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Sándor L, Paál G. Design space exploration of flow diverter hydraulic resistance parameters in sidewall intracranial aneurysms. Comput Methods Biomech Biomed Engin 2024; 27:931-942. [PMID: 37231591 DOI: 10.1080/10255842.2023.2215369] [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: 03/16/2023] [Accepted: 05/07/2023] [Indexed: 05/27/2023]
Abstract
Intracranial aneurysms are nowadays treated with endovascular flow diverter devices to avoid sac rupture. This study explores how different linear and quadratic hydrodynamic resistance parameters reduce the flow in the sac for five patient-specific sidewall aneurysms.The 125 performed blood flow simulations included the stents using a Darcy-Forcheimer porous layer approach based on real-life stent characteristics. Time- and space-averaged velocity magnitudes were strongly affected by the linear coefficient with a power-law relationship. Quadratic coefficients alter the flow in a minor way due to the low-velocity levels in the aneurysm sac and neck region.
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Affiliation(s)
- Levente Sándor
- Faculty of Mechanical Engineering, Department of Hydrodynamic Systems, Budapest University of Technology and Economics, Budapest, Hungary
| | - György Paál
- Faculty of Mechanical Engineering, Department of Hydrodynamic Systems, Budapest University of Technology and Economics, Budapest, Hungary
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2
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Xia Y, Ravikumar N, Lassila T, Frangi AF. Virtual high-resolution MR angiography from non-angiographic multi-contrast MRIs: synthetic vascular model populations for in-silico trials. Med Image Anal 2023; 87:102814. [PMID: 37196537 DOI: 10.1016/j.media.2023.102814] [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: 02/11/2022] [Revised: 04/04/2023] [Accepted: 04/08/2023] [Indexed: 05/19/2023]
Abstract
Despite success on multi-contrast MR image synthesis, generating specific modalities remains challenging. Those include Magnetic Resonance Angiography (MRA) that highlights details of vascular anatomy using specialised imaging sequences for emphasising inflow effect. This work proposes an end-to-end generative adversarial network that can synthesise anatomically plausible, high-resolution 3D MRA images using commonly acquired multi-contrast MR images (e.g. T1/T2/PD-weighted MR images) for the same subject whilst preserving the continuity of vascular anatomy. A reliable technique for MRA synthesis would unleash the research potential of very few population databases with imaging modalities (such as MRA) that enable quantitative characterisation of whole-brain vasculature. Our work is motivated by the need to generate digital twins and virtual patients of cerebrovascular anatomy for in-silico studies and/or in-silico trials. We propose a dedicated generator and discriminator that leverage the shared and complementary features of multi-source images. We design a composite loss function for emphasising vascular properties by minimising the statistical difference between the feature representations of the target images and the synthesised outputs in both 3D volumetric and 2D projection domains. Experimental results show that the proposed method can synthesise high-quality MRA images and outperform the state-of-the-art generative models both qualitatively and quantitatively. The importance assessment reveals that T2 and PD-weighted images are better predictors of MRA images than T1; and PD-weighted images contribute to better visibility of small vessel branches towards the peripheral regions. In addition, the proposed approach can generalise to unseen data acquired at different imaging centres with different scanners, whilst synthesising MRAs and vascular geometries that maintain vessel continuity. The results show the potential for use of the proposed approach to generating digital twin cohorts of cerebrovascular anatomy at scale from structural MR images typically acquired in population imaging initiatives.
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Affiliation(s)
- Yan Xia
- Centre for Computational Imaging and Simulation Technologies in Biomedicine (CISTIB), School of Computing, University of Leeds, Leeds, UK.
| | - Nishant Ravikumar
- Centre for Computational Imaging and Simulation Technologies in Biomedicine (CISTIB), School of Computing, University of Leeds, Leeds, UK
| | - Toni Lassila
- Centre for Computational Imaging and Simulation Technologies in Biomedicine (CISTIB), School of Computing, University of Leeds, Leeds, UK
| | - Alejandro F Frangi
- Centre for Computational Imaging and Simulation Technologies in Biomedicine (CISTIB), School of Computing, University of Leeds, Leeds, UK; Leeds Institute for Cardiovascular and Metabolic Medicine (LICAMM), School of Medicine, University of Leeds, Leeds, UK; Medical Imaging Research Center (MIRC), Cardiovascular Science and Electronic Engineering Departments, KU Leuven, Leuven, Belgium; Alan Turing Institute, London, UK
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3
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Wang T, Ugurlu H, Yan Y, Li M, Li M, Wild AM, Yildiz E, Schneider M, Sheehan D, Hu W, Sitti M. Adaptive wireless millirobotic locomotion into distal vasculature. Nat Commun 2022; 13:4465. [PMID: 35915075 PMCID: PMC9343456 DOI: 10.1038/s41467-022-32059-9] [Citation(s) in RCA: 31] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Accepted: 07/14/2022] [Indexed: 11/23/2022] Open
Abstract
Microcatheters have enabled diverse minimally invasive endovascular operations and notable health benefits compared with open surgeries. However, with tortuous routes far from the arterial puncture site, the distal vascular regions remain challenging for safe catheter access. Therefore, we propose a wireless stent-shaped magnetic soft robot to be deployed, actively navigated, used for medical functions, and retrieved in the example M4 segment of the middle cerebral artery. We investigate shape-adaptively controlled locomotion in phantoms emulating the physiological conditions here, where the lumen diameter shrinks from 1.5 mm to 1 mm, the radius of curvature of the tortuous lumen gets as small as 3 mm, the lumen bifurcation angle goes up to 120°, and the pulsatile flow speed reaches up to 26 cm/s. The robot can also withstand the flow when the magnetic actuation is turned off. These locomotion capabilities are confirmed in porcine arteries ex vivo. Furthermore, variants of the robot could release the tissue plasminogen activator on-demand locally for thrombolysis and function as flow diverters, initiating promising therapies towards acute ischemic stroke, aneurysm, arteriovenous malformation, dural arteriovenous fistulas, and brain tumors. These functions should facilitate the robot's usage in new distal endovascular operations.
