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Jeken-Rico P, Chau Y, Goetz A, Lannelongue V, Sédat J, Hachem E. Virtual flow diverter deployment and embedding for hemodynamic simulations. Comput Biol Med 2024; 180:109023. [PMID: 39163828 DOI: 10.1016/j.compbiomed.2024.109023] [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: 06/08/2024] [Revised: 08/03/2024] [Accepted: 08/11/2024] [Indexed: 08/22/2024]
Abstract
Flow-diverter stents offer clinicians an effective solution for treating intracranial aneurysms, especially in cases where other devices may be unsuitable. However, strongly deviating success rates among different centres, manufacturers, and aneurysm phenotypes highlight the need for better in-situ studies of these devices. To support research in this area, virtual stenting algorithms have been proposed that, combined with computational fluid dynamics, provide insights into the hemodynamic alterations induced by the device. Yet, many existing algorithms rely on uncertain parameters, such as the forces applied during operation, fail to predict the length of the device after deployment, or lack robust validation steps, raising concerns about their reliability. Therefore, we developed a robust deployment technique that builds upon the geometrical features of the vessel and includes advancements from previous works. The algorithm is detailed and validated against literature examples, in-vitro experiments, and patient data, achieving a mean angular error below 5° in the latter. Furthermore, we describe and demonstrate how the deployed device can be embedded in a computational mesh using open-source tools and anisotropic meshing routines.
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Affiliation(s)
- Pablo Jeken-Rico
- Mines Paris, Université PSL, CEMEF, UMR7635 CNRS, Sophia Antipolis, 06904, France.
| | - Yves Chau
- Department of Neuro-Interventional and Vascular Interventional, University Hospital of Nice, Nice, 06000, France
| | - Aurèle Goetz
- Mines Paris, Université PSL, CEMEF, UMR7635 CNRS, Sophia Antipolis, 06904, France
| | - Vincent Lannelongue
- Mines Paris, Université PSL, CEMEF, UMR7635 CNRS, Sophia Antipolis, 06904, France
| | - Jacques Sédat
- Department of Neuro-Interventional and Vascular Interventional, University Hospital of Nice, Nice, 06000, France
| | - Elie Hachem
- Mines Paris, Université PSL, CEMEF, UMR7635 CNRS, Sophia Antipolis, 06904, France
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2
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Bérod A, Mut F, Cebral J, Mendez S, Chnafa C, Nicoud F. Assessing a heterogeneous model for accounting for endovascular devices in hemodynamic simulations of cerebral aneurysms. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2023; 39:e3762. [PMID: 37515447 DOI: 10.1002/cnm.3762] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Revised: 12/18/2022] [Accepted: 07/12/2023] [Indexed: 07/30/2023]
Abstract
The heterogeneous model developed by Berod et al [Int J Numer Method Biomed Eng 38, 2021] for representing the hemodynamic effects of endovascular prostheses is applied to a series of 10 patient specific cerebral aneurysms, 6 being treated by flow diverters, 4 being equipped with WEBs. Two markers correlated with the medical outcome of the treatment are used to assess the potential of the model, namely the saccular mean velocity and the inflow rate at the neck of the aneurysm. The comparison with the corresponding wire-resolved simulations is very favorable in both cases, and the model-based simulations also retrieve the jetting-type flows generated downstream of the struts. Noteworthy, the very same model was used for representing the flow diverters and the WEBs, showing the versatility and robustness of the heterogeneous modeling of the devices.
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Affiliation(s)
| | - Fernando Mut
- Bioengineering Department, Volgenau School of Engineering, George Mason University, Fairfax, Virginia, USA
| | - Juan Cebral
- Bioengineering Department, Volgenau School of Engineering, George Mason University, Fairfax, Virginia, USA
| | - Simon Mendez
- CNRS, IMAG, Université de Montpellier, Montpellier, France
| | | | - Franck Nicoud
- CNRS, IMAG, Université de Montpellier, Montpellier, France
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3
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Stahl J, Marsh LMM, Thormann M, Ding A, Saalfeld S, Behme D, Berg P. Assessment of the flow-diverter efficacy for intracranial aneurysm treatment considering pre- and post-interventional hemodynamics. Comput Biol Med 2023; 156:106720. [PMID: 36878124 DOI: 10.1016/j.compbiomed.2023.106720] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Revised: 02/08/2023] [Accepted: 02/26/2023] [Indexed: 03/02/2023]
Abstract
Endovascular treatment of intracranial aneurysms with flow diverters (FD) has become one of the most promising interventions. Due to its woven high-density structure they are particularly applicable for challenging lesions. Although several studies have already conducted realistic hemodynamic quantification of the FD efficacy, a comparison with morphologic post-interventional data is still missing. This study analyses the hemodynamics of ten intracranial aneurysm patients treated with a novel FD device. Based on pre- and post-interventional 3D digital subtraction angiography image data, patient-specific 3D models of both treatment states are generated applying open source threshold-based segmentation methods. Using a fast virtual stenting approach, the real stent positions available in the post-interventional data are virtually replicated and both treatment scenarios were characterized using image-based blood flow simulations. The results show FD-induced flow reductions at the ostium by a decrease in mean neck flow rate (51%), inflow concentration index (56%) and mean inflow velocity (53%). Intraluminal reductions in flow activity for time-averaged wall shear stress (47%) and kinetic energy (71%) are present as well. However, an intra-aneurysmal increase in flow pulsatility (16%) for the post-interventional cases can be observed. Patient-specific FD simulations demonstrate the desired flow redirection and activity reduction inside the aneurysm beneficial for thrombosis formation. Differences in the magnitude of hemodynamic reduction exist over the cardiac cycle which may be addressed in a clinical setting by anti-hypertensive treatment in selected cases.
