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Findlay MC, Bounajem MT, Kim RB, Henson JC, Azab MA, Cutler CB, Khan M, Brandon C, Budohoski KP, Rennert RC, Couldwell WT. Subtemporal Approach for the Treatment of Ruptured and Unruptured Distal Basilar Artery Aneurysms: Is There a Contemporary Use? Oper Neurosurg (Hagerstown) 2024:01787389-990000000-01154. [PMID: 38690880 DOI: 10.1227/ons.0000000000001185] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2024] [Accepted: 03/07/2024] [Indexed: 05/03/2024] Open
Abstract
BACKGROUND AND OBJECTIVES Distal basilar artery aneurysms (DBAs) are high-risk lesions for which endovascular treatment is preferred because of their deep location, yet indications for open clipping nonetheless remain. The subtemporal approach allows for early proximal control and direct visualization of critical posterior perforating arteries, especially for posterior-projecting aneurysms. Our objective was to describe our clinical experience with the subtemporal approach for clipping DBAs in the evolving endovascular era. METHODS This was a retrospective, single-institution case series of patients with DBAs treated with microsurgery over a 21-year period (2002-2023). Demographic, clinical, and surgical data were collected for analysis. RESULTS Twenty-seven patients underwent clipping of 11 ruptured and 16 unruptured DBAs with a subtemporal approach (24 female; mean age 53 years). Ten patients had expanded craniotomies for treatment of additional aneurysms. The aneurysm occlusion rate was 100%. Good neurological outcomes as defined by the modified Rankin Scale score ≤2 and Glasgow Outcome Scale score ≥4 were achieved in 21/27 patients (78%). Two patients died before hospital discharge, one from vasospasm-induced strokes and another from an intraoperative myocardial infarction. CONCLUSION These results demonstrate that microsurgical clip ligation of DBAs using the subtemporal approach remains a viable option for complex lesions not amenable to endovascular management.
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Affiliation(s)
| | - Michael T Bounajem
- Department of Neurosurgery, Clinical Neurosciences Center, University of Utah, Salt Lake City, Utah, USA
| | - Robert B Kim
- Department of Neurosurgery, Clinical Neurosciences Center, University of Utah, Salt Lake City, Utah, USA
| | - J Curran Henson
- Department of Surgery, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
| | - Mohammed A Azab
- Biomedical Sciences, Boise State University, Boise, Idaho, USA
| | - Christopher B Cutler
- Chicago Medical School at Rosalind Franklin University of Medicine and Science, North Chicago, Illinois, USA
| | - Majid Khan
- School of Medicine, University of Nevada, Reno, Nevada, USA
| | - Cameron Brandon
- School of Medicine, University of Utah, Salt Lake City, Utah, USA
| | - Karol P Budohoski
- Department of Neurosurgery, Clinical Neurosciences Center, University of Utah, Salt Lake City, Utah, USA
| | - Robert C Rennert
- Department of Neurosurgery, Clinical Neurosciences Center, University of Utah, Salt Lake City, Utah, USA
| | - William T Couldwell
- Department of Neurosurgery, Clinical Neurosciences Center, University of Utah, Salt Lake City, Utah, USA
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Ballambat RP, Zuber M, Khader SMA, Ayachit A, Ahmad KAB, Vedula RR, Kamath SG, Shuaib IL. Influence of postural changes on haemodynamics in internal carotid artery bifurcation aneurysm using numerical methods. Vis Comput Ind Biomed Art 2022; 5:11. [PMID: 35394268 PMCID: PMC8993999 DOI: 10.1186/s42492-022-00107-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2021] [Accepted: 03/14/2022] [Indexed: 01/09/2023] Open
Abstract
Cerebral intracranial aneurysms are serious problems that can lead to stroke, coma, and even death. The effect of blood flow on cerebral aneurysms and their relationship with rupture are unknown. In addition, postural changes and their relevance to haemodynamics of blood flow are difficult to measure in vivo using clinical imaging alone. Computational simulations investigating the detailed haemodynamics in cerebral aneurysms have been developed in recent times not only to understand the progression and rupture but also for clinical evaluation and treatment. In the present study, the haemodynamics of a patient-specific case of a large aneurysm on the left side internal carotid bifurcation (LICA) and no aneurysm on the right side internal carotid bifurcation (RICA) was investigated. The simulation of these patient-specific models using fluid–structure interaction provides a valuable comparison of flow behavior between normal and aneurysm models. The influences of postural changes were investigated during standing, sleeping, and head-down (HD) position. Significant changes in flow were observed during the HD position and quit high arterial blood pressure in the internal carotid artery (ICA) aneurysm model was established when compared to the normal ICA model. The velocity increased abruptly during the HD position by more than four times (LICA and RICA) and wall shear stress by four times (LICA) to ten times (RICA). The complex spiral flow and higher pressures prevailing within the dome increase the risk of aneurysm rupture.
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Affiliation(s)
- Raghuvir Pai Ballambat
- Department of Mechanical and Industrial Engineering, Manipal Institute of Technology, Manipal Academy of Higher Education, Manipal, 576104, India
| | - Mohammad Zuber
- Department of Aeronautical and Automobile Engineering, Manipal Institute of Technology, Manipal Academy of Higher Education, Manipal, 576104, India
| | - Shah Mohammed Abdul Khader
- Department of Mechanical and Industrial Engineering, Manipal Institute of Technology, Manipal Academy of Higher Education, Manipal, 576104, India.
| | - Anurag Ayachit
- Department of Radiology and Imaging, Kasturba Medical College, Manipal Academy of Higher Education, Manipal, 576104, India
| | - Kamarul Arifin Bin Ahmad
- Department of Aerospace Engineering, Faculty of Engineering, Universitist Putra Malaysia, 43499, Kuala Lumpur, Malaysia
| | - Rajanikanth Rao Vedula
- Department of Radiology and Imaging, Kasturba Medical College, Manipal Academy of Higher Education, Manipal, 576104, India
| | - Sevagur Ganesh Kamath
- Department of Cardio-Vascular and Thoracic Surgery, Kasturba Medical College, Manipal Academy of Higher Education, Manipal, 576104, India
| | - Ibrahim Lutfi Shuaib
- Advanced Medical and Dental Institute, Universiti Sains Malaysia, 13200, George Town, Malaysia
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Lampropoulos DS, Bourantas GC, Zwick BF, Kagadis GC, Wittek A, Miller K, Loukopoulos VC. Simulation of intracranial hemodynamics by an efficient and accurate immersed boundary scheme. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2021; 37:e3524. [PMID: 34448366 DOI: 10.1002/cnm.3524] [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: 07/16/2021] [Accepted: 08/10/2021] [Indexed: 06/13/2023]
Abstract
We use computational fluid dynamics (CFD) to simulate blood flow in intracranial aneurysms (IAs). Despite ongoing improvements in the accuracy and efficiency of body-fitted CFD solvers, generation of a high quality mesh appears as the bottleneck of the flow simulation and strongly affects the accuracy of the numerical solution. To overcome this drawback, we use an immersed boundary method. The proposed approach solves the incompressible Navier-Stokes equations on a rectangular (box) domain discretized using uniform Cartesian grid using the finite element method. The immersed object is represented by a set of points (Lagrangian points) located on the surface of the object. Grid local refinement is applied using an automated algorithm. We verify and validate the proposed method by comparing our numerical findings with published experimental results and analytical solutions. We demonstrate the applicability of the proposed scheme on patient-specific blood flow simulations in IAs.