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Affiliation(s)
- Tianlu Wang
- Physical Intelligence Department, Max Planck Institute for Intelligent Systems, 70569, Stuttgart, Germany
- Department of Information Technology and Electrical Engineering, ETH Zurich, 8092, Zurich, Switzerland
| | - Halim Ugurlu
- Physical Intelligence Department, Max Planck Institute for Intelligent Systems, 70569, Stuttgart, Germany
- Clinic for Neuroradiology, Klinikum Stuttgart, 70174, Stuttgart, Germany
- Department of Biophysics, Aydın Adnan Menderes University, Graduate School of Health Sciences, 09010, Aydın, Turkey
| | - Yingbo Yan
- Physical Intelligence Department, Max Planck Institute for Intelligent Systems, 70569, Stuttgart, Germany
| | - Mingtong Li
- Physical Intelligence Department, Max Planck Institute for Intelligent Systems, 70569, Stuttgart, Germany
| | - Meng Li
- Physical Intelligence Department, Max Planck Institute for Intelligent Systems, 70569, Stuttgart, Germany
| | - Anna-Maria Wild
- Physical Intelligence Department, Max Planck Institute for Intelligent Systems, 70569, Stuttgart, Germany
| | - Erdost Yildiz
- Physical Intelligence Department, Max Planck Institute for Intelligent Systems, 70569, Stuttgart, Germany
| | - Martina Schneider
- Physical Intelligence Department, Max Planck Institute for Intelligent Systems, 70569, Stuttgart, Germany
| | - Devin Sheehan
- Physical Intelligence Department, Max Planck Institute for Intelligent Systems, 70569, Stuttgart, Germany
| | - Wenqi Hu
- Physical Intelligence Department, Max Planck Institute for Intelligent Systems, 70569, Stuttgart, Germany.
| | - Metin Sitti
- Physical Intelligence Department, Max Planck Institute for Intelligent Systems, 70569, Stuttgart, Germany.
- Department of Information Technology and Electrical Engineering, ETH Zurich, 8092, Zurich, Switzerland.
- School of Medicine and College of Engineering, Koç University, 34450, Istanbul, Turkey.
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Berod A, Chnafa C, Mendez S, Nicoud F. A heterogeneous model of endovascular devices for the treatment of intracranial aneurysms. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2022; 38:e3552. [PMID: 34806847 DOI: 10.1002/cnm.3552] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Revised: 03/25/2021] [Accepted: 07/31/2021] [Indexed: 06/13/2023]
Abstract
Numerical computations of hemodynamics inside intracranial aneurysms treated by endovascular braided devices such as flow-diverters contribute to understanding and improving such treatment procedures. Nevertheless, these simulations yield high computational and meshing costs due to the heterogeneity of length scales between the dense weave of the fine struts of the device and the arterial volume. Homogeneous strategies developed over the last decade to circumvent this issue substitute local dissipations due to the wires with a global effect in the form of a pressure-drop across the device surface. However, these methods cannot accurately reproduce the flow-patterns encountered near the struts, the latter strongly dictating the intra-saccular flow environment. In this work, a versatile theoretical framework which aims at correctly reproducing the local flow heterogeneities due to the wires while keeping memory consumption, meshing and computational times as low as possible is introduced. This model reproduces the drag forces exerted by the device struts onto the fluid, thus producing local and heterogeneous effects on the flow. Extensive validation for various flow and geometric configurations using an idealized device is performed. To further illustrate the method capabilities, a real patient-specific aneurysm endovascularly treated with a flow-diverter is used, enabling quantitative comparisons with classical approaches for both intra-saccular velocities and computational costs reduction. The proposed heterogeneous model endeavors to bridge the gap between computational fluid dynamics and clinical applications and ushers in a new era of numerical treatment planning with minimally costing computational tools.
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Affiliation(s)
- Alain Berod
- IMAG, Univ Montpellier, CNRS, Montpellier, France
- Sim&Cure, Montpellier, France
| | | | - Simon Mendez
- IMAG, Univ Montpellier, CNRS, Montpellier, France
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Kim S, Yang H, Hong I, Oh JH, Kim YB. Computational Study of Hemodynamic Changes Induced by Overlapping and Compacting of Stents and Flow Diverter in Cerebral Aneurysms. Front Neurol 2021; 12:705841. [PMID: 34408723 PMCID: PMC8365227 DOI: 10.3389/fneur.2021.705841] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Accepted: 07/14/2021] [Indexed: 11/13/2022] Open
Abstract
Purpose: The flow diversion effect of an intracranial stent is closely related to its metal coverage rate (MCR). In this study, the flow diversion effects of Enterprise and low-profile visualized intraluminal support (LVIS) stents are compared with those of a Pipeline flow diverter, focusing on the MCR change. Moreover, the changes in the flow diversion effect caused by the additional manipulations of overlapping and compaction are verified using computational fluid dynamics (CFD) analysis. Methods: CFD analysis was performed using virtually generated stents mounted in an idealized aneurysm model. First, the flow diversion effects of single Enterprise, LVIS, and Pipeline devices were analyzed. The Enterprise and LVIS were sequentially overlapped and compared with a Pipeline, to evaluate the effect of stent overlapping. The effect of compacting a stent was evaluated by comparing the flow diversion effects of a single and two compacted LVIS with those of two overlapped, uncompacted LVIS and uncompacted and compacted Pipeline. Quantitative analysis was performed to evaluate the hemodynamic parameters of energy loss, average velocity, and inflow rate. Results: Statistically significant correlations were observed between the reduction rates of the hemodynamic parameters and MCR. The single LVIS without compaction induced a reduction in all the hemodynamic parameters comparable to those of the three overlapped Enterprise. Moreover, the two overlapped, uncompacted LVIS showed a flow diversion effect as large as that induced by the single uncompacted Pipeline. Compacted stents induced a better flow diversion effect than uncompacted stents. The single compacted LVIS induced a flow diversion effect similar to that induced by the two uncompacted LVIS or single uncompacted Pipeline. Conclusions: The MCR of a stent correlates with its flow diversion effect. Overlapping and compaction can increase the MCR of an intracranial stent and achieve a flow diversion effect as large as that observed with a flow diverter.