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Affiliation(s)
- Janneck Stahl
- Research Campus STIMULATE, University of Magdeburg, Magdeburg, 39106, Germany; Department of Fluid Dynamics and Technical Flows, University of Magdeburg, Magdeburg, 39106, Germany.
| | | | - Maximilian Thormann
- University Clinic for Neuroradiology, University Hospital Magdeburg, Magdeburg, 39120, Germany
| | | | - Sylvia Saalfeld
- Research Campus STIMULATE, University of Magdeburg, Magdeburg, 39106, Germany; Department of Simulation and Graphics, University of Magdeburg, Magdeburg, 39106, Germany
| | - Daniel Behme
- Research Campus STIMULATE, University of Magdeburg, Magdeburg, 39106, Germany; University Clinic for Neuroradiology, University Hospital Magdeburg, Magdeburg, 39120, Germany
| | - Philipp Berg
- Research Campus STIMULATE, University of Magdeburg, Magdeburg, 39106, Germany; Department of Medical Engineering, University of Magdeburg, Magdeburg, 39106, Germany
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4
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Simulation of intra-saccular devices for pre-operative device size selection: Method and validation for sizing and porosity simulation. Comput Biol Med 2022; 147:105744. [PMID: 35763930 DOI: 10.1016/j.compbiomed.2022.105744] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Revised: 05/24/2022] [Accepted: 06/11/2022] [Indexed: 11/24/2022]
Abstract
Intra-saccular devices (ID) are novel braided devices used for complex intracranial aneurysms treatment. Treatment success is associated with correct device size selection. A technique that predicts the ID size within the aneurysm before intervention will provide a powerful computational tool to aid the interventionist during device selection. We present a method to calculate the device's final height, radial expansion and porosity within the patient's anatomy, which allows assessing different device sizes before treatment takes place. The proposed sizing technique was tested in-vitro and in real patient's geometries obtained from 3DRA angiographic images of 8 unruptured aneurysms previously treated with IDs. The obtained simulated height was compared to the real height, with a mean error of less than 0.28 mm (±0.44). The porosity calculation method was tested in-vitro with an error of 0.02 (±0.022). The results of both sizing and porosity experiments resemble well measures from real patients. This methodology could be used before treatment to provide the interventionist with additional information that allows selecting the device that best fits the patient's aneurysm to be treated.
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5
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Reorowicz P, Tyfa Z, Obidowski D, Wiśniewski K, Stefańczyk L, Jóźwik K, Levy ML. Blood flow through the fusiform aneurysm treated with the Flow Diverter stent – Numerical investigations. Biocybern Biomed Eng 2022. [DOI: 10.1016/j.bbe.2022.02.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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6
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Derqui B, Filimonau V, Matute J. Assessing the scale of adoption of sustainability practices by community pharmacies in Spain in the time of COVID-19. SUSTAINABLE PRODUCTION AND CONSUMPTION 2021; 27:1626-1636. [PMID: 36118164 PMCID: PMC9464268 DOI: 10.1016/j.spc.2021.03.034] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2020] [Revised: 03/24/2021] [Accepted: 03/30/2021] [Indexed: 06/02/2023]
Abstract
Community pharmacies play a critical societal role and are well placed to enable the progress of national health systems towards sustainability. Nevertheless, there is a dearth of research which has been set up to understand sustainability practices adopted by community pharmacies and evaluate the drivers behind their adoption. This study undertook an exploratory analysis of 95 community pharmacies in Spain, measured their engagement with sustainability practices and assessed these practices in light of the COVID-19 pandemic. The results demonstrated the room for improvement in the adoption of green procurement practices in pharmacies and in their engagement with the community. Moreover, the study showcased that, during the COVID-19 crisis, the pharmacies with the largest extent of adoption of sustainability practices implemented preventative measures against the pandemic in a more diverse number during the first weeks of the lockdown, compared to their less sustainable counterparts. This indicates that, to build resilience to future (health) crises, the implementation of sustainable practices in community pharmacies should be encouraged by both policy makers and pharmaceutical firms.
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Affiliation(s)
- Belén Derqui
- Department of Business Management, IQS School of Management, Universitat Ramon Llull
| | | | - Jorge Matute
- Department of Business Management, IQS School of Management, Universitat Ramon Llull
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7
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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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8
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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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9
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Sindeev S, Kirschke JS, Prothmann S, Frolov S, Liepsch D, Berg P, Zimmer C, Friedrich B. Evaluation of flow changes after telescopic stenting of a giant fusiform aneurysm of the vertebrobasilar junction. Biomed Eng Online 2019; 18:82. [PMID: 31340820 PMCID: PMC6657177 DOI: 10.1186/s12938-019-0699-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Accepted: 07/11/2019] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The use of flow-diverters for non-saccular cerebral posterior circulation aneurysms requires complex deployment techniques and is associated with high mortality and morbidity. Therefore, further studies are required to clarify the effect of stenting on post-treatment hemodynamics in such aneurysms. In this study, we evaluated flow alterations in a treated giant fusiform aneurysm of the vertebrobasilar junction and correlated them with the clinical outcome. METHODS A patient-specific aneurysm model was acquired by rotational angiography, and three SILK flow-diverters (4.5 × 40, 5 × 40 and 5.5 × 40 mm) were virtually deployed in series along the basilar and right vertebral arteries. Image-based blood flow simulations before and after the treatment were performed under realistic pulsatile flow conditions. The flow reduction, velocity and wall shear stress (WSS) distribution, streamlines and WSS-derived parameters were evaluated before and after the treatment. RESULTS The computed velocity streamlines showed substantial alterations of the flow pattern in the aneurysm and successful redirection of blood flow along the series of flow-diverters with no flow through the overlapping stents. The obtained flow reduction of 86% was sufficient to create thrombogenic flow conditions. Moreover, a 6.2-fold increase in relative residence time and a decrease by 87% of time-averaged WSS contributed to a successful treatment outcome observed during the follow-up. CONCLUSIONS We found a correlation between the numerically predicted flow alterations and the available treatment outcome. This shows the potential of image-based simulations to be used in clinical practice for treatment planning and estimation of possible risk factors associated with a complex stent deployment in fusiform aneurysms of the posterior circulation.