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Affiliation(s)
| | - George C Bourantas
- Intelligent Systems for Medicine Laboratory, The University of Western Australia, Perth, Australia
| | - Benjamin F Zwick
- Intelligent Systems for Medicine Laboratory, The University of Western Australia, Perth, Australia
| | - George C Kagadis
- Department of Medical Physics, School of Medicine, University of Patras, Rion, Greece
- Department of Imaging Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Adam Wittek
- Intelligent Systems for Medicine Laboratory, The University of Western Australia, Perth, Australia
| | - Karol Miller
- Intelligent Systems for Medicine Laboratory, The University of Western Australia, Perth, Australia
- Harvard Medical School, Harvard University, Boston, Massachusetts, USA
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4
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Morphological and Hemodynamic Changes during Cerebral Aneurysm Growth. Brain Sci 2021; 11:brainsci11040520. [PMID: 33921861 PMCID: PMC8073033 DOI: 10.3390/brainsci11040520] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Revised: 04/05/2021] [Accepted: 04/09/2021] [Indexed: 11/17/2022] Open
Abstract
Computational fluid dynamics (CFD) has grown as a tool to help understand the hemodynamic properties related to the rupture of cerebral aneurysms. Few of these studies deal specifically with aneurysm growth and most only use a single time instance within the aneurysm growth history. The present retrospective study investigated four patient-specific aneurysms, once at initial diagnosis and then at follow-up, to analyze hemodynamic and morphological changes. Aneurysm geometries were segmented via the medical image processing software Mimics. The geometries were meshed and a computational fluid dynamics (CFD) analysis was performed using ANSYS. Results showed that major geometry bulk growth occurred in areas of low wall shear stress (WSS). Wall shape remodeling near neck impingement regions occurred in areas with large gradients of WSS and oscillatory shear index. This study found that growth occurred in areas where low WSS was accompanied by high velocity gradients between the aneurysm wall and large swirling flow structures. A new finding was that all cases showed an increase in kinetic energy from the first time point to the second, and this change in kinetic energy seems correlated to the change in aneurysm volume.
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5
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Lipp SN, Niedert EE, Cebull HL, Diorio TC, Ma JL, Rothenberger SM, Stevens Boster KA, Goergen CJ. Computational Hemodynamic Modeling of Arterial Aneurysms: A Mini-Review. Front Physiol 2020; 11:454. [PMID: 32477163 PMCID: PMC7235429 DOI: 10.3389/fphys.2020.00454] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Accepted: 04/09/2020] [Indexed: 01/02/2023] Open
Abstract
Arterial aneurysms are pathological dilations of blood vessels, which can be of clinical concern due to thrombosis, dissection, or rupture. Aneurysms can form throughout the arterial system, including intracranial, thoracic, abdominal, visceral, peripheral, or coronary arteries. Currently, aneurysm diameter and expansion rates are the most commonly used metrics to assess rupture risk. Surgical or endovascular interventions are clinical treatment options, but are invasive and associated with risk for the patient. For aneurysms in locations where thrombosis is the primary concern, diameter is also used to determine the level of therapeutic anticoagulation, a treatment that increases the possibility of internal bleeding. Since simple diameter is often insufficient to reliably determine rupture and thrombosis risk, computational hemodynamic simulations are being developed to help assess when an intervention is warranted. Created from subject-specific data, computational models have the potential to be used to predict growth, dissection, rupture, and thrombus-formation risk based on hemodynamic parameters, including wall shear stress, oscillatory shear index, residence time, and anomalous blood flow patterns. Generally, endothelial damage and flow stagnation within aneurysms can lead to coagulation, inflammation, and the release of proteases, which alter extracellular matrix composition, increasing risk of rupture. In this review, we highlight recent work that investigates aneurysm geometry, model parameter assumptions, and other specific considerations that influence computational aneurysm simulations. By highlighting modeling validation and verification approaches, we hope to inspire future computational efforts aimed at improving our understanding of aneurysm pathology and treatment risk stratification.
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Affiliation(s)
- Sarah N Lipp
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, United States
| | - Elizabeth E Niedert
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, United States
| | - Hannah L Cebull
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, United States
| | - Tyler C Diorio
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, United States
| | - Jessica L Ma
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, United States
| | - Sean M Rothenberger
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, United States
| | - Kimberly A Stevens Boster
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, United States.,School of Mechanical Engineering, Purdue University, West Lafayette, IN, United States
| | - Craig J Goergen
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, United States
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6
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Yuan J, Huang C, Lai N, Li Z, Jiang X, Wang X, Zhao X, Wu D, Liu J, Xia D, Fang X. Hemodynamic and Morphological Analysis of Mirror Aneurysms Prior to Rupture. Neuropsychiatr Dis Treat 2020; 16:1339-1347. [PMID: 32547037 PMCID: PMC7266525 DOI: 10.2147/ndt.s254124] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
OBJECTIVE Hemodynamic factors are thought to play important roles in the pathogenesis, progression, and rupture of cerebral aneurysms. Previous hemodynamic studies have been based on comparisons between post-ruptured and unruptured aneurysms. Nevertheless, changes of aneurysm morphology after rupture render these results unreliable. Moreover, pressure, age, gender, and the morphology of the parent artery also influence these results. Therefore, in the present study, we identified hemodynamic and morphological characteristics of aneurysms prior to rupture using twelve mirror aneurysms. MATERIALS AND METHODS From our database, we retrospectively analyzed twelve mirror aneurysms (MANs) prior to rupture. Each mirror aneurysm was divided into the prior to rupture or the unruptured group. Patient-specific models were reconstructed from three-dimensional (3D) images of all patients. Hemodynamic and morphological factors were analyzed and compared. RESULTS Compared with the unruptured side of MANs, aneurysms prior to rupture were significantly larger and significantly more irregular in shape; they also had significantly higher aspect ratio (AR), size ratio (SR), undulation index (UI), ellipticity index (EI), percentage of low wall shear stress area (LSA) and significantly lower normal wall shear stress (NWSS). The oscillatory shear index (OSI) and nonsphericity index (NSI) in the aneurysms prior to rupture were non-significantly higher than those of the unruptured group. CONCLUSION MANs prior to rupture may be extremely useful models to assess the risk of aneurysm rupture. Larger size, irregular shape, higher AR, SR, UI, NI, and lower WSS may be associated with aneurysms at risk for rupture.
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Affiliation(s)
- Jinlong Yuan
- Department of Neurosurgery, The First Affiliated Hospital of Wannan Medical College (Yijishan Hospital), Wuhu, People's Republic of China
| | - Chenlei Huang
- Department of Clinical Laboratory, The First Affiliated Hospital of Wannan Medical College (Yijishan Hospital), Wuhu, People's Republic of China
| | - Niansheng Lai
- Department of Neurosurgery, The First Affiliated Hospital of Wannan Medical College (Yijishan Hospital), Wuhu, People's Republic of China
| | - Zhenbao Li
- Department of Neurosurgery, The First Affiliated Hospital of Wannan Medical College (Yijishan Hospital), Wuhu, People's Republic of China
| | - Xiaochun Jiang
- Department of Neurosurgery, The First Affiliated Hospital of Wannan Medical College (Yijishan Hospital), Wuhu, People's Republic of China
| | - Xuanzhi Wang
- Department of Neurosurgery, The First Affiliated Hospital of Wannan Medical College (Yijishan Hospital), Wuhu, People's Republic of China
| | - Xintong Zhao
- Department of Neurosurgery, The First Affiliated Hospital of Wannan Medical College (Yijishan Hospital), Wuhu, People's Republic of China
| | - Degang Wu
- Department of Neurosurgery, The First Affiliated Hospital of Wannan Medical College (Yijishan Hospital), Wuhu, People's Republic of China
| | - Jiaqiang Liu
- Department of Neurosurgery, The First Affiliated Hospital of Wannan Medical College (Yijishan Hospital), Wuhu, People's Republic of China
| | - Dayong Xia
- Department of Neurosurgery, The First Affiliated Hospital of Wannan Medical College (Yijishan Hospital), Wuhu, People's Republic of China
| | - Xinggen Fang
- Department of Neurosurgery, The First Affiliated Hospital of Wannan Medical College (Yijishan Hospital), Wuhu, People's Republic of China
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Park CS, Hartung G, Alaraj A, Du X, Charbel FT, Linninger AA. Quantification of blood flow patterns in the cerebral arterial circulation of individual (human) subjects. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2020; 36:e3288. [PMID: 31742921 DOI: 10.1002/cnm.3288] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Revised: 10/04/2019] [Accepted: 11/15/2019] [Indexed: 06/10/2023]
Abstract
There is a growing research interest in quantifying blood flow distribution for the entire cerebral circulation to sharpen diagnosis and improve treatment options for cerebrovascular disease of individual patients. We present a methodology to reconstruct subject-specific cerebral blood flow patterns in accordance with physiological and fluid mechanical principles and optimally informed by in vivo neuroimage data of cerebrovascular anatomy and arterial blood flow rates. We propose an inverse problem to infer blood flow distribution across the visible portion of the arterial network that best matches subject-specific anatomy and a given set of volumetric flow measurements. The optimization technique also mitigates the effect of uncertainties by reconciling incomplete flow data and by dissipating unavoidable acquisition errors associated with medical imaging data.