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Affiliation(s)
- Sunghan Kim
- Department of Neurosurgery, Bucheon St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, South Korea.,Department of Neurosurgery, Severance Stroke Center, Severance Hospital, Yonsei University College of Medicine, Seoul, South Korea
| | - Hyeondong Yang
- Department of Mechanical Engineering and BK21 FOUR ERICA-ACE Center, Hanyang University, Ansan, South Korea
| | - Ineui Hong
- Department of Mechanical Engineering and BK21 FOUR ERICA-ACE Center, Hanyang University, Ansan, South Korea
| | - Je Hoon Oh
- Department of Mechanical Engineering and BK21 FOUR ERICA-ACE Center, Hanyang University, Ansan, South Korea
| | - Yong Bae Kim
- Department of Neurosurgery, Severance Stroke Center, Severance Hospital, Yonsei University College of Medicine, Seoul, South Korea
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Nada A, Hassan MA, Fakhr MA, El-Wakad MTI. Studying the effect of stent thickness and porosity on post-stent implantation hemodynamics. J Med Eng Technol 2021; 45:408-416. [PMID: 33945392 DOI: 10.1080/03091902.2021.1912204] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
This study investigates the effect of stent thickness and stent porosity which are important factors determining the post-treatment intra-aneurysmal hemodynamics. The study uses computational fluid dynamics (CFD) to estimate the hemodynamic behaviour: flow velocity, pressure distributions, time-averaged wall shear stress (TAWSS), oscillatory shear index (OSI), besides relative residence time (RRT) blood flow distribution in a proposed stent and three other commercially available stents. The hemodynamic behaviour is compared between four different cases. In each case, each stent has the specific thickness and porosity values. The results show that the velocity magnitude inside the sac declined in thinner stents and lower porosity stents, TAWSS on the aneurysmal wall declined linearly in lower porosity stents, OSI and RRT increased obviously in thicker stents and higher porosity stents. Finally, the results conclude that the stent with the lowest thickness and porosity has the best performance that leads to post-stent thrombus formation and healing. However, the proposed stent design, a more porous construct, has a higher RRT compared to the used commercially available stents, which helps promote the thrombus growth inside the aneurysm sac.
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Affiliation(s)
- Ayat Nada
- Department of Computers and Systems, Electronics Research Institute, Giza, Egypt
| | - Mohammed A Hassan
- Department of Biomedical Engineering, Faculty of Engineering, Helwan University, Cairo, Egypt
| | - Mahmoud A Fakhr
- Department of Computers and Systems, Electronics Research Institute, Giza, Egypt
| | - Mohamed Tarek I El-Wakad
- Department of Biomedical Engineering, Faculty of Engineering and Technology, Future University, Cairo, Egypt
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Suzuki T, Hasegawa H, Ando K, Shibuya K, Takahashi H, Saito S, Oishi M, Fujii Y. Possibility of Worsening Flow Diversion Effect Due to Morphological Changes of a Stented Artery With Multiple Overlapping Stents for Partially Thrombosed Vertebral Artery Aneurysms. Front Neurol 2021; 11:611124. [PMID: 33384657 PMCID: PMC7770215 DOI: 10.3389/fneur.2020.611124] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Accepted: 11/23/2020] [Indexed: 11/13/2022] Open
Abstract
Background: Morphological changes of a stented artery can cause a flow diversion effect to reduce intra-aneurysmal flow; however, there is a potential for the negative effect of increased intra-aneurysmal flow. We present cases with multiple overlapping stents for a partially thrombosed vertebral artery aneurysm and characterize the hemodynamic properties of a recurrent case by focusing on the morphological changes of the stented artery. Methods: Between October 2017 and April 2019, four consecutive cases of symptomatic unruptured large and giant partially thrombosed vertebral artery aneurysms were treated with multiple overlapping low-profile visualized intraluminal support stents and no coils. Both angiographic and clinical outcomes were assessed. Computational fluid dynamics analysis was performed to clarify hemodynamic features. The degree of pressure elevation was calculated as the pressure difference (Pd). Wall shear stress (WSS) was also calculated. Results: In three of the four cases, successful flow reduction was achieved with no morphological change of the stented arteries. The patients' symptoms were gradually improved. The remaining case required additional stents after the initial treatment. In the recurrent case, Pd was noticeably elevated at the aneurysm neck after treatment, and WSS was generally increased in the area due to altered blood flow into the aneurysm dome caused by morphological changes of the stented artery. Conclusion: Overlapping stents can be used for the treatment of large and giant thrombosed vertebral artery aneurysms with flow diversion effect; however, morphological changes of the stented artery requires careful attention as it may lead to an increase in the intra-aneurysmal flow, causing negative outcomes.
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Affiliation(s)
- Tomoaki Suzuki
- Department of Neurosurgery, Brain Research Institute, Niigata University, Niigata, Japan
| | - Hitoshi Hasegawa
- Department of Neurosurgery, Brain Research Institute, Niigata University, Niigata, Japan
| | - Kazuhiro Ando
- Department of Neurosurgery, Brain Research Institute, Niigata University, Niigata, Japan
| | - Kouhei Shibuya
- Department of Neurosurgery, Brain Research Institute, Niigata University, Niigata, Japan
| | - Haruhiko Takahashi
- Department of Neurosurgery, Brain Research Institute, Niigata University, Niigata, Japan
| | - Shoji Saito
- Department of Neurosurgery, Brain Research Institute, Niigata University, Niigata, Japan
| | - Makoto Oishi
- Department of Neurosurgery, Brain Research Institute, Niigata University, Niigata, Japan
| | - Yukihiko Fujii
- Department of Neurosurgery, Brain Research Institute, Niigata University, Niigata, Japan
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8
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Ding A, Braschkat A, Guber A, Cattaneo G. New Concept of Patient-specific Flow Diversion Treatment of Intracranial Aneurysms : Design Aspects and in vitro Fluid Dynamics. Clin Neuroradiol 2020; 31:671-679. [PMID: 32651611 DOI: 10.1007/s00062-020-00930-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Accepted: 06/20/2020] [Indexed: 11/29/2022]
Abstract
PURPOSE Current flow diverter (FD) designs limit the possibilities to achieve ideal functional parameters for intra-aneurysmal flow alteration in the implanted state. In this work, we evaluate the technical feasibility of a new patient-specific FD concept and the impact on intra-aneurysmal flow reduction compared to standard FD. METHODS Based on a literature review, we defined functional requirements, followed by the design and manufacturing of two different prototypes, which we implanted in a patient-specific phantom model. Functional porosity distributions and contour parameters were evaluated in the implanted state and compared to standard FD. Subsequently, we carried out a series of particle image velocimetry (PIV) measurements, in order to assess the impact on intra-aneurysmal flow. RESULTS With both patient-specific prototypes, it was possible to achieve stronger intra-aneurysmal flow reductions in terms of maximum and mean velocity and vorticity than a standard FD; however, one design showed a strong sensitivity against malpositioning. Overall, fluid dynamics parameters correlated with geometrical aspects such as the porosity and its grade of homogeneity. Beyond that, we found influences by the FD contour projection within the aneurysm, especially connected to the formation of in-jets. CONCLUSION Our results show that there is a technically feasible concept, which enables a more specific adjustment of functional FD parameters and more effective intra-aneurysmal flow reduction. This could potentially lead to improvements in the efficacy of aneurysm occlusion in cases with challenging fluid dynamics.