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Affiliation(s)
- Sergey Sindeev
- Department of Biomedical Engineering, Tambov State Technical University, Tambov, Russia
| | - Jan Stephan Kirschke
- Department of Diagnostic and Interventional Neuroradiology, Klinikum Rechts der Isar, Technical University of Munich, Ismaninger Strasse 22, 81675, Munich, Germany
| | - Sascha Prothmann
- Department of Neuroradiology, Helios Klinikum München West, Munich, Germany
| | - Sergey Frolov
- Department of Biomedical Engineering, Tambov State Technical University, Tambov, Russia
| | - Dieter Liepsch
- Department of Building Services Engineering, Munich University of Applied Sciences, Munich, Germany
| | - Philipp Berg
- Research Campus STIMULATE, University of Magdeburg, Magdeburg, Germany
| | - Claus Zimmer
- Department of Diagnostic and Interventional Neuroradiology, Klinikum Rechts der Isar, Technical University of Munich, Ismaninger Strasse 22, 81675, Munich, Germany
| | - Benjamin Friedrich
- Department of Diagnostic and Interventional Neuroradiology, Klinikum Rechts der Isar, Technical University of Munich, Ismaninger Strasse 22, 81675, Munich, Germany.
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10
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Multiple Aneurysms AnaTomy CHallenge 2018 (MATCH): Phase I: Segmentation. Cardiovasc Eng Technol 2018; 9:565-581. [DOI: 10.1007/s13239-018-00376-0] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Accepted: 08/20/2018] [Indexed: 10/28/2022]
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11
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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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12
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Alkhalili K, Hannallah J, Cobb M, Chalouhi N, Philips JL, Echeverria AB, Jabbour P, Babiker MH, Frakes DH, Gonzalez LF. The Effect of Stents in Cerebral Aneurysms: A Review. Asian J Neurosurg 2018; 13:201-211. [PMID: 29682009 PMCID: PMC5898080 DOI: 10.4103/1793-5482.175639] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
The etiology of up to 95% of cerebral aneurysms may be accounted for by hemodynamically-induced factors that create vascular injury. The purpose of this review is to describe key physical properties that stents have and how they affect cerebral aneurysms. We performed a two-step screening process. First, a structured search was performed using the PubMed database. The following search terms and keywords were used: “Hemodynamics,” “wall shear stress (WSS),” “velocity,” “viscosity,” “cerebral aneurysm,” “intracranial aneurysm,” “stent,” “flow diverter,” “stent porosity,” “stent geometry,” “stent configuration,” and “stent design.” Reports were considered if they included original data, discussed hemodynamic changes after stent-based treatment of cerebral aneurysms, examined the hemodynamic effects of stent deployment, and/or described the geometric characteristics of both stents and the aneurysms they were used to treat. The search strategy yielded a total of 122 articles, 61 were excluded after screening the titles and abstracts. Additional articles were then identified by cross-checking reference lists. The final collection of 97 articles demonstrates that the geometric characteristics and configurations of deployed stents influenced hemodynamic parameters such as aneurysmal WSS, inflow, and pressure. The geometric characteristics of the aneurysm and its position also had significant influences on intra-aneurysmal hemodynamics after treatment. In conclusion, changes in specific aneurysmal hemodynamic parameters that result from stenting relate to a number of factors including the geometric properties and configurations of deployed stents, the geometric properties of the aneurysm, and the pretreatment hemodynamics.
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Affiliation(s)
- Kenan Alkhalili
- Department of Surgery, University of Arizona, Tucson, Arizona, USA
| | - Jack Hannallah
- Department of Surgery, University of Arizona, Tucson, Arizona, USA
| | - Mary Cobb
- Division of Neurosurgery, Duke University, Durham, NC, USA
| | - Nohra Chalouhi
- Department of Neurosurgery, Thomas Jefferson University, Philadelphia, PA, USA
| | - Jessica L Philips
- Department of Neurosurgery, Thomas Jefferson University, Philadelphia, PA, USA
| | | | - Pascal Jabbour
- Department of Neurosurgery, Thomas Jefferson University, Philadelphia, PA, USA
| | | | - David H Frakes
- Division of Neurosurgery, Duke University, Durham, NC, USA
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13
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Sindeev S, Arnold PG, Frolov S, Prothmann S, Liepsch D, Balasso A, Berg P, Kaczmarz S, Kirschke JS. Phase-contrast MRI versus numerical simulation to quantify hemodynamical changes in cerebral aneurysms after flow diverter treatment. PLoS One 2018; 13:e0190696. [PMID: 29304062 PMCID: PMC5755883 DOI: 10.1371/journal.pone.0190696] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2017] [Accepted: 12/19/2017] [Indexed: 02/05/2023] Open
Abstract
Cerebral aneurysms are a major risk factor for intracranial bleeding with devastating consequences for the patient. One recently established treatment is the implantation of flow-diverters (FD). Methods to predict their treatment success before or directly after implantation are not well investigated yet. The aim of this work was to quantitatively study hemodynamic parameters in patient-specific models of treated cerebral aneurysms and its correlation with the clinical outcome. Hemodynamics were evaluated using both computational fluid dynamics (CFD) and phase contrast (PC) MRI. CFD simulations and in vitro MRI measurements were done under similar flow conditions and results of both methods were comparatively analyzed. For preoperative and postoperative distribution of hemodynamic parameters, CFD simulations and PC-MRI velocity measurements showed similar results. In both cases where no occlusion of the aneurysm was observed after six months, a flow reduction of about 30-50% was found, while in the clinically successful case with complete occlusion of the aneurysm after 6 months, the flow reduction was about 80%. No vortex was observed in any of the three models after treatment. The results are in agreement with recent studies suggesting that CFD simulations can predict post-treatment aneurysm flow alteration already before implantation of a FD and PC-MRI could validate the predicted hemodynamic changes right after implantation of a FD.
