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Chassagne F, Barbour MC, Chivukula VK, Machicoane N, Kim LJ, Levitt MR, Aliseda A. The effect of Dean, Reynolds, and Womersley number on the flow in a spherical cavity on a curved round pipe. Part 1. Fluid mechanics in the cavity as a canonical flow representing intracranial aneurysms. JOURNAL OF FLUID MECHANICS 2021; 915:A123. [PMID: 34024939 PMCID: PMC8136084 DOI: 10.1017/jfm.2020.1114] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Flow in side-wall cerebral aneurysms can be ideally modelled as the combination of flow over a spherical cavity and flow in a curved circular pipe, two canonical flows. Flow in a curved pipe is known to depend on the Dean number De, combining the effects of Reynolds number, Re, and of the curvature along the pipe centreline, κ. Pulsatility in the flow introduces a dependency on the Womersley number Wo. Using stereo PIV measurements, this study investigated the effect of these three key non-dimensional parameters, by modifying pipe curvature (De), flow-rate (Re), and pulsatility frequency (Wo), on the flow patterns in a spherical cavity. A single counter-rotating vortex was observed in the cavity for all values of pipe curvature κ and Re, for both steady and pulsatile inflow conditions. Increasing the pipe curvature impacted both the flow patterns in the pipe and the cavity, by shifting the velocity profile towards the cavity opening and increasing the flow rate into the cavity. The circulation in the cavity was found to collapse well with only the Dean number, for both steady and pulsatile inflows. For pulsatile inflow, the counter-rotating vortex was unstable and the location of its centre over time was impacted by the curvature of the pipe, as well as the Re and the Wo in the freestream. The circulation in the cavity was higher for steady inflow than for the equivalent average Reynolds and Dean number pulsatile inflow, with very limited impact of the Womersley in the range studied.
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Affiliation(s)
- Fanette Chassagne
- Department of Mechanical Engineering, University of Washington, Seattle, WA 98105, USA
| | - Michael C. Barbour
- Department of Mechanical Engineering, University of Washington, Seattle, WA 98105, USA
| | - Venkat K. Chivukula
- Biomedical and Chemical Engineering and Sciences, Florida Institute of Technology, Melbourne, FL 32901, USA
| | | | - Louis J. Kim
- Department of Neurological Surgery, University of Washington, Seattle, WA 98107, USA
- Department of Radiology, University of Washington, Seattle, WA 98107, USA
| | - Michael R. Levitt
- Department of Mechanical Engineering, University of Washington, Seattle, WA 98105, USA
- Department of Neurological Surgery, University of Washington, Seattle, WA 98107, USA
- Department of Radiology, University of Washington, Seattle, WA 98107, USA
| | - Alberto Aliseda
- Department of Mechanical Engineering, University of Washington, Seattle, WA 98105, USA
- Department of Neurological Surgery, University of Washington, Seattle, WA 98107, USA
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Hu J, Albadawi H, Oklu R, Chong BW, Deipolyi AR, Sheth RA, Khademhosseini A. Advances in Biomaterials and Technologies for Vascular Embolization. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2019; 31:e1901071. [PMID: 31168915 PMCID: PMC7014563 DOI: 10.1002/adma.201901071] [Citation(s) in RCA: 98] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Revised: 03/24/2019] [Indexed: 05/03/2023]
Abstract
Minimally invasive transcatheter embolization is a common nonsurgical procedure in interventional radiology used for the deliberate occlusion of blood vessels for the treatment of diseased or injured vasculature. A wide variety of embolic agents including metallic coils, calibrated microspheres, and liquids are available for clinical practice. Additionally, advances in biomaterials, such as shape-memory foams, biodegradable polymers, and in situ gelling solutions have led to the development of novel preclinical embolic agents. The aim here is to provide a comprehensive overview of current and emerging technologies in endovascular embolization with respect to devices, materials, mechanisms, and design guidelines. Limitations and challenges in embolic materials are also discussed to promote advancement in the field.
