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Huang F, Janiga G, Berg P, Hosseini SA. On flow fluctuations in ruptured and unruptured intracranial aneurysms: resolved numerical study. Sci Rep 2024; 14:19658. [PMID: 39179594 PMCID: PMC11344026 DOI: 10.1038/s41598-024-70340-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2024] [Accepted: 08/14/2024] [Indexed: 08/26/2024] Open
Abstract
Flow fluctuations have emerged as a promising hemodynamic metric for understanding of hemodynamics in intracranial aneurysms. Several investigations have reported flow instabilities using numerical tools. In this study, the occurrence of flow fluctuations is investigated using either Newtonian or non-Newtonian fluid models in five patient-specific intracranial aneurysms using high-resolution lattice Boltzmann simulation methods. Flow instabilities are quantified by computing power spectral density, proper orthogonal decomposition, and fluctuating kinetic energy of velocity fluctuations. Our simulations reveal substantial flow instabilities in two of the ruptured aneurysms, where the pulsatile inflow through the neck leads to hydrodynamic instability, particularly around the rupture position, throughout the entire cardiac cycle. In other monitoring points, the flow instability is primarily observed during the deceleration phase; typically, the fluctuations begin just after peak systole, gradually decay, and the flow returns to its original, laminar pulsatile state during diastole. Additionally, we assess the rheological impact on flow dynamics. The disparity between Newtonian and non-Newtonian outcomes remains minimal in unruptured aneurysms, with less than a 5% difference in key metrics. However, in ruptured cases, adopting a non-Newtonian model yields a substantial increase in the fluctuations within the aneurysm sac, with up to a 30% higher fluctuating kinetic energy compared to the Newtonian model. The study highlights the importance of using appropriate high-resolution simulations and non-Newtonian models to capture flow fluctuation characteristics that may be critical for assessing aneurysm rupture risk.
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Affiliation(s)
- Feng Huang
- Laboratory of Fluid Dynamics and Technical Flows, Otto-von-Guericke-University Magdeburg, D-39106, Magdeburg, Germany
| | - Gábor Janiga
- Laboratory of Fluid Dynamics and Technical Flows, Otto-von-Guericke-University Magdeburg, D-39106, Magdeburg, Germany
| | - Philipp Berg
- Research Campus STIMULATE, Otto-von-Guericke-University Magdeburg, D-39106, Magdeburg, Germany
- Department of Medical Engineering, Otto-von-Guericke-University Magdeburg, D-39106, Magdeburg, Germany
| | - Seyed Ali Hosseini
- Department of Mechanical and Process Engineering, ETH Zürich, 8092, Zürich, Switzerland.
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Tarkiainen J, Pyysalo L, Hinkka T, Pienimäki JP, Ronkainen A, Frösen J. Stability of infundibular dilatations: a single center follow-up study and systematic review of the literature. Acta Neurochir (Wien) 2024; 166:48. [PMID: 38286939 PMCID: PMC10824818 DOI: 10.1007/s00701-024-05890-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2023] [Accepted: 12/15/2023] [Indexed: 01/31/2024]
Abstract
PURPOSE Although infundibular dilatations (IDs) have been thought to be benign anatomical variants, case reports suggest that they can grow and rupture. The aim of this study was to determine whether IDs have a tendency to grow or rupture. METHODS The study population was collected from the Tampere University Hospital (TAUH) Aneurysm Database. The presence of IDs was screened from the medical records and imaging studies of 356 intracranial aneurysm patients left to follow-up from 2005 to 2020. The imaging studies were reviewed to confirm the IDs, and their clinical course. Finally, we performed a systematic review of published cases of ID leading to aneurysmatic rupture from PubMed. RESULTS We found 97 typical IDs in 83 patients and 9 preaneurysmal lesions resembling ID in 9 patients. Out of the typical cone-shaped IDs, none grew or ruptured in a total follow-up of 409 patient-years. One preaneurysmal lesion ruptured during a follow-up: this lesion had components of both infundibular dilatation and aneurysm at the beginning of follow-up. In the systematic literature search, we found 20 cases of aneurysmatic SAHs originating from an ID. Of those, only 7 had imaging available prerupture. All 7 IDs were typically cone-shaped, but a branching vessel originating from the apex of ID was only seen in 4/7. CONCLUSION Typical infundibular dilatations seem to be benign anatomical variants that are stable and, thus, do not need prophylactic treatment or imaging follow-up. Likely, the SAHs reported from IDs were actually caused by misdiagnosed preaneurysmal lesions.