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Affiliation(s)
- Andreas Ding
- Acandis GmbH, R&D, Pforzheim, Baden-Württemberg, Germany. .,, Weltzienstr. 24, 76135, Karlsruhe, Germany.
| | | | - Andreas Guber
- Institute of Microstructure Technology, Karlsruhe Institute of Technology, Karlsruhe, Baden-Württemberg, Germany
| | - Giorgio Cattaneo
- Institute of Biomedical Engineering, University of Stuttgart, Stuttgart, Baden-Württemberg, Germany
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Intra-aneurysmal pressure changes during stent-assisted coiling. PLoS One 2020; 15:e0233981. [PMID: 32497124 PMCID: PMC7272096 DOI: 10.1371/journal.pone.0233981] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Accepted: 05/16/2020] [Indexed: 01/14/2023] Open
Abstract
We aimed to examine aneurysm hemodynamics with intra-saccular pressure measurement, and compare the effects of coiling, stenting and stent-assisted coiling in proximal segments of intracranial circulation. A cohort of 45 patients underwent elective endovascular coil embolization (with or without stent) for intracranial aneurysm at our department. Arterial pressure transducer was used for all measurements. It was attached to proximal end of the microcatheter. Measurements were taken in the parent artery before and after embolization, at the aneurysm dome before embolization, after stent implantation, and after embolization. Stent-assisted coiling was performed with 4 different stents: LVIS and LVIS Jr (Microvention, Tustin, CA, USA), Leo (Balt, Montmorency, France), Barrel VRD (Medtronic/ Covidien, Irvine, CA, USA). Presence of the stent showed significant reverse correlation with intra-aneurysmal pressure–both systolic and diastolic—after its implantation (r = -0.70 and r = -0.75, respectively), which was further supported by correlations with stent cell size–r = 0.72 and r = 0.71, respectively (P<0.05). Stent implantation resulted in significant decrease in diastolic intra-aneurysmal pressure (p = 0.046). Systolic or mean intra-aneurysmal pressure did not differ significantly. Embolization did not significantly change the intra-aneurysmal pressure in matched pairs, regardless of the use of stent (p>0.05). In conclusion, low-profile braided stents show a potential to divert blood flow, there was significant decrease in diastolic pressure after stent placement. Flow-diverting properties were related to stent porosity. Coiling does not significantly change the intra-aneurysmal pressure, regardless of packing density.
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Su T, Reymond P, Brina O, Bouillot P, Machi P, Delattre BMA, Jin L, Lövblad KO, Vargas MI. Large Neck and Strong Ostium Inflow as the Potential Causes for Delayed Occlusion of Unruptured Sidewall Intracranial Aneurysms Treated by Flow Diverter. AJNR Am J Neuroradiol 2020; 41:488-494. [PMID: 32054620 DOI: 10.3174/ajnr.a6413] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2019] [Accepted: 12/23/2019] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE Flow diverter-induced hemodynamic change plays an important role in the mechanism of intracranial aneurysm occlusion. Our aim was to explore the relationship between aneurysm features and flow-diverter treatment of unruptured sidewall intracranial aneurysms. MATERIALS AND METHODS MR imaging, 4D phase-contrast, was prospectively performed before flow diverter implantation in each patient with unruptured intracranial aneurysm. Two postprocedure follow-ups were scheduled at 6 and 12 months. Responses were grouped according to whether the aneurysms were occluded or remnant. Preprocedural aneurysm geometries and ostium hemodynamics in 38 patients were compared between the 2 groups at 6 and 12 months. Receiver operating characteristic curve analyses were performed for significant geometric and hemodynamic continuous parameters. RESULTS After the 6-month assessment, 21 of 41 intracranial aneurysms were occluded, and 9 additional aneurysms were occluded at 12 months. Geometrically, the ostium maximum diameter was significantly larger in the remnant group at 6 and 12 months (both P < .001). Hemodynamically, the proximal inflow zone was more frequently observed in the remnant group at 6 months. Several preprocedural ostium hemodynamic parameters were significantly higher in the remnant group. As a prediction for occlusion, the areas under the curve of the ostium maximum diameter (for 6 and 12 months), systolic inflow rate ratio (for 6 months), and systolic inflow area (for 12 months) reached 0.843, 0.883, 0.855, and 0.860, respectively. CONCLUSIONS Intracranial aneurysms with a large ostium and strong ostium inflow may need a longer time for occlusion. Preprocedural 4D flow MR imaging can well illustrate ostium hemodynamics and characterize aneurysm treatment responses.