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Affiliation(s)
- Jingjie Hu
- Division of Vascular & Interventional Radiology, Minimally Invasive Therapeutics Laboratory, Mayo Clinic, 13400 East Shea Blvd., Scottsdale, Arizona 85259, USA
| | - Hassan Albadawi
- Division of Vascular & Interventional Radiology, Minimally Invasive Therapeutics Laboratory, Mayo Clinic, 13400 East Shea Blvd., Scottsdale, Arizona 85259, USA
| | - Rahmi Oklu
- Division of Vascular & Interventional Radiology, Minimally Invasive Therapeutics Laboratory, Mayo Clinic, 13400 East Shea Blvd., Scottsdale, Arizona 85259, USA
| | - Brian W Chong
- Departments of Radiology and Neurological Surgery, Mayo Clinic, 13400 East Shea Blvd., Scottsdale, Arizona 85259, USA
| | - Amy R. Deipolyi
- Department of Interventional Radiology, Memorial Sloan Kettering Cancer Center, Weill Cornell Medical Center, 1275 York Avenue, New York, New York 10065, USA
| | - Rahul A. Sheth
- Department of Interventional Radiology, The University of Texas MD Anderson Cancer Center, Houston, Texas 77054, USA
| | - Ali Khademhosseini
- Department of Bioengineering, Department of Radiological Sciences, Department of Chemical and Biomolecular Engineering, Center for Minimally Invasive Therapeutics, California Nanosystems Institute, University of California, 410 Westwood Plaza, Los Angeles, California 90095, USA
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Asgharzadeh H, Asadi H, Meng H, Borazjani I. A non-dimensional parameter for classification of the flow in intracranial aneurysms. II. Patient-specific geometries. PHYSICS OF FLUIDS (WOODBURY, N.Y. : 1994) 2019; 31:031905. [PMID: 30967745 PMCID: PMC6436177 DOI: 10.1063/1.5081451] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Accepted: 02/14/2019] [Indexed: 05/21/2023]
Abstract
A simple parameter, called the Aneurysm number (An) which is defined as the ratio of transport to vortex time scales, has been shown to classify the flow mode in simplified aneurysm geometries. Our objective is to test the hypothesis that An can classify the flow in patient-specific intracranial aneurysms (IA). Therefore, the definition of this parameter is extended to anatomic geometries by using hydraulic diameter and the length of expansion area in the approximate direction of the flow. The hypothesis is tested using image-based flow simulations in five sidewall and four bifurcation geometries, i.e., if An ≲ 1 (shorter transport time scale), then the fluid is transported across the neck before the vortex could be formed, creating a quasi-stationary shear layer (cavity mode). By contrast, if An ≳ 1 (shorter vortex time scale), a vortex is formed. The results show that if An switches from An ≲ 1 to An ≳ 1, then the flow mode switches from the cavity mode to the vortex mode. However, if An does not switch, then the IAs stay in the same mode. It is also shown that IAs in the cavity mode have significantly lower An, temporal fluctuations of wall shear stress and oscillatory shear index (OSI) compared to the vortex mode (p < 0.01). In addition, OSI correlates with An in each flow mode and with pulsatility index in each IA. This suggests An to be a viable hemodynamic parameter which can be easily calculated without the need for detailed flow measurements/ simulations.
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Affiliation(s)
- Hafez Asgharzadeh
- Department of Mechanical and Aerospace
Engineering, University at Buffalo, The State University of New York,
Buffalo, New York 14260, USA
| | - Hossein Asadi
- J. Mike Walker ’66 Department of Mechanical
Engineering, Texas A&M University, College Station, Texas 77843,
USA
| | - Hui Meng
- Department of Mechanical and Aerospace
Engineering, University at Buffalo, The State University of New York,
Buffalo, New York 14260, USA
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Kurşun B, Uğur L, Keskin G. Hemodynamic effect of bypass geometry on intracranial aneurysm: A numerical investigation. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2018; 158:31-40. [PMID: 29544788 DOI: 10.1016/j.cmpb.2018.02.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Revised: 12/28/2017] [Accepted: 02/02/2018] [Indexed: 06/08/2023]
Abstract
BACKGROUND AND OBJECTIVE Hemodynamic analyzes are used in the clinical investigation and treatment of cardiovascular diseases. In the present study, the effect of bypass geometry on intracranial aneurysm hemodynamics was investigated numerically. Pressure, wall shear stress (WSS) and velocity distribution causing the aneurysm to grow and rupture were investigated and the best conditions were tried to be determined in case of bypassing between basilar (BA) and left/right posterior arteries (LPCA/RPCA) for different values of parameters. METHODS The finite volume method was used for numerical solutions and calculations were performed with the ANSYS-Fluent software. The SIMPLE algorithm was used to solve the discretized conservation equations. Second Order Upwind method was preferred for finding intermediate point values in the computational domain. As the blood flow velocity changes with time, the blood viscosity value also changes. For this reason, the Carreu model was used in determining the viscosity depending on the velocity. RESULTS Numerical study results showed that when bypassed, pressure and wall shear stresses reduced in the range of 40-70% in the aneurysm. Numerical results obtained are presented in graphs including the variation of pressure, wall shear stress and velocity streamlines in the aneurysm. CONCLUSION Considering the numerical results for all parameter values, it is seen that the most important factors affecting the pressure and WSS values in bypassing are the bypass position on the basilar artery (Lb) and the diameter of the bypass vessel (d). Pressure and wall shear stress reduced in the range of 40-70% in the aneurysm in the case of bypass for all parameters. This demonstrates that pressure and WSS values can be greatly reduced in aneurysm treatment by bypassing in cases where clipping or coil embolization methods can not be applied.
