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Chung BJ, Mut F, Putman CM, Hamzei-Sichani F, Brinjikji W, Kallmes D, Jimenez CM, Cebral JR. Identification of Hostile Hemodynamics and Geometries of Cerebral Aneurysms: A Case-Control Study. AJNR Am J Neuroradiol 2018; 39:1860-1866. [PMID: 30166431 DOI: 10.3174/ajnr.a5764] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Accepted: 06/27/2018] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE Hostile hemodynamic conditions and geometries are thought to predispose aneurysms for instability and rupture. This study compares stable, unstable, and ruptured aneurysms while controlling for location and patient characteristics. MATERIALS AND METHODS The hemodynamics and geometries of 165 stable, 65 unstable, and 554 ruptured aneurysms were compared. Hemodynamics was modeled using image-based computational fluid dynamics. Case-control pairs were selected matching aneurysm location, patient age, and sex. Paired Wilcoxon tests were used to compare hemodynamic and geometric variables among different aneurysm groups. The pairing was repeated 100 times, and the combined P values were calculated and adjusted for multiple testing. RESULTS Ruptured aneurysms had lower minimum wall shear stress (P = .03), higher maximum wall shear stress (P = .03), more concentrated (P = .03) and mean oscillatory shear stress (P = .03), higher maximum velocity (P = .03), and more complex flows (vortex core-line length, P = .03) than stable aneurysms. Similarly, unstable aneurysms had more concentrated shear stress (P = .04) and more complex flows (vortex core-line length, P = .04) than stable aneurysms. Compared with stable aneurysms, ruptured aneurysms were larger (size ratio, aneurysm size/vessel size, P = .03), more elongated (aspect ratio, P = .03), and irregular (nonsphericity index, P = .03). Similarly, unstable aneurysms were larger (size ratio, P = .04), more elongated (aspect ratio, P = .04), and irregular (bulge location, P = .04; area-weighted Gaussian curvature; P = .04) than stable aneurysms. No significant differences were found between unstable and ruptured aneurysms. CONCLUSIONS Unstable and ruptured aneurysms have more complex flows with concentrated wall shear stress and are larger, more elongated, and irregular than stable aneurysms, independent of aneurysm location and patient sex and age.
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Affiliation(s)
- B J Chung
- From the Bioengineering and Mechanical Engineering Departments (B.J.C., F.M., J.R.C.), Volgenau School of Engineering George Mason University, Fairfax, Virginia
| | - F Mut
- From the Bioengineering and Mechanical Engineering Departments (B.J.C., F.M., J.R.C.), Volgenau School of Engineering George Mason University, Fairfax, Virginia
| | - C M Putman
- Interventional Neuroradiology Unit (C.M.P.), Inova Fairfax Hospital, Falls Church, Virginia
| | - F Hamzei-Sichani
- Department of Neurological Surgery (F.H.-S.), University of Massachusetts, Worcester, Massachusetts
| | - W Brinjikji
- Department of Radiology (W.B., D.K.), Mayo Clinic, Rochester, Minnesota
| | - D Kallmes
- Department of Radiology (W.B., D.K.), Mayo Clinic, Rochester, Minnesota
| | - C M Jimenez
- Neurosurgery Department (C.M.J.), University of Antioquia, Medellin, Colombia
| | - J R Cebral
- From the Bioengineering and Mechanical Engineering Departments (B.J.C., F.M., J.R.C.), Volgenau School of Engineering George Mason University, Fairfax, Virginia
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Doddasomayajula R, Chung BJ, Mut F, Jimenez CM, Hamzei-Sichani F, Putman CM, Cebral JR. Hemodynamic Characteristics of Ruptured and Unruptured Multiple Aneurysms at Mirror and Ipsilateral Locations. AJNR Am J Neuroradiol 2017; 38:2301-2307. [PMID: 28982787 DOI: 10.3174/ajnr.a5397] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2017] [Accepted: 08/01/2017] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE Different hemodynamic patterns have been associated with aneurysm rupture. The objective was to test whether hemodynamic characteristics of the ruptured aneurysm in patients with multiple aneurysms were different from those in unruptured aneurysms in the same patient. MATERIALS AND METHODS Twenty-four mirror and 58 ipsilateral multiple aneurysms with 1 ruptured and the others unruptured were studied. Computational fluid dynamics models were created from 3D angiographies. Case-control studies of mirror and ipsilateral aneurysms were performed with paired Wilcoxon tests. RESULTS In mirror pairs, the ruptured aneurysm had more oscillatory wall shear stress (P = .007) than the unruptured one and tended to be more elongated (higher aspect ratio), though this trend achieved only marginal significance (P = .03, 1-sided test). In ipsilateral aneurysms, ruptured aneurysms had larger maximum wall shear (P = .05), more concentrated (P < .001) and oscillatory wall shear stress (P < .001), stronger (P < .001) and more concentrated inflow jets (P < .001), larger maximum velocity (P < .001), and more complex flow patterns (P < .001) compared with unruptured aneurysms. Additionally, ruptured aneurysms were larger (P < .001) and more elongated (P < .001) and had wider necks (P < .001) and lower minimum wall shear stress (P < .001) than unruptured aneurysms. CONCLUSIONS High wall shear stress oscillations and larger aspect ratios are associated with rupture in mirror aneurysms. Adverse flow conditions characterized by high and concentrated inflow jets; high, concentrated, and oscillatory wall shear stress; and strong, complex and unstable flow patterns are associated with rupture in ipsilateral multiple aneurysms. In multiple ipsilateral aneurysms, these unfavorable flow conditions are more likely to develop in larger, more elongated, more wide-necked, and more distal aneurysms.
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Affiliation(s)
- R Doddasomayajula
- From the Bioengineering Department (R.D., B.J.C., F.M., J.R.C.), George Mason University, Fairfax, Virginia
| | - B J Chung
- From the Bioengineering Department (R.D., B.J.C., F.M., J.R.C.), George Mason University, Fairfax, Virginia
| | - F Mut
- From the Bioengineering Department (R.D., B.J.C., F.M., J.R.C.), George Mason University, Fairfax, Virginia
| | - C M Jimenez
- Neurosurgery Department (C.M.J.), University of Antioquia, Medellin, Colombia
| | - F Hamzei-Sichani
- Department of Neurosurgery (F.H.-S.), Mt. Sinai Medical Center, New York, New York
| | - C M Putman
- Interventional Neuroradiology (C.M.P.), Inova Fairfax Hospital, Falls Church, Virginia
| | - J R Cebral
- From the Bioengineering Department (R.D., B.J.C., F.M., J.R.C.), George Mason University, Fairfax, Virginia
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Chung BJ, Doddasomayajula R, Mut F, Detmer F, Pritz MB, Hamzei-Sichani F, Brinjikji W, Kallmes DF, Jimenez CM, Putman CM, Cebral JR. Angioarchitectures and Hemodynamic Characteristics of Posterior Communicating Artery Aneurysms and Their Association with Rupture Status. AJNR Am J Neuroradiol 2017; 38:2111-2118. [PMID: 28860212 DOI: 10.3174/ajnr.a5358] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Accepted: 06/09/2017] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE Intracranial aneurysms originating at the posterior communicating artery are known to have high rupture risk compared with other locations. We tested the hypothesis that different angioarchitectures (ie, branch point configuration) of posterior communicating artery aneurysms are associated with aneurysm hemodynamics, which in turn predisposes aneurysms to rupture. MATERIALS AND METHODS A total of 313 posterior communicating artery aneurysms (145 ruptured, 168 unruptured) were studied with image-based computational fluid dynamics. Aneurysms were classified into different angioarchitecture types depending on the location of the aneurysm with respect to parent artery bifurcation. Hemodynamic characteristics were compared between ruptured and unruptured aneurysms, as well as among aneurysms with different angioarchitectures. RESULTS Angioarchitecture was associated with rupture (P = .003). Ruptured aneurysms had higher, more concentrated, and more oscillatory wall shear stress distributions (maximum wall shear stress, P < .001; shear concentration index, P < .001; mean oscillatory shear index, P < .001), stronger and more concentrated inflow jets (represented as Q, P = .01; inflow concentration index, P < .001), and more complex and unstable flow patterns (vortex core length, P < .001; proper orthogonal decomposition entropy, P < .001) compared with unruptured aneurysms. These adverse conditions were more common in aneurysms with bifurcation-type angioarchitectures compared with those with lateral or sidewall angioarchitectures. Interestingly, ruptured aneurysms also had lower normalized mean wall shear stress (P = .02) and minimum wall shear stress (P = .002) than unruptured aneurysms. CONCLUSIONS High-flow intrasaccular hemodynamic characteristics, commonly found in bifurcation-type angioarchitectures, are associated with the posterior communicating artery aneurysm rupture status. These characteristics include strong and concentrated inflow jets, concentrated regions of elevated wall shear stress, oscillatory wall shear stress, lower normalized wall shear stress, and complex and unstable flow patterns.
