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Xiang J, Tutino VM, Snyder KV, Meng H. CFD: computational fluid dynamics or confounding factor dissemination? The role of hemodynamics in intracranial aneurysm rupture risk assessment. AJNR Am J Neuroradiol 2013; 35:1849-57. [PMID: 24029393 DOI: 10.3174/ajnr.a3710] [Citation(s) in RCA: 119] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Image-based computational fluid dynamics holds a prominent position in the evaluation of intracranial aneurysms, especially as a promising tool to stratify rupture risk. Current computational fluid dynamics findings correlating both high and low wall shear stress with intracranial aneurysm growth and rupture puzzle researchers and clinicians alike. These conflicting findings may stem from inconsistent parameter definitions, small datasets, and intrinsic complexities in intracranial aneurysm growth and rupture. In Part 1 of this 2-part review, we proposed a unifying hypothesis: both high and low wall shear stress drive intracranial aneurysm growth and rupture through mural cell-mediated and inflammatory cell-mediated destructive remodeling pathways, respectively. In the present report, Part 2, we delineate different wall shear stress parameter definitions and survey recent computational fluid dynamics studies, in light of this mechanistic heterogeneity. In the future, we expect that larger datasets, better analyses, and increased understanding of hemodynamic-biologic mechanisms will lead to more accurate predictive models for intracranial aneurysm risk assessment from computational fluid dynamics.
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Affiliation(s)
- J Xiang
- From the Toshiba Stroke and Vascular Research Center (J.X., V.M.T., K.V.S., H.M.) Departments of Neurosurgery (J.X.)
| | - V M Tutino
- From the Toshiba Stroke and Vascular Research Center (J.X., V.M.T., K.V.S., H.M.) Biomedical Engineering (V.M.T.)
| | - K V Snyder
- From the Toshiba Stroke and Vascular Research Center (J.X., V.M.T., K.V.S., H.M.)
| | - H Meng
- From the Toshiba Stroke and Vascular Research Center (J.X., V.M.T., K.V.S., H.M.) Mechanical and Aerospace Engineering (H.M.), University at Buffalo, State University of New York, Buffalo, New York.
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52
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Morales HG, Larrabide I, Geers AJ, Aguilar ML, Frangi AF. Newtonian and non-Newtonian blood flow in coiled cerebral aneurysms. J Biomech 2013; 46:2158-64. [DOI: 10.1016/j.jbiomech.2013.06.034] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2013] [Revised: 06/18/2013] [Accepted: 06/30/2013] [Indexed: 10/26/2022]
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53
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Arbia G, Corsini C, Esmaily Moghadam M, Marsden AL, Migliavacca F, Pennati G, Hsia TY, Vignon-Clementel IE. Numerical blood flow simulation in surgical corrections: what do we need for an accurate analysis? J Surg Res 2013; 186:44-55. [PMID: 23993199 DOI: 10.1016/j.jss.2013.07.037] [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] [Received: 04/30/2013] [Revised: 07/17/2013] [Accepted: 07/18/2013] [Indexed: 10/26/2022]
Abstract
BACKGROUND Computational fluid dynamics has been increasingly used in congenital heart surgery to simulate pathophysiological blood flow, investigate surgical options, or design medical devices. Several commercial and research computational or numerical codes have been developed. They present different approaches to numerically solve the blood flow equations, raising the question whether these numerical codes are equally reliable to achieve accurate simulation results. Accordingly, we sought to examine the influence of numerical code selection in several complex congenital cardiac operations. MATERIAL AND METHODS The main steps of blood flow simulations are detailed (geometrical mesh, boundary conditions, and solver numerical methods) for congenital cardiac operations of increasing complexity. The first case tests different numerical solutions against an analytical, or exact, solution. In the second case, the three-dimensional domain is a patient-specific superior cavopulmonary anastomosis. As an analytical solution does not exist in such a complex geometry, different numerical solutions are compared. Finally, a realistic case of a systemic-to-pulmonary shunt is presented with both geometrically and physiologically challenging conditions. For all, solutions from a commercially available code and an open-source research code are compared. RESULTS In the first case, as the mesh or solver numerical method is refined, the simulation results for both codes converged to the analytical solution. In the second example, velocity differences between the two codes are greater when the resolution of the mesh were lower and less refined. The third case with realistic anatomy reveals that the pulsatile complex flow is very similar for both codes. CONCLUSIONS The precise setup of the numerical cases has more influence on the results than the choice of numerical codes. The need for detailed construction of the numerical model that requires high computational cost depends on the precision needed to answer the biomedical question at hand and should be assessed for each problem on a combination of clinically relevant patient-specific geometry and physiological conditions.