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Affiliation(s)
- T Su
- From the Department of Interventional Radiology (T.S., L.J.), Beijing Friendship Hospital, Capital Medical University, Beijing, People's Republic of China
| | - P Reymond
- Division of Neuroradiology and Neuro-Interventional Radiology (P.R., O.B., P.M., K.O.L., M.I.V.)
| | - O Brina
- Division of Neuroradiology and Neuro-Interventional Radiology (P.R., O.B., P.M., K.O.L., M.I.V.)
| | - P Bouillot
- and Division of Radiology (B.M.A.D.), University Hospitals of Geneva, Geneva, Switzerland
| | - P Machi
- Division of Neuroradiology and Neuro-Interventional Radiology (P.R., O.B., P.M., K.O.L., M.I.V.)
| | - B M A Delattre
- Department of Quantum Matter Physics (P.B.), University of Geneva, Geneva, Switzerland
| | - L Jin
- From the Department of Interventional Radiology (T.S., L.J.), Beijing Friendship Hospital, Capital Medical University, Beijing, People's Republic of China
| | - K O Lövblad
- Division of Neuroradiology and Neuro-Interventional Radiology (P.R., O.B., P.M., K.O.L., M.I.V.)
| | - M I Vargas
- Division of Neuroradiology and Neuro-Interventional Radiology (P.R., O.B., P.M., K.O.L., M.I.V.)
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11
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Joshi KC, Larrabide I, Saied A, Elsaid N, Fernandez H, Lopes DK. Software-based simulation for preprocedural assessment of braided stent sizing: a validation study. J Neurosurg 2019; 131:1423-1429. [PMID: 30497172 DOI: 10.3171/2018.5.jns18976] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2018] [Accepted: 05/29/2018] [Indexed: 11/06/2022]
Abstract
OBJECTIVE The authors sought to validate the use of a software-based simulation for preassessment of braided self-expanding stents in the treatment of wide-necked intracranial aneurysms. METHODS This was a retrospective, observational, single-center study of 13 unruptured and ruptured intracranial aneurysms treated with braided self-expanding stents. Pre- and postprocedural angiographic studies were analyzed. ANKYRAS software was used to compare the following 3 variables: the manufacturer-given nominal length (NL), software-calculated simulated length (SL), and the actual measured length (ML) of the stent. Appropriate statistical methods were used to draw correlations among the 3 lengths. RESULTS In this study, data obtained in 13 patients treated with braided self-expanding stents were analyzed. Data for the 3 lengths were collected for all patients. Error discrepancy was calculated by mean squared error (NL to ML -22.2; SL to ML -6.14, p < 0.05), mean absolute error (NL to ML 3.88; SL to ML -1.84, p < 0.05), and mean error (NL to ML -3.81; SL to ML -1.22, p < 0.05). CONCLUSIONS The ML was usually less than the NL given by the manufacturer, indicating significant change in length in most cases. Computational software-based simulation for preassessment of the braided self-expanding stents is a safe and effective way for accurately calculating the change in length to aid in choosing the right-sized stent for optimal placement in complex intracranial vasculature.
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Affiliation(s)
| | | | - Ahmed Saied
- 3Department of Neurology, Mansoura University, Mansoura, Egypt; and
| | - Nada Elsaid
- 1Department of Neurosurgery, Rush Medical Center, Chicago, Illinois
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Marsh LMM, Barbour MC, Chivukula VK, Chassagne F, Kelly CM, Levy SH, Kim LJ, Levitt MR, Aliseda A. Platelet Dynamics and Hemodynamics of Cerebral Aneurysms Treated with Flow-Diverting Stents. Ann Biomed Eng 2019; 48:490-501. [PMID: 31549329 DOI: 10.1007/s10439-019-02368-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2019] [Accepted: 09/13/2019] [Indexed: 02/06/2023]
Abstract
Flow-diverting stents (FDS) are used to treat cerebral aneurysms. They promote the formation of a stable thrombus within the aneurysmal sac and, if successful, isolate the aneurysmal dome from mechanical stresses to prevent rupture. Platelet activation, a mechanism necessary for thrombus formation, is known to respond to biomechanical stimuli, particularly to the platelets' residence time and shear stress exposure. Currently, there is no reliable method for predicting FDS treatment outcomes, either a priori or after the procedure. Eulerian computational fluid dynamic (CFD) studies of aneurysmal flow have searched for predictors of endovascular treatment outcome; however, the hemodynamics of thrombus formation cannot be fully understood without considering the platelets' trajectories and their mechanics-triggered activation. Lagrangian analysis of the fluid mechanics in the aneurysmal vasculature provides novel metrics by tracking the platelets' residence time (RT) and shear history (SH). Eulerian and Lagrangian parameters are compared for 19 patient-specific cases, both pre- and post-treatment, to assess the degree of change caused by the FDS and subsequent treatment efficacy.
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Affiliation(s)
- Laurel M M Marsh
- Mechanical Engineering, University of Washington, 4000 15th Ave NE, Box 352600, Seattle, WA, 98195, USA
| | - Michael C Barbour
- Mechanical Engineering, University of Washington, 4000 15th Ave NE, Box 352600, Seattle, WA, 98195, USA
| | - Venkat Keshav Chivukula
- Mechanical Engineering, University of Washington, 4000 15th Ave NE, Box 352600, Seattle, WA, 98195, USA
| | - Fanette Chassagne
- Mechanical Engineering, University of Washington, 4000 15th Ave NE, Box 352600, Seattle, WA, 98195, USA
| | - Cory M Kelly
- Neurological Surgery, University of Washington, Seattle, WA, USA.,Stroke & Applied NeuroScience Center, University of Washington, Seattle, WA, USA
| | - Samuel H Levy
- Neurological Surgery, University of Washington, Seattle, WA, USA.,Stroke & Applied NeuroScience Center, University of Washington, Seattle, WA, USA
| | - Louis J Kim
- Neurological Surgery, University of Washington, Seattle, WA, USA.,Stroke & Applied NeuroScience Center, University of Washington, Seattle, WA, USA.,Radiology, University of Washington, Seattle, WA, USA
| | - Michael R Levitt
- Mechanical Engineering, University of Washington, 4000 15th Ave NE, Box 352600, Seattle, WA, 98195, USA.,Neurological Surgery, University of Washington, Seattle, WA, USA.,Stroke & Applied NeuroScience Center, University of Washington, Seattle, WA, USA.,Radiology, University of Washington, Seattle, WA, USA
| | - Alberto Aliseda
- Mechanical Engineering, University of Washington, 4000 15th Ave NE, Box 352600, Seattle, WA, 98195, USA. .,Neurological Surgery, University of Washington, Seattle, WA, USA. .,Stroke & Applied NeuroScience Center, University of Washington, Seattle, WA, USA.
