion for terminating virtual stent expanding that was based on the collision detection of the axis aligned bounding boxes was applied, making the stent expansion free of edge effect. The experiment results of the virtual stenting and the corresponding CFD simulations exhibited the efficacy and accuracy of the ACM based method, which are valuable to intervention scheme selection and therapy plan confirmation.
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Affiliation(s)
- Jingru Zhong
- Capital Medical University, Department of Biomedical Engineering, Beijing, 100069, China
| | - Yunling Long
- Capital Medical University, Department of Biomedical Engineering, Beijing, 100069, China
| | - Huagang Yan
- Capital Medical University, Department of Biomedical Engineering, Beijing, 100069, China
| | - Qianqian Meng
- Capital Medical University, Department of Biomedical Engineering, Beijing, 100069, China
| | - Jing Zhao
- Capital Medical University, Department of Biomedical Engineering, Beijing, 100069, China
| | - Ying Zhang
- Capital Medical University, Beijing Tiantan Hospital, Beijing Neurosurgical Institute, Department of Interventional Neuroradiology, Beijing, 100050, China
| | - Xinjian Yang
- Capital Medical University, Beijing Tiantan Hospital, Beijing Neurosurgical Institute, Department of Interventional Neuroradiology, Beijing, 100050, China
| | - Haiyun Li
- Capital Medical University, Department of Biomedical Engineering, Beijing, 100069, China
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42
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Iannaccone F, De Beule M, De Bock S, Van der Bom IMJ, Gounis MJ, Wakhloo AK, Boone M, Verhegghe B, Segers P. A Finite Element Method to Predict Adverse Events in Intracranial Stenting Using Microstents: In Vitro Verification and Patient Specific Case Study. Ann Biomed Eng 2015; 44:442-52. [DOI: 10.1007/s10439-015-1505-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Accepted: 11/05/2015] [Indexed: 11/28/2022]
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43
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Jou LD, Chintalapani G, Mawad ME. Metal coverage ratio of pipeline embolization device for treatment of unruptured aneurysms: Reality check. Interv Neuroradiol 2015; 22:42-8. [PMID: 26628457 DOI: 10.1177/1591019915617315] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2015] [Accepted: 10/01/2015] [Indexed: 01/10/2023] Open
Abstract
BACKGROUND AND PURPOSE The metal coverage ratio (MCR) of a flow diverter influences the intra-aneurysmal hemodynamics; a high MCR will occlude an aneurysm early, while a low MCR may delay aneurysm occlusion. The true MCR of a pipeline embolization device (PED) could be lower due to oversize, device deformation, or aneurysm location. In this study deviation of the true MCR from the nominal MCR is assessed and whether their difference affects aneurysm occlusion rate is determined. METHODS A total of 40 consecutive patients, each of them treated by one PED for their aneurysms at the internal carotid artery (ICA), were retrospectively analyzed. The DynaCT images of these deployed PEDs were used to determine their true dimensions and estimate three MCRs (local, mean, and nominal). These data were compared in two groups of patients who had different aneurysm outcomes at six months. RESULTS The difference in the local MCR between two groups is small, but statistically significant (24.5% vs 21.6%, p=05). The local MCR is consistently lower than the nominal MCRs (23.2% vs 30.2%, p<0.001); however, the difference between the mean and local MCRs is small (23.9% vs 23.2%). CONCLUSIONS An expectation that a PED can achieve a MCR of 30% may not be reasonable. Device oversize and deformation during deployment lower the local MCR by 5-7%. A lowered MCR affects the aneurysm occlusion rate at six months.
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Affiliation(s)
- Liang-Der Jou
- Department of Radiology, Baylor College of Medicine, Houston, Texas, USA
| | | | - Michel E Mawad
- Department of Radiology, Baylor College of Medicine, Houston, Texas, USA
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44
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Gentric JC, Salazkin I, Gevry G, Raymond J, Darsaut T. Compaction of flow diverters improves occlusion of experimental wide-necked aneurysms. J Neurointerv Surg 2015; 8:1072-7. [PMID: 26453605 DOI: 10.1136/neurintsurg-2015-012016] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2015] [Accepted: 09/17/2015] [Indexed: 11/04/2022]
Abstract
INTRODUCTION Flow diverters (FDs) are increasingly used in the treatment of wide-necked aneurysms. OBJECTIVE To examine the hypothesis that intentional FD compaction might improve aneurysm occlusion rates. METHODS Bilateral wide-necked carotid aneurysms were created in 12 dogs. Endovascular treatment was performed 1 month later, using Pipeline embolization devices deployed with compaction across the aneurysm neck (n=12). Group 1a consisted of aneurysms treated with a single compacted FD (n=8), while group 1b aneurysms required two compacted FDs (n=4). Control aneurysms were treated with a single non-compacted FD (group 3; n=6), or not treated (group 4; n=4). Angiographic results were compared at 3 months. Pathology specimens were photographed and the neointimal coverage of devices scored using an ordinal grading system. RESULTS Twenty-two of 24 aneurysms were patent at 1 month. Deployment with compaction was successful in eight cases (group 1a aneurysms). The compaction maneuver led to immediate FD prolapse into the aneurysm in four cases, rescued by deploying a second, telescoping FD (forming group 1b aneurysms). One compacted device later migrated distally, leaving the aneurysm untreated. Angiographic results differed significantly between groups (p=0.0002). At 3 months, aneurysms successfully treated with a single compacted FD were more often occluded at 3 months (7/7) than aneurysms flow-diverted without compaction (2/6; p=0.021). All aneurysms treated with two compacted FDs were occluded, while all untreated aneurysms remained patent. There were no parent vessel stenoses. CONCLUSIONS Compaction of FDs can improve angiographic occlusion of experimental wide-necked aneurysms.