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Affiliation(s)
- B J Chung
- From the Bioengineering Department (B.J.C., R.D., F.M., F.D., M.B.P., J.R.C.), George Mason University, Fairfax, Virginia
| | - R Doddasomayajula
- From the Bioengineering Department (B.J.C., R.D., F.M., F.D., M.B.P., J.R.C.), George Mason University, Fairfax, Virginia
| | - F Mut
- From the Bioengineering Department (B.J.C., R.D., F.M., F.D., M.B.P., J.R.C.), George Mason University, Fairfax, Virginia
| | - F Detmer
- From the Bioengineering Department (B.J.C., R.D., F.M., F.D., M.B.P., J.R.C.), George Mason University, Fairfax, Virginia
| | - M B Pritz
- From the Bioengineering Department (B.J.C., R.D., F.M., F.D., M.B.P., J.R.C.), George Mason University, Fairfax, Virginia
| | - F Hamzei-Sichani
- Department of Neurosurgery (F.H.-S.), Mt. Sinai Medical Center, New York, New York
| | - W Brinjikji
- Department of Radiology (W.B., D.F.K.), Mayo Clinic, Rochester, Minnesota
| | - D F Kallmes
- Department of Radiology (W.B., D.F.K.), Mayo Clinic, Rochester, Minnesota
| | - C M Jimenez
- Neurosurgery Department (C.M.J.), University of Antioquia, Medellín, Colombia
| | - C M Putman
- Interventional Neuroradiology Unit (C.M.P.), Inova Fairfax Hospital, Falls Church, Virginia
| | - J R Cebral
- From the Bioengineering Department (B.J.C., R.D., F.M., F.D., M.B.P., J.R.C.), George Mason University, Fairfax, Virginia
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Doddasomayajula R, Chung B, Hamzei-Sichani F, Putman CM, Cebral JR. Differences in Hemodynamics and Rupture Rate of Aneurysms at the Bifurcation of the Basilar and Internal Carotid Arteries. AJNR Am J Neuroradiol 2017; 38:570-576. [PMID: 28209576 DOI: 10.3174/ajnr.a5088] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Accepted: 10/11/2016] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE Cerebral aneurysms in the posterior circulation are known to have a higher rupture risk than those in the anterior circulation. We sought to test the hypothesis that differences in hemodynamics can explain the difference in rupture rates. MATERIALS AND METHODS A total of 117 aneurysms, 63 at the tip of the basilar artery (27 ruptured, 36 unruptured, rupture rate = 43%) and 54 at the bifurcation of the internal carotid artery (11 ruptured, 43 unruptured, rupture rate = 20%) were analyzed with image-based computational fluid dynamics. Several hemodynamic variables were compared among aneurysms at each location and between ruptured and unruptured aneurysms at each location. RESULTS On average, aneurysms at the basilar tip had more concentrated inflow (P < .001), a larger inflow rate (P < .001), a larger maximum oscillatory shear index (P = .003), more complex flows (P = .033), and smaller areas under low wall shear stress (P < .001) than aneurysms at the bifurcation of the internal carotid artery. In general, ruptured aneurysms had larger inflow concentration (P = .02), larger shear concentration (P = .02), more complex flows (P < .001), and smaller minimum wall shear stress (P = .003) than unruptured aneurysms. CONCLUSIONS High flow conditions, characterized by large and concentrated inflow jets, complex and oscillatory flow patterns, and wall shear stress distributions with focalized regions of high shear and large regions of low shear, are associated with aneurysm rupture, especially for basilar tip aneurysms. The higher flow conditions in basilar tip aneurysms could explain their increased rupture risk compared with internal carotid bifurcation aneurysms.
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Affiliation(s)
- R Doddasomayajula
- From the Bioengineering Department (R.D., B.C., J.R.C.), Volgenau School of Engineering, George Mason University, Fairfax, Virginia
| | - B Chung
- From the Bioengineering Department (R.D., B.C., J.R.C.), Volgenau School of Engineering, George Mason University, Fairfax, Virginia
| | - F Hamzei-Sichani
- Department of Neurosurgery (F.H.-S.), Icahn School of Medicine at Mount Sinai, New York, New York
| | - C M Putman
- Interventional Neuroradiology (C.M.P.), Inova Fairfax Hospital, Falls Church, Virginia
| | - J R Cebral
- From the Bioengineering Department (R.D., B.C., J.R.C.), Volgenau School of Engineering, George Mason University, Fairfax, Virginia
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Dare AO, Chaloupka JC, Putman CM, Mayer PL, Schneck MJ, Fayad PB. Vertebrobasilar Dissection in a Duplicated Cervical Vertebral Artery: A Possible Pathoetiologic Association? ACTA ACUST UNITED AC 2016. [DOI: 10.1177/153857449703100113] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
A thirty-eight-year-old man with extensive spontaneous vertebrobasilar dissection in asso ciation with duplication of the ipsilateral proximal vertebral artery is described. He had no relevant medical history. The development of a spontaneous arterial dissection in a duplicated arterial system suggests a pathoetiologic association that may further expand the list of cerebrovascular pathology occurring with fenestration/duplications.
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Affiliation(s)
- Amos O. Dare
- Interventional Neuroradiology Service, Department of Diagnostic Radiology, Yale University School of Medicine
| | - John C. Chaloupka
- Interventional Neuroradiology Service, Department of Diagnostic Radiology, Yale University School of Medicine, Department of Surgery (Neurosurgery), Yale University School of Medicine
| | - Christopher M. Putman
- Interventional Neuroradiology Service, Department of Diagnostic Radiology, Yale University School of Medicine
| | - Peter L. Mayer
- Department of Surgery (Neurosurgery), Yale University School of Medicine
| | - Michael J. Schneck
- Section of Vascular Neurology, Department of Neurology, Yale University School of Medicine, New Haven, Connecticut
| | - Pierre B. Fayad
- Section of Vascular Neurology, Department of Neurology, Yale University School of Medicine, New Haven, Connecticut
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Castro MA, Ahumada Olivares MC, Putman CM, Cebral JR. Unsteady wall shear stress analysis from image-based computational fluid dynamic aneurysm models under Newtonian and Casson rheological models. Med Biol Eng Comput 2014; 52:827-39. [PMID: 25154981 DOI: 10.1007/s11517-014-1189-z] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2014] [Accepted: 08/14/2014] [Indexed: 11/24/2022]
Abstract
The aim of this work was to determine whether or not Newtonian rheology assumption in image-based patient-specific computational fluid dynamics (CFD) cerebrovascular models harboring cerebral aneurysms may affect the hemodynamics characteristics, which have been previously associated with aneurysm progression and rupture. Ten patients with cerebral aneurysms with lobulations were considered. CFD models were reconstructed from 3DRA and 4DCTA images by means of region growing, deformable models, and an advancing front technique. Patient-specific FEM blood flow simulations were performed under Newtonian and Casson rheological models. Wall shear stress (WSS) maps were created and distributions were compared at the end diastole. Regions of lower WSS (lobulation) and higher WSS (neck) were identified. WSS changes in time were analyzed. Maximum, minimum and time-averaged values were calculated and statistically compared. WSS characterization remained unchanged. At high WSS regions, Casson rheology systematically produced higher WSS minimum, maximum and time-averaged values. However, those differences were not statistically significant. At low WSS regions, when averaging over all cases, the Casson model produced higher stresses, although in some cases the Newtonian model did. However, those differences were not significant either. There is no evidence that Newtonian model overestimates WSS. Differences are not statistically significant.
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Affiliation(s)
- Marcelo A Castro
- Grupo de Investigación y Desarrollo en Bioingeniería, Universidad Tecnológica Nacional, Facultad Regional Buenos Aires, CONICET, Medrano 951, CP 1179, Buenos Aires, Argentina,
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Cebral JR, Vazquez M, Sforza DM, Houzeaux G, Tateshima S, Scrivano E, Bleise C, Lylyk P, Putman CM. Analysis of hemodynamics and wall mechanics at sites of cerebral aneurysm rupture. J Neurointerv Surg 2014; 7:530-6. [DOI: 10.1136/neurintsurg-2014-011247] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2014] [Accepted: 04/28/2014] [Indexed: 11/03/2022]
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Sforza DM, Putman CM, Cebral JR. Computational fluid dynamics in brain aneurysms. Int J Numer Method Biomed Eng 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] [What about the content of this article? (0)] [Affiliation(s)] [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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Sforza DM, Putman CM, Tateshima S, Viñuela F, Cebral JR. Effects of perianeurysmal environment during the growth of cerebral aneurysms: a case study. AJNR Am J Neuroradiol 2012; 33:1115-20. [PMID: 22300939 DOI: 10.3174/ajnr.a2908] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE The natural history of cerebral aneurysms is thought to be governed by multifactorial processes involving hemodynamics, biomechanics, mechanobiology, and perianeurysmal environment. The purpose of this study was to highlight the importance of considering the influence of contacts with perianeurysmal environment structures on the hemodynamics and geometric evolution of intracranial aneurysms. MATERIALS AND METHODS A large aneurysm of the basilar artery in contact with bone and observed to grow during a 4-year follow-up period was selected for study. Anatomic models were constructed from longitudinal CTA images acquired at 1-year intervals during the observation period. Computational fluid dynamics simulations were carried out under pulsatile flow conditions to analyze the blood flow pattern and WSS distribution in the aneurysm during its evolution. RESULTS The aneurysm was observed to grow against the bone, resulting in a geometric change of the proximal parent artery, which, in turn, induced substantial changes in the aneurysm hemodynamics. In particular, a region of elevated WSS created by the inflow streams was observed to shift locations around the place where the aneurysm enlarged in contact with the bone as the aneurysm progressed. In addition, a "notch" near the distal end of the aneurysm, away from the bone and subject to relatively high WSS, was observed to grow and, later, completely disappear. CONCLUSIONS Contacts with perianeurysmal structures need to be considered and analyzed to assess whether they could exert a significant influence on the geometric evolution of each individual intracranial aneurysm and its hemodynamics.
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Affiliation(s)
- D M Sforza
- Center for Computational Fluid Dynamics, School of Physics, Astronomy and Computational Sciences, George Mason University, Fairfax, Virginia.
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Raschi M, Mut F, Byrne G, Putman CM, Tateshima S, Viñuela F, Tanoue T, Tanishita K, Cebral JR. CFD and PIV analysis of hemodynamics in a growing intracranial aneurysm. Int J Numer Method Biomed Eng 2012; 28:214-28. [PMID: 22548127 PMCID: PMC3338124 DOI: 10.1002/cnm.1459] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Hemodynamics is thought to be a fundamental factor in the formation, progression, and rupture of cerebral aneurysms. Understanding these mechanisms is important to improve their rupture risk assessment and treatment. In this study, we analyze the blood flow field in a growing cerebral aneurysm using experimental particle image velocimetry (PIV) and computational fluid dynamics (CFD) techniques. Patient-specific models were constructed from longitudinal 3D computed tomography angiography images acquired at 1-y intervals. Physical silicone models were constructed from the computed tomography angiography images using rapid prototyping techniques, and pulsatile flow fields were measured with PIV. Corresponding CFD models were created and run under matching flow conditions. Both flow fields were aligned, interpolated, and compared qualitatively by inspection and quantitatively by defining similarity measures between the PIV and CFD vector fields. Results showed that both flow fields were in good agreement. Specifically, both techniques provided consistent representations of the main intra-aneurysmal flow structures and their change during the geometric evolution of the aneurysm. Despite differences observed mainly in the near wall region, and the inherent limitations of each technique, the information derived is consistent and can be used to study the role of hemodynamics in the natural history of intracranial aneurysms.