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Affiliation(s)
- Chang S Park
- Department of Bioengineering, University of Illinois at Chicago, Chicago, Illinois
| | - Grant Hartung
- Department of Bioengineering, University of Illinois at Chicago, Chicago, Illinois
| | - Ali Alaraj
- Department of Neurosurgery, University of Illinois at Chicago, Chicago, Illinois
| | - Xinjian Du
- Department of Neurosurgery, University of Illinois at Chicago, Chicago, Illinois
| | - Fady T Charbel
- Department of Neurosurgery, University of Illinois at Chicago, Chicago, Illinois
| | - Andreas A Linninger
- Department of Bioengineering, University of Illinois at Chicago, Chicago, Illinois
- Department of Neurosurgery, University of Illinois at Chicago, Chicago, Illinois
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8
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Hodis S. Correlation of flow complexity parameter with aneurysm rupture status. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2018; 34:e3131. [PMID: 30021249 DOI: 10.1002/cnm.3131] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2017] [Accepted: 07/07/2018] [Indexed: 05/22/2023]
Abstract
Ruptured aneurysms are known to have complex flow patterns and concentrated inflow jet, but a quantifiable measure for the degree of flow complexity in patient-specific geometries has not been established. Previously, we proposed a flow complexity parameter that provides a quantitative description of the complexity of flow patterns through calculated curvature and torsion of the flow field. The purpose of the current study was to provide an analytic solution of the flow complexity parameter and assess a possible correlation with the rupture status of cerebral aneurysms by analyzing the parameter on five ruptured and five unruptured aneurysms from anterior communicating artery. We analyzed the flow complexity parameter in jet and non-jet regions in order to measure the concentration of the jet flow and the complexity of the non-jet flow. We found that on average, in a ruptured case the jet region is significantly less complex (4.5 times) than the jet region in an unruptured case, while the non-jet region is significantly more complex (3.5 times) than the non-jet region in an unruptured case. We also found a strong positive correlation of the non-jet complexity with dome volume in ruptured cases, but no correlation of jet complexity with dome volume. These findings suggest that a ruptured aneurysm has more than 4 times more concentrated inflow jet and more than 3 times more complex flow patterns in non-jet region than an unruptured aneurysm. This newly implemented kinematic parameter provides a measurable degree of complexity of flow patterns in cerebral aneurysms that can better assess aneurysm rupture risk.
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Affiliation(s)
- Simona Hodis
- Department of Mathematics, Texas A&M University-Kingsville, Kingsville, Texas
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9
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Wang Y, Leng X, Zhou X, Li W, Siddiqui AH, Xiang J. Hemodynamics in a Middle Cerebral Artery Aneurysm Before Its Growth and Fatal Rupture: Case Study and Review of the Literature. World Neurosurg 2018; 119:e395-e402. [PMID: 30071328 DOI: 10.1016/j.wneu.2018.07.174] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Revised: 07/19/2018] [Accepted: 07/19/2018] [Indexed: 10/28/2022]
Abstract
BACKGROUND Hemodynamics plays an important role in the natural history of intracranial aneurysms. However, it is difficult to obtain longitudinal aneurysm image data. In this study, we had a rare chance to follow the process of growth and rupture of a middle cerebral artery (MCA) aneurysm. The aim of this study was to investigate the role of hemodynamics for growth and rupture in this particular aneurysm patient. METHODS A 57-year-old woman presented with 2 unruptured MCA aneurysms and 1 ruptured anterior choroidal artery (AchA) aneurysm. The unruptured left MCA aneurysm grew in 7 months and ruptured at 11 months. The rupture region was confirmed during the clipping treatment. Computational fluid dynamic (CFD) simulations were conducted on the AchA and MCA aneurysms in 3 serial imaging procedures, and calculated hemodynamics was correlated with aneurysm growth and rupture. RESULTS The ruptured right AchA aneurysm had much lower wall shear stress (WSS) and higher oscillatory shear index (OSI) than the unruptured left MCA aneurysm. Comparison of the aneurysm growth region with the WSS distribution showed that growth occurred in a high WSS area. During the progression of the MCA aneurysm, we observed that the high aneurysmal WSS region grew first and then the growing region changed into a low WSS level; eventually, rupture occurred in a low WSS area. CONCLUSIONS This case suggests that aneurysm rupture might be associated with low WSS and high OSI, whereas aneurysm growth may be related to high WSS in this particular individual MCA aneurysm patient.
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Affiliation(s)
- Yang Wang
- Department of Neurosurgery, The First Affiliated Hospital of Nanchang University, Nanchang University, Nanchang, China
| | | | - Xiaobin Zhou
- Department of Neurosurgery, The First Affiliated Hospital of Nanchang University, Nanchang University, Nanchang, China
| | - Wenqiang Li
- Department of Neurosurgery, The First Affiliated Hospital of Nanchang University, Nanchang University, Nanchang, China
| | - Adnan H Siddiqui
- Toshiba Stroke and Vascular Research Center, University at Buffalo, State University of New York, Buffalo, New York, USA; Department of Neurosurgery, University at Buffalo, State University of New York, Buffalo, New York, USA; Department of Radiology, University at Buffalo, State University of New York, Buffalo, New York, USA
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10
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Rafat M, Stone HA, Auguste DT, Dabagh M, Randles A, Heller M, Rabinov JD. Impact of diversity of morphological characteristics and Reynolds number on local hemodynamics in basilar aneurysms. AIChE J 2018. [DOI: 10.1002/aic.16091] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Marjan Rafat
- School of Engineering and Applied SciencesHarvard UniversityCambridge MA 02138
| | - Howard A. Stone
- School of Engineering and Applied SciencesHarvard UniversityCambridge MA 02138
| | - Debra T. Auguste
- School of Engineering and Applied SciencesHarvard UniversityCambridge MA 02138
| | - Mahsa Dabagh
- Dept. of Biomedical EngineeringDuke UniversityDurham NC 27708
| | - Amanda Randles
- Dept. of Biomedical EngineeringDuke UniversityDurham NC 27708
| | - Martin Heller
- Dept. of Micro‐ and NanotechnologyTechnical University of Denmark, DTU NanotechKongens Lyngby DK‐2800 Denmark
| | - James D. Rabinov
- Dept. of Radiology and NeurosurgeryMassachusetts General HospitalBoston MA 02114
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11
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Ren Y, Chen GZ, Liu Z, Cai Y, Lu GM, Li ZY. Reproducibility of image-based computational models of intracranial aneurysm: a comparison between 3D rotational angiography, CT angiography and MR angiography. Biomed Eng Online 2016; 15:50. [PMID: 27150439 PMCID: PMC4858827 DOI: 10.1186/s12938-016-0163-4] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2015] [Accepted: 04/25/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Reconstruction of patient-specific biomechanical model of intracranial aneurysm has been based on different imaging modalities. However, different imaging techniques may influence the model geometry and the computational fluid dynamics (CFD) simulation. The aim of this study is to evaluate the differences of the morphological and hemodynamic parameters in the computational models reconstructed from computed tomography angiography (CTA), magnetic resonance angiography (MRA) and 3D rotational angiography (3DRA). METHODS Ten patients with cerebral aneurysms were enrolled in the study. MRA, CTA and 3DRA were performed on all patients. For each patient, three patient-specific models were reconstructed respectively based on the three sets of imaging data of the patient. CFD simulations were performed on each model. Model geometry and hemodynamic parameters were compared between the three models. RESULTS In terms of morphological parameters, by comparing CTA based models (CM) and 3DRA based models (DM) which were treated as the "standard models", the aspect ratio had the minimum difference (Δ = 8.3 ± 1.72 %, P = 0.953) and the surface distance was 0.25 ± 0.07 mm. Meanwhile, by comparing MRA based models (MM) and DM, the size had the minimum difference (Δ = 6.6 ± 1.85 %, P = 0.683) and the surface distance was 0.36 ± 0.1 mm. In respect of hemodynamic parameters, all three models showed a similar distribution: low average WSS at the sack, high OSI at the body and high average WSSG at the neck. However, there was a large variation in the average WSS (Δ = 34 ± 5.13 % for CM, Δ = 40.6 ± 9.21 % for MM). CONCLUSION CTA and MRA have no significant differences in reproducing intracranial aneurysm geometry. The CFD results suggests there might be some significant differences in hemodynamic parameters between the three imaging-based models and this needs to be considered when interpreting the CFD results of different imaging-based models. If we only need to study the main flow patterns, three types of image-based model might be all suitable for patient-specific computational modeling studies.