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Affiliation(s)
- Jean-Christophe Gentric
- Department of Radiology, Centre Hospitalier de l'Université de Montréal (CHUM), Notre-Dame Hospital, Montreal, Quebec, Canada Groupe d'étude de la Thrombose en Bretagne Occidentale (GETBO, EA 3878), Brest, France
| | - Igor Salazkin
- Laboratory of Interventional Neuroradiology, Centre Hospitalier de l'Université de Montréal, Notre-Dame Hospital Research Centre (CRCHUM), Montreal, Quebec, Canada
| | - Guylaine Gevry
- Laboratory of Interventional Neuroradiology, Centre Hospitalier de l'Université de Montréal, Notre-Dame Hospital Research Centre (CRCHUM), Montreal, Quebec, Canada
| | - Jean Raymond
- Department of Radiology, Centre Hospitalier de l'Université de Montréal (CHUM), Notre-Dame Hospital, Montreal, Quebec, Canada Laboratory of Interventional Neuroradiology, Centre Hospitalier de l'Université de Montréal, Notre-Dame Hospital Research Centre (CRCHUM), Montreal, Quebec, Canada
| | - Tim Darsaut
- Division of Neurosurgery, Department of Surgery, University of Alberta Hospital, Mackenzie Health Sciences Centre, Edmonton, Alberta, Canada
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45
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Janiga G, Daróczy L, Berg P, Thévenin D, Skalej M, Beuing O. An automatic CFD-based flow diverter optimization principle for patient-specific intracranial aneurysms. J Biomech 2015; 48:3846-52. [PMID: 26472308 DOI: 10.1016/j.jbiomech.2015.09.039] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2015] [Revised: 09/18/2015] [Accepted: 09/24/2015] [Indexed: 11/26/2022]
Abstract
The optimal treatment of intracranial aneurysms using flow diverting devices is a fundamental issue for neuroradiologists as well as neurosurgeons. Due to highly irregular manifold aneurysm shapes and locations, the choice of the stent and the patient-specific deployment strategy can be a very difficult decision. To support the therapy planning, a new method is introduced that combines a three-dimensional CFD-based optimization with a realistic deployment of a virtual flow diverting stent for a given aneurysm. To demonstrate the feasibility of this method, it was applied to a patient-specific intracranial giant aneurysm that was successfully treated using a commercial flow diverter. Eight treatment scenarios with different local compressions were considered in a fully automated simulation loop. The impact on the corresponding blood flow behavior was evaluated qualitatively as well as quantitatively, and the optimal configuration for this specific case was identified. The virtual deployment of an uncompressed flow diverter reduced the inflow into the aneurysm by 24.4% compared to the untreated case. Depending on the positioning of the local stent compression below the ostium, blood flow reduction could vary between 27.3% and 33.4%. Therefore, a broad range of potential treatment outcomes was identified, illustrating the variability of a given flow diverter deployment in general. This method represents a proof of concept to automatically identify the optimal treatment for a patient in a virtual study under certain assumptions. Hence, it contributes to the improvement of virtual stenting for intracranial aneurysms and can support physicians during therapy planning in the future.