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Affiliation(s)
- Sergey Sindeev
- Department of Biomedical Engineering, Tambov State Technical University, Tambov, Russia
- * E-mail:
| | - Philipp Georg Arnold
- Department of Neuroradiology, Klinikum rechts der Isar of Technical University of Munich, Munich, Germany
| | - Sergey Frolov
- Department of Biomedical Engineering, Tambov State Technical University, Tambov, Russia
| | - Sascha Prothmann
- Department of Neuroradiology, Klinikum rechts der Isar of Technical University of Munich, Munich, Germany
| | - Dieter Liepsch
- Department of Building Services Engineering, Chemical Engineering for Paper and Packaging, Print and Media Technologies, Munich University of Applied Sciences, Munich, Germany
| | - Andrea Balasso
- Department of Earth and Environmental Sciences, Ludwig-Maximilian-University of Munich, Munich, Germany
| | - Philipp Berg
- Department of Fluid Dynamics and Technical Flows, University of Magdeburg, Magdeburg, Germany
| | - Stephan Kaczmarz
- Department of Neuroradiology, Klinikum rechts der Isar of Technical University of Munich, Munich, Germany
| | - Jan Stefan Kirschke
- Department of Neuroradiology, Klinikum rechts der Isar of Technical University of Munich, Munich, Germany
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14
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Sarrami-Foroushani A, Lassila T, Frangi AF. Virtual endovascular treatment of intracranial aneurysms: models and uncertainty. WILEY INTERDISCIPLINARY REVIEWS-SYSTEMS BIOLOGY AND MEDICINE 2017; 9. [PMID: 28488754 DOI: 10.1002/wsbm.1385] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Revised: 01/09/2017] [Accepted: 02/07/2017] [Indexed: 01/11/2023]
Abstract
Virtual endovascular treatment models (VETMs) have been developed with the view to aid interventional neuroradiologists and neurosurgeons to pre-operatively analyze the comparative efficacy and safety of endovascular treatments for intracranial aneurysms. Based on the current state of VETMs in aneurysm rupture risk stratification and in patient-specific prediction of treatment outcomes, we argue there is a need to go beyond personalized biomechanical flow modeling assuming deterministic parameters and error-free measurements. The mechanobiological effects associated with blood clot formation are important factors in therapeutic decision making and models of post-treatment intra-aneurysmal biology and biochemistry should be linked to the purely hemodynamic models to improve the predictive power of current VETMs. The influence of model and parameter uncertainties associated to each component of a VETM is, where feasible, quantified via a random-effects meta-analysis of the literature. This allows estimating the pooled effect size of these uncertainties on aneurysmal wall shear stress. From such meta-analyses, two main sources of uncertainty emerge where research efforts have so far been limited: (1) vascular wall distensibility, and (2) intra/intersubject systemic flow variations. In the future, we suggest that current deterministic computational simulations need to be extended with strategies for uncertainty mitigation, uncertainty exploration, and sensitivity reduction techniques. WIREs Syst Biol Med 2017, 9:e1385. doi: 10.1002/wsbm.1385 For further resources related to this article, please visit the WIREs website.
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Affiliation(s)
- Ali Sarrami-Foroushani
- Center for Computational Imaging and Simulation Technologies in Biomedicine (CISTIB), The University of Sheffield, Sheffield, UK
| | - Toni Lassila
- Center for Computational Imaging and Simulation Technologies in Biomedicine (CISTIB), The University of Sheffield, Sheffield, UK
| | - Alejandro F Frangi
- Center for Computational Imaging and Simulation Technologies in Biomedicine (CISTIB), The University of Sheffield, Sheffield, UK
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15
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Iosif C, Berg P, Ponsonnard S, Carles P, Saleme S, Pedrolo-Silveira E, Mendes G, Waihrich E, Trolliard G, Couquet CY, Yardin C, Mounayer C. Role of terminal and anastomotic circulation in the patency of arteries jailed by flow-diverting stents: animal flow model evaluation and preliminary results. J Neurosurg 2016; 125:898-908. [DOI: 10.3171/2015.8.jns151296] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECTIVE
The authors describe herein the creation of an animal model capable of producing quantifiable data regarding blood flow rate and velocity modifications in terminal and anastomotic types of cerebrofacial circulation. They also present the preliminary results of a translational study aimed at investigating the role of terminal and anastomotic types of circulation in arterial branches jailed by flow-diverting stents as factors contributing to arterial patency or occlusion.
METHODS
Two Large White swine were used to validate a terminal-type arterial model at the level of the right ascending pharyngeal artery (APhA), created exclusively by endovascular means. Subsequently 4 Large White swine, allocated to 2 groups corresponding to the presence (Group B) or absence (Group A) of terminal-type flow modification, underwent placement of flow-diverting stents. Blood flow rates and velocities were quantified using a dedicated time-resolved 3D phase-contrast MRA sequence before and after stenting. Three months after stent placement, the stented arteries were evaluated with digital subtraction angiography (DSA) and scanning electron microscopy (SEM). Patent (circulating) ostia quantification was performed on the SEM images.