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Affiliation(s)
- Yuan Ren
- State Key Laboratory of Bioelectronics, Southeast University, Nanjing, 210096, P.R. China.,School of Biological Science and Medical Engineering, Southeast University, Nanjing, 210096, P.R. China
| | - Guo-Zhong Chen
- Department of Medical Imaging, Jinling Hospital, Medical School of Nanjing University, Nanjing, 210002, P.R. China
| | - Zhen Liu
- State Key Laboratory of Bioelectronics, Southeast University, Nanjing, 210096, P.R. China.,School of Biological Science and Medical Engineering, Southeast University, Nanjing, 210096, P.R. China
| | - Yan Cai
- State Key Laboratory of Bioelectronics, Southeast University, Nanjing, 210096, P.R. China. .,School of Biological Science and Medical Engineering, Southeast University, Nanjing, 210096, P.R. China.
| | - Guang-Ming Lu
- Department of Medical Imaging, Jinling Hospital, Medical School of Nanjing University, Nanjing, 210002, P.R. China.
| | - Zhi-Yong Li
- State Key Laboratory of Bioelectronics, Southeast University, Nanjing, 210096, P.R. China. .,School of Biological Science and Medical Engineering, Southeast University, Nanjing, 210096, P.R. China. .,School of Chemistry, Physics and Mechanical Engineering, Queensland University of Technology, Brisbane, QLD, 4001, Australia.
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12
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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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Using Computational Fluid Dynamics Analysis to Characterize Local Hemodynamic Features of Middle Cerebral Artery Aneurysm Rupture Points. World Neurosurg 2015; 83:80-6. [DOI: 10.1016/j.wneu.2013.02.012] [Citation(s) in RCA: 67] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2012] [Revised: 11/06/2012] [Accepted: 02/01/2013] [Indexed: 11/19/2022]
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14
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Rayz VL, Abla A, Boussel L, Leach JR, Acevedo-Bolton G, Saloner D, Lawton MT. Computational modeling of flow-altering surgeries in basilar aneurysms. Ann Biomed Eng 2014; 43:1210-22. [PMID: 25348846 DOI: 10.1007/s10439-014-1170-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2014] [Accepted: 10/16/2014] [Indexed: 11/29/2022]
Abstract
In cases where surgeons consider different interventional options for flow alterations in the setting of pathological basilar artery hemodynamics, a virtual model demonstrating the flow fields resulting from each of these options can assist in making clinical decisions. In this study, image-based computational fluid dynamics (CFD) models were used to simulate the flow in four basilar artery aneurysms in order to evaluate postoperative hemodynamics that would result from flow-altering interventions. Patient-specific geometries were constructed using MR angiography and velocimetry data. CFD simulations carried out for the preoperative flow conditions were compared to in vivo phase-contrast MRI measurements (4D Flow MRI) acquired prior to the interventions. The models were then modified according to the procedures considered for each patient. Numerical simulations of the flow and virtual contrast transport were carried out in each case in order to assess postoperative flow fields and estimate the likelihood of intra-aneurysmal thrombus deposition following the procedures. Postoperative imaging data, when available, were used to validate computational predictions. In two cases, where the aneurysms involved vital pontine perforator arteries branching from the basilar artery, idealized geometries of these vessels were incorporated into the CFD models. The effect of interventions on the flow through the perforators was evaluated by simulating the transport of contrast in these vessels. The computational results were in close agreement with the MR imaging data. In some cases, CFD simulations could help determine which of the surgical options was likely to reduce the flow into the aneurysm while preserving the flow through the basilar trunk. The study demonstrated that image-based computational modeling can provide guidance to clinicians by indicating possible outcome complications and indicating expected success potential for ameliorating pathological aneurysmal flow, prior to a procedure.
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Affiliation(s)
- V L Rayz
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA, USA,
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15
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Karmonik C, Diaz O, Klucznik R, Grossman RG, Zhang YJ, Britz G, Lv N, Huang Q. Quantitative comparison of hemodynamic parameters from steady and transient CFD simulations in cerebral aneurysms with focus on the aneurysm ostium. J Neurointerv Surg 2014; 7:367-72. [DOI: 10.1136/neurintsurg-2014-011182] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2014] [Accepted: 03/24/2014] [Indexed: 11/03/2022]
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16
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Naughton NM, Plourde BD, Stark JR, Hodis S, Abraham JP. Impacts of waveforms on the fluid flow, wall shear stress, and flow distribution in cerebral aneurysms and the development of a universal reduced pressure. ACTA ACUST UNITED AC 2014. [DOI: 10.4236/jbise.2014.71002] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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17
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Ford MD, Piomelli U. Exploring high frequency temporal fluctuations in the terminal aneurysm of the basilar bifurcation. J Biomech Eng 2013; 134:091003. [PMID: 22938370 DOI: 10.1115/1.4007279] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Cerebral aneurysms are a common cause of death and disability. Of all the cardiovascular diseases, aneurysms are perhaps the most strongly linked with the local fluid mechanic environment. Aside from early in vivo clinical work that hinted at the possibility of high-frequency intra-aneurysmal velocity oscillations, flow in cerebral aneurysms is most often assumed to be laminar. This work investigates, through the use of numerical simulations, the potential for disturbed flow to exist in the terminal aneurysm of the basilar bifurcation. The nature of the disturbed flow is explored using a series of four idealized basilar tip models, and the results supported by four patient specific terminal basilar tip aneurysms. All four idealized models demonstrated instability in the inflow jet through high frequency fluctuations in the velocity and the pressure at approximately 120 Hz. The instability arises through a breakdown of the inflow jet, which begins to oscillate upon entering the aneurysm. The wall shear stress undergoes similar high-frequency oscillations in both magnitude and direction. The neck and dome regions of the aneurysm present 180 deg changes in the direction of the wall shear stress, due to the formation of small recirculation zones near the shear layer of the jet (at the frequency of the inflow jet oscillation) and the oscillation of the impingement zone on the dome of the aneurysm, respectively. Similar results were observed in the patient-specific models, which showed high frequency fluctuations at approximately 112 Hz in two of the four models and oscillations in the magnitude and direction of the wall shear stress. These results demonstrate that there is potential for disturbed laminar unsteady flow in the terminal aneurysm of the basilar bifurcation. The instabilities appear similar to the first instability mode of a free round jet.
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Affiliation(s)
- Matthew D Ford
- Department of Mechanical and Materials Engineering, Queen's University, Kingston, Ontario K7L 3N6, Canada.