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Affiliation(s)
- Gábor Janiga
- Laboratory of Fluid Dynamics and Technical Flows, University of Magdeburg "Otto von Guericke" Universitätsplatz, 2 D-39106 Magdeburg, Germany.
| | - László Daróczy
- Laboratory of Fluid Dynamics and Technical Flows, University of Magdeburg "Otto von Guericke" Universitätsplatz, 2 D-39106 Magdeburg, Germany
| | - Philipp Berg
- Laboratory of Fluid Dynamics and Technical Flows, University of Magdeburg "Otto von Guericke" Universitätsplatz, 2 D-39106 Magdeburg, Germany
| | - Dominique Thévenin
- Laboratory of Fluid Dynamics and Technical Flows, University of Magdeburg "Otto von Guericke" Universitätsplatz, 2 D-39106 Magdeburg, Germany
| | - Martin Skalej
- Institute for Neuroradiology, University of Magdeburg "Otto von Guericke", Germany
| | - Oliver Beuing
- Institute for Neuroradiology, University of Magdeburg "Otto von Guericke", Germany
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46
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Karunanithi K, Lee CJ, Chong W, Qian Y. The influence of flow diverter’s angle of curvature across the aneurysm neck on its haemodynamics. Proc Inst Mech Eng H 2015; 229:560-9. [DOI: 10.1177/0954411915593303] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Flow diverter stents have provided a new method of endovascular reconstruction for large and complex aneurysms. Understanding the impact of the flow diverter’s angle of curvature across the neck and its metal coverage rate on the haemodynamics of aneurysm is crucial to maximize the mass flow reduction inside the aneurysm, post-deployment. The aim of this study is to understand the correlation between the angle of curvature of flow diverter across the aneurysm neck and the metal coverage rate, and the aneurysm’s haemodynamics, using computational fluid dynamics. Varying the flow diverter angle resulted in varying metal coverage rate across the aneurysm neck for two patient vessel geometries, A (straight artery) and B (curved artery) with aspect ratios of 3.1 and 2.9, respectively. The results indicate that there exists a relationship between the aneurysm’s haemodynamics and the flow diverter’s angle of curvature across its neck. Moreover, the calculations indicated that cases with a moderately curved flow diverter, with an associated metal coverage rate of 50%–60%, achieve maximum flow reduction inside the aneurysm due to a stable flow resistance in the direction normal to the blood flow.
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Affiliation(s)
- Kaavya Karunanithi
- Australian School of Advanced Medicine, Macquarie University, Macquarie Park, NSW, Australia
| | - Chang Joon Lee
- Australian School of Advanced Medicine, Macquarie University, Macquarie Park, NSW, Australia
| | | | - Yi Qian
- Australian School of Advanced Medicine, Macquarie University, Macquarie Park, NSW, Australia
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47
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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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48
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Macdonald RL. Flow diverters: one device does not fit all. J Neurosurg 2015; 123:829-30. [PMID: 26090837 DOI: 10.3171/2014.12.jns142537] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- R Loch Macdonald
- Division of Neurosurgery, St. Michael's Hospital, Labatt Family Centre of Excellence in Brain Injury and Trauma Research, Keenan Research Centre for Biomedical Science, and the Li Ka Shing Knowledge Institute of St. Michael's Hospital, Department of Surgery, University of Toronto, Ontario, Canada
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49
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Xiang J, Damiano RJ, Lin N, Snyder KV, Siddiqui AH, Levy EI, Meng H. High-fidelity virtual stenting: modeling of flow diverter deployment for hemodynamic characterization of complex intracranial aneurysms. J Neurosurg 2015; 123:832-40. [PMID: 26090829 DOI: 10.3171/2014.11.jns14497] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECT Flow diversion via Pipeline Embolization Device (PED) represents the most recent advancement in endovascular therapy of intracranial aneurysms. This exploratory study aims at a proof of concept for an advanced device-modeling tool in conjunction with computational fluid dynamics (CFD) to evaluate flow modification effects by PED in actual, treated cases. METHODS The authors performed computational modeling of 3 PED-treated complex aneurysm cases. The patient in Case 1 had a fusiform vertebral aneurysm treated with a single PED. In Case 2 the patient had a giant internal carotid artery (ICA) aneurysm treated with 2 PEDs. Case 3 consisted of tandem ICA aneurysms (III-a and III-b) treated by a single PED. The authors' recently developed high-fidelity virtual stenting (HiFiVS) technique was used to recapitulate the clinical deployment process of PEDs in silico for these 3 cases. Pretreatment and posttreatment aneurysmal hemodynamics studies performed using CFD simulation were analyzed. Changes in aneurysmal flow velocity, inflow rate, wall shear stress (WSS), and turnover time were calculated and compared with the clinical outcome. RESULTS In Case 1 (occluded within the first 3 months), the aneurysm had the most drastic flow reduction after PED placement; the aneurysmal average velocity, inflow rate, and average WSS were decreased by 76.3%, 82.5%, and 74.0%, respectively, whereas the turnover time was increased to 572.1% of its pretreatment value. In Case 2 (occluded at 6 months), aneurysmal average velocity, inflow rate, and average WSS were decreased by 39.4%, 38.6%, and 59.1%, respectively, and turnover time increased to 163.0%. In Case 3, Aneurysm III-a (occluded at 6 months) had a decrease by 38.0%, 28.4%, and 50.9% in average velocity, inflow rate, and average WSS, respectively, and turnover time increased to 139.6%, which was quite similar to Aneurysm II. Surprisingly, the adjacent Aneurysm III-b had more substantial flow reduction (a decrease by 77.7%, 53.0%, and 84.4% in average velocity, inflow rate, and average WSS, respectively, and an increase to 213.0% in turnover time) than Aneurysm III-a, which qualitatively agreed with angiographic observation at 3-month follow-up. However, Aneurysm III-b remained patent at both 6 months and 9 months. A closer examination of the vascular anatomy in Case 3 revealed blood draining to the ophthalmic artery off Aneurysm III-b, which may have prevented its complete thrombosis. CONCLUSIONS This proof-of-concept study demonstrates that HiFiVS modeling of flow diverter deployment enables detailed characterization of hemodynamic alteration by PED placement. Posttreatment aneurysmal flow reduction may be correlated with aneurysm occlusion outcome. However, predicting aneurysm treatment outcome by flow diverters also requires consideration of other factors, including vascular anatomy.