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Affiliation(s)
- Jeremias Tarkiainen
- Department of Neurosurgery, Tampere University Hospital and University of Tampere, Tampere, Finland.
- Hemorrhagic Brain Pathology Research Group, Faculty of Medical Technology and Health Sciences, Tampere University, Tampere, Finland.
| | - Liisa Pyysalo
- Hemorrhagic Brain Pathology Research Group, Faculty of Medical Technology and Health Sciences, Tampere University, Tampere, Finland
- Department of Rehabilitation, Tampere University Hospital, Tampere, Finland
| | - Tero Hinkka
- Department of Radiology, Tampere University Hospital and University of Tampere, Tampere, Finland
| | - Juha-Pekka Pienimäki
- Department of Radiology, Tampere University Hospital and University of Tampere, Tampere, Finland
| | - Antti Ronkainen
- Department of Neurosurgery, Tampere University Hospital and University of Tampere, Tampere, Finland
| | - Juhana Frösen
- Department of Neurosurgery, Tampere University Hospital and University of Tampere, Tampere, Finland
- Hemorrhagic Brain Pathology Research Group, Faculty of Medical Technology and Health Sciences, Tampere University, Tampere, Finland
- Tays Research Services, Wellbeing Services County of Pirkanmaa, Tampere University Hospital, Tampere, Finland
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Manopoulos C, Seferlis K, Raptis A, Kouerinis I, Mathioulakis D. Mechanics of ascending aortic aneurysms based on a modulus of elasticity dependent on aneurysm diameter and pressure. Comput Methods Biomech Biomed Engin 2023:1-16. [PMID: 38008970 DOI: 10.1080/10255842.2023.2285722] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Accepted: 11/15/2023] [Indexed: 11/28/2023]
Abstract
The mechanical stresses and strains are examined, in ascending thoracic aortic aneurysm (aTAA) models, in a patient-specific aTAA as well as in healthy thoracic aortic models, via Finite Element Analysis. The aneurysms are assumed spherical, 1.5 mm thick, with diameters between 47 mm and 80 mm, eccentrically positioned. The geometry and wall thickness distribution of the aorta along its length are based on open literature data for an average patient age of 66.25 years, accounting for the Body Surface Area (BSA) parameter. The vessel wall material is assumed isotropic and incompressible, with its Young's modulus varying with the aneurysm diameter and the applied intraluminal pressure (120 mmHg to 240 mmHg). In the aTAAs, peak stresses were found to increase nonlinearly with aneurysm diameter (for a given pressure) tending to reach a plateau, appearing at the proximal area of the aneurysm, whereas lower stresses were found at its distal part and even smaller at the aneurysm maximum diameter. Regarding the patient-specific aTAA model, the peak stresses appeared at the distal part of the aneurysm where a tear of the intima layer was detected during surgical intervention. Peak strains exhibited for each pressure a maximum at a certain aneurysm diameter beyond which they dropped so that essentially the vessel wall's distensibility was thus reduced. Examining more than 100 geometry cases and employing a failure stress criterion, the rupture diameter thresholds were estimated to be 65, 52.5, 50 and 47.5 mm for a pressure of 120, 160, 200 and 240 mmHg respectively.