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18
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Yu Y, Xu J, Fang Y, Wu X, Yang P, Jiang C, Qian Y, Liu J, Huang Q. Analysis of morphologic and hemodynamic parameters for unruptured posterior communicating artery aneurysms with oculomotor nerve palsy. AJNR Am J Neuroradiol 2013; 34:2187-91. [PMID: 23744688 DOI: 10.3174/ajnr.a3575] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE Posterior communicating artery aneurysms with oculomotor nerve palsy may imply sudden enlargement of the aneurysm sac and have a high risk of rupture. Our aim was to identify the morphologic and hemodynamic parameters in this special period of aneurysm progression and to assess related rupture risk indices. MATERIALS AND METHODS We analyzed the morphologic and hemodynamic parameters of 9 unruptured posterior communicating artery aneurysms with oculomotor nerve palsy and 9 ruptured ones. The morphologic parameters were measured and calculated from patient-specific 3D rotational angiographic images, and pulsatile computational fluid dynamic simulation was then performed for hemodynamic parameters. RESULTS There was no significant statistical difference between the 2 groups in size, aspect ratio, size ratio, aneurysm angle, or vessel angle; analysis only demonstrated a significantly lower wall shear stress of the aneurysm wall in the symptomatic unruptured group in hemodynamics (P = .024), whereas there were no differences in wall shear stress of the parent artery, low wall shear stress area, and oscillatory shear index. CONCLUSIONS From morphologic and hemodynamic perspectives, we demonstrated that posterior communicating artery aneurysms with oculomotor nerve palsy had characteristics similar to those of ruptured ones, except for lower wall shear stress on the aneurysm wall, which might indicate an important role in aneurysm rupture.
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Affiliation(s)
- Y Yu
- Department of Neurosurgery, Changhai Hospital, Second Military Medical University, Shanghai, China
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19
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Kono K, Fujimoto T, Shintani A, Terada T. Hemodynamic characteristics at the rupture site of cerebral aneurysms: a case study. Neurosurgery 2013; 71:E1202-8; discussion 1209. [PMID: 22922678 DOI: 10.1227/neu.0b013e31826f7ede] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND AND IMPORTANCE Hemodynamics play an important role in the mechanisms of aneurysm formation, growth, and rupture. However, little is known about the hemodynamics of rupture sites. CLINICAL PRESENTATION We incidentally acquired 3-dimensional images before and at the moment of rebleeding of a cerebral aneurysm in a patient. Comparison of these 2 images enabled precise identification of the rupture site. On the basis of computational fluid dynamics simulation, we propose that there are characteristic hemodynamic parameters of the rupture site in cerebral aneurysms. We evaluated flow velocity, wall shear stress (WSS), pressure, and the oscillatory shear index to determine characteristic parameters at the rupture site. Among the hemodynamic parameters in the cardiac cycle, the rupture site was most markedly distinguished by a combination of low WSS at end diastole and high pressure at peak systole. The flow patterns around the rupture site uniquely changed in the cardiac cycle. The rupture site was an impingement zone at peak systole. Flow separation at the rupture site was observed at end diastole. CONCLUSION In this case, a region with low WSS at end diastole and high pressure at peak systole was at the rupture site. A possible mechanism of rupture in this particular aneurysm is that low WSS at end diastole caused degeneration and thinning of the aneurysm wall and that high pressure at peak systole (impingement zone) resulted in rupture of the thinning wall.
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Affiliation(s)
- Kenichi Kono
- Department of Neurosurgery, Wakayama Rosai Hospital, Wakayama, Japan.
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20
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Morphology of Middle Cerebral Artery Aneurysms: Impact on Surgical Strategy and on Postoperative Outcome. ACTA ACUST UNITED AC 2013. [DOI: 10.1155/2013/838292] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The outcome of middle cerebral artery (MCA) aneurysm clipping depends on the presence of subarachnoid hemorrhage (SAH). Moreover, it is influenced by anatomical features of the aneurysm and its parent artery. We hypothesized that morphological characteristics of the aneurysm may be predictive for postoperative outcome. Therefore, we identified radiographic assessable details that predicted the surgical difficulty and the risk for new ischemia. The angiograms of 151 consecutive patients (82 presenting with SAH) were analyzed in a standardized fashion focusing on 12 defined morphological aspects. The results were correlated to intraoperative rupture and to postoperative ischemia. Aneurysms presenting with SAH were associated with irregular shape, larger maximum diameter, and larger dome-to-base distance (DBD) and were located more frequently on the M2 segment. Multivariate analysis revealed 6 independent predictors for intraoperative rupture: SAH, location on M2 segment, DBD, maximum diameter, diameter of the parent MCA, and the presence of branching vessel. Independent predictors of surgery-related ischemia were identified: SAH, irregular shape, location on M2 segment, DBD, and the neck-to-vessel ratio (NVR). In MCA aneurysms, independent predictors for the risk of rupture intraoperatively and for the postsurgical outcome were the presence of SAH, location on the M2-segment, size (DBD), and the broadness of the neck.
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21
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Hodis S, Uthamaraj S, Lanzino G, Kallmes DF, Dragomir-Daescu D. Computational fluid dynamics simulation of an anterior communicating artery ruptured during angiography. J Neurointerv Surg 2013; 6:e14. [PMID: 23493342 DOI: 10.1136/neurintsurg-2012-010596.rep] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
We present a computational fluid dynamics (CFD) analysis of the hemodynamic environment of an anterior communicating artery that spontaneously ruptured immediately following three-dimensional rotational angiography. Subsequent digital subtraction angiography allowed for the localization of the point of rupture within the aneurysm dome. CFD analysis demonstrated a concentrated jet that impinged directly at the site of rupture. Peak systolic pressure and wall shear stress were both maximal near the rupture location.
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Affiliation(s)
- Simona Hodis
- Department of Radiology, Mayo Clinic, Rochester, Minnesota, USA
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22
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Hodis S, Uthamaraj S, Lanzino G, Kallmes DF, Dragomir-Daescu D. Computational fluid dynamics simulation of an anterior communicating artery ruptured during angiography. BMJ Case Rep 2013; 2013:bcr-2012-010596. [PMID: 23475991 DOI: 10.1136/bcr-2012-010596] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
We present a computational fluid dynamics (CFD) analysis of the hemodynamic environment of an anterior communicating artery that spontaneously ruptured immediately following three-dimensional rotational angiography. Subsequent digital subtraction angiography allowed for the localization of the point of rupture within the aneurysm dome. CFD analysis demonstrated a concentrated jet that impinged directly at the site of rupture. Peak systolic pressure and wall shear stress were both maximal near the rupture location.
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Affiliation(s)
- Simona Hodis
- Department of Radiology, Mayo Clinic, Rochester, Minnesota, USA
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23
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Cebral JR, Raschi M. Suggested connections between risk factors of intracranial aneurysms: a review. Ann Biomed Eng 2012; 41:1366-83. [PMID: 23242844 DOI: 10.1007/s10439-012-0723-0] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2012] [Accepted: 12/07/2012] [Indexed: 12/01/2022]
Abstract
The purpose of this article is to review studies of aneurysm risk factors and the suggested hypotheses that connect the different risk factors and the underlying mechanisms governing the aneurysm natural history. The result of this work suggests that at the center of aneurysm evolution there is a cycle of wall degeneration and weakening in response to changing hemodynamic loading and biomechanic stress. This progressive wall degradation drives the geometrical evolution of the aneurysm until it stabilizes or ruptures. Risk factors such as location, genetics, smoking, co-morbidities, and hypertension seem to affect different components of this cycle. However, details of these interactions or their relative importance are still not clearly understood.
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Affiliation(s)
- Juan R Cebral
- Center for Computational Fluid Dynamics, George Mason University, Fairfax, VA, USA.