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13
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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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14
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Chen J, Zhang Y, Tian Z, Li W, Zhang Q, Zhang Y, Liu J, Yang X. Relationship between haemodynamic changes and outcomes of intracranial aneurysms after implantation of the pipeline embolisation device: a single centre study. Interv Neuroradiol 2019; 25:671-680. [PMID: 31088244 DOI: 10.1177/1591019919849673] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
BACKGROUND Intracranial aneurysms are increasingly being treated by the placement of flow diverters; however, the factors affecting the outcome of aneurysms treated using flow diverters remain unclarified. METHODS The present study investigated 94 aneurysms treated with pipeline embolisation device placement, and used a computational fluid dynamics method to explore the factors influencing the outcome of aneurysms. RESULTS Seventy-six completely occluded aneurysms and 18 incompletely occluded aneurysms were analysed. Before treatment, inflow jets were found in 13 (72.2%) aneurysms in the incompletely occluded group and 34 (44.7%) in the completely occluded group (P = 0.292). After deployment of the pipeline embolisation device, inflow jets remained in nine (50%) aneurysms in the incompletely occluded group and nine (11.8%) in the completely occluded group (P = 0.001). In the incompletely occluded group, regions with inflow jets after treatment corresponded with the patent areas shown on follow-up digital subtraction angiography. The mean reduction ratios of velocity in the whole aneurysm and on the neck plane were lower in the incompletely occluded than in the completely occluded group (P = 0.003; P = 0.017). Multivariate analysis revealed that the only independent risk factors for incomplete aneurysm occlusion were the reduction ratios of velocity (in the whole aneurysm, threshold 0.362, P = 0.005; on the neck plane, threshold 0.273, P = 0.015). CONCLUSIONS After pipeline embolisation device placement, reduction ratios of velocity in the whole aneurysm of less than 0.362 and on the neck plane of less than 0.273 are significantly associated with a greater risk of aneurysm incomplete occlusion. In addition, the persistence of inflow jets in aneurysms is associated with incomplete occlusion in the inflow jet area.
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Affiliation(s)
- Junfan Chen
- Department of Interventional Neuroradiology, Beijing Neurosurgical Institute, Beijing, China
| | - Yisen Zhang
- Department of Interventional Neuroradiology, Beijing Neurosurgical Institute, Beijing, China
| | - Zhongbin Tian
- Department of Interventional Neuroradiology, Beijing Neurosurgical Institute, Beijing, China
| | - Wenqiang Li
- Department of Interventional Neuroradiology, Beijing Neurosurgical Institute, Beijing, China
| | - Qianqian Zhang
- Department of Interventional Neuroradiology, Beijing Neurosurgical Institute, Beijing, China
| | - Ying Zhang
- Department of Interventional Neuroradiology, Beijing Neurosurgical Institute, Beijing, China
| | - Jian Liu
- Department of Interventional Neuroradiology, Beijing Tiantan Hospital, Beijing, China
| | - Xinjian Yang
- Department of Interventional Neuroradiology, Beijing Neurosurgical Institute, Beijing, China
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15
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CFD-Based Comparison Study of a New Flow Diverting Stent and Commercially-Available Ones for the Treatment of Cerebral Aneurysms. APPLIED SCIENCES-BASEL 2019. [DOI: 10.3390/app9071341] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Flow-diverting stents (FDSs) show considerable promise for the treatment of cerebral aneurysms by diverting blood flow away from the aneurysmal sacs, however, post-treatment complications such as failure of occlusion and subarachnoid haemorrhaging remain and vary with the FDS used. Based on computational fluid dynamics (CFD), this study aimed to investigate the performance of a new biodegradable stent as compared to two metallic commercially available FDSs. CFD models were developed for an idealized cerebral artery with a sidewall aneurysmal sac treated by deploying the aforementioned stents of different porosities (90, 80, and 70 % ) respectively. By using these models, the simulation and analysis were performed, with a focus on comparing the local hemodynamics or the blood flow in the stented arteries as compared to the one without the stent deployment. For the comparison, we computed and compared the flow velocity, wall shear stress (WSS) and pressure distributions, as well as the WSS related indices, all of which are of important parameters for studying the occlusion and potential rupture of the aneurysm. Our results illustrate that the WSS decreases within the aneurysmal sac on the treated arteries, which is more significant for the stents with lower porosity or finer mesh. Our results also show that the maximum WSS near the aneurysmal neck increases regardless of the stents used. In addition, the WSS related indices including the time-average WSS, oscillatory shear index and relative residence time show different distributions, depending on the FDSs. Together, we found that the finer mesh stents provide more flow reduction and smaller region characterized by high oscillatory shear index, while the new stent has a higher relative residence time.
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16
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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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Zhang Y, Ma C, Liang S, Yan P, Liang F, Guo F, Jiang C. Morphologic Feature Elongation Can Predict Occlusion Status Following Pipeline Embolization of Intracranial Aneurysms. World Neurosurg 2018; 119:e934-e940. [DOI: 10.1016/j.wneu.2018.08.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Revised: 08/02/2018] [Accepted: 08/03/2018] [Indexed: 11/30/2022]
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18
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FROLOV SV, SINDEEV SV, LIEPSCH D, BALASSO A, ARNOLD P, KIRSCHKE JS, PROTHMANN S, POTLOV AYU. NEWTONIAN AND NON-NEWTONIAN BLOOD FLOW AT A 90∘-BIFURCATION OF THE CEREBRAL ARTERY: A COMPARATIVE STUDY OF FLUID VISCOSITY MODELS. J MECH MED BIOL 2018. [DOI: 10.1142/s0219519418500434] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The majority of numerical simulations assumes blood as a Newtonian fluid due to an underestimation of the effect of non-Newtonian blood behavior on hemodynamics in the cerebral arteries. In the present study, we evaluated the effect of non-Newtonian blood properties on hemodynamics in the idealized 90[Formula: see text]-bifurcation model, using Newtonian and non-Newtonian fluids and different flow rate ratios between the parent artery and its branch. The proposed Local viscosity model was employed for high-precision representation of blood viscosity changes. The highest velocity differences were observed at zones with slow recirculating flow. During the systolic peak the average difference was 17–22%, whereas at the end of diastole the difference increased to 27–60% depending on the flow rate ratio. The main changes in the viscosity distribution were observed distal to the flow separation point, where the non-Newtonian fluid model produced 2.5 times higher viscosity. A presence of such high viscosity region substantially affected the size of the flow recirculation zone. The observed differences showed that non-Newtonian blood behavior had a significant effect on hemodynamic parameters and should be considered in the future studies of blood flow in cerebral arteries.