RESULTS
Terminal-type flow modification was feasible; an increase of 75.8% in mean blood velocities was observed in the right APhAs. The mean blood flow rate for Group A was 0.31 ± 0.19 ml/sec (95% CI −1.39 to 2.01) before stenting and 0.21 ± 0.07 ml/sec (95% CI −0.45 to 0.87) after stenting. The mean blood flow rate for Group B was 0.87 ± 0.32 ml/sec (95% CI −1.98 to 3.73) before stenting and 0.76 ± 0.13 ml/sec (95% CI −0.41 to 1.93) after stenting. Mean flow rates after stenting showed a statistically significant difference between Groups A and B (Welch test). Mean and maximal blood velocities were reduced in Group A cases and did not decrease in Group B cases. Control DSA and SEM findings showed near occlusion of the jailed APhAs in both cases of anastomotic circulation (mean patent ostium surface 32,776 μm2) and patency in both cases of terminal-type circulation (mean patent ostium surface 422,334 μm2).
CONCLUSIONS
Terminal-type arterial modification in swine APhAs is feasible. Sufficient data were acquired to perform an a priori analysis for further research. Flow diversion at the level of the APhA ostium resulted in significant stenosis in cases of anastomotic circulation, while sufficient patency was observed in terminal-type circulation.
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Affiliation(s)
- Christina Iosif
- Departments of 1Interventional Neuroradiology and
- 2Applied Medical Research Team (ERMA)
| | - Philipp Berg
- 3Laboratory of Fluid Dynamics and Technical Flows, University of Magdeburg “Otto von Guerike,” Magdeburg, Germany
| | | | - Pierre Carles
- 5Science of Ceramic Processes and Surface Treatments, CNRS, UMR 7315, European Ceramic Center, University of Limoges
| | | | | | | | | | - Gilles Trolliard
- 5Science of Ceramic Processes and Surface Treatments, CNRS, UMR 7315, European Ceramic Center, University of Limoges
| | | | - Catherine Yardin
- 2Applied Medical Research Team (ERMA)
- 7Department of Histology, Cytology, Cellular Biology and Cytogenetics, Mother and Child (HME) University Hospital, Limoges, France; and
| | - Charbel Mounayer
- Departments of 1Interventional Neuroradiology and
- 2Applied Medical Research Team (ERMA)
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16
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Song Y, Choe J, Liu H, Park KJ, Yu H, Lim OK, Kim H, Park D, Ge J, Suh DC. Virtual stenting of intracranial aneurysms: application of hemodynamic modification analysis. Acta Radiol 2016; 57:992-7. [PMID: 26503958 DOI: 10.1177/0284185115613653] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2015] [Accepted: 09/30/2015] [Indexed: 11/16/2022]
Abstract
BACKGROUND Practical application of hemodynamic modification analysis based on computational fluid dynamics (CFD) in intracranial aneurysms is still under study. PURPOSE To determine the clinical applicability of virtual stenting of aneurysms by comparing the simulated results with clinical outcome of real stenting. MATERIAL AND METHODS Three-dimensional (3D) digital subtraction angiography (DSA) images were imported to a dedicated integrated prototypic CFD platform (Siemens Healthcare GmbH) which allows all necessary steps of 3D models for CFD analysis. The results of CFD simulation with virtual implantation of a stent can be visualized in the same platform for qualitative comparisons on a color-coded volume visualization window. Five small intracranial aneurysms with and without virtual stenting were analyzed and assessed on a qualitative level. Expert rating were performed for evaluating the simulated results, and comparing those to the long-term follow-up outcomes of real stenting. RESULTS CFD simulation after virtual stenting was feasible in five differently located aneurysms and corresponded to the long-term changes of stented aneurysms by showing alteration in flow pattern. There was no significant difference (P = 0.5) between the simulated hemodynamic changes after virtual stenting and the angiographic changes after stenting in four aneurysms except one. There was good agreement regarding the assessment of the changes by two raters (kappa = 0.657). CONCLUSION CFD analysis using patient-specific virtual stenting of the CFD platform may be used as a simple and less time-consuming test tool predicting the involution of aneurysms after stent placement by analyzing the vector visualization of the flow changes.
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Affiliation(s)
- Yunsun Song
- Department of Radiology, University of Ulsan, College of Medicine, Asan Medical Center, Seoul, Republic of Korea
| | - Jooae Choe
- Department of Radiology, University of Ulsan, College of Medicine, Asan Medical Center, Seoul, Republic of Korea
| | - Hairi Liu
- Department of Radiology, University of Ulsan, College of Medicine, Asan Medical Center, Seoul, Republic of Korea
- Department of Interventional Radiology, Taizhou People’s Hospital, Taizhou, Jiangsu Province, PR China
| | - Kye Jin Park
- Department of Radiology, University of Ulsan, College of Medicine, Asan Medical Center, Seoul, Republic of Korea
| | - HyungBin Yu
- Imaging & IT Workflow & Solutions Division, Healthcare Sector, Siemens Ltd. Seoul, Seoul, Republic of Korea
| | - Ok Kyun Lim
- Department of Radiology, University of Ulsan, College of Medicine, Asan Medical Center, Seoul, Republic of Korea
| | - Hyoweon Kim
- Department of Radiology, University of Ulsan, College of Medicine, Asan Medical Center, Seoul, Republic of Korea
| | - Darlene Park
- Department of Radiology, University of Ulsan, College of Medicine, Asan Medical Center, Seoul, Republic of Korea
| | - Jiajia Ge
- Angiography & Interventional X-Ray systems, Healthcare sector, Siemens Ltd., Shanghai, PR China
| | - Dae Chul Suh
- Department of Radiology, University of Ulsan, College of Medicine, Asan Medical Center, Seoul, Republic of Korea
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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: 15] [Impact Index Per Article: 1.9] [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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18
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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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19