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24
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Karmonik C, Partovi S, Davies MG, Bismuth J, Shah DJ, Bilecen D, Staub D, Noon GP, Loebe M, Bongartz G, Lumsden AB. Integration of the computational fluid dynamics technique with MRI in aortic dissections. Magn Reson Med 2012; 69:1438-42. [PMID: 22700326 DOI: 10.1002/mrm.24376] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2012] [Revised: 05/17/2012] [Accepted: 05/23/2012] [Indexed: 11/05/2022]
Abstract
Short-term and long-term prognosis and their determining factors of Type III/Stanford B aortic dissections (TB-AD), which separate the aorta distal at the origin of the subclavian artery into a true lumen and false lumen, have been elusive: One quarter of patients thought to be treated successfully, either by medical or by surgical means, do not survive 3 years. Unfavorable hemodynamic conditions are believed to lead to false lumen pressure increases and complications. A better characterization of TB-AD hemodynamics may therefore impact therapeutic decision making and improve outcome. The large variations in TB-AD morphology and hemodynamics favor a patient-specific approach. Magnetic resonance imaging with its capability to provide high-resolution structural images of the lumen and aortic wall and also to quantify aortic flow and kinetics of an exogenous tracer is a promising clinical modality for developing a deeper understanding of TB-AD hemodynamics in an individual patient. With the information obtained with magnetic resonance imaging, computational fluid dynamics simulations can be performed to augment the image information. Here, an overview of the interplay of magnetic resonance imaging and computational fluid dynamics techniques is given illustrating the synergy of these two approaches toward a comprehensive morphological and hemodynamic characterization of TB-AD.
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Affiliation(s)
- Christof Karmonik
- Methodist DeBakey Heart & Vascular Center, The Methodist Hospital, Houston, Texas 77030, USA.
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25
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Sforza DM, Putman CM, Cebral JR. Computational fluid dynamics in brain aneurysms. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2012; 28:801-808. [PMID: 25364852 PMCID: PMC4221804 DOI: 10.1002/cnm.1481] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2011] [Revised: 10/04/2011] [Accepted: 10/05/2011] [Indexed: 05/30/2023]
Abstract
Because of its ability to deal with any geometry, image-based computational fluid dynamics (CFD) has been progressively used to investigate the role of hemodynamics in the underlying mechanisms governing the natural history of cerebral aneurysms. Despite great progress in methodological developments and many studies using patient-specific data, there are still significant controversies about the precise governing processes and divergent conclusions from apparently contradictory results. Sorting out these issues requires a global vision of the state of the art and a unified approach to solving this important scientific problem. Towards this end, this paper reviews the contributions made using patient-specific CFD models to further the understanding of these mechanisms, and highlights the great potential of patient-specific computational models for clinical use in the assessment of aneurysm rupture risk and patient management.
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Affiliation(s)
- Daniel M Sforza
- Center for Computational Fluid Dynamics, School of Physics, Astronomy and Computational Sciences, George Mason University, 4400 University Drive, MSN 6A2, Fairfax, VA 22030, USA.
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26
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Large Basilar Aneurysm with Posterior Inferior Cerebellar Artery Stroke and Consequential Fatal Subarachnoid Hemorrhage. Case Rep Emerg Med 2012; 2012:204585. [PMID: 23326705 PMCID: PMC3542926 DOI: 10.1155/2012/204585] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2012] [Accepted: 08/15/2012] [Indexed: 11/27/2022] Open
Abstract
Basilar artery aneurysm presenting a stroke is rare, and we present a case of this along with a discussion of the management options available.
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27
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Grobovschek M, Himmer M, Wolfsgruber P, Weymayr F. Intracranial Aneurysms and Vascular Malformations: Diagnosis for Therapy. Neuroradiol J 2011; 24:889-94. [DOI: 10.1177/197140091102400611] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2010] [Accepted: 12/12/2011] [Indexed: 11/16/2022] Open
Abstract
In the second part of our overviewstudy the diagnosis for the treatment of our patients with intracranial vascular malformations (aneurysms / AVMF– arteriovenous malformations) is again shown in a region of about 500.000 inhabitants and just an overview of the outcome. This second part will be an overall comparison between the former diagnostic for the treatment and the here described diagnostic for the treatment (CTA, MRA, DSA rot / microsurgery, endovascular interventional techniques etc.), concerning also the topography and the demography. The future trends are also outlined.
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Affiliation(s)
- M. Grobovschek
- Institute of Clinical Neuroradiology Christian-Doppler-Klinik, PMU Paracelsus Privatmedizinische Universität; Salzburg, Austria
| | - M. Himmer
- Institute of Clinical Neuroradiology Christian-Doppler-Klinik, PMU Paracelsus Privatmedizinische Universität; Salzburg, Austria
| | - P. Wolfsgruber
- Institute of Clinical Neuroradiology Christian-Doppler-Klinik, PMU Paracelsus Privatmedizinische Universität; Salzburg, Austria
| | - F. Weymayr
- Institute of Clinical Neuroradiology Christian-Doppler-Klinik, PMU Paracelsus Privatmedizinische Universität; Salzburg, Austria
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28
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Cebral J, Mut F, Sforza D, Löhner R, Scrivano E, Lylyk P, Putman C. Clinical Application of Image-Based CFD for Cerebral Aneurysms. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2011; 27:977-992. [PMID: 21822465 PMCID: PMC3150562 DOI: 10.1002/cnm.1373] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
During the last decade, the convergence of medical imaging and computational modeling technologies has enabled tremendous progress in the development and application of image-based computational fluid dynamics modeling of patient-specific blood flows. These techniques have been used for studying the basic mechanisms involved in the initiation and progression of vascular diseases, for studying possible ways to improve the diagnosis and evaluation of patients by incorporating hemodynamics information to the anatomical data typically available, and for the development of computational tools that can be used to improve surgical and endovascular treatment planning. However, before these technologies can have a significant impact on the routine clinical practice, it is still necessary to demonstrate the connection between the extra information provided by the models and the natural progression of vascular diseases and the outcome of interventions. This paper summarizes some of our contributions in this direction, focusing in particular on cerebral aneurysms.
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29
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Doenitz C, Schebesch KM, Zoephel R, Brawanski A. A mechanism for the rapid development of intracranial aneurysms: a case study. Neurosurgery 2011; 67:1213-21; discussion 1221. [PMID: 20948398 DOI: 10.1227/neu.0b013e3181f34def] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Despite technical and diagnostic progress there are still open questions in the understanding of the pathophysiology of intracranial aneurysms. OBJECTIVE Within 44 days we observed the de novo genesis and rupture of an aneurysm of the basilar artery in a patient. We performed computational fluid dynamics on 3-dimensional (3D) models of the inconspicuous vessel and the same vessel with aneurysm. Based on the simulations we propose a mechanism of genesis of fast-growing aneurysms. METHODS Three-dimensional mesh models were built using computed tomography-angiography slices. Flow was modeled as a non-Newtonian blood model with shear-dependent dynamic viscosity. We investigated flow velocity, wall pressure, impingement point, wall shear stress (WSS), and asymmetric flows in 3D models of the vessel tree of the basilar artery. RESULTS Impingement point and wall pressure had no clear relation to the origin of the aneurysm. The impingement point faded away during aneurysm growth. Instead we found an area of permanently low WSS in the original basilar artery. This location corresponded to the origin of the later developing aneurysm. Aneurysm growth was facilitated by an increasing overall expansion of the basilar tip and a constant decrease of WSS. CONCLUSION Assuming a preexisting reduced resistibility of the vessel wall to pressure changes and an area of permanently low WSS, an increase in pressure induces geometrical changes. These cause changes of intravascular flow distribution, lowering the already low WSS in specific locations. This leads to endothelial damage in this area and to a decreasing stability of the vessel wall, causing aneurysm development, growth, and rupture.
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Affiliation(s)
- Christian Doenitz
- Department of Neurosurgery, University of Regensburg Medical Center, Regensburg, Germany.