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Affiliation(s)
- Gregory Arbia
- INRIA Paris-Rocquencourt, Le Chesnay Cedex, France; UPMC Univ Paris 6, Laboratoire Jacques-Louis Lions, Paris, France
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Castro MA. Understanding the role of hemodynamics in the initiation, progression, rupture, and treatment outcome of cerebral aneurysm from medical image-based computational studies. ISRN RADIOLOGY 2013; 2013:602707. [PMID: 24967285 PMCID: PMC4045510 DOI: 10.5402/2013/602707] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 05/15/2013] [Accepted: 06/19/2013] [Indexed: 12/31/2022]
Abstract
About a decade ago, the first image-based computational hemodynamic studies of cerebral aneurysms were presented. Their potential for clinical applications was the result of a right combination of medical image processing, vascular reconstruction, and grid generation techniques used to reconstruct personalized domains for computational fluid and solid dynamics solvers and data analysis and visualization techniques. A considerable number of studies have captivated the attention of clinicians, neurosurgeons, and neuroradiologists, who realized the ability of those tools to help in understanding the role played by hemodynamics in the natural history and management of intracranial aneurysms. This paper intends to summarize the most relevant results in the field reported during the last years.
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Affiliation(s)
- Marcelo A. Castro
- Grupo de Investigación y Desarrollo en Bioingeniería, Facultad Regional Buenos Aires, Universidad Tecnológica Nacional, CONICET, Medrano 951, CP 1179, Buenos Aires, Argentina
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Jeong W, Han MH, Rhee K. Effects of framing coil shape, orientation, and thickness on intra-aneurysmal flow. Med Biol Eng Comput 2013; 51:981-90. [DOI: 10.1007/s11517-013-1073-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2012] [Accepted: 03/29/2013] [Indexed: 11/30/2022]
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Babiker MH, Gonzalez LF, Albuquerque F, Collins D, Elvikis A, Zwart C, Roszelle B, Frakes DH. An In Vitro Study of Pulsatile Fluid Dynamics in Intracranial Aneurysm Models Treated with Embolic Coils and Flow Diverters. IEEE Trans Biomed Eng 2013. [DOI: 10.1109/tbme.2012.2228002] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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57
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Otani T, Nakamura M, Fujinaka T, Hirata M, Kuroda J, Shibano K, Wada S. Computational fluid dynamics of blood flow in coil-embolized aneurysms: effect of packing density on flow stagnation in an idealized geometry. Med Biol Eng Comput 2013; 51:901-10. [PMID: 23529587 DOI: 10.1007/s11517-013-1062-5] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2012] [Accepted: 03/10/2013] [Indexed: 11/30/2022]
Abstract
Coil embolization is performed to induce flow stagnation in cerebral aneurysms and enhance blood clot formation, thus preventing rupture and further growth. We investigated hemodynamics in differently positioned aneurysms coiled at various packing densities to determine the effective packing density in terms of flow stagnation. As a first step, hemodynamic simulations were conducted for idealized geometries of both terminal- and sidewall-type aneurysms. Porous media modeling was employed to describe blood flow in coil-embolized aneurysms. The stagnant volume ratio (SVR) was analyzed to quantify the efficacy of coil embolization. Regardless of aneurysm type and angle, SVR increased with increasing packing density, but the increase in SVR varied depending on type. For sidewall-type aneurysms, the packing density required to achieve 60 % SVR was 20 %, roughly independent of aneurysm angle; flow stagnation was achieved at low packing density. In contrast, in terminal-type aneurysms, the packing density required to achieve 60 % SVR was highly dependent on aneurysm angle, accomplishing a 20 % packing density only for lower angles. Indications are that a relatively high packing density would be required, particularly when these aneurysms are angled against the parent artery. The packing density required for flow stagnation varies depending on aneurysm type and relative position.