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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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20
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21
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Berg P, Iosif C, Ponsonnard S, Yardin C, Janiga G, Mounayer C. Endothelialization of over- and undersized flow-diverter stents at covered vessel side branches: An in vivo and in silico study. J Biomech 2016; 49:4-12. [DOI: 10.1016/j.jbiomech.2015.10.047] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2015] [Revised: 10/28/2015] [Accepted: 10/31/2015] [Indexed: 11/28/2022]
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22
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Berg P, Roloff C, Beuing O, Voss S, Sugiyama SI, Aristokleous N, Anayiotos AS, Ashton N, Revell A, Bressloff NW, Brown AG, Jae Chung B, Cebral JR, Copelli G, Fu W, Qiao A, Geers AJ, Hodis S, Dragomir-Daescu D, Nordahl E, Bora Suzen Y, Owais Khan M, Valen-Sendstad K, Kono K, Menon PG, Albal PG, Mierka O, Münster R, Morales HG, Bonnefous O, Osman J, Goubergrits L, Pallares J, Cito S, Passalacqua A, Piskin S, Pekkan K, Ramalho S, Marques N, Sanchi S, Schumacher KR, Sturgeon J, Švihlová H, Hron J, Usera G, Mendina M, Xiang J, Meng H, Steinman DA, Janiga G. The Computational Fluid Dynamics Rupture Challenge 2013—Phase II: Variability of Hemodynamic Simulations in Two Intracranial Aneurysms. J Biomech Eng 2015; 137:121008. [DOI: 10.1115/1.4031794] [Citation(s) in RCA: 67] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2014] [Indexed: 11/08/2022]
Abstract
With the increased availability of computational resources, the past decade has seen a rise in the use of computational fluid dynamics (CFD) for medical applications. There has been an increase in the application of CFD to attempt to predict the rupture of intracranial aneurysms, however, while many hemodynamic parameters can be obtained from these computations, to date, no consistent methodology for the prediction of the rupture has been identified. One particular challenge to CFD is that many factors contribute to its accuracy; the mesh resolution and spatial/temporal discretization can alone contribute to a variation in accuracy. This failure to identify the importance of these factors and identify a methodology for the prediction of ruptures has limited the acceptance of CFD among physicians for rupture prediction. The International CFD Rupture Challenge 2013 seeks to comment on the sensitivity of these various CFD assumptions to predict the rupture by undertaking a comparison of the rupture and blood-flow predictions from a wide range of independent participants utilizing a range of CFD approaches. Twenty-six groups from 15 countries took part in the challenge. Participants were provided with surface models of two intracranial aneurysms and asked to carry out the corresponding hemodynamics simulations, free to choose their own mesh, solver, and temporal discretization. They were requested to submit velocity and pressure predictions along the centerline and on specified planes. The first phase of the challenge, described in a separate paper, was aimed at predicting which of the two aneurysms had previously ruptured and where the rupture site was located. The second phase, described in this paper, aims to assess the variability of the solutions and the sensitivity to the modeling assumptions. Participants were free to choose boundary conditions in the first phase, whereas they were prescribed in the second phase but all other CFD modeling parameters were not prescribed. In order to compare the computational results of one representative group with experimental results, steady-flow measurements using particle image velocimetry (PIV) were carried out in a silicone model of one of the provided aneurysms. Approximately 80% of the participating groups generated similar results. Both velocity and pressure computations were in good agreement with each other for cycle-averaged and peak-systolic predictions. Most apparent “outliers” (results that stand out of the collective) were observed to have underestimated velocity levels compared to the majority of solutions, but nevertheless identified comparable flow structures. In only two cases, the results deviate by over 35% from the mean solution of all the participants. Results of steady CFD simulations of the representative group and PIV experiments were in good agreement. The study demonstrated that while a range of numerical schemes, mesh resolution, and solvers was used, similar flow predictions were observed in the majority of cases. To further validate the computational results, it is suggested that time-dependent measurements should be conducted in the future. However, it is recognized that this study does not include the biological aspects of the aneurysm, which needs to be considered to be able to more precisely identify the specific rupture risk of an intracranial aneurysm.
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Affiliation(s)
- Philipp Berg
- University of Magdeburg, Magdeburg 39106, Germany
| | | | - Oliver Beuing
- University Hospital of Magdeburg, Magdeburg 39120, Germany
| | - Samuel Voss
- University of Magdeburg, Magdeburg 39106, Germany
| | | | | | | | - Neil Ashton
- The University of Manchester, Manchester M60 1QD, UK
| | | | | | | | | | | | | | - Wenyu Fu
- Beijing University of Technology, Beijing 100124, China
| | - Aike Qiao
- Beijing University of Technology, Beijing 100124, China
| | | | - Simona Hodis
- Texas A&M University, Kingsville, TX 78363
- Mayo Clinic, Rochester, MN 55905
| | | | | | | | | | | | - Kenichi Kono
- Wakayama Rosai Hospital, Wakayama 640-8505, Japan
| | - Prahlad G. Menon
- Sun Yat-sen University—Carnegie Mellon University Joint Institute of Engineering, Pittsburgh, PA 15219
| | - Priti G. Albal
- Sun Yat-sen University—Carnegie Mellon University Joint Institute of Engineering, Pittsburgh, PA 15219
| | - Otto Mierka
- University of Dortmund, Dortmund 44227, Germany
| | | | | | | | - Jan Osman
- Charité-Universitätsmedizin Berlin, Berlin 13353, Germany
| | | | | | | | | | | | | | - Susana Ramalho
- blueCAPE Lda—CAE Solutions, Milharado 2665-305, Portugal
| | - Nelson Marques