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Affiliation(s)
- Christos Manopoulos
- Laboratory of Biofluid Mechanics and Biomedical Technology, School of Mechanical Engineering, National Technical University of Athens, Athens, Greece
| | - Konstantinos Seferlis
- Laboratory of Biofluid Mechanics and Biomedical Technology, School of Mechanical Engineering, National Technical University of Athens, Athens, Greece
| | - Anastasios Raptis
- Laboratory of Biofluid Mechanics and Biomedical Technology, School of Mechanical Engineering, National Technical University of Athens, Athens, Greece
| | - Ilias Kouerinis
- 1st Department of Cardiothoracic Surgery, 'Hippocration' Hospital; National and Kapodistrian University of Athens Medical School, Athens, Greece
| | - Dimitrios Mathioulakis
- Laboratory of Biofluid Mechanics and Biomedical Technology, School of Mechanical Engineering, National Technical University of Athens, Athens, Greece
- School of Engineering, Bahrain Polytechnic, Isa Town, Kingdom of Bahrain
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Cheng L, Huang Y, Yao H, Luo J, Zhang L, Fu R, Lv J, Yang B, Yan L. Wall Shear Stress Reduction Activates Angiotensin II to Facilitate Aneurysmal Subarachnoid Hemorrhage in Intracranial Aneurysms Through MicroRNA-29/The Growth Factor-Beta Receptor Type II/Smad3 Axis. World Neurosurg 2023; 176:e314-e326. [PMID: 37230243 DOI: 10.1016/j.wneu.2023.05.056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Revised: 05/16/2023] [Accepted: 05/17/2023] [Indexed: 05/27/2023]
Abstract
OBJECTIVE We tried to broaden our knowledge of the possible role of wall shear stress (WSS) in the occurrence of intracranial aneurysms (IAs). METHODS Genes implicated in IAs and genes related to WSS were predicted through in silico analysis. Rat models of IAs were established, in which the expression patterns of angiotensin II (Ang II) were characterized, and WSS was assessed. Vascular endothelial cells isolated from rats bearing IAs were treated with microRNA-29 (miR-29) mimic/inhibitor, small interfering RNA-TGF-β receptor type II (TGFBR2)/overexpressed TGFBR2, Ang II, or angiotensin-converting enzyme (ACE) inhibitor. Then, the endothelial-to-mesenchymal transition (EndMT) was evaluated by flow cytometry. Finally, the volume of IAs and risk of subarachnoid hemorrhage were analyzed in vivo in response to miR-29 gain of function. RESULTS WSS was decreased in the IA bearing arteries, which showed a positive correlation with ACE and Ang II in the vascular tissues of IA rats. Reduced miR-29 and increased ACE, Ang II, and TGFBR2 were detected in the vascular tissues of IA rats. Ang II inhibited miR-29, which targeted TGFBR2. Downregulated TGFBR2 was accompanied by suppression of Smad3 phosphorylation. Through impairing miR-29-dependent inhibition of TGFBR2, Ang II enhanced EndMT. In vivo data confirmed that treatment of miR-29 agomir delayed the formation of IA and decreased the risk of subarachnoid hemorrhage. CONCLUSIONS The current study provided evidence that WSS reduction could activate Ang II, reduce miR-29 expression, and activate the TGFBR2/Smad3 axis, thus promoting EndMT and accelerating the progression of IAs.
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Affiliation(s)
- Longhai Cheng
- Department of Neurosurgery, Taihe Hospital, Hubei University of Medicine, Shiyan, P.R. China
| | - Yan Huang
- Department of Neurosurgery, Taihe Hospital, Hubei University of Medicine, Shiyan, P.R. China
| | - Hong Yao
- Department of Neurosurgery, Taihe Hospital, Hubei University of Medicine, Shiyan, P.R. China
| | - Jie Luo
- Department of Neurosurgery, Taihe Hospital, Hubei University of Medicine, Shiyan, P.R. China
| | - Li Zhang
- Department of Neurosurgery, Taihe Hospital, Hubei University of Medicine, Shiyan, P.R. China
| | - Rui Fu
- Department of Neurosurgery, Taihe Hospital, Hubei University of Medicine, Shiyan, P.R. China
| | - Junti Lv
- Department of Neurosurgery, Taihe Hospital, Hubei University of Medicine, Shiyan, P.R. China.
| | - Bowen Yang
- Department of Neurosurgery, Taihe Hospital, Hubei University of Medicine, Shiyan, P.R. China
| | - Lidong Yan
- Department of Neurosurgery, Taihe Hospital, Hubei University of Medicine, Shiyan, P.R. China
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Rutman AM, Wangaryattawanich P, Aksakal M, Mossa-Basha M. Incidental vascular findings on brain magnetic resonance angiography. Br J Radiol 2023; 96:20220135. [PMID: 35357891 PMCID: PMC9975521 DOI: 10.1259/bjr.20220135] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2022] [Revised: 03/21/2022] [Accepted: 03/24/2022] [Indexed: 01/27/2023] Open
Abstract
Given the ever-increasing utilization of magnetic resonance angiography, incidental vascular findings are increasingly discovered on exams performed for unconnected indications. Some incidental lesions represent pathology and require further intervention and surveillance, such as aneurysm, certain vascular malformations, and arterial stenoses or occlusions. Others are benign or represent normal anatomic variation, and may warrant description, but not further work-up. This review describes the most commonly encountered incidental findings on magnetic resonance angiography, their prevalence, clinical implications, and any available management recommendations.