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Affiliation(s)
- Marcelo Raschi
- Center for Computational Fluid Dynamics George Mason University Fairfax, VA, USA
| | - Fernando Mut
- Center for Computational Fluid Dynamics George Mason University Fairfax, VA, USA
| | - Greg Byrne
- Center for Computational Fluid Dynamics George Mason University Fairfax, VA, USA
| | | | - Satoshi Tateshima
- Department of Radiological Sciences David Geffen School of Medicine, UCLA Los Angeles, CA, USA
| | - Fernando Viñuela
- Department of Radiological Sciences David Geffen School of Medicine, UCLA Los Angeles, CA, USA
| | - Tetsuya Tanoue
- Department of Systems Design Engineering Keio University, Yokohama, Japan
| | - Kazuo Tanishita
- Department of Systems Design Engineering Keio University, Yokohama, Japan
| | - Juan R. Cebral
- Center for Computational Fluid Dynamics George Mason University Fairfax, VA, USA
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Cebral JR, Mut F, Raschi M, Scrivano E, Ceratto R, Lylyk P, Putman CM. Aneurysm rupture following treatment with flow-diverting stents: computational hemodynamics analysis of treatment. AJNR Am J Neuroradiol 2010; 32:27-33. [PMID: 21071533 DOI: 10.3174/ajnr.a2398] [Citation(s) in RCA: 248] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE Flow-diverting approaches to intracranial aneurysm treatment had many promising early results, but recent apparently successful treatments have been complicated by later aneurysm hemorrhage. We analyzed 7 cases of aneurysms treated with flow diversion to explore the possible rupture mechanisms. MATERIALS AND METHODS CFD analysis of pre- and posttreatment conditions was performed on 3 giant aneurysms that ruptured after treatment and 4 successfully treated aneurysms. Pre- and posttreatment hemodynamics were compared including WSS, relative blood flows, vascular resistances, and pressures, to identify the effects of flow-diverter placements. RESULTS Expected reductions in aneurysm velocity and WSS were obtained, indicating effective flow diversion from the sac into the parent artery, consistent with periprocedural observations. In each case with postaneurysm rupture, the result of flow diversion led to an increase in pressure within the aneurysm. This pressure increase is related to larger effective resistance in the parent artery from placement of the devices and, in 2 cases, the reduction of a preaneurysm stenosis. CONCLUSIONS Flow-diversion devices can cause intra-aneurysmal pressure increases, which can potentially lead to rupture, especially for giant aneurysms. This relates both to changes in the parent artery configuration, such as reduction of a proximal stenosis, and to the flow diversion into higher resistance parent artery pathways combined with cerebral autoregulation, leading to higher pressure gradients. These may be important effects that should be considered when planning interventions. Potentially dangerous cases could be identified with angiography and/or patient-specific CFD models.
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Affiliation(s)
- J R Cebral
- Center for Computational Fluid Dynamics, George Mason University, Fairfax, Virginia 22030, USA.
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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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Oubel E, Cebral JR, De Craene M, Blanc R, Blasco J, Macho J, Putman CM, Frangi AF. Wall motion estimation in intracranial aneurysms. Physiol Meas 2010; 31:1119-35. [DOI: 10.1088/0967-3334/31/9/004] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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Abstract
BACKGROUND AND PURPOSE Intracranial aneurysms with irregular shapes and blebs or secondary outpouchings have been correlated with increased rupture risk. The purpose of this study was to investigate possible associations between the local hemodynamics and the formation of blebs in cerebral aneurysms. MATERIALS AND METHODS Computational models of 20 cerebral aneurysms harboring 30 well-defined blebs were constructed from 3D rotational angiographies. Models representing the aneurysm before bleb formation were constructed by virtually removing the blebs from the anatomic models. Computational fluid dynamics simulations of the aneurysm before and after bleb formation were performed under pulsatile flows. Flow and WSS visualizations were used to analyze the local hemodynamics in the region of the aneurysm that developed the bleb. RESULTS Most blebs (80%) occurred at or adjacent to the aneurysm region with the highest WSS before bleb formation, and near the flow impaction zone. Most blebs (83%) were found in regions of the aneurysm previously subjected to high or moderate WSS and progressed to low WSS states after the blebs were formed. Most blebs (77%) were aligned or adjacent to the inflow jet, whereas 17% were aligned with the outflow jet, and only 6% were not aligned with the flow direction. In addition, 90% of the aneurysms had maximal WSS higher than or similar to the WSS in the parent artery. CONCLUSIONS Blebs form at or adjacent to regions of high WSS and are aligned with major intra-aneurysmal flow structures. Formation of blebs results in a lower WSS state with formation of a counter current vortex. These findings imply that locally elevated WSS could contribute to the focalized wall damage that formed these structures.
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Affiliation(s)
- J R Cebral
- Center for Computational Fluid Dynamics, Department of Computational and Data Sciences, College of Sciences, George Mason University, Fairfax, Virginia 22030, USA.
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16
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Cebral JR, Putman CM, Alley MT, Hope T, Bammer R, Calamante F. Hemodynamics in Normal Cerebral Arteries: Qualitative Comparison of 4D Phase-Contrast Magnetic Resonance and Image-Based Computational Fluid Dynamics. J Eng Math 2009; 64:367-378. [PMID: 19684874 PMCID: PMC2726749 DOI: 10.1007/s10665-009-9266-2] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Detailed knowledge of the hemodynamic conditions in normal cerebral arteries is important for a better understanding of the underlying mechanisms leading to the initiation and progression of cerebrovascular diseases. Information about the baseline values of hemodynamic variables such as wall shear stresses is necessary for comparison to pathological conditions such as in cerebral aneurysms or arterial stenoses. The purpose of this study was to compare the blood flow patterns in cerebral arteries of normal subjects determined by 4D phase-contrast magnetic resonance and image-based computational fluid dynamics techniques in order to assess their consistency and to highlight their differences. The goal was not to validate (or disprove) any of the two methodologies but rather to identify regions where disagreements are to be expected and to provide guidance when interpreting the data produced by each technique.
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Affiliation(s)
- Juan R Cebral
- Center for Computational Fluid Dynamics, George Mason University, Fairfax, Virginia, USA
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Castro MA, Putman CM, Sheridan MJ, Cebral JR. Hemodynamic patterns of anterior communicating artery aneurysms: a possible association with rupture. AJNR Am J Neuroradiol 2009; 30:297-302. [PMID: 19131411 DOI: 10.3174/ajnr.a1323] [Citation(s) in RCA: 134] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE The anterior communicating artery (AcomA) is a predilect location of aneurysms which typically carry higher rupture risks than other locations in the anterior circulation. The purpose of this study was to characterize the different flow types present in AcomA aneurysms and to investigate possible associations with rupture. MATERIALS AND METHODS Patient-specific computational models of 26 AcomA aneurysms were constructed from 3D rotational angiography images. Bilateral images were acquired in 15 patients who had both A1 segments of the anterior cerebral arteries, and models of the whole anterior circulation were created by fusing the reconstructed left and right arterial trees. Computational fluid dynamics simulations were performed under pulsatile flow conditions measured on a healthy subject. Visualizations of flow velocity, instantaneous streamlines, and wall shear stress (WSS) were performed. These were analyzed for flow patterns, size of the impaction zone, and peak WSS and then correlations were made with prior history of rupture. RESULTS Aneurysms with small impaction zones were more likely to have ruptured than those with large impaction zones (83% versus 63%). Maximum intra-aneurysmal WSS (MWSS) for the unruptured aneurysms ranged from 10 to 230 dyne/cm(2) (mean, 114 dyne/cm(2)) compared with ruptured aneurysms, which ranged from 35 to 1500 dyne/cm(2) (mean, 271 dyne/cm(2)). This difference in MWSS was statistically significant at 90% confidence levels (P = .10). CONCLUSIONS Aneurysms with small impaction zones, higher flow rates entering the aneurysm, and elevated MWSS are associated with a clinical history of previous rupture.
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Affiliation(s)
- M A Castro
- Department of Computational and Data Sciences, College of Sciences, George Mason University, Fairfax, Va., USA
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Abstract
The initiation and progression of cerebral aneurysms are degenerative processes of the arterial wall driven by a complex interaction of biological and hemodynamic factors. Endothelial cells on the artery wall respond physiologically to blood-flow patterns. In normal conditions, these responses are associated with nonpathological tissue remodeling and adaptation. The combination of abnormal blood patterns and genetics predisposition could lead to the pathological formation of aneurysms. Here, we review recent progress on the basic mechanisms of aneurysm formation and evolution, with a focus on the role of hemodynamic patterns.
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Affiliation(s)
- Daniel M. Sforza
- Center for Computational Fluid Dynamics, George Mason University, Fairfax, Virginia 22030
| | - Christopher M. Putman
- Interventional Neuroradiology, Inova Fairfax Hospital, Falls Church, Virginia 22042
- Department of Neurosurgery, School of Medicine, George Washington University, Washington, DC 20037
| | - Juan Raul Cebral
- Center for Computational Fluid Dynamics, George Mason University, Fairfax, Virginia 22030
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Abstract
Major neurologic morbidity and mortality with vertebroplasty are rare. We describe a 71-year-old woman who had a stroke approximately 30 minutes after vertebroplasty. Imaging revealed that bone cement had embolized to the left middle cerebral artery. Emergency embolectomy was attempted but was unsuccessful. This report emphasizes the need to be aware that intracranial embolization of polymethylmethacrylate can occur and describes management strategies to consider.
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Affiliation(s)
- F A Marden
- Department of Radiology, Inova Fairfax Hospital, Falls Church, VA, USA.
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Abstract
BACKGROUND AND PURPOSE Hemodynamics is thought to play an important role in the mechanisms of cerebral aneurysm initiation, progression, and rupture. The purpose of this study was to present a hemodynamic study of a cerebral aneurysm immediately before its rupture to assess whether previously identified hemodynamic characteristics would classify this aneurysm in the high-risk category. MATERIALS AND METHODS A patient-specific computational fluid dynamics model was constructed from 3D rotational angiographic images acquired just hours before the aneurysm had ruptured. A pulsatile flow simulation was carried out, and the hemodynamics characterized by the concentration of the inflow jet, the size of the flow impingement region, and the complexity and stability of the flow pattern. RESULTS We found that the aneurysm had a concentrated inflow jet that impacted onto a small region of the dome of the aneurysm and created a complex, unstable flow pattern. CONCLUSIONS This study supports the proposition that hemodynamic characteristics derived from image-based computational models can be used to identify cerebral aneurysms at high risk for rupture.