- blueCAPE Lda—CAE Solutions, Milharado 2665-305, Portugal
| | | | | | | | | | | | - Gabriel Usera
- Universidad de la República, Montevideo 11300, Uruguay
| | | | - Jianping Xiang
- University at Buffalo—State University of New York, Buffalo, NY 14203
| | - Hui Meng
- University at Buffalo—State University of New York, Buffalo, NY 14203
| | | | - Gábor Janiga
- University of Magdeburg, Magdeburg 39106, Germany
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23
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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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Nam HG, Yoo CM, Baek SM, Kim HK, Shin JH, Hwang MH, Jo GE, Kim KS, Cho JH, Lee SH, Kim HC, Lim CH, Choi H, Sun K. Enhancement of Mechanical Properties and Testing of Nitinol Stents in Cerebral Aneurysm Simulation Models. Artif Organs 2015; 39:E213-26. [DOI: 10.1111/aor.12564] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Hyo Geun Nam
- Department of Medical Sciences; Graduate School of Medicine; Korea University; Seoul Korea
| | - Chang Min Yoo
- Department of Medical Sciences; Graduate School of Medicine; Korea University; Seoul Korea
| | - Seoung Min Baek
- Department of Medical Sciences; Graduate School of Medicine; Korea University; Seoul Korea
| | - Han Ki Kim
- Department of Mechanical Engineering; Dankook University; Yongin Korea
| | - Jae Hee Shin
- Department of Medical Sciences; Graduate School of Medicine; Korea University; Seoul Korea
| | - Min Ho Hwang
- Department of Medical Sciences; Graduate School of Medicine; Korea University; Seoul Korea
| | - Ga Eun Jo
- Department of Medical Sciences; Graduate School of Medicine; Korea University; Seoul Korea
| | - Kyong Soo Kim
- Department of Medical Sciences; Graduate School of Medicine; Korea University; Seoul Korea
| | - Jae Hwa Cho
- College of Medicine; Radiation Applied Life Science; Seoul National University; Seoul Korea
| | - Seung Hoon Lee
- Department of Otorhinolaryngology-Head and Neck Surgery; College of Medicine; Korea University; Seoul Korea
| | - Ho Chul Kim
- Department of Radiological Science; Eulji University; Seongnam Korea
| | - Chun Hak Lim
- Department of Anesthesiology and Pain Medicine; College of Medicine; Korea University; Seoul Korea
| | - Hyuk Choi
- Department of Medical Sciences; Graduate School of Medicine; Korea University; Seoul Korea
| | - Kyung Sun
- Thoracic and Cardiovascular Surgery; College of Medicine; Korea University; Seoul Korea
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25
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Interactive virtual stent planning for the treatment of coarctation of the aorta. Int J Comput Assist Radiol Surg 2015; 11:133-44. [PMID: 25976833 DOI: 10.1007/s11548-015-1220-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2015] [Accepted: 05/01/2015] [Indexed: 02/06/2023]
Abstract
PURPOSE The coarctation of the aorta (CoA), a local narrowing of the aortic arch, accounts for 7 % of all congenital heart defects. Stenting is a recommended therapy to reduce the pressure gradient. This procedure is associated with complications such as the development of adverse flow conditions. A computer-aided treatment planning based on flow simulations can help to predict possible complications. The virtual stent planning is an important, intermediate step in the treatment planning pipeline. We present a novel approach that automatically suggests a stent setup and provides a set of intuitive parameters that allow for an interactive adaption of the suggested stent placement and induced deformation. METHODS A high-quality mesh and a centerline are automatically generated. The stent-induced deformation is realized through a deformation of the centerline and a vertex displacement with respect to the deformed centerline and additional stent parameters. The parameterization is automatically derived from the underlying data and can be optionally altered through a condensed set of clinically sound parameters. RESULTS The automatic deformation can be generated in about 25 s on a consumer system. The interactive adaption can be performed in real time. Compared with manual expert reconstructions of the stented vessel section, the mean difference of vessel path and diameter is below 1 mm. CONCLUSION Our approach enables a medical user to easily generate a plausibly deformed vessel mesh which is necessary as input for a simulation-based treatment planning of CoA.
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Anzai H, Falcone JL, Chopard B, Hayase T, Ohta M. Optimization of strut placement in flow diverter stents for four different aneurysm configurations. J Biomech Eng 2014; 136:061006. [PMID: 24718997 DOI: 10.1115/1.4027411] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2013] [Accepted: 04/11/2014] [Indexed: 11/08/2022]
Abstract
A modern technique for the treatment of cerebral aneurysms involves insertion of a flow diverter stent. Flow stagnation, produced by the fine mesh structure of the diverter, is thought to promote blood clotting in an aneurysm. However, apart from its effect on flow reduction, the insertion of the metal device poses the risk of occlusion of a parent artery. One strategy for avoiding the risk of arterial occlusion is the use of a device with a higher porosity. To aid the development of optimal stents in the view point of flow reduction maintaining a high porosity, we used lattice Boltzmann flow simulations and simulated annealing optimization to investigate the optimal placement of stent struts. We constructed four idealized aneurysm geometries that resulted in four different inflow characteristics and employed a stent model with 36 unconnected struts corresponding to the porosity of 80%. Assuming intracranial flow, steady flow simulation with Reynolds number of 200 was applied for each aneurysm. Optimization of strut position was performed to minimize the average velocity in an aneurysm while maintaining the porosity. As the results of optimization, we obtained nonuniformed structure as optimized stent for each aneurysm geometry. And all optimized stents were characterized by denser struts in the inflow area. The variety of inflow patterns that resulted from differing aneurysm geometries led to unique strut placements for each aneurysm type.