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30
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Geers AJ, Larrabide I, Radaelli AG, Bogunovic H, Kim M, Gratama van Andel HAF, Majoie CB, VanBavel E, Frangi AF. Patient-specific computational hemodynamics of intracranial aneurysms from 3D rotational angiography and CT angiography: an in vivo reproducibility study. AJNR Am J Neuroradiol 2011; 32:581-6. [PMID: 21183614 DOI: 10.3174/ajnr.a2306] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE Patient-specific simulations of the hemodynamics in intracranial aneurysms can be constructed by using image-based vascular models and CFD techniques. This work evaluates the impact of the choice of imaging technique on these simulations. MATERIALS AND METHODS Ten aneurysms, imaged with 3DRA and CTA, were analyzed to assess the reproducibility of geometric and hemodynamic variables across the 2 modalities. RESULTS Compared with 3DRA models, we found that CTA models often had larger aneurysm necks (P = .05) and that most of the smallest vessels (between 0.7 and 1.0 mm in diameter) could not be reconstructed successfully with CTA. With respect to the values measured in the 3DRA models, the flow rate differed by 14.1 ± 2.8% (mean ± SE) just proximal to the aneurysm and 33.9 ± 7.6% at the aneurysm neck. The mean WSS on the aneurysm differed by 44.2 ± 6.0%. Even when normalized to the parent vessel WSS, a difference of 31.4 ± 9.9% remained, with the normalized WSS in most cases being larger in the CTA model (P = .04). Despite these substantial differences, excellent agreement (κ ≥ 0.9) was found for qualitative variables that describe the flow field, such as the structure of the flow pattern and the flow complexity. CONCLUSIONS Although relatively large differences were found for all evaluated quantitative hemodynamic variables, the main flow characteristics were reproduced across imaging modalities.
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Affiliation(s)
- A J Geers
- Center for Computational Imaging and Simulation Technologies in Biomedicine, Department of Information and Communication Technologies, Universitat Pompeu Fabra, Barcelona, Spain
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31
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Rahman M, Ogilvy CS, Zipfel GJ, Derdeyn CP, Siddiqui AH, Bulsara KR, Kim LJ, Riina HA, Mocco J, Hoh BL. Unruptured Cerebral Aneurysms Do Not Shrink When They Rupture: Multicenter Collaborative Aneurysm Study Group. Neurosurgery 2011; 68:155-60; discussion 160-1. [DOI: 10.1227/neu.0b013e3181ff357c] [Citation(s) in RCA: 83] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Abstract
BACKGROUND:
The International Study of Intracranial Aneurysms found that for patients with no previous history of subarachnoid hemorrhage, small (< 7 mm) anterior circulation and posterior circulation aneurysms had a 0% and 2.5% risk of subarachnoid hemorrhage over 5 years, respectively.
OBJECTIVE:
To determine whether cerebral aneurysms shrink with rupture.
METHODS:
The clinical databases of 7 sites were screened for patients with imaging of cerebral aneurysms before and after rupture. Inclusion criteria included documented subarachnoid hemorrhage by imaging or lumbar puncture and intracranial imaging before and after cerebral aneurysm rupture. The patients were evaluated for aneurysm maximal height, maximal width, neck diameter, and other measurement parameters. Only a change of ≥ 2 mm was considered a true change.
RESULTS:
Data on 13 patients who met inclusion criteria were collected. The median age was 60, and 11 of the 13 patients (84.6%) were female. Only 5 patients had posterior circulation aneurysms. None of the aneurysms had a significant decrease in size. One aneurysm decreased by 1.8 mm in maximum size after rupture (7.7%). Six aneurysms had an increase in maximum size of at least 2 mm after rupture (46.2%) with a mean increase of 3.5 mm (± 0.5 mm).
CONCLUSION:
Unruptured aneurysms do not shrink when they rupture. The large percentage of ruptured small aneurysms in previous studies were likely small before they ruptured.
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Affiliation(s)
- Maryam. Rahman
- Department of Neurosurgery, University of Florida, Gainesville, Florida
| | | | - Gregory J. Zipfel
- Department of Neurosurgery, Washington University, St Louis, Missouri
| | - Colin P. Derdeyn
- Department of Neurosurgery, Washington University, St Louis, Missouri
| | - Adnan H. Siddiqui
- Department of Neurosurgery, University at Buffalo, Buffalo, New York
| | - Ketan R. Bulsara
- Department of Neurosurgery, Yale University, New Haven, Connecticut
| | - Louis J. Kim
- Department of Neurosurgery, University of Washington, Seattle, Washington
| | - Howard A. Riina
- Department of Neurosurgery, Weill Cornell Medical College, New York, New York
| | - J. Mocco
- Department of Neurosurgery, University of Florida, Gainesville, Florida
| | - Brian L. Hoh
- Department of Neurosurgery, University of Florida, Gainesville, Florida
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32
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Reply on comments on: “Influence of parent vessel dominancy on fluid dynamics of anterior communicating artery aneurysms” by T. Hassan, A. A. Hassan, and Y. Ahmed (2010) Acta Neurochirurgica. Acta Neurochir (Wien) 2010. [DOI: 10.1007/s00701-010-0887-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Cebral JR, Mut F, Weir J, Putman CM. Association of hemodynamic characteristics and cerebral aneurysm rupture. AJNR Am J Neuroradiol 2010; 32:264-70. [PMID: 21051508 DOI: 10.3174/ajnr.a2274] [Citation(s) in RCA: 268] [Impact Index Per Article: 19.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE Hemodynamic factors are thought to play an important role in the initiation, growth, and rupture of cerebral aneurysms. This report describes a study of the associations between qualitative intra-aneurysmal hemodynamics and the rupture of cerebral aneurysms. MATERIALS AND METHODS Two hundred ten consecutive aneurysms were analyzed by using patient-specific CFD simulations under pulsatile flow conditions. The aneurysms were classified into categories by 2 blinded observers, depending on the complexity and stability of the flow pattern, size of the impingement region, and inflow concentration. A statistical analysis was then performed with respect to the history of previous rupture. Interobserver variability analysis was performed. RESULTS Ruptured aneurysms were more likely to have complex flow patterns (83%, P < .001), stable flow patterns (75%, P = .0018), concentrated inflow (66%, P = <.0001), and small impingement regions (76%, P = .0006) compared with unruptured aneurysms. Interobserver variability analyses indicated that all the classifications performed were in very good agreement-that is, well within the 95% CI. CONCLUSIONS A qualitative hemodynamic analysis of cerebral aneurysms by using image-based patient-specific geometries has shown that concentrated inflow jets, small impingement regions, complex flow patterns, and unstable flow patterns are correlated with a clinical history of prior aneurysm rupture. These qualitative measures provide a starting point for more sophisticated quantitative analysis aimed at assigning aneurysm risk of future rupture. These analyses highlight the potential for CFD to play an important role in the clinical determination of aneurysm risks.
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Affiliation(s)
- J R Cebral
- Department of Computational and Data Sciences, Center for Computational Fluid Dynamics, George Mason University, Fairfax, Virginia 22030, USA.
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34
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Computational Hemodynamics in Cerebral Aneurysms: The Effects of Modeled Versus Measured Boundary Conditions. Ann Biomed Eng 2010; 39:884-96. [DOI: 10.1007/s10439-010-0187-z] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2010] [Accepted: 10/09/2010] [Indexed: 10/18/2022]
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Ford MD, Hoi Y, Piccinelli M, Antiga L, Steinman DA. An objective approach to digital removal of saccular aneurysms: technique and applications. Br J Radiol 2010; 82 Spec No 1:S55-61. [PMID: 20348537 DOI: 10.1259/bjr/67593727] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
Human studies of haemodynamic factors in the pathogenesis of cerebral aneurysms require knowledge of the pre-aneurysmal vasculature. This paper presents an objective and automated technique to digitally remove an aneurysm and reconstruct the parent artery, based on lumen geometries segmented from angiographic images. Relying on robust computational geometry concepts, notably Voronoi diagrams of the digitised lumen surface, the aneurysm attachment region is first defined objectively using lumen centrelines. Centrelines within this region are replaced by smooth interpolations, which then guide the interpolation of Voronoi points within the attachment region. Combined with Voronoi points from outside the attachment region, the parent artery lumen, without the aneurysm, can be reconstructed. Plausible reconstructions were obtained, automatically, for a set of 10 side-wall or terminal aneurysms, of various sizes and shapes, from the ANEURISK project data set. Application of image-based computational fluid dynamics analysis to a five side-wall aneurysm cases data set revealed an association between the recently proposed gradient oscillatory number (GON) and the site of aneurysm formation in four of five cases; however, elevated GON was also evident at non-aneurysmal sites. A potential application to the automated delineation of aneurysms for morphological characterisations is also suggested. The proposed approach may serve as a broad platform for investigating haemodynamic and morphological factors in aneurysm initiation, rupture and therapy in a way amenable to large-scale clinical studies or routine clinical use. Nevertheless, while the parent artery reconstructions are plausible, it remains to be proven that they are faithful representations of the pre-aneurysmal artery.