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Affiliation(s)
- J R Cebral
- Center for Computational Fluid Dynamics, George Mason University, Fairfax, VA 22030, USA.
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Marden FA, Putman CM. Perianeurysm edema with second-generation bioactive coils. ACTA ACUST UNITED AC 2008; 69:627-32; discussion 632. [DOI: 10.1016/j.surneu.2007.01.069] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2006] [Accepted: 01/18/2007] [Indexed: 10/22/2022]
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Abstract
Subject-specific computational and experimental models of hemodynamics in cerebral aneurysms require the specification of physiologic flow conditions. Because patient-specific flow data are not always available, researchers have used 'typical' or population average flow rates and waveforms. However, in order to be able to compare the magnitude of hemodynamic variables between different aneurysms or groups of aneurysms (e.g. ruptured versus unruptured) it is necessary to scale the flow rates to the area of the inflow artery. In this work, a relationship between flow rates and vessel areas is derived from phase-contrast magnetic resonance measurements in the internal carotid arteries and vertebral arteries of normal subjects.
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Affiliation(s)
- J R Cebral
- Center for Computational Fluid Dynamics, George Mason University, Fairfax, VA 22030, USA.
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Marden FA, Putman CM, Grant JM, Greenberg J. Moyamoya disease associated with hemoglobin Fairfax and beta-thalassemia. Pediatr Neurol 2008; 38:130-2. [PMID: 18206795 DOI: 10.1016/j.pediatrneurol.2007.09.011] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/21/2007] [Revised: 04/25/2007] [Accepted: 09/13/2007] [Indexed: 10/22/2022]
Abstract
Moyamoya disease is a rare cerebrovascular condition characterized by steno-occlusive disease of the major intracranial arteries at the base of the brain, and the appearance of innumerable, tiny, arterial collaterals that resemble a "puff of smoke." Although it has been associated with hematologic diseases such as sickle-cell disease, the association with other hemoglobinopathies is less frequently observed. We describe the association of a unique hemoglobinopathy (hemoglobin Fairfax) with beta-thalassemia and moyamoya disease in a 9-year-old girl with a history of stroke. To our knowledge, this is the first report of this unstable hemoglobin with moyamoya disease, and it emphasizes the potential for cerebral infarction due to the severe anemia of hemolytic disease.
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Affiliation(s)
- Franklin A Marden
- Department of Radiology, Inova Fairfax Hospital, Falls Church, Virginia, USA.
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Cebral JR, Pergolizzi RS, Putman CM. Computational fluid dynamics modeling of intracranial aneurysms: qualitative comparison with cerebral angiography. Acad Radiol 2007; 14:804-13. [PMID: 17574131 DOI: 10.1016/j.acra.2007.03.008] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2006] [Revised: 03/08/2007] [Accepted: 03/09/2007] [Indexed: 11/23/2022]
Abstract
RATIONALE AND OBJECTIVE The purpose of this study is to determine whether computational fluid dynamics modeling can correctly predict the location of the major intra-aneurysmal flow structures that can be identified by conventional angiography. MATERIALS AND METHODS Patient-specific models of three cerebral aneurysms were constructed from three-dimensional rotational angiography images and computational fluid dynamic simulations performed. Using these velocity fields, contrast transport was simulated and visualizations constructed to provide a "virtual" angiogram. These models were then compared to images from high frame rate conventional angiography to compare flow structures. RESULTS Computational fluid dynamics simulations showed three distinct flow types ranging from simple to complex. Virtual angiographic images showed good agreement with images from conventional angiography for all three aneurysms with analogous size and orientation of the inflow jet, regions of impaction, and flow type. Large intra-aneurysmal vortices and regions of outflow also corresponded between the images. CONCLUSIONS Patient-specific image-based computational models of cerebral aneurysms can realistically reproduce the major intra-aneurysmal flow structures observed with conventional angiography. The agreement between computational models and angiographic structures is less for slower zones of recirculation later in the cardiac cycle.
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Affiliation(s)
- Juan R Cebral
- School of Computational Sciences, George Mason University, Fairfax, VA 22030, USA
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25
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Cebral JR, Radaelli A, Frangi A, Putman CM. Qualitative comparison of intra-aneurysmal flow structures determined from conventional and virtual angiograms. ACTA ACUST UNITED AC 2007. [DOI: 10.1117/12.709231] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
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Castro MA, Putman CM, Cebral JR. Patient-specific computational fluid dynamics modeling of anterior communicating artery aneurysms: a study of the sensitivity of intra-aneurysmal flow patterns to flow conditions in the carotid arteries. AJNR Am J Neuroradiol 2006; 27:2061-8. [PMID: 17110667 PMCID: PMC7977194] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
BACKGROUND AND PURPOSE The purpose of this study was to investigate the effects of unequal physiologic flow conditions in the internal carotid arteries (ICAs) on the hemodynamics of anterior communicating artery aneurysms. METHODS Patient-specific computational fluid dynamics models of 2 cerebral aneurysms were constructed from bilateral 3D rotational angiograms. The flow dynamics of the aneurysm sac were analyzed under the effect of unequal mean flows, phase shifts, and waveforms between the ICAs. A total of 9 simulations were performed for each patient; cine flow velocity simulations and unsteady wall shear stress (WSS) maps were created for each flow condition. Time-dependent curves of average WSS magnitude over selected regions on the aneurysms were constructed. RESULTS Mean flow unbalances in the feeding vessels tended to shift the regions of elevated WSS towards the dominating inflow jet and to change the magnitude of the WSS peaks. The overall qualitative appearance of the WSS distribution and velocity simulations was not substantially affected. Phase and waveform asymmetry increased the temporal complexity of the hemodynamic patterns and tended to destabilize the flow pattern. CONCLUSIONS Differences in the relative phase and waveform shape in ICAs can significantly affect the complexity and stability of the hemodynamic force distributions. The magnitude of these effects is related to the geometry of the aneurysm and the feeding vessels. Conditions affecting the flow characteristics in the parent arteries of cerebral aneurysms with more than 1 avenue of inflow should be incorporated into flow models.
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Affiliation(s)
- M A Castro
- College of Sciences, Department of Computational and Data Sciences, George Mason University, Fairfax, VA, USA
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Castro MA, Putman CM, Cebral JR. Computational fluid dynamics modeling of intracranial aneurysms: effects of parent artery segmentation on intra-aneurysmal hemodynamics. AJNR Am J Neuroradiol 2006; 27:1703-9. [PMID: 16971618 PMCID: PMC8139802] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
PURPOSE The purpose of this study is to show the influence of the upstream parent artery geometry on intraaneurysmal hemodynamics of cerebral aneurysms. METHODS Patient-specific models of 4 cerebral aneurysms (1 posterior communicating artery [PcomA], 2 middle cerebral artery [MCA], and 1 anterior communicating artery [AcomA]) were constructed from 3D rotational angiography images. Two geometric models were constructed for each aneurysm. One model had the native parent vessel geometry; the second model was truncated approximately 1 cm upstream from the aneurysm, and the parent artery replaced with a straight cylinder. Corresponding finite element grids were generated and computational fluid dynamics simulations were carried out under pulsatile flow conditions. The intra-aneurysmal flow patterns and wall shear stress (WSS) distributions were visualized and compared. RESULTS Models using the truncated parent vessel underestimated the WSS in the aneurysms in all cases and shifted the impaction zone to the neck compared with the native geometry. These effects were more pronounced in the PcomA and AcomA aneurysms where upstream curvature was substantial. The MCA aneurysm with a long M1 segment was the least effected. The more laminar flow pattern within the parent vessel in truncated models resulted in a less complex intra-aneurysmal flow patterns with fewer vortices and less velocity at the dome. CONCLUSIONS Failure to properly model the inflow stream contributed by the upstream parent artery can significantly influence the results of intra-aneurysmal hemodynamic models. The upstream portion of the parent vessel of cerebral aneurysms should be included to accurately represent the intra-aneurysmal hemodynamics.
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Affiliation(s)
- M A Castro
- School of Computational Sciences, George Mason University, Fairfax, VA 22042, USA
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Castro MA, Putman CM, Cebral JR. Patient-specific computational modeling of cerebral aneurysms with multiple avenues of flow from 3D rotational angiography images. Acad Radiol 2006; 13:811-21. [PMID: 16777554 DOI: 10.1016/j.acra.2006.03.011] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2005] [Revised: 03/21/2006] [Accepted: 03/21/2006] [Indexed: 11/22/2022]
Abstract
RATIONALE AND OBJECTIVES Previous studies of aneurysm flow dynamics based on three-dimensional (3D) rotational angiography (RA) images were limited to aneurysms with a single route of blood inflow. However, aneurysms of the circle of Willis frequently involve locations with more than one source of inflow, such as aneurysms of the anterior communicating artery. The highest resolution images of cerebral vessels are from RA images, but this technique is limited to visualizing only one route of inflow at a time, leaving a significant limitation in the application of 3DRA image sets for clinical studies of patient-specific computational fluid dynamics (CFD) simulations. In this report, subject-specific models of cerebral aneurysms with multiple avenues of flow are constructed from RA images by using a novel combination of image co-registration and surface merging techniques. MATERIALS AND METHODS RA images are obtained by means of contrast injection in each vessel that provides inflow to the aneurysm. Anatomic models are constructed independently of each of these vascular trees and fused together into a single model. The model is used to construct a finite element grid for CFD simulations of hemodynamics. RESULTS Three examples of patient-specific models are presented: an anterior communicating artery aneurysm, a basilar tip aneurysm, and a model of an entire circle of Willis with five coincident aneurysms. The method is evaluated with a numeric phantom of an aneurysm in the anterior communicating artery. CONCLUSION These examples show that this new technique can be used to create merged network numeric models for CFD modeling. Furthermore, intra-aneurysmal flow patterns are influenced strongly by merging of the two inflow streams. This effect decreases as distance from the merging streams increases.