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Affiliation(s)
- Jianping Xiang
- Toshiba Stroke and Vascular Research Center.,Department of Neurosurgery.,Department of Mechanical and Aerospace Engineering
| | - Robert J Damiano
- Toshiba Stroke and Vascular Research Center.,Department of Mechanical and Aerospace Engineering
| | - Ning Lin
- Department of Neurosurgery.,Department of Neurosurgery, Weill Cornell Medical Center and NewYork-Presbyterian Hospital, New York, New York
| | - Kenneth V Snyder
- Toshiba Stroke and Vascular Research Center.,Department of Neurosurgery.,Department of Radiology, University at Buffalo, The State University of New York, Buffalo; and
| | - Adnan H Siddiqui
- Toshiba Stroke and Vascular Research Center.,Department of Neurosurgery.,Department of Radiology, University at Buffalo, The State University of New York, Buffalo; and
| | - Elad I Levy
- Toshiba Stroke and Vascular Research Center.,Department of Neurosurgery.,Department of Radiology, University at Buffalo, The State University of New York, Buffalo; and
| | - Hui Meng
- Toshiba Stroke and Vascular Research Center.,Department of Neurosurgery.,Department of Mechanical and Aerospace Engineering.,Department of Biomedical Engineering, and
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50
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Cebral JR, Mut F, Raschi M, Hodis S, Ding YH, Erickson BJ, Kadirvel R, Kallmes DF. Analysis of flow changes in side branches jailed by flow diverters in rabbit models. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2014; 30:988-999. [PMID: 24729467 PMCID: PMC4466553 DOI: 10.1002/cnm.2640] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2013] [Revised: 03/17/2014] [Accepted: 03/17/2014] [Indexed: 06/03/2023]
Abstract
Understanding the flow alteration in side branches during flow diversion treatment of cerebral aneurysms is important to prevent ischemic complications and improve device designs. Flow diverters were placed in the aorta of four rabbits crossing the origin of side arteries. Subject-specific computational models were constructed from 3D angiographies and Doppler ultrasounds (DUSs). Flow simulations were run before and after virtually deploying the flow diverters, assuming distal resistances remained unchanged after treatment. All jailed arteries remained patent angiographically 8 weeks after treatment. The computational models estimated decreases compared to pretreatment in the mean flow rates between 2% and 20% and in peak flow rates between 5% and 36%. The major changes were observed during systole. Flow patterns did not exhibit recirculation zones before treatment. Implantation of the flow diverters altered the flow structure only locally near the device wires. No major recirculation regions were created or destroyed. Flow diverters seem safe with respect to perforator or side branch occlusion. Relatively small changes in flow rates through jailed arteries are expected, even for moderate to large degrees of coverage of their origins. These results seem consistent with previous clinical experiences where no or very few complications related to perforator occlusion have been reported.
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Affiliation(s)
- Juan R. Cebral
- Center for Computational Fluid Dynamics College of Sciences, George Mason University Fairfax, Virginia, USA
| | - Fernando Mut
- Center for Computational Fluid Dynamics College of Sciences, George Mason University Fairfax, Virginia, USA
| | - Marcelo Raschi
- Center for Computational Fluid Dynamics College of Sciences, George Mason University Fairfax, Virginia, USA
| | - Simona Hodis
- Department of Radiology Mayo Clinic Rochester, Minnesota, USA
| | - Yong-Hong Ding
- Department of Radiology Mayo Clinic Rochester, Minnesota, USA
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