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Affiliation(s)
| | | | - Mehmet Aksakal
- Department of Radiology, University of Washington School of Medicine, Seattle, WA, United States
| | - Mahmud Mossa-Basha
- Department of Radiology, University of North Carolina, Chapel Hill, NC, USA
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Gao F, Chen B, Zhou T, Luo H. Research on the effect of visceral artery Aneurysm's cardiac morphological variation on hemodynamic situation based on time-resolved CT-scan and computational fluid dynamics. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2022; 221:106928. [PMID: 35701249 DOI: 10.1016/j.cmpb.2022.106928] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Revised: 05/30/2022] [Accepted: 05/31/2022] [Indexed: 06/15/2023]
Abstract
BACKGROUND AND OBJECTIVE Muscular arteries and related aneurysms keep deforming during the cardiac cycle. However, current patient-specific computational fluid dynamics (CFD) analyses of aneurysms are usually based on individual cardiac phase images. The cardiac deformation and displacement characteristics of muscle arteries and aneurysms, as well as their impact on CFD results, have not been adequately explored. The present study tried to illustrate the cardiac morphological variation of visceral muscular arteries (VMAs) & aneurysms (VAAs) and evaluate its influence on the hemodynamic situation at lesion locations. METHODS Four-dimensional computed tomography angiogram (4D-CTA) images of six patients with VAAs were acquired. Medical image registration is used to capture cardiac variations of VMAs. The steady-state CFD simulation is performed on twelve different time-phase geometries. Deformation, displacement, wall shear stress (WSS), velocity, and pressure values at pathological locations are compared to illustrate the deforming characteristics of VAAs and their influence on CFD simulation results. RESULTS The deformation and displacement characteristics of lesion locations for six specific patients show a pulsatile pattern. Maximum displacements are always less than 4 mm. The ratio fluctuations of endovascular cavity volume and vascular inner wall surface area, which were employed to depict cardiac deformation, are always less than 20%. According to CFD simulations based on deformed VMAs, WSS has a larger coefficient of variation (COV) than velocity and pressure. Except for one patient's WSS, the COVs of different hemodynamic parameters obtained from simulation results are always less than 10%. CONCLUSIONS Based on 4D-CTA images, we confirmed that cardiovascular circulation has a periodic impact on the morphologic characteristics of VMAs. A wave that has extended throughout the studied region is observed. It has a dominant influence on the displacement of VMAs. According to CFD results, the influence of the VMAs' deformation and displacement on different hemodynamic parameters is distinct. The variance in WSS is more prominent compared to pressure and velocity. On most occasions, the influence of the VMAs' periodic deformation and displacement on simulation results is insignificant. However, the variant simulation results induced by deforming VMAs cannot be simply ignored.
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Affiliation(s)
- Fan Gao
- Department of Simulation Science and Technology, Boea Wisdom (Hangzhou) Network Technology Co., Ltd, Hangzhou 310000, China.
| | - Bing Chen
- Division of Vascular Surgery, Department of Surgery, Second Affiliated Hospital of Medical College, Zhejiang University, Hangzhou 310052, China.
| | - Tao Zhou
- Department of Simulation Science and Technology, Boea Wisdom (Hangzhou) Network Technology Co., Ltd, Hangzhou 310000, China.
| | - Huan Luo
- Department of Simulation Science and Technology, Boea Wisdom (Hangzhou) Network Technology Co., Ltd, Hangzhou 310000, China.
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Pacheco DRQ. On the numerical treatment of viscous and convective effects in relative pressure reconstruction methods. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2022; 38:e3562. [PMID: 34873867 PMCID: PMC9286393 DOI: 10.1002/cnm.3562] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Revised: 11/29/2021] [Accepted: 12/01/2021] [Indexed: 06/13/2023]
Abstract
The mechanism of many cardiovascular diseases can be understood by studying the pressure distribution in blood vessels. Direct pressure measurements, however, require invasive probing and provide only single-point data. Alternatively, relative pressure fields can be reconstructed from imaging-based velocity measurements by considering viscous and inertial forces. Both contributions can be potential troublemakers in pressure reconstruction: the former due to its higher-order derivatives, and the latter because of the quadratic nonlinearity in the convective acceleration. Viscous and convective terms can be treated in various forms, which, although equivalent for ideal measurements, can perform differently in practice. In fact, multiple versions are often used in literature, with no apparent consensus on the more suitable variants. In this context, the present work investigates the performance of different versions of relative pressure estimators. For viscous effects, in particular, two new modified estimators are presented to circumvent second-order differentiation without requiring surface integrals. In-silico and in-vitro data in the typical regime of cerebrovascular flows are considered, allowing a systematic noise sensitivity study. Convective terms are shown to be the main source of error, even for flows with pronounced viscous component. Moreover, the conservation (often integrated) form of convection exhibits higher noise sensitivity than the standard convective description, in all three families of estimators considered here. For the classical pressure Poisson estimator, the present modified version of the viscous term tends to yield better accuracy than the (recently introduced) integrated form, although this effect is in most cases negligible when compared to convection-related errors.