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Affiliation(s)
- Burak Kurşun
- Mechanical Engineering Department, Amasya University, 05100, Turkey
| | - Levent Uğur
- Mechanical Engineering Department, Amasya University, 05100, Turkey.
| | - Gökhan Keskin
- Internal Medical Sciences Department, Amasya University, 05100, Turkey
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Zhang Q, Liu J, Zhang Y, Zhang Y, Tian Z, Li W, Chen J, Mo X, Cai Y, Paliwal N, Meng H, Wang Y, Wang S, Yang X. Efficient simulation of a low-profile visualized intraluminal support device: a novel fast virtual stenting technique. Chin Neurosurg J 2018; 4:6. [PMID: 32922867 PMCID: PMC7398371 DOI: 10.1186/s41016-018-0112-0] [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] [Received: 11/15/2017] [Accepted: 02/28/2018] [Indexed: 11/17/2022] Open
Abstract
Background The low-profile visualized intraluminal support (LVIS) stent has become a promising endovascular option for treating intracranial aneurysms. To achieve better treatment of aneurysms using LVIS, we developed a fast virtual stenting technique for use with LVIS (F-LVIS) to evaluate hemodynamic changes in the aneurysm and validate its reliability. Methods A patient-specific aneurysm was selected for making comparisons between the real LVIS (R-LVIS) and the F-LVIS. To perform R-LVIS stenting, a hollow phantom based on a patient-specific aneurysm was fabricated using a three-dimensional printer. An R-LVIS was released in the phantom according to standard procedure. F-LVIS was then applied successfully in this aneurysm model. The computational fluid dynamics (CFD) values were calculated for both the F-LVIS and R-LVIS models. Qualitative and quantitative comparisons of the two models focused on hemodynamic parameters. Results The hemodynamic characteristics for R-LVIS and F-LVIS were well matched. Representative contours of velocities and wall shear stress (WSS) were consistently similar in both distribution and magnitude. The velocity vectors also showed high similarity, although the R-LVIS model showed faster and more fluid streams entering the aneurysm. Variation tendencies of the velocity in the aneurysm and the WSS on the aneurysm wall were also similar in the two models, with no statistically significant differences in either velocity or WSS. Conclusions The results of the computational hemodynamics indicate that F-LVIS is suitable for evaluating hemodynamic factors. This novel F-LVIS is considered efficient, practical, and effective.
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Affiliation(s)
- Qianqian Zhang
- Department of Interventional Neuroradiology, Beijing Neurosurgical Institute and Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Jian Liu
- Department of Interventional Neuroradiology, Beijing Neurosurgical Institute and Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Yisen Zhang
- Department of Interventional Neuroradiology, Beijing Neurosurgical Institute and Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Ying Zhang
- Department of Interventional Neuroradiology, Beijing Neurosurgical Institute and Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Zhongbin Tian
- Department of Interventional Neuroradiology, Beijing Neurosurgical Institute and Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Wenqiang Li
- Department of Neurosurgery, The First Affiliated Hospital, Nanchang University, Nanchang, China
| | - Junfan Chen
- Department of Interventional Neuroradiology, Beijing Neurosurgical Institute and Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Xiao Mo
- Capital Medical University School of Biomedical Engineering, Beijing Key Laboratory of Fundamental Research on Biomechanics in Clinical Application, Beijing, China
| | - Yunhan Cai
- Institute of Biomechanics, Department of Aeronautics and Astronautics, Fudan University, Shanghai, China
| | - Nikhil Paliwal
- Toshiba Stroke and Vascular Research Center, University at Buffalo, The State University of New York, Buffalo, New York USA.,Department of Mechanical and Aerospace Engineering, University at Buffalo, The State University of New York, Buffalo, New York USA
| | - Hui Meng
- Toshiba Stroke and Vascular Research Center, University at Buffalo, The State University of New York, Buffalo, New York USA.,Department of Mechanical and Aerospace Engineering, University at Buffalo, The State University of New York, Buffalo, New York USA.,Department of Neurosurgery, University at Buffalo, The State University of New York, Buffalo, New York USA
| | - Yang Wang
- Department of Neurosurgery, The First Affiliated Hospital, Nanchang University, Nanchang, China
| | - Shengzhang Wang
- Institute of Biomechanics, Department of Aeronautics and Astronautics, Fudan University, Shanghai, China
| | - Xinjian Yang
- Department of Interventional Neuroradiology, Beijing Neurosurgical Institute and Beijing Tiantan Hospital, Capital Medical University, Beijing, China
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