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Affiliation(s)
- Tomohiro Otani
- Graduate School of Engineering Science, Osaka University, Machikaneyama-chou 1-3, Toyonaka, Osaka 560-8531, Japan
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58
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Computer Simulations in Stroke Prevention: Design Tools and Virtual Strategies Towards Procedure Planning. Cardiovasc Eng Technol 2013. [DOI: 10.1007/s13239-013-0134-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Morales HG, Larrabide I, Geers AJ, San Román L, Blasco J, Macho JM, Frangi AF. A virtual coiling technique for image-based aneurysm models by dynamic path planning. IEEE TRANSACTIONS ON MEDICAL IMAGING 2013; 32:119-129. [PMID: 23008248 DOI: 10.1109/tmi.2012.2219626] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Computational algorithms modeling the insertion of endovascular devices, such as coil or stents, have gained an increasing interest in recent years. This scientific enthusiasm is due to the potential impact that these techniques have to support clinicians by understanding the intravascular hemodynamics and predicting treatment outcomes. In this work, a virtual coiling technique for treating image-based aneurysm models is proposed. A dynamic path planning was used to mimic the structure and distribution of coils inside aneurysm cavities, and to reach high packing densities, which is desirable by clinicians when treating with coils. Several tests were done to evaluate the performance on idealized and image-based aneurysm models. The proposed technique was validated using clinical information of real coiled aneurysms. The virtual coiling technique reproduces the macroscopic behavior of inserted coils and properly captures the densities, shapes and coil distributions inside aneurysm cavities. A practical application was performed by assessing the local hemodynamic after coiling using computational fluid dynamics (CFD). Wall shear stress and intra-aneurysmal velocities were reduced after coiling. Additionally, CFD simulations show that coils decrease the amount of contrast entering the aneurysm and increase its residence time.
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Affiliation(s)
- Hernán G Morales
- Center for Computational Imaging and Simulation Technologies in Biomedicine (CISTIB), Information and Communications Technologies Department, Universitat Pompeu Fabra (UPF), Barcelona, Spain.
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Janiga G, Berg P, Beuing O, Neugebauer M, Gasteiger R, Preim B, Rose G, Skalej M, Thévenin D. Recommendations for accurate numerical blood flow simulations of stented intracranial aneurysms. ACTA ACUST UNITED AC 2013; 58:303-14. [DOI: 10.1515/bmt-2012-0119] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2012] [Accepted: 04/03/2013] [Indexed: 11/15/2022]
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Larrabide I, Villa-Uriol MC, Cárdenes R, Barbarito V, Carotenuto L, Geers AJ, Morales HG, Pozo JM, Mazzeo MD, Bogunović H, Omedas P, Riccobene C, Macho JM, Frangi AF. AngioLab--a software tool for morphological analysis and endovascular treatment planning of intracranial aneurysms. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2012; 108:806-819. [PMID: 22749086 DOI: 10.1016/j.cmpb.2012.05.006] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2011] [Revised: 04/18/2012] [Accepted: 05/04/2012] [Indexed: 06/01/2023]
Abstract
Determining whether and how an intracranial aneurysm should be treated is a tough decision that clinicians face everyday. Emerging computational tools could help clinicians analyze clinical data and make these decisions. AngioLab is a single graphical user interface, developed on top of the open source framework GIMIAS, that integrates some of the latest image analysis and computational modeling tools for intracranial aneurysms. Two workflows are available: Advanced Morphological Analysis (AMA) and Endovascular Treatment Planning (ETP). AngioLab has been evaluated by a total of 62 clinicians, who considered the information provided by AngioLab relevant and meaningful. They acknowledged the emerging need of these type of tools and the potential impact they might have on the clinical decision-making process.