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Affiliation(s)
- Douglas R. Q. Pacheco
- Institute of Applied MathematicsGraz University of TechnologyGrazAustria
- Present address:
Graz Center of Computational EngineeringGraz University of TechnologyGrazAustria
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Zimny M, Kawlewska E, Hebda A, Wolański W, Ładziński P, Kaspera W. Wall shear stress gradient is independently associated with middle cerebral artery aneurysm development: a case-control CFD patient-specific study based on 77 patients. BMC Neurol 2021; 21:281. [PMID: 34281533 PMCID: PMC8287678 DOI: 10.1186/s12883-021-02251-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2021] [Accepted: 05/10/2021] [Indexed: 11/12/2022] Open
Abstract
Background Previously published computational fluid dynamics (CFD) studies regarding intracranial aneurysm (IA) formation present conflicting results. Our study analysed the involvement of the combination of high wall shear stress (WSS) and a positive WSS gradient (WSSG) in IA formation. Methods We designed a case-control study with a selection of 38 patients with an unruptured middle cerebral artery (MCA) aneurysm and 39 non-aneurysmal controls to determine the involvement of WSS, oscillatory shear index (OSI), the WSSG and its absolute value (absWSSG) in aneurysm formation based on patient-specific CFD simulations using velocity profiles obtained from transcranial colour-coded sonography. Results Among the analysed parameters, only the WSSG had significantly higher values compared to the controls (11.05 vs − 14.76 [Pa/mm], P = 0.020). The WSS, absWSSG and OSI values were not significantly different between the analysed groups. Logistic regression analysis identified WSS and WSSG as significant co-predictors for MCA aneurysm formation, but only the WSSG turned out to be a significant independent prognosticator (OR: 1.009; 95% CI: 1.001–1.017; P = 0.025). Significantly more patients (23/38) in the case group had haemodynamic regions of high WSS combined with a positive WSSG near the bifurcation apex, while in the control group, high WSS was usually accompanied by a negative WSSG (14/39). From the analysis of the ROC curve for WSSG, the area under the curve (AUC) was 0.654, with the optimal cut-off value −0.37 Pa/mm. The largest AUC was recognised for combined WSS and WSSG (AUC = 0.671). Our data confirmed that aneurysms tend to form near the bifurcation apices in regions of high WSS values accompanied by positive WSSG. Conclusions The development of IAs is determined by an independent effect of haemodynamic factors. High WSS impacts MCA aneurysm formation, while a positive WSSG mainly promotes this process.
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Affiliation(s)
- Mikołaj Zimny
- Department of Neurosurgery, Medical University of Silesia, Regional Hospital, Sosnowiec, Poland
| | - Edyta Kawlewska
- Department of Biomechatronics, Silesian University of Technology, Zabrze, Poland
| | - Anna Hebda
- Maria Sklodowska-Curie National Research Institute of Oncology, Gliwice, Poland
| | - Wojciech Wolański
- Department of Biomechatronics, Silesian University of Technology, Zabrze, Poland
| | - Piotr Ładziński
- Department of Neurosurgery, Medical University of Silesia, Regional Hospital, Sosnowiec, Poland
| | - Wojciech Kaspera
- Department of Neurosurgery, Medical University of Silesia, Regional Hospital, Sosnowiec, Poland.