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Affiliation(s)
- S. V. FROLOV
- Biomedical Engineering Department, Tambov State Technical University, Sovetskaya Street, 106, Tambov, Russia
| | - S. V. SINDEEV
- Biomedical Engineering Department, Tambov State Technical University, Sovetskaya Street, 106, Tambov, Russia
| | - D. LIEPSCH
- Department of Building Services Engineering, Paper and Packaging Technology and Print and Media Technology, Munich University of Applied Sciences, Lothstrasse, 34, Munich, Germany
| | - A. BALASSO
- Department of Earth and Environmental Sciences, Ludwig-Maximilians-University, Luisenstrasse Strasse, 37, Munich, Germany
| | - P. ARNOLD
- Department of Diagnostic and Interventional Neuroradiology, Klinikum Rechts der Isar, Technical University of Munich, Ismaninger Strasse, 22, Munich, Germany
| | - J. S. KIRSCHKE
- Department of Diagnostic and Interventional Neuroradiology, Klinikum Rechts der Isar, Technical University of Munich, Ismaninger Strasse, 22, Munich, Germany
| | - S. PROTHMANN
- Institute of Diagnostic and Interventional Neuroradiology, HELIOS Klinikum Munchen West Steinerweg, 5, Munich, Germany
| | - A. YU. POTLOV
- Biomedical Engineering Department, Tambov State Technical University, Sovetskaya Street, 106, Tambov, Russia
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19
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Casciaro ME, Dottori J, El-Batti S, Alsac JM, Mousseaux E, Larrabide I, Craiem D. Effects on Aortoiliac Fluid Dynamics After Endovascular Sealing of Abdominal Aneurysms. Vasc Endovascular Surg 2018; 52:621-628. [PMID: 30058480 DOI: 10.1177/1538574418791059] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVES: To evaluate the effects on aortoiliac fluid dynamics after the implantation of an endograft based on endovascular aneurysm sealing (EVAS) versus endovascular aneurysm repair (EVAR) strategy. METHODS: An adaptive geometrical deformable model was used for aortic lumen segmentation in 8 patients before and after the surgery. Abdominal aneurysms were treated with an endograft based on the EVAS system (Nellix, n = 4) and with a device based on an anatomical fixation technology (n = 4). Pressure, blood velocity, and wall shear stress (WSS) were estimated at different aortic regions using computational fluid dynamics methods. Physiologic inlet/outlet flow values at the abdominal aorta, the celiac trunk, and the mesenteric and the renal arteries were set. Pressure references were set at iliac arteries outlet. RESULTS: Maximum aneurysm sizes were similar for both groups in the preoperative scans. The lumen area was lower after EVAR ( P < .05) and EVAS ( P < .01) compared to preoperative aortic lumen sizes. Pressure increase was higher in the proximal abdominal aorta after EVAS compared to EVAR (2.3 ± 0.3 mm Hg vs 0.9 ± 0.3 mm Hg, P < .001). Peak blood velocities inside the endografts were 3-fold higher for EVAS compared to EVAR (54 ± 5 cm/s vs 17 ± 4 cm/s, P < .01). Velocities at the iliac arteries also remained higher for EVAS (38 ± 4 cm/s vs 24 ± 4 cm/s, P < .05). Peak WSS at the iliac arteries remained higher for EVAS compared to EVAR group ( P < .05). CONCLUSION: The significant modification of the aortic bifurcation anatomy after EVAS alters aortoiliac fluid dynamics, showing a pressure impact at the renal arteries level and an acceleration of the blood velocity at the iliac region with a concomitant increase in peak WSS.
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Affiliation(s)
- Mariano E Casciaro
- 1 Instituto de Medicina Traslacional, Trasplante y Bioingeniería (IMeTTyB), Universidad Favaloro-CONICET, Buenos Aires, Argentina
| | | | - Salma El-Batti
- 3 APHP, Hôpital Européen Georges Pompidou, Paris, France
| | | | - Elie Mousseaux
- 3 APHP, Hôpital Européen Georges Pompidou, Paris, France
| | | | - Damian Craiem
- 1 Instituto de Medicina Traslacional, Trasplante y Bioingeniería (IMeTTyB), Universidad Favaloro-CONICET, Buenos Aires, Argentina.,3 APHP, Hôpital Européen Georges Pompidou, Paris, France
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20
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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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21
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Bhogal P, AlMatter M, Hellstern V, Ganslandt O, Bäzner H, Henkes H, Aguilar-Pérez M. The Combined Use of Intraluminal and Intrasaccular Flow Diversion for the Treatment of Intracranial Aneurysms: Report of 25 Cases. Neurointervention 2018; 13:20-31. [PMID: 29535895 PMCID: PMC5847887 DOI: 10.5469/neuroint.2018.13.1.20] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2018] [Revised: 02/23/2018] [Accepted: 02/26/2018] [Indexed: 11/29/2022] Open
Abstract
PURPOSE The Medina Embolic Device (MED) is a new intrasaccular device with promising early results. Previously we documented our initial experience of this device both alone and in combination with other devices including flow diverter stents (FDS). We sought to determine the effect of the MED + FDS strategy for the treatment of selected aneurysms. MATERIALS AND METHODS We performed a retrospective analysis of prospectively collected data to identify all patients with aneurysms treated using both the MED and intraluminal FDS. We present our technical success rate, early and mid-term angiographic follow-up, and clinical outcome data. RESULTS We identified 25 non-consecutive patients. The treatment was staged in 9 patients and in a single session 16 patients. The average age was 61±12.8 years (range 40-82). The average fundus height was 11±3.6 mm and average fundus width was 10.1±3.4 mm. In the staged cohort (n=9) at delayed angiography (mean 10 mths) 8 aneurysms (89%) showed complete exclusion (mRRC 1) and in one patient there was a parent vessel occlusion. In the simultaneous cohort delayed angiography (n=10, mean 8.1 months) demonstrated complete occlusion (mRRC 1) in 6 aneurysms (60%), 3 neck remnants (mRRC 2) (30%) and 1 patient (10%) showed persistent aneurysmal filling (mRRC 3a). There were 5 complications with permanent morbidity (mRS >2) in two patients. There were no mortalities. CONCLUSION The MED can be successfully used in combination with intraluminal FDS and in selected aneurysms this may represent an alternative to FDS and adjunctive coiling.