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Affiliation(s)
- Marcelo A Castro
- School of Computational Sciences, George Mason University, 4400 University Drive, MSN 4C7, Fairfax, VA 22030, USA
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Biega TJ, Putman CM, Marden FA. Spontaneous Dissection of the Internal Carotid Artery During Magnetic Resonance Imaging. J Comput Assist Tomogr 2006; 30:646-8. [PMID: 16845297 DOI: 10.1097/00004728-200607000-00015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Spontaneous dissection of the internal carotid artery is an increasingly recognized condition that is readily identifiable with magnetic resonance imaging and -angiography. Early recognition of this entity is essential for optimizing medical management and avoiding potential cerebral infarction. We present a case of dissection of the internal carotid artery that occurred during magnetic resonance imaging and describe the immediate imaging characteristics.
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Affiliation(s)
- Timothy J Biega
- Department of Radiology, George Washington University Hospital, Washington, DC 20052, USA
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Ledezma CJ, Hoh BL, Carter BS, Pryor JC, Putman CM, Ogilvy CS. Complications of Cerebral Arteriovenous Malformation Embolization: Multivariate Analysis of Predictive Factors. Neurosurgery 2006; 58:602-11; discussion 602-11. [PMID: 16575323 DOI: 10.1227/01.neu.0000204103.91793.77] [Citation(s) in RCA: 126] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Abstract
OBJECTIVE:
Embolization is an important therapeutic modality in the multidisciplinary management of arteriovenous malformations (AVM); however, prior series have reported a wide variability in overall complication rates caused by embolization (10–50% neurological deficit, 1–4% mortality). In this study, we reviewed our experience with AVM embolization and analyzed factors that might predict complications and clinical outcomes after AVM embolization.
METHODS:
We analyzed our combined neurovascular unit's results with AVM embolization from 1993 to 2004 for the following outcomes measures: 1) clinically significant complications, 2) technical complications without clinical sequelae, 3) discharge Glasgow Outcome Scale score, and 4) death. To determine embolization efficacy, we analyzed perioperative blood transfusion and rate of AVM obliteration. Univariate and multivariate analyses were performed for patient age, sex, history of rupture, history of seizure, associated aneurysms, AVM size, deep venous drainage, eloquent location, Spetzler-Martin grade, number of embolization stages, number of pedicles embolized, and primary treatment modality.
RESULTS:
Over an 11 year period, 295 embolization procedures (761 pedicles embolized) were performed in 168 patients with embolization as the primary treatment modality (n = 16) or as an adjunct to surgery (n = 124) or radiosurgery (n = 28). There were a total of 27 complications in this series, of which 11 were clinically significant (6.5% of patients, 3.7% per procedure), and 16 were technical complications (9.5% of patients, 5.4% per procedure). Excellent or good outcomes (Glasgow Outcome Scale ≥ 4) were observed in 152 (90.5%) patients. Unfavorable outcomes (Glasgow Outcome Scale 1–3) as a direct result of embolization were both 3.0% at discharge and at follow-up, with a 1.2% embolization-related mortality. In the 124 surgical patients, 96.8% had complete AVM obliteration after initial resection, and 31% received perioperative transfusion (mean 1.4 units packed red blood cells per surgical patient). Predictors of unfavorable outcome caused by embolization by univariate analysis were deep venous drainage (P < 0.05), Spetzler-Martin Grade III to V (P < 0.05), and periprocedural hemorrhage (P < 0.0001) and by multivariate analysis were Spetzler-Martin III to V (odds ratio 10.6, P = 0.03) and periprocedural hemorrhage (odds ratio 17, P = 0.004).
CONCLUSION:
In a single-center, retrospective, nonrandomized study, 90.5% of patients had excellent or good outcomes after AVM embolization, with a complication rate lower than previously reported. Spetzler-Martin grade III to V and periprocedural hemorrhage were the most important predictive factors in determining outcome after embolization.
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Affiliation(s)
- Carlos J Ledezma
- Department of Neurological Surgery, Keck School of Medicine, University of Southern California, Los Angeles, California, USA
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Cebral JR, Castro MA, Burgess JE, Pergolizzi RS, Sheridan MJ, Putman CM. Characterization of cerebral aneurysms for assessing risk of rupture by using patient-specific computational hemodynamics models. AJNR Am J Neuroradiol 2005; 26:2550-9. [PMID: 16286400 PMCID: PMC7976176] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
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 pilot clinical study of the association between intra-aneurysmal hemodynamic characteristics from computational fluid dynamic models and the rupture of cerebral aneurysms. METHODS A total of 62 patient-specific models of cerebral aneurysms were constructed from 3D angiography images. Computational fluid dynamics simulations were performed under pulsatile flow conditions measured on a normal subject. The aneurysms were classified into different categories, depending on the complexity and stability of the flow pattern, the location and size of the flow impingement region, and the size of the inflow jet. The 62 models consisted of 25 ruptured and 34 unruptured aneurysms and 3 cases with unknown histories of hemorrhage. The hemodynamic features were analyzed for associations with history of rupture. RESULTS A large variety of flow patterns was observed: 72% of ruptured aneurysms had complex or unstable flow patterns, 80% had small impingement regions, and 76% had small jet sizes. By contrast, unruptured aneurysms accounted for 73%, 82%, and 75% of aneurysms with simple stable flow patterns, large impingement regions, and large jet sizes, respectively. Aneurysms with small impingement sizes were 6.3 times more likely to have experienced rupture than those with large impingement sizes (P = .01). CONCLUSIONS Image-based patient-specific numeric models can be constructed in an efficient manner that allows clinical studies of intra-aneurysmal hemodynamics. A simple flow characterization system was proposed, and interesting trends in the association between hemodynamic features and aneurysmal rupture were found. Simple stable patterns, large impingement regions, and jet sizes were more commonly seen with unruptured aneurysms. By contrast, ruptured aneurysms were more likely to have disturbed flow patterns, small impingement regions, and narrow jets.
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Affiliation(s)
- Juan R Cebral
- Department of Radiology, Inova Fairfax Hospital, Falls Church, VA 22042, USA
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Cebral JR, Castro MA, Appanaboyina S, Putman CM, Millan D, Frangi AF. Efficient pipeline for image-based patient-specific analysis of cerebral aneurysm hemodynamics: technique and sensitivity. IEEE Trans Med Imaging 2005; 24:457-67. [PMID: 15822804 DOI: 10.1109/tmi.2005.844159] [Citation(s) in RCA: 331] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Hemodynamic factors are thought to be implicated in the progression and rupture of intracranial aneurysms. Current efforts aim to study the possible associations of hemodynamic characteristics such as complexity and stability of intra-aneurysmal flow patterns, size and location of the region of flow impingement with the clinical history of aneurysmal rupture. However, there are no reliable methods for measuring blood flow patterns in vivo. In this paper, an efficient methodology for patient-specific modeling and characterization of the hemodynamics in cerebral aneurysms from medical images is described. A sensitivity analysis of the hemodynamic characteristics with respect to variations of several variables over the expected physiologic range of conditions is also presented. This sensitivity analysis shows that although changes in the velocity fields can be observed, the characterization of the intra-aneurysmal flow patterns is not altered when the mean input flow, the flow division, the viscosity model, or mesh resolution are changed. It was also found that the variable that has the greater impact on the computed flow fields is the geometry of the vascular structures. We conclude that with the proposed modeling pipeline clinical studies involving large numbers cerebral aneurysms are feasible.
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Affiliation(s)
- Juan R Cebral
- School of Computational Sciences, George Mason University, 4400 University Drive, MSN 4C7, Fairfax, VA 22030, USA.
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de Crespigny AJ, D'Arceuil HE, Maynard KI, He J, McAuliffe D, Norbash A, Sehgal PK, Hamberg L, Hunter G, Budzik RF, Putman CM, Gonzalez RG. Acute studies of a new primate model of reversible middle cerebral artery occlusion. J Stroke Cerebrovasc Dis 2005; 14:80-7. [PMID: 17904005 DOI: 10.1016/j.jstrokecerebrovasdis.2004.12.005] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2004] [Accepted: 12/06/2004] [Indexed: 11/29/2022] Open
Abstract
The recent failure of many clinical trials of neuroprotective compounds may be due in part to poor animal models of human stroke. We have developed an endovascular stroke model in nonhuman primates that is compatible with serial magnetic resonance imaging (MRI) monitoring. Using cynomologous macaques (n = 4), a microcatheter was navigated transarterially (under fluoroscopic guidance) from the femoral artery to the middle cerebral artery (MCA). The microcatheter was wedged in a branch of the MCA for 3 hours to cause focal cerebral ischemia, as verified angiographically. During occlusion and/or reperfusion, animals were scanned with MRI, and imaging findings were compared with the stained brain sections. All animals demonstrated small stroke lesions in the expected vascular territory, as seen on diffusion-weighted MRI and confirmed by postmortem examination. Reperfusion after 3 hours was confirmed angiographically (n = 2) and also by MRI (n = 4). The mean initial lesion volume, measured on the postreperfusion MRI scans, was 2.3 +/- 1.3 mL (n = 4). There was good agreement between anatomic location of the lesion on MRI and postmortem histological staining (n = 3). A "minimally invasive" primate model of focal cerebral ischemia was developed that is ideally suited to MRI studies of both acute and chronic stroke. By using serial MRI scans to measure changes in lesion size over time, we will be able to control for variability in lesion size/location. This model should prove useful as a test bed for new stroke therapies, in which noninvasive imaging findings are readily comparable to human stroke.