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Yuan J, Li Z, Jiang X, Lai N, Wang X, Zhao X, Wu D, Liu J, Xia D, Huang C, Fang X. Hemodynamic and Morphological Differences Between Unruptured Carotid-Posterior Communicating Artery Bifurcation Aneurysms and Infundibular Dilations of the Posterior Communicating Artery. Front Neurol 2020; 11:741. [PMID: 32793106 PMCID: PMC7393924 DOI: 10.3389/fneur.2020.00741] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Accepted: 06/16/2020] [Indexed: 11/13/2022] Open
Abstract
Objective: Posterior communicating artery bifurcation aneurysms (PcomA-BAs) and infundibular dilations (PcomA-IDs) are found at the junction between the internal carotid artery (ICA) and the posterior communicating artery (PcomA). Several studies found that PcomA-IDs potentially progress to aneurysms and can even rupture. In our clinical practice, digital subtraction angiography (DSA) helps differentiate PcomA-IDs from unruptured PcomA-BAs. However, when PcomA-IDs are >3 mm in diameter or PcomA are absent on DSA, it is challenging to use DSA to differentiate PcomA-IDs from unruptured PcomA-BAs. Hemodynamic and morphological factors are thought to play important roles in the pathogenesis, progression, and rupture of cerebral aneurysms. We compared hemodynamic and morphological differences in unruptured PcomA-BAs and PcomA-IDs to better manage PcomA-IDs. Methods: We included 83 PcomA-IDs and 115 unruptured PcomA-BAs dignosed and measured using DSA from January 2015 to January 2019. Computational fluid dynamics was performed on these patient-specific models reconstructed using axial slices in DICOM format. Clinical, hemodynamic, and morphological factors were compared between the PcomA-IDs and PcomA-BAs. Significant parameters were analyzed using binary logistic regression analysis to identify independent risk factors. Receiver operating characteristic (ROC) analysis was performed on the independent risk factors to acquire cutoff values. Results: One hemodynamic and four morphyological parameters were significantly different between PcomA-IDs and PcomA-BAs: normalized wall shear stress (NWSS), size, the angle between the ophthalmic segment of the ICA and the PcomA (APcomA), the angle between the ophthalmic and the communicating segment of the ICA (AICA) and the diameter of the PcomA (DPcomA). Binary logistic regression analysis showed that small size and DPcomA as well as APcomA were all independent significant factors characterizing the status of PcomA-IDs and the ROC analysis for independent risk factors indicated the cutoff values of size, APcomA, and DPcomA were 3.45 mm, 66.27°, and 1.24 mm, respectively. Conclusions: Size, DpcomA, and ApcomA could independently characterize the status of PcomA-IDs. These might help us better differentiate them from real aneurysms and guide its management.
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Affiliation(s)
- Jinlong Yuan
- Department of Neurosurgery, The First Affiliated Hospital of Wannan Medical College (Yijishan Hospital), Wuhu, China
| | - Zhenbao Li
- Department of Neurosurgery, The First Affiliated Hospital of Wannan Medical College (Yijishan Hospital), Wuhu, China
| | - Xiaochun Jiang
- Department of Neurosurgery, The First Affiliated Hospital of Wannan Medical College (Yijishan Hospital), Wuhu, China
| | - Niansheng Lai
- Department of Neurosurgery, The First Affiliated Hospital of Wannan Medical College (Yijishan Hospital), Wuhu, China
| | - Xuanzhi Wang
- Department of Neurosurgery, The First Affiliated Hospital of Wannan Medical College (Yijishan Hospital), Wuhu, China
| | - Xintong Zhao
- Department of Neurosurgery, The First Affiliated Hospital of Wannan Medical College (Yijishan Hospital), Wuhu, China
| | - Degang Wu
- Department of Neurosurgery, The First Affiliated Hospital of Wannan Medical College (Yijishan Hospital), Wuhu, China
| | - Jiaqiang Liu
- Department of Neurosurgery, The First Affiliated Hospital of Wannan Medical College (Yijishan Hospital), Wuhu, China
| | - Dayong Xia
- Department of Neurosurgery, The First Affiliated Hospital of Wannan Medical College (Yijishan Hospital), Wuhu, China
| | - Chenlei Huang
- Department of Clinical Laboratory, The First Affiliated Hospital of Wannan Medical College (Yijishan Hospital), Wuhu, China
| | - Xinggen Fang
- Department of Neurosurgery, The First Affiliated Hospital of Wannan Medical College (Yijishan Hospital), Wuhu, China
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Zhang J, Brindise MC, Rothenberger S, Schnell S, Markl M, Saloner D, Rayz VL, Vlachos PP. 4D Flow MRI Pressure Estimation Using Velocity Measurement-Error-Based Weighted Least-Squares. IEEE TRANSACTIONS ON MEDICAL IMAGING 2020; 39:1668-1680. [PMID: 31751234 DOI: 10.1109/tmi.2019.2954697] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
This work introduces a 4D flow magnetic resonance imaging (MRI) pressure reconstruction method which employs weighted least-squares (WLS) for pressure integration. Pressure gradients are calculated from the velocity fields, and velocity errors are estimated from the velocity divergence for incompressible flow. Pressure gradient errors are estimated by propagating the velocity errors through Navier-Stokes momentum equation. A weight matrix is generated based on the pressure gradient errors, then employed for pressure reconstruction. The pressure reconstruction method was demonstrated and analyzed using synthetic velocity fields as well as Poiseuille flow measured using in vitro 4D flow MRI. Performance of the proposed WLS method was compared to the method of solving the pressure Poisson equation which has been the primary method used in the previous studies. Error analysis indicated that the proposed method is more robust to velocity measurement errors. Improvement on pressure results was found to be more significant for the cases with spatially-varying velocity error level, with reductions in error ranging from 50% to over 200%. Finally, the method was applied to flow in patient-specific cerebral aneurysms. Validation was performed with in vitro flow data collected using Particle Tracking Velocimetry (PTV) and in vivo flow measurement obtained using 4D flow MRI. Pressure calculated by WLS, as opposed to the Poisson equation, was more consistent with the flow structures and showed better agreement between the in vivo and in vitro data. These results suggest the utility of WLS method to obtain reliable pressure field from clinical flow measurement data.