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Affiliation(s)
- Pervinder Bhogal
- Neuroradiological Clinic, Neurocenter, Klinikum Stuttgart, Germany
| | | | | | | | - Hansjörg Bäzner
- Neurological Clinic, Neurocenter, Klinikum Stuttgart, Germany
| | - Hans Henkes
- Neuroradiological Clinic, Neurocenter, Klinikum Stuttgart, Germany
- Medical Faculty, University Duisburg-Essen, Germany
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22
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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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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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24
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Dholakia R, Sadasivan C, Fiorella DJ, Woo HH, Lieber BB. Hemodynamics of Flow Diverters. J Biomech Eng 2017; 139:2569375. [DOI: 10.1115/1.4034932] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2016] [Indexed: 01/17/2023]
Abstract
Cerebral aneurysms are pathological focal evaginations of the arterial wall at and around the junctions of the circle of Willis. Their tenuous walls predispose aneurysms to leak or rupture leading to hemorrhagic strokes with high morbidity and mortality rates. The endovascular treatment of cerebral aneurysms currently includes the implantation of fine-mesh stents, called flow diverters, within the parent artery bearing the aneurysm. By mitigating flow velocities within the aneurysmal sac, the devices preferentially induce thrombus formation in the aneurysm within hours to days. In response to the foreign implant, an endothelialized arterial layer covers the luminal surface of the device over a period of days to months. Organization of the intraneurysmal thrombus leads to resorption and shrinkage of the aneurysm wall and contents, eventually leading to beneficial remodeling of the pathological site to a near-physiological state. The devices' primary function of reducing flow activity within aneurysms is corollary to their mesh structure. Complete specification of the device mesh structure, or alternately device permeability, necessarily involves the quantification of two variables commonly used to characterize porous media—mesh porosity and mesh pore density. We evaluated the flow alteration induced by five commercial neurovascular devices of varying porosity and pore density (stents: Neuroform, Enterprise, and LVIS; flow diverters: Pipeline and FRED) in an idealized sidewall aneurysm model. As can be expected in such a model, all devices substantially reduced intraneurysmal kinetic energy as compared to the nonstented case with the coarse-mesh stents inducing a 65–80% reduction whereas the fine-mesh flow diverters induced a near-complete flow stagnation (∼98% reduction). We also note a trend toward greater device efficacy (lower intraneurysmal flow) with decreasing device porosity and increasing device pore density. Several such flow studies have been and are being conducted in idealized as well as patient-derived geometries with the overarching goals of improving device design, facilitating treatment planning (what is the optimal device for a specific aneurysm), and predicting treatment outcome (will a specific aneurysm treated with a specific device successfully occlude over the long term). While the results are generally encouraging, there is poor standardization of study variables between different research groups, and any consensus will only be reached after standardized studies are conducted on collectively large datasets. Biochemical variables may have to be incorporated into these studies to maximize predictive values.
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Affiliation(s)
- Ronak Dholakia
- Department of Neurological Surgery, Stony Brook University Medical Center, Stony Brook, NY 11794
| | - Chander Sadasivan
- Department of Neurological Surgery, Stony Brook University Medical Center, Stony Brook, NY 11794
| | - David J. Fiorella
- Department of Neurological Surgery, Stony Brook University Medical Center, Stony Brook, NY 11794
| | - Henry H. Woo
- Department of Neurological Surgery, Stony Brook University Medical Center, Stony Brook, NY 11794
| | - Baruch B. Lieber
- Professor Department of Neurological Surgery, Stony Brook University Medical Center, HSC T12, Room 080, 100 Nicolls Road, Stony Brook, NY 11794-8122 e-mail:
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Bouillot P, Brina O, Ouared R, Lovblad KO, Farhat M, Mendes Pereira V. Hemodynamic transition driven by stent porosity in sidewall aneurysms. J Biomech 2015; 48:1300-9. [DOI: 10.1016/j.jbiomech.2015.02.020] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2014] [Revised: 02/04/2015] [Accepted: 02/15/2015] [Indexed: 10/23/2022]
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Liu J, Fan J, Xiang J, Zhang Y, Yang X. Hemodynamic characteristics of large unruptured internal carotid artery aneurysms prior to rupture: a case control study. J Neurointerv Surg 2015; 8:367-72. [DOI: 10.1136/neurintsurg-2014-011577] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2014] [Accepted: 01/13/2015] [Indexed: 11/03/2022]
Abstract
ObjectivePost-ruptured intracranial aneurysm geometry models have been widely used in computational fluid dynamic studies to assess hemodynamic parameters associated with aneurysm rupture. However, their results may not be valid due to the morphological changes of the aneurysm after rupture. Our aim was to identify the hemodynamic features of aneurysms prior to rupture in comparison with unruptured aneurysms.Materials and methodsWe retrospectively identified three large unruptured internal carotid artery (ICA) aneurysms (pre-ruptured group) with adequate image quality just before rupture. Matched with the same location and similar size, eight unruptured aneurysms (unruptured group) were selected as controls during the same time period. Flow simulations for these aneurysms were performed to compare differences in hemodynamics.ResultsCompared with unruptured aneurysms, pre-ruptured aneurysms had a significantly more irregular aneurysm shape, a higher aspect ratio, and lower aneurysm averaged wall shear stress (WSS) (p=0.024, p=0.048, and p=0.048, respectively). Although pre-ruptured aneurysms had a lower low WSS area and higher Oscillatory Shear Index, these were not statistically significant.ConclusionsFor large unruptured ICA aneurysms, low WSS, higher aspect ratio, and irregular shape were indicators of fatal rupture. Early treatment for such lesions with flow diverter and coils may be the best therapeutic option.
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