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Affiliation(s)
- Alex J de Crespigny
- Neuroradiology Section, Department of Radiology, Massachusetts General Hospital, Boston, MA, USA
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Rabinov JD, Hellinger FR, Morris PP, Ogilvy CS, Putman CM. Endovascular management of vertebrobasilar dissecting aneurysms. AJNR Am J Neuroradiol 2003. [PMID: 12917140 DOI: 10.1016/s1076-6332(03)00018-7d] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
BACKGROUND AND PURPOSE Several approaches to the treatment of dissecting aneurysms of the vertebrobasilar system have been used. We evaluated our endovascular experience, which includes trapping and proximal occlusion. METHODS Thirty-five patients with intradural vertebrobasilar dissecting aneurysms presented to our institution between 1992 and 2002. Twenty-six were treated by endovascular means and two with surgery. In the endovascular group, 14 were in a supra-posterior inferior cerebellar artery (PICA) location, and three of these extended to the vertebrobasilar junction on the initial angiogram. Ten were located in an infra-PICA location, or no antegrade flow was seen in the PICA or anterior spinal artery. Two were located at the PICA with antegrade flow preserved in the branch. Twelve lesions were treated with trapping; another 14 were initially treated with proximal occlusion techniques, two of which eventually required trapping procedures. Follow-up images were obtained within 1 year of initial treatment in 24 patients. Mean follow-up for these patients was 3.5 years. RESULTS Initial treatments were technically successful and without complication in all 26 patients. Follow-up examinations showed complete cure in 19 of 24 patients. One patient died of global ischemia after presenting as Hunt and Hess grade 5 with subarachanoid hemorrhage. Two recurrent hemorrhages occurred in patients in the proximal occlusion group; one died, and the other underwent a trapping procedure. One patient developed contralateral vertebral dissection 24 hours after occlusion of a dissecting aneurysm of the dominant vertebral artery and died of a brain stem infarct. Another died of probable vasospasm, and the last died of an unknown cause 1 month after treatment. Two patients had recanalization despite an initial trapping procedure, both underwent further treatment. Mortality rate was 20% in the treated group (including the two patients treated surgically), with four of five deaths occurring during the initial hospital course. Mortality rate was 50% in the six patients in the untreated group who were available for follow-up. CONCLUSION Dissecting aneurysms of the vertebrobasilar system remain high-risk lesions because of their natural history. They can be managed by endovascular methods according to aneurysm location, configuration, collateral circulation, and time of presentation. Trapping results in better prevention of rehemorrhage. Proximal occlusion can achieve occlusion without manipulation of the affected segment when more direct endovascular occlusion or stent placement cannot be performed.
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Affiliation(s)
- James D Rabinov
- Department of Interventional Neuroradiology, Massachusetts General Hospital, Boston, MA 02114, USA
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Rabinov JD, Hellinger FR, Morris PP, Ogilvy CS, Putman CM. Endovascular management of vertebrobasilar dissecting aneurysms. AJNR Am J Neuroradiol 2003; 24:1421-8. [PMID: 12917140 PMCID: PMC7973671] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/04/2023]
Abstract
BACKGROUND AND PURPOSE Several approaches to the treatment of dissecting aneurysms of the vertebrobasilar system have been used. We evaluated our endovascular experience, which includes trapping and proximal occlusion. METHODS Thirty-five patients with intradural vertebrobasilar dissecting aneurysms presented to our institution between 1992 and 2002. Twenty-six were treated by endovascular means and two with surgery. In the endovascular group, 14 were in a supra-posterior inferior cerebellar artery (PICA) location, and three of these extended to the vertebrobasilar junction on the initial angiogram. Ten were located in an infra-PICA location, or no antegrade flow was seen in the PICA or anterior spinal artery. Two were located at the PICA with antegrade flow preserved in the branch. Twelve lesions were treated with trapping; another 14 were initially treated with proximal occlusion techniques, two of which eventually required trapping procedures. Follow-up images were obtained within 1 year of initial treatment in 24 patients. Mean follow-up for these patients was 3.5 years. RESULTS Initial treatments were technically successful and without complication in all 26 patients. Follow-up examinations showed complete cure in 19 of 24 patients. One patient died of global ischemia after presenting as Hunt and Hess grade 5 with subarachanoid hemorrhage. Two recurrent hemorrhages occurred in patients in the proximal occlusion group; one died, and the other underwent a trapping procedure. One patient developed contralateral vertebral dissection 24 hours after occlusion of a dissecting aneurysm of the dominant vertebral artery and died of a brain stem infarct. Another died of probable vasospasm, and the last died of an unknown cause 1 month after treatment. Two patients had recanalization despite an initial trapping procedure, both underwent further treatment. Mortality rate was 20% in the treated group (including the two patients treated surgically), with four of five deaths occurring during the initial hospital course. Mortality rate was 50% in the six patients in the untreated group who were available for follow-up. CONCLUSION Dissecting aneurysms of the vertebrobasilar system remain high-risk lesions because of their natural history. They can be managed by endovascular methods according to aneurysm location, configuration, collateral circulation, and time of presentation. Trapping results in better prevention of rehemorrhage. Proximal occlusion can achieve occlusion without manipulation of the affected segment when more direct endovascular occlusion or stent placement cannot be performed.
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Affiliation(s)
- James D Rabinov
- Department of Interventional Neuroradiology, Massachusetts General Hospital, Boston, MA 02114, USA
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Hoh BL, Carter BS, Putman CM, Ogilvy CS. Important factors for a combined neurovascular team to consider in selecting a treatment modality for patients with previously clipped residual and recurrent intracranial aneurysms. Neurosurgery 2003; 52:732-8; discussion 738-9. [PMID: 12657168 DOI: 10.1227/01.neu.0000053209.61909.f2] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2002] [Accepted: 12/04/2002] [Indexed: 11/19/2022] Open
Abstract
OBJECTIVE Intracranial residual and recurrent aneurysms can occur after surgical clipping, with risks of growth and rupture. In the past, surgical reoperation, which can be associated with higher risk than the initial operation, was the only available treatment. A combined neurovascular team that uses both surgical and endovascular therapies could maximize efficacy and outcomes while minimizing risks in these difficult cases. The indications for which surgical or endovascular treatment should be used to treat patients with residual or recurrent aneurysms, however, have not been elucidated well. We have reviewed the 10-year experience of our combined neurovascular team to determine in a retrospective manner which factors were important to treatment modality selection for patients with these residual and recurrent lesions. METHODS From 1991 to 2001, the combined neurovascular unit at the Massachusetts General Hospital treated 25 residual and recurrent previously clipped aneurysms (15 had been clipped at other centers). Only patients in whom a clip had been placed were included in the study; patients who did not have a clip placed or whose aneurysms were wrapped or coated were excluded. The radiographic studies and clinical data were reviewed retrospectively to determine the efficacy, outcomes, and factors important to the selection of treatment strategy in these patients. RESULTS The patients' clinical presentations were radiographic follow-up, 17 patients; rehemorrhage, 3; mass effect, 3; and thromboembolism, 2. The mean aneurysm recurrence or residual size was 11 mm (range, 4-26 mm). The mean interval until representation was 6.6 years (range, 1 wk-25 yr). Treatment consisted of: coiling, 11 patients; reclipping, 8; proximal parent vessel balloon occlusion, 2; extracranial-intracranial bypass with coil occlusion of aneurysm and parent vessel, 2; extracranial-intracranial bypass with clip trapping, 1; and extracranial-intracranial bypass with proximal clip occlusion of parent vessel, 1. The mean radiographic follow-up period was 11 months. Complete angiographic occlusion was found in 19 aneurysms (76%), at least 90% occlusion was found in 4 aneurysms (16%), intentional partial coil obliteration was found in 1 fusiform lesion (4%), and intentional retrograde flow was found in 1 fusiform lesion (4%). Clinical outcomes were excellent or good in 19 patients (76%). Twenty-one patients (84%) were neurologically the same after retreatment (13 remained neurologically intact, and 8 had preexisting neurological deficits that did not change). Three patients (12%) had new neurological deficits after retreatment, and one patient (4%) died. There were four complications of retreatment (16%), one of which was a fatal hemorrhage in a patient 1 month after intentional partial coil obliteration of a fusiform vertebrobasilar junction aneurysm. Factors important to the selection of treatment modality were recurrence or residual location (all posterior circulation lesions were treated endovascularly), lesion size (lesions larger than 10 mm were treated endovascularly or with the use of combined techniques), and aneurysm morphology (fusiform and wide-necked lesions were treated endovascularly or with the use of combined techniques). CONCLUSION The proper selection of surgical or endovascular treatment for residual and recurrent previously clipped aneurysms can achieve excellent radiographic efficacy with low mortality. Factors important to the selection of treatment by this combined neurovascular team were posterior circulation location, aneurysm size larger than 10 mm, and fusiform morphology, which were treated endovascularly or with the use of combined techniques because of the higher surgical risk associated with these factors. For aneurysms with lower surgical risk, such as some anterior circulation aneurysms and aneurysms smaller than 10 mm, we prefer to perform a reoperation because of superior radiographic cure without compromising the outcome.
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Affiliation(s)
- Brian L Hoh
- Neurosurgical and Endovascular Neurosurgery Services, Massachusetts General Hospital, Harvard Medical School, Boston 02114, USA
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Ogilvy CS, Hoh BL, Singer RJ, Putman CM. Clinical and radiographic outcome in the management of posterior circulation aneurysms by use of direct surgical or endovascular techniques. Neurosurgery 2002; 51:14-21; discussion 21-2. [PMID: 12182412 DOI: 10.1097/00006123-200207000-00003] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
OBJECTIVE Posterior circulation aneurysms can be difficult lesions to treat surgically, and they have potential for high morbidity and mortality, particularly in elderly patients or those in poor neurological condition. In an effort to improve outcomes, our combined neurosurgical and neuroendovascular unit has used both surgical clipping and endovascular coiling techniques to treat posterior circulation aneurysms. Patients considered at high risk for surgery were managed with endovascular treatment. METHODS From 1990 to 1998, 197 posterior circulation aneurysms in 189 patients were treated in our combined neurovascular unit. Of these aneurysms, 128 were ruptured, 63 were unruptured, and 6 had a distant history of rupture in patients who came to our center for delayed or repeat treatment. A total of 132 aneurysms were treated with surgical clipping (85 ruptured, 46 unruptured, and 1 with distant history of rupture) and 65 aneurysms were treated with endovascular coiling (43 ruptured, 17 unruptured, and 5 with distant history of rupture). Dissecting aneurysms of the vertebral or posteroinferior cerebellar arteries or aneurysms treated with proximal (Hunterian) occlusion were excluded from this analysis. Surgical risk was assessed using a previously described system (Massachusetts General Hospital [MGH] grade), which incorporates age, Hunt and Hess grade, size of lesion, and Fisher grade. RESULTS Overall clinical outcomes at 1 year of follow-up were 77.2% excellent or good, 10.2% fair, 4.1% poor, and 8.6% dead. Surgical treatment resulted in 95.6% complete aneurysm occlusion and 4.4% with residual aneurysm after surgical treatment, whereas endovascular treatment resulted in 32.3% complete occlusion, 26.2% with residual aneurysm, and 41.5% with partial occlusion. In most cases, however, treatment with Guglielmi detachable coils (Boston Scientific/Target, Fremont, CA) was performed for palliation rather than complete radiographic occlusion. Outcome was closely associated with MGH grade with either treatment modality. Excellent/good outcomes were achieved in 96, 92.3, 82.9, 46.2, and 0% of surgically treated patients with MGH Grades of 0, 1, 2, 3, and 4, respectively. In comparison, excellent/good outcomes were achieved in 100, 84.2, 61.9, 0, and 50% of endovascularly treated patients with MGH Grades of 0, 1, 2, 3, and 4, respectively. CONCLUSION A combined surgical and endovascular approach to posterior circulation aneurysms can achieve good outcomes in high-risk surgical patients treated by use of coiling techniques.