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Gao BL, Li TX, Zhang XJ, Zhang DH, Hao WL, Fan QY, Li CH. Cerebral arterial infundibula are preaneurysmal lesions caused by direct flow impact. World Neurosurg 2020:S1878-8750(20)30045-0. [PMID: 31954894 DOI: 10.1016/j.wneu.2019.12.183] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2019] [Revised: 12/25/2019] [Accepted: 12/26/2019] [Indexed: 11/19/2022]
Abstract
PURPOSE To investigate whether arterial infundibular widening is a preaneurysmal lesion or not. METHODS Two hundred and nine patients with cerebral angiography were enrolled. The morphology, size and location of infundibula and cerebral aneurysms were studied in two-dimensional angiography and three-dimensional software space. Computational fluid dynamics (CFD) analysis was performed. RESULTS 234 infundibula and 129 infundibulum-like aneurysms (IFAs) were detected. In two-dimensional space, the typical morphology of an infundibulum was a symmetric dilatation at the arterial branch origin with a small vessel branch emanating from the tip and a wide base connecting the parent artery. In three-dimensional space, the infundibulum was dissymmetric with always one side longer than the other side. Furthermore, the infundibulum tilted upstream rather than downstream, with the longer side located downstream and the shorter side upstream in all cases. All the 129 IFAs occurred on the distal wall of the vessel branch origin, and no IFAs grew from the proximal wall of the branch origin. The possible development process of an infundibulum to an IFA was described in four development stages. The CFD analysis revealed that these lesions were associated with direct flow impingement in all cases. All the hemodynamic parameters on the distal wall of infundibula and IFAs were significantly (P<0.0001 or P<0.05) decreased compared with on the distal wall after virtual lesion removal. CONCLUSION The infundibulum is a preaneurysmal lesion associated with high total pressure and high wall shear stress resulted from direct flow impingement and will progress to an aneurysm with time.
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Affiliation(s)
- Bu-Lang Gao
- Henan Provincial People's Hospital, Zhengzhou University; Shijiazhuang First Hospital, Hebei Medical University.