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Affiliation(s)
- Ignacio Larrabide
- Networking Biomedical Research Center on Bioengineering, Biomaterials and Nanomedicine, Barcelona, Spain.
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Morales HG, Larrabide I, Geers AJ, Dai D, Kallmes DF, Frangi AF. Analysis and quantification of endovascular coil distribution inside saccular aneurysms using histological images. J Neurointerv Surg 2012; 5 Suppl 3:iii33-7. [PMID: 22914746 DOI: 10.1136/neurintsurg-2012-010456] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
OBJECTIVE Endovascular coiling is often performed by first placing coils along the aneurysm wall to create a frame and then by filling up the aneurysm core. However, little attention has been paid to quantifying this filling strategy and to see how it changes for different packing densities. The purpose of this work is to analyze and quantify endovascular coil distribution inside aneurysms based on serial histological images of experimental aneurysms. METHOD Seventeen histological images from 10 elastase-induced saccular aneurysms in rabbits treated with coils were studied. In-slice coil density, defined as the area taken up by coil winds, was calculated on each histological image. Images were analyzed by partitioning the aneurysm along its longitudinal and radial axes. Coil distribution was quantified by measuring and comparing the in-slice coil density of each partition. RESULTS Mean total in-slice coil density was 22.0 ± 6.2% (range 10.1-30.2%). The density was non-significantly different (p = 0.465) along the longitudinal axis. A significant difference (p < 0.001) between peripheral and core densities was found. Additionally, the peripheral-core density ratio was observed to be inversely proportional to the total in-slice coil density (R(2)=0.57, p <0.001). This ratio was near unity for high in-slice coil density (around 30%). CONCLUSIONS These findings demonstrate and confirm that coils tend to be located near the aneurysm periphery when few are inserted. However, when more coils are added, the radial distribution becomes more homogeneous. Coils are homogeneously distributed along the longitudinal axis.
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Affiliation(s)
- Hernán G Morales
- Center for Computational Imaging and Simulation Technologies in Biomedicine (CISTIB), Information and Communication Technologies Department, Universitat Pompeu Fabra, Barcelona, Spain
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Ugron Á, Szikora I, Paál G. Haemodynamic changes induced by intrasaccular packing on intracranial aneurysms: A computational fluid dynamic study. Interv Med Appl Sci 2012. [DOI: 10.1556/imas.4.2012.2.4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Abstract
Endovascular treatment of intracranial aneurysms is a routine medical practice. The most widely used technique is the packing the aneurysm sac with an embolic material. To gain deeper understanding in the effects of specific treatment methods, the intra-aneurysmal haemodynamics are studied with the help of patient-specific computational models. Numerical simulations demonstrated that embolisation with liquid polymer results in an overall decrease of the wall shear stress and pressure in the aneurysm region. Within the range of clinically relevant packing density, simulation of coil embolisation showed homogenisation and decrease of the wall loads on the aneurysm sac. Increasing the packing density above 20% produces little or no further reduction of intra-aneurysmal flow. Sufficient packing of the aneurysm sac results in significant intra-aneurysmal flow decrease associated with reduced wall loads but locally increased pressure or wall shear stress zones may appear depending on the specific vessel geometry.
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Affiliation(s)
- Ádám Ugron
- 1 Department of Hydrodynamic Systems, Budapest University of Technology and Economics, Budapest, Hungary
- 3 Budapest University of Technology and Economics, P.O. Box 91, H-1521, Budapest, Hungary
| | - István Szikora
- 2 National Institute of Neurosciences, Budapest, Hungary
| | - György Paál
- 1 Department of Hydrodynamic Systems, Budapest University of Technology and Economics, Budapest, Hungary
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