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Affiliation(s)
- Christopher S Ogilvy
- Department of Neurosurgery, Massachusetts General Hospital, Harvard Medical School, Boston 02114, USA.
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Hamberg LM, Hunter GJ, Maynard KI, Owen C, Morris PP, Putman CM, Ogilvy C, González RG. Functional CT perfusion imaging in predicting the extent of cerebral infarction from a 3-hour middle cerebral arterial occlusion in a primate stroke model. AJNR Am J Neuroradiol 2002; 23:1013-21. [PMID: 12063235 PMCID: PMC7976909] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/25/2023]
Abstract
BACKGROUND AND PURPOSE Our purpose was to determine whether cerebral perfusion functional CT (fCT), performed after endovascular middle cerebral artery (MCA) occlusion, can be used to predict final cerebral infarction extent in a primate model. METHODS fCT with bolus tracking was performed before and 30 and 150 minutes after 3-hour digital subtraction angiography (DSA)-guided endovascular MCA occlusion in five baboons. Parametric cerebral blood flow (CBF), cerebral blood volume (CBV) and mean transit time (MTT) maps were constructed by voxel-by-voxel gamma variate fitting and used to determine lesion sizes. Animals were sacrificed 48 hours after the occlusion, and ex vivo MR imaging was performed. Lesion sizes on fCT and MR images were compared. RESULTS Hypoperfusion was clearly identified on all images obtained after MCA occlusion. Thirty and 150 minutes after occlusion onset, respectively, mean lesion sizes were 737 mm(2) +/- 33 and 737 mm(2) +/- 44 for CBF, 722 mm(2) +/- 32 and 730 mm(2) +/- 43 for CBV, and 819 mm(2) +/- 14 and 847 mm(2) +/- 11 for MTT. Mean outcome infarct size on MR images was 733 mm(2) +/- 30. Measurements based on CBV and CBF (R(2) = 0.97 and 0.96, P <.001), but not MTT (R(2) = 0.40, P >.5), were highly correlated with final lesion size. CONCLUSION An endovascular approach to MCA occlusion provides a minimally invasive, reproducible animal model for controlled studies of cerebral ischemia and infarction. Derived cerebral perfusion maps closely predict the 48-hour infarct size after 3-hour MCA occlusion.
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Affiliation(s)
- Leena M Hamberg
- MGH Perfusion and Physiology Analysis Laboratory, Department of Neuroradiology, the Massachusetts General Hospital and Harvard Medical School, Boston 02114, USA
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Ogilvy CS, Lagares A, Putman CM. Posterior Fossa Decompression and Clot Evacuation for Fourth Ventricle Hemorrhage after Aneurysmal Rupture: Case Report. Neurosurgery 2002. [DOI: 10.1227/00006123-200205000-00050] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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Abstract
OBJECT Although the pathophysiology of spinal dural arteriovenous fistulas (AVFs) has recently been elucidated, the optimal treatment strategy for these lesions has yet to be defined. Current management techniques include endovascular embolization or microsurgical obliteration. METHODS The authors reviewed the records and angiograms of all patients with spinal dural AVFs treated at Massachusetts General Hospital over a 6-year period (1992-1998). During this period, it was intended initially to treat all patients with embolization and to reserve surgery for those in whom endovascular treatment failed or in cases in which pretreatment evaluation suggested that endovascular therapy would be ineffective or unsafe. A total of 26 patients with spinal dural AVFs were treated: there were 22 men and 4 women with a mean age of 65 years (range 39-79 years). Lesions were located in the following areas: five in foramen magnum/cervical, 13 in thoracic, five in lumbar, and three in sacral. Twenty-three (88%) of 26 patients underwent embolization and three (12%) of 23 patients underwent surgery as the primary mode of treatment. Of the 23 patients in whom embolization was performed or attempted, nine (39%) ultimately required surgery. All patients were stabilized or improved following definitive treatment, as assessed by the Aminoff-Logue scores. There was one death secondary to a myocardial infarction. CONCLUSIONS These data demonstrate that endovascular therapy can be successful as an initial treatment for the majority of patients; however, there is a 39% failure rate, which is not observed following surgical therapy. Once a definitive therapy has been achieved using either technique virtually all patients are either stabilized or improved.
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Affiliation(s)
- Emad N Eskandar
- Neurosurgical Service, Massachusetts General Hospital, Boston, Massachusetts 02114, USA
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Eskandar EN, Borges LF, Budzik RF, Putman CM, Ogilvy CS. Spinal dural arteriovenous fistulas: experience with endovascular and surgical therapy. J Neurosurg Spine 2002. [DOI: 10.3171/spi.2002.96.2.0162] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Object. Although the pathophysiology of spinal dural arteriovenous fistulas (AVFs) has recently been elucidated, the optimal treatment strategy for these lesions has yet to be defined. Current management techniques include endovascular embolization or microsurgical obliteration.
Methods. The authors reviewed the records and angiograms of all patients with spinal dural AVFs treated at Massachusetts General Hospital over a 6-year period (1992–1998). During this period, it was intended initially to treat all patients with embolization and to reserve surgery for those in whom endovascular treatment failed or in cases in which pretreatment evaluation suggested that endovascular therapy would be ineffective or unsafe.
A total of 26 patients with spinal dural AVFs were treated: there were 22 men and 4 women with a mean age of 65 years (range 39–79 years). Lesions were located in the following areas: five in foramen magnum/cervical, 13 in thoracic, five in lumbar, and three in sacral. Twenty-three (88%) of 26 patients underwent embolization and three (12%) of 23 patients underwent surgery as the primary mode of treatment. Of the 23 patients in whom embolization was performed or attempted, nine (39%) ultimately required surgery. All patients were stabilized or improved following definitive treatment, as assessed by the Aminoff—Logue scores. There was one death secondary to a myocardial infarction.
Conclusions. These data demonstrate that endovascular therapy can be successful as an initial treatment for the majority of patients; however, there is a 39% failure rate, which is not observed following surgical therapy. Once a definitive therapy has been achieved using either technique virtually all patients are either stabilized or improved.
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Hoh BL, Putman CM, Budzik RF, Ogilvy CS. Surgical and endovascular flow disconnection of intracranial pial single-channel arteriovenous fistulae. Neurosurgery 2001; 49:1351-63; discussion 1363-4. [PMID: 11846934 DOI: 10.1097/00006123-200112000-00011] [Citation(s) in RCA: 103] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2001] [Accepted: 06/28/2001] [Indexed: 11/26/2022] Open
Abstract
INTRODUCTION Intracranial pial single-channel arteriovenous (AV) fistulae are rare vascular lesions of the brain. They differ from AV malformations in that they lack a true "nidus" and are composed of one or more direct arterial connections to a single venous channel. They often are associated with a venous varix because of their high-flow nature. The pathological aspects of pial AV fistulae arise from their high-flow dynamics; therefore, we think that disconnection of the AV shunt is enough to obliterate the lesion, and that lesion resection is unnecessary. Flow disconnection can be accomplished via surgical or endovascular means. Certain lesions have angiogeometric configurations, however, that are unfavorable for endovascular treatment. We reviewed the experience in our combined neurosurgical and neuroendovascular unit in the treatment of patients with pial single-channel AV fistulae. METHODS From 1991 to 1999, the combined neurovascular unit at the Massachusetts General Hospital treated nine consecutive patients with nontraumatic intracranial pial single-channel AV fistulae. Carotid-cavernous fistulae and vein of Galen malformations were excluded from this analysis. The combined neurovascular team planned the treatment strategy for each patient on the basis of the anatomic location and the angiogeometry of each lesion. We retrospectively reviewed the medical records, office charts, operative reports, endovascular reports, and x-rays for each patient. Radiographic outcome was assessed by use of posttreatment angiography. Clinical outcome was assessed by an independent nurse practitioner. RESULTS A treatment strategy of flow disconnection was used in all nine patients and was accomplished surgically in six patients, endovascularly in two patients, and by combined techniques in one patient. All nine lesions were completely obliterated as demonstrated radiographically, including obliteration of the venous varices associated with three of the lesions. With a mean long-term clinical follow-up of 3.2 years (range, 0.3-8.4 yr), four patients were neurologically excellent with no deficits, two patients had pretreatment neurological deficits that did not worsen after treatment, one patient had transient dysphonia and dysphagia postoperatively that resolved, one patient had mild weakness after treatment, and one patient had moderate homonymous hemianopia after treatment. CONCLUSION Single-channel pial AV fistulae can be treated by a strategy of flow disconnection. Resection of the lesion is not necessary. Flow disconnection can be accomplished either surgically or endovascularly; however, certain angiogeometric configurations are more favorable for surgical treatment. An experienced combined neurosurgical and neuroendovascular team can carefully determine the most appropriate treatment modality on the basis of patient-specific and angiospecific factors.