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The 'Sphere': A Dedicated Bifurcation Aneurysm Flow-Diverter Device. Cardiovasc Eng Technol 2014; 5:334-347. [PMID: 25400707 PMCID: PMC4226933 DOI: 10.1007/s13239-014-0188-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/29/2014] [Accepted: 07/15/2014] [Indexed: 11/03/2022]
Abstract
We present flow-based results from the early stage design cycle, based on computational modeling, of a prototype flow-diverter device, known as the 'Sphere', intended to treat bifurcation aneurysms of the cerebral vasculature. The device is available in a range of diameters and geometries and is constructed from a single loop of NITINOL® wire. The 'Sphere' reduces aneurysm inflow by means of a high-density, patterned, elliptical surface that partially occludes the aneurysm neck. The device is secured in the healthy parent vessel by two armatures in the shape of open loops, resulting in negligible disruption of parent or daughter vessel flow. The device is virtually deployed in six anatomically accurate bifurcation aneurysms: three located at the Basilar tip and three located at the terminus bifurcation of the Internal Carotid artery (at the meeting of the middle cerebral and anterior cerebral arteries). Both steady state and transient flow simulations reveal that the device presents with a range of aneurysm inflow reductions, with mean flow reductions falling in the range of 30.6-71.8% across the different geometries. A significant difference is noted between steady state and transient simulations in one geometry, where a zone of flow recirculation is not captured in the steady state simulation. Across all six aneurysms, the device reduces the WSS magnitude within the aneurysm sac, resulting in a hemodynamic environment closer to that of a healthy vessel. We conclude from extensive CFD analysis that the 'Sphere' device offers very significant levels of flow reduction in a number of anatomically accurate aneurysm sizes and locations, with many advantages compared to current clinical cylindrical flow-diverter designs. Analysis of the device's mechanical properties and deployability will follow in future publications.
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Accuracy and Reproducibility of Patient-Specific Hemodynamic Models of Stented Intracranial Aneurysms: Report on the Virtual Intracranial Stenting Challenge 2011. Ann Biomed Eng 2014; 43:154-67. [DOI: 10.1007/s10439-014-1082-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2014] [Accepted: 07/31/2014] [Indexed: 10/24/2022]
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Oeltze S, Lehmann DJ, Kuhn A, Janiga G, Theisel H, Preim B. Blood Flow Clustering and Applications in Virtual Stenting of Intracranial Aneurysms. IEEE TRANSACTIONS ON VISUALIZATION AND COMPUTER GRAPHICS 2014; 20:686-701. [PMID: 26357292 DOI: 10.1109/tvcg.2013.2297914] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Understanding the hemodynamics of blood flow in vascular pathologies such as intracranial aneurysms is essential for both their diagnosis and treatment. Computational fluid dynamics (CFD) simulations of blood flow based on patient-individual data are performed to better understand aneurysm initiation and progression and more recently, for predicting treatment success. In virtual stenting, a flow-diverting mesh tube (stent) is modeled inside the reconstructed vasculature and integrated in the simulation. We focus on steady-state simulation and the resulting complex multiparameter data. The blood flow pattern captured therein is assumed to be related to the success of stenting. It is often visualized by a dense and cluttered set of streamlines.We present a fully automatic approach for reducing visual clutter and exposing characteristic flow structures by clustering streamlines and computing cluster representatives. While individual clustering techniques have been applied before to streamlines in 3D flow fields, we contribute a general quantitative and a domain-specific qualitative evaluation of three state-of-the-art techniques. We show that clustering based on streamline geometry as well as on domain-specific streamline attributes contributes to comparing and evaluating different virtual stenting strategies. With our work, we aim at supporting CFD engineers and interventional neuroradiologists.
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Approximating hemodynamics of cerebral aneurysms with steady flow simulations. J Biomech 2014; 47:178-85. [DOI: 10.1016/j.jbiomech.2013.09.033] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2013] [Revised: 09/10/2013] [Accepted: 09/17/2013] [Indexed: 11/19/2022]
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Ma D, Dumont TM, Kosukegawa H, Ohta M, Yang X, Siddiqui AH, Meng H. High fidelity virtual stenting (HiFiVS) for intracranial aneurysm flow diversion: in vitro and in silico. Ann Biomed Eng 2013; 41:2143-56. [PMID: 23604850 DOI: 10.1007/s10439-013-0808-4] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2012] [Accepted: 04/05/2013] [Indexed: 11/30/2022]
Abstract
A flow diverter (FD) is a flexible, densely braided stent-mesh device placed endoluminally across an intracranial aneurysm to induce its thrombotic occlusion. FD treatment planning using computational virtual stenting and flow simulation requires accurate representation of the expanded FD geometry. We have recently developed a high fidelity virtual stenting (HiFiVS) technique based on finite element analysis to simulate detailed FD deployment processes in patient-specific aneurysms (Ma et al. J. Biomech. 45:2256-2263,(2012)). This study tests if HiFiVS simulation can recapitulate real-life FD implantation. We deployed two identical FDs (Pipeline Embolization Device) into phantoms of a wide-necked segmental aneurysm using a clinical push-pull technique with different delivery wire advancements. We then simulated these deployment processes using HiFiVS and compared results against experimental recording. Stepwise comparison shows that the simulations precisely reproduced the FD deployment processes recorded in vitro. The local metal coverage rate and pore density quantifications demonstrated that simulations reproduced detailed FD mesh geometry. These results provide validation of the HiFiVS technique, highlighting its unique capability of accurately representing stent intervention in silico.
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Affiliation(s)
- Ding Ma
- Toshiba Stroke and Vascular Research Center, University at Buffalo, State University of New York, 875 Ellicott Street, Buffalo, NY 14203, USA
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Computer Simulations in Stroke Prevention: Design Tools and Virtual Strategies Towards Procedure Planning. Cardiovasc Eng Technol 2013. [DOI: 10.1007/s13239-013-0134-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Tang AYS, Chan HN, Tsang ACO, Leung GKK, Leung KM, Yu ACH, Chow KW. The effects of stent porosity on the endovascular treatment of intracranial aneurysms located near a bifurcation. ACTA ACUST UNITED AC 2013. [DOI: 10.4236/jbise.2013.68099] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Janiga G, Berg P, Beuing O, Neugebauer M, Gasteiger R, Preim B, Rose G, Skalej M, Thévenin D. Recommendations for accurate numerical blood flow simulations of stented intracranial aneurysms. ACTA ACUST UNITED AC 2013; 58:303-14. [DOI: 10.1515/bmt-2012-0119] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2012] [Accepted: 04/03/2013] [Indexed: 11/15/2022]
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