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Affiliation(s)
- M D Ford
- Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, ON, Canada
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Sforza DM, Putman CM, Scrivano E, Lylyk P, Cebral JR. Blood-flow characteristics in a terminal basilar tip aneurysm prior to its fatal rupture. AJNR Am J Neuroradiol 2010; 31:1127-31. [PMID: 20150312 DOI: 10.3174/ajnr.a2021] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE The development and validation of methods to stratify the risk of rupture of cerebral aneurysms is highly desired because current treatment risks can exceed the natural risk of rupture. Because unruptured aneurysms are typically treated before they rupture, it is very difficult to connect the proposed risk indices to the rupture of an individual aneurysm. The purpose of this case study was to analyze the hemodynamic environment of a saccular aneurysm of the terminal morphology subtype that was imaged just before its rupture and to test whether the hemodynamic characteristics would designate this particular aneurysm as at high risk. MATERIALS AND METHODS A patient-specific CFD model was constructed from 3DRA images acquired just hours before the aneurysm ruptured. A pulsatile flow calculation was performed, and hemodynamic characteristics previously connected to rupture were analyzed. RESULTS It was found that the aneurysm had a concentrated inflow stream, small impingement region, complex intra-aneurysmal flow structure, asymmetric flow split from the parent vessel to the aneurysm and daughter branches, and high levels of aneurysmal WSS near the impaction zone. CONCLUSIONS The hemodynamic characteristics observed in this aneurysm right before its rupture are consistent with previous studies correlating aneurysm rupture and hemodynamic patterns in saccular and terminal aneurysms. This study supports the notion that hemodynamic information may be used to help stratify the rupture risk of cerebral aneurysms.
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Affiliation(s)
- D M Sforza
- Department of Computational and Data Sciences, Center for Computational Fluid Dynamics, George Mason University, 4400 University Drive, Fairfax, VA 22030, USA
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Neal ML, Kerckhoffs R. Current progress in patient-specific modeling. Brief Bioinform 2010; 11:111-26. [PMID: 19955236 PMCID: PMC2810113 DOI: 10.1093/bib/bbp049] [Citation(s) in RCA: 99] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2009] [Revised: 09/20/2009] [Indexed: 11/13/2022] Open
Abstract
We present a survey of recent advancements in the emerging field of patient-specific modeling (PSM). Researchers in this field are currently simulating a wide variety of tissue and organ dynamics to address challenges in various clinical domains. The majority of this research employs three-dimensional, image-based modeling techniques. Recent PSM publications mostly represent feasibility or preliminary validation studies on modeling technologies, and these systems will require further clinical validation and usability testing before they can become a standard of care. We anticipate that with further testing and research, PSM-derived technologies will eventually become valuable, versatile clinical tools.
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Affiliation(s)
- Maxwell Lewis Neal
- Division of Biomedical and Health Informatics, University of Washington, USA
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Baek H, Jayaraman MV, Richardson PD, Karniadakis GE. Flow instability and wall shear stress variation in intracranial aneurysms. J R Soc Interface 2009; 7:967-88. [PMID: 20022896 DOI: 10.1098/rsif.2009.0476] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
We investigate the flow dynamics and oscillatory behaviour of wall shear stress (WSS) vectors in intracranial aneurysms using high resolution numerical simulations. We analyse three representative patient-specific internal carotid arteries laden with aneurysms of different characteristics: (i) a wide-necked saccular aneurysm, (ii) a narrower-necked saccular aneurysm, and (iii) a case with two adjacent saccular aneurysms. Our simulations show that the pulsatile flow in aneurysms can be subject to a hydrodynamic instability during the decelerating systolic phase resulting in a high-frequency oscillation in the range of 20-50 Hz, even when the blood flow rate in the parent vessel is as low as 150 and 250 ml min(-1) for cases (iii) and (i), respectively. The flow returns to its original laminar pulsatile state near the end of diastole. When the aneurysmal flow becomes unstable, both the magnitude and the directions of WSS vectors fluctuate at the aforementioned high frequencies. In particular, the WSS vectors around the flow impingement region exhibit significant spatio-temporal changes in direction as well as in magnitude.
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Affiliation(s)
- H Baek
- Division of Applied Mathematics, Brown University, Providence, RI 02912, USA
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Baek H, Jayaraman MV, Karniadakis GE. Wall shear stress and pressure distribution on aneurysms and infundibulae in the posterior communicating artery bifurcation. Ann Biomed Eng 2009; 37:2469-87. [PMID: 19757058 DOI: 10.1007/s10439-009-9794-y] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2009] [Accepted: 08/31/2009] [Indexed: 11/26/2022]
Abstract
A growing number of cases of rupture at an infundibulum, progression of infundibulum to a frank aneurysm, and subarachnoid hemorrhage (SAH) in the posterior communicating artery (PCoA) have been reported. Using patient-specific geometric models of the supraclinoid internal carotid artery (ICA) with PCoA infundibulum or aneurysm, high-resolution computational fluid dynamics simulations were performed by solving the Navier-Stokes equations with a spectral/hp element method. Simulation results show that the flow impinges at the distal wall of infundibulum near the outside of the ICA bend and creates a region of higher pressure (4-5 mmHg) surrounded by a band of a high wall shear stress (WSS) (20-30 N/m(2) on average). At the proximal end of the infundibulum, another stagnation area is formed characterized by low WSS (<1 N/m(2)) and high oscillating shear index. This impingement region seems to coincide with the locations of the rupture of infundibulae or progression to aneurysms. In addition, the pulsatile flow becomes unstable due to the presence of aneurysms or aneurysm-like infundibulae, and this leads to WSS temporal fluctuations inside the aneurysm, which may accelerate the degenerative processes in the vessel walls.
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Affiliation(s)
- Hyoungsu Baek
- Division of Applied Mathematics, Brown University, Providence, RI, 02912, USA
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The role of computational fluid dynamics in the management of unruptured intracranial aneurysms: a clinicians' view. COMPUTATIONAL INTELLIGENCE AND NEUROSCIENCE 2009:760364. [PMID: 19696903 PMCID: PMC2729101 DOI: 10.1155/2009/760364] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/11/2009] [Revised: 04/24/2009] [Accepted: 06/09/2009] [Indexed: 11/18/2022]
Abstract
Objective. The
importance of hemodynamics in the
etiopathogenesis of intracranial aneurysms (IAs)
is widely accepted. Computational fluid dynamics
(CFD) is being used increasingly for hemodynamic
predictions. However, alogn with the continuing
development and validation of these
tools, it is imperative to collect
the opinion of the clinicians.
Methods. A workshop on CFD was
conducted during the European Society of
Minimally Invasive Neurological Therapy (ESMINT)
Teaching Course, Lisbon, Portugal.
36 delegates, mostly clinicians,
performed supervised CFD analysis for an IA, using the
@neuFuse software developed within the European
project @neurIST. Feedback on the workshop was
collected and analyzed. The
performance was assessed on a scale of 1 to 4
and, compared with experts' performance.
Results. Current dilemmas in
the management of unruptured IAs remained the
most important motivating factor to attend the
workshop and majority of participants showed interest in participating in a
multicentric trial. The participants achieved
an average score of 2.52 (range 0–4) which was 63% (range 0–100%) of an expert user. Conclusions.
Although participants showed a manifest interest
in CFD, there was a clear
lack of awareness concerning the role of
hemodynamics in the etiopathogenesis of IAs and
the use of CFD in this context. More efforts
therefore are required to enhance understanding of the
clinicians in the subject.
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