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Affiliation(s)
- B L Hoh
- Neurosurgical Service, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts 02114, USA
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Hoh BL, Putman CM, Ogilvy CS. 812 Surgical and Endovascular Treatment of Complex Cervical and Petrous Carotid Lesions. Neurosurgery 2001. [DOI: 10.1227/00006123-200108000-00176] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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Hoh BL, Putman CM, Budzik RF, Carter BS, Ogilvy CS. Combined surgical and endovascular techniques of flow alteration to treat fusiform and complex wide-necked intracranial aneurysms that are unsuitable for clipping or coil embolization. J Neurosurg 2001; 95:24-35. [PMID: 11453395 DOI: 10.3171/jns.2001.95.1.0024] [Citation(s) in RCA: 103] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
OBJECT Certain intracranial aneurysms, because of their fusiform or complex wide-necked structure, giant size, or involvement with critical perforating or branch vessels. are unamenable to direct surgical clipping or endovascular coil treatment. Management of such lesions requires alternative or novel treatment strategies. Proximal and distal occlusion (trapping) is the most effective strategy. In lesions that cannot be trapped, alteration in blood flow to the "inflow zone," the site most vulnerable to aneurysm growth and rupture, is used. METHODS From 1991 to 1999 the combined neurosurgical-neuroendovascular team at the Massachusetts General Hospital (MGH) managed 48 intracranial aneurysms that could not be clipped or occluded. Intracavernous internal carotid artery aneurysms were excluded from this analysis. By applying a previously described aneurysm rupture risk classification system (MGH Grades 0-5) based on the age of the patient, aneurysm size, Hunt and Hess grade, Fisher grade, and whether the aneurysm was a giant lesion located in the posterior circulation, the authors found that a significant number of patients were at moderate risk (MGH Grade 2; 31.3% of patients) and at high risk (MGH Grades 3 or 4; 22.9%) for treatment-related morbidity. The lesions were treated using a variety of strategies--surgical, endovascular, or a combination of modalities. Aneurysms that could not be trapped or occluded were treated using a paradigm of flow alteration, with flow redirected from either native collateral networks or from a surgically performed vascular bypass. Overall clinical outcomes were determined using the Glasgow Outcome Scale (GOS). A GOS score of 5 or 4 was achieved in 77.1%, a GOS score of 3 or 2 in 8.3%, and death (GOS 1) occurred in 14.6% of the patients. Procedure-related complications occurred in 27.1% of cases; the major morbidity rate was 6.3% and the mortality rate was 10.4%. Three patients experienced aneurysmal hemorrhage posttreatment; in two patients this event proved to be fatal. Aneurysms with MGH Grades 0, 1, 2, 3, and 4 were associated with favorable outcomes (GOS scores of 5 or 4) in 100%, 92.8%, 71.4%, 50%, and 0% of instances, respectively. CONCLUSIONS Despite a high incidence of transient complications, intracranial aneurysms that cannot be clipped or occluded require alternative surgical and endovascular treatment strategies. In those aneurysms that cannot safely be trapped or occluded, one approach is the treatment strategy of flow alteration.
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Affiliation(s)
- B L Hoh
- Neurosurgical Service, Massachusetts General Hospital, Harvard Medical School, Boston 02114, USA
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Lev MH, Farkas J, Rodriguez VR, Schwamm LH, Hunter GJ, Putman CM, Rordorf GA, Buonanno FS, Budzik R, Koroshetz WJ, Gonzalez RG. CT angiography in the rapid triage of patients with hyperacute stroke to intraarterial thrombolysis: accuracy in the detection of large vessel thrombus. J Comput Assist Tomogr 2001; 25:520-8. [PMID: 11473180 DOI: 10.1097/00004728-200107000-00003] [Citation(s) in RCA: 185] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
PURPOSE The purpose of this work was to evaluate the accuracy of CT angiography (CTA) for the detection of large vessel intracranial thrombus in clinically suspected hyperacute (<6 h) stroke patients. METHOD Forty-four consecutive intraarterial thrombolysis candidates underwent noncontrast CT followed immediately by CTA. Axial source and two-dimensional collapsed maximum intensity projection reformatted CTA images were rated for the presence or absence of large vessel occlusion. Five hundred seventy-two circle-of-Willis vessels were reviewed; arteriographic correlation was available for 224 of these. RESULTS Sensitivity and specificity for the detection of large vessel occlusion were 98.4 and 98.1%; accuracy, calculated using receiver operating characteristic analysis, was 99%. Mean time for acquisition, reconstruction, and analysis of CTA images was approximately 15 min. CONCLUSION CTA is highly accurate for the detection and exclusion of large vessel intracranial occlusion and may therefore be valuable in the rapid triage of hyperacute stroke patients to intraarterial thrombolytic treatment.
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Affiliation(s)
- M H Lev
- Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114-9657, USA.
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Lagares A, Putman CM, Ogilvy CS. Posterior fossa decompression and clot evacuation for fourth ventricle hemorrhage after aneurysmal rupture: case report. Neurosurgery 2001; 49:208-11. [PMID: 11440445 DOI: 10.1097/00006123-200107000-00033] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
OBJECTIVE AND IMPORTANCE Massive intraventricular hemorrhage due to aneurysmal rupture is associated with a dismal prognosis. An intraventricular clot causing fourth ventricle dilation can cause compression to the brainstem similar to other posterior fossa masses such as cerebellar hemorrhage or infarction. The presence of fourth ventricle dilation carries a very high risk of death within 48 hours. Neither ventricular drainage nor fibrinolytic infusion has been successful in eliminating clots of the fourth ventricle. Posterior fossa decompression and direct evacuation of the clot could have good results in relieving brainstem compression caused by the clot. CLINICAL PRESENTATION A 45-year-old woman was admitted to our intensive care unit after experiencing an aneurysmal subarachnoid hemorrhage. The neurological examination at admission revealed that she was in Grade V according to the World Federation of Neurological Surgeons grading system, but brainstem reflexes were present. Computed tomographic scanning revealed a massive intraventricular hemorrhage, with fourth ventricle dilation caused by an intraventricular clot. Bilateral external ventricular drains were placed to relieve elevated intracranial pressure. Cerebral angiography revealed a 1-cm basilar tip aneurysm, which was embolized with Guglielmi detachable coils (Boston Scientific, Boston, MA) during the same procedure. INTERVENTION Given the patient's poor neurological condition, it was decided that brainstem compression should be relieved. A posterior fossa decompressive craniectomy was performed immediately after coil therapy, with direct evacuation of the intraventricular clot. The patient experienced a clear improvement in the level of consciousness and has achieved a good neurological result at early follow-up. CONCLUSION Dilation of the fourth ventricle by an intraventricular clot is a sign of brainstem compression that can be relieved by posterior fossa decompression and direct clot evacuation.
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Affiliation(s)
- A Lagares
- Neurosurgical Service, Massachusetts General Hospital, Harvard Medical School, Boston 02114, USA
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Lagares A, Putman CM, Ogilvy CS. Posterior Fossa Decompression and Clot Evacuation for Fourth Ventricle Hemorrhage after Aneurysmal Rupture: Case Report. Neurosurgery 2001. [DOI: 10.1227/00006123-200107000-00033] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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Abstract
OBJECTIVE AND IMPORTANCE The goal of this report was to describe aneurysms arising from the lateral spinal artery. The locations of aneurysms contributing to subarachnoid hemorrhage (SAH) have been well characterized and are primarily in the circle of Willis or at the bifurcation points of the internal carotid artery or the vertebrobasilar system. Although the spinal arteries are also in direct communication with the subarachnoid space, aneurysms of these arteries that lead to SAH are rare. To date, only aneurysms of the anterior and posterior spinal arteries have been described. In this communication, we report two patients with aneurysms of the lateral spinal artery who presented with SAH. CLINICAL PRESENTATION Review of our neurointerventional database from 1997 to the present revealed two patients with lateral spinal artery aneurysms. The medical records, as well as the operative and radiological findings, were reviewed for both patients. In both cases, the lateral spinal arteries were involved as collateral pathways for occlusive vertebral lesions, suggesting hemodynamic stress as a cause. INTERVENTION Endovascular treatment was attempted in both cases and was successful in one; open surgery, with aneurysm resection, was performed in the other case. We review the vascular anatomic features of the spinal cord as they relate to the lateral spinal artery, as well as treatment options for lateral spinal artery aneurysms. CONCLUSION Lateral spinal artery aneurysms are a rare cause of SAH. Both endovascular and surgical treatment options are available.
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Affiliation(s)
- C C Chen
- Department of Interventional Neuroradiology, Massachusetts General Hospital, Harvard Medical School, Boston 02114, USA
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Bellon RJ, Putman CM, Budzik RF, Pergolizzi RS, Reinking GF, Norbash AM. Rheolytic thrombectomy of the occluded internal carotid artery in the setting of acute ischemic stroke. AJNR Am J Neuroradiol 2001; 22:526-30. [PMID: 11237980 PMCID: PMC7976829] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
Abstract
BACKGROUND AND PURPOSE Acute thromboembolic stroke complicated by ipsilateral carotid occlusion may present both mechanical and inflow-related barriers to effective intracranial thrombolysis. We sought to review our experience with a novel method of mechanical thrombectomy, in such cases, using the Possis AngioJet system, a rheolytic thrombectomy device. METHODS A review of our interventional neuroradiology database revealed three patients in whom an occluded cervical internal carotid artery was encountered during endovascular treatment for acute stroke and in whom thrombectomy was attempted, using the 5F Possis AngioJet thrombectomy catheter. The medical records and radiographic studies of these patients were reviewed. RESULTS Three patients were identified (ages, 52--84 years). Two patients had isolated occlusion of the internal carotid artery; in one patient, thrombus extended down into the common carotid artery. Treatment was initiated within 190 to 360 minutes of stroke onset. Thrombectomy of the carotid artery was deemed necessary because of poor collateral flow to the affected hemisphere (chronic contralateral internal carotid artery occlusion [one patient] and thrombus extending to the carotid "T" [one patient]) or inability to pass a microcatheter through the occluded vessel (one patient). Adjunctive therapy included pharmacologic thrombolysis with tissue plasminogen activator (all patients), carotid angioplasty and stenting (two patients), and middle cerebral artery angioplasty (one patient). Patency of the carotid artery was reestablished in two patients, with some residual thrombus burden. In the third patient, the device was able to create a channel through the column of thrombus, allowing intracranial access. CONCLUSION Rheolytic thrombectomy shows potential for rapid, large-burden thrombus removal in cases of internal carotid artery thrombosis, allowing expedient access to the intracranial circulation for additional thrombolytic therapy.
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Affiliation(s)
- R J Bellon
- Department of Interventional Neuroradiology, Massachusetts General Hospital, Boston, MA 02114, USA
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