| | - Tian-Xiao Li
- Henan Provincial People's Hospital, Zhengzhou University
| | | | | | - Wei-Li Hao
- Shijiazhuang First Hospital, Hebei Medical University
| | - Qiong-Ying Fan
- Qinzhou Municipal Hospital For Maternal and Children's Health Care
| | - Cong-Hui Li
- The First Hospital of Hebei Medical University
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Dmytriw AA, Bisson DA, Phan K, Amirabadi A, Branson H, Dirks PB, Shroff M, Muthusami P. Locations, associations and temporal evolution of intracranial arterial infundibular dilatations in children. J Neurointerv Surg 2019; 12:495-498. [PMID: 31699885 DOI: 10.1136/neurintsurg-2019-015433] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Revised: 10/11/2019] [Accepted: 10/13/2019] [Indexed: 11/03/2022]
Abstract
BACKGROUND There are few data in the literature on the characteristics and natural history of intracranial arterial infundibular dilatations in children. METHODS An institutional review board-approved retrospective review was performed of infundibula reported on MR angiography in patients <18 years of age at our tertiary pediatric institute from 1998 to 2016. Clinical data (age, sex, diagnosis, other vascular variants/pathologies) were recorded and images assessed for vessel of origin, infundibulum size and exact location. Ratios of infundibulum:parent artery were assessed at diagnosis and last follow-up. Temporal evolution to aneurysm was evaluated. RESULTS We found 60 intracranial infundibula in 60 children (male:female=27:33; mean age 9.7±5.2 years, range 2-18 years,). Family history of aneurysms was present in 2/60 (3.3%). Syndromic association was found in 14/60 (23.3%), most frequently sickle cell disease (4/14=28.6%). Mean infundibulum size was 2.2±0.5 mm, with mean ratio to parent artery of 0.54±0.17. The most common location was on the P1-posterior cerebral artery (34/63=56.7%), whereas posterior communicating infundibula were seen in only 4/60 (6.7%) cases. Other cerebrovascular variants were seen in 12/60 (20%) patients. On follow-up imaging (in 32/60 patients over 86 patient-years, mean 32.3±35.7 months), no significant change in infundibulum:parent artery ratio was noted. None of the infundibular dilatations showed interval evolution to aneurysm. CONCLUSION We present the largest reported cohort of pediatric intracranial arterial infundibula, which we found to be distinct from their adult counterparts with regard to location, etiology and temporal evolution. Growth over time and/or aneurysmal formation are rare, not necessitating frequent short-term imaging surveillance during childhood.
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Affiliation(s)
- Adam A Dmytriw
- Department of Diagnostic Imaging & Image Guided Therapy, The Hospital for Sick Children, University of Toronto, Toronto, ON, Canada
| | - Daniel-Alexandre Bisson
- Department of Diagnostic Imaging & Image Guided Therapy, The Hospital for Sick Children, University of Toronto, Toronto, ON, Canada
| | - Kevin Phan
- Department of Diagnostic Imaging & Image Guided Therapy, The Hospital for Sick Children, University of Toronto, Toronto, ON, Canada
| | - Afsaneh Amirabadi
- Department of Diagnostic Imaging & Image Guided Therapy, The Hospital for Sick Children, University of Toronto, Toronto, ON, Canada
| | - Helen Branson
- Department of Diagnostic Imaging & Image Guided Therapy, The Hospital for Sick Children, University of Toronto, Toronto, ON, Canada
| | - Peter B Dirks
- Division of Neurosurgery, The Hospital for Sick Children, University of Toronto, Toronto, ON, Canada
| | - Manohar Shroff
- Department of Diagnostic Imaging & Image Guided Therapy, The Hospital for Sick Children, University of Toronto, Toronto, ON, Canada
| | - Prakash Muthusami
- Department of Diagnostic Imaging & Image Guided Therapy, The Hospital for Sick Children, University of Toronto, Toronto, ON, Canada
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Ba D, Zhu Z, Yue X, Xu P, Yan P, Xiao D. Computational Fluid Dynamics Analysis of Carotid-Ophthalmic Aneurysms with Concomitant Ophthalmic Artery Infundibulum in a Patient-Specific Model. World Neurosurg 2019; 125:e1023-e1033. [PMID: 30771545 DOI: 10.1016/j.wneu.2019.02.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Revised: 02/01/2019] [Accepted: 02/02/2019] [Indexed: 11/25/2022]
Abstract
BACKGROUND Although previous studies have reported cases of coexistence of carotid-ophthalmic aneurysm and ophthalmic artery (OA) infundibulum, the hemodynamic characteristics of this complicated structure and its damaging effects on vision remain to be elucidated. The aim of the present study was to analyze this artery structure using computational fluid dynamics (CFD) techniques. METHODS We have presented the case of a patient with a diagnosis of carotid-ophthalmic aneurysm, who had been experiencing blurred vision. A transient analysis was performed to investigate the blood flowing in the parent artery. Hemodynamic parameters such as streamline, wall shear stress (WSS), oscillatory shear index (OSI), and relative residence time were obtained. RESULTS When the inlet velocity of the parent artery was at the second peak, the flow rate and intensity of the vortex reached their maximum. In the aneurysm neck, a region of high time-averaged WSS (TAWSS) and a region of low TAWSS with a high OSI coexisted. In addition, a relaxation area was found. In the aneurysm dome, the minimum TAWSS was 2.5 Pa, the maximum OSI was 0.48, and the 2 regions did not overlap. In the OA infundibulum, the maximum OSI and relative residence time were 0.47 and 39.2, respectively; the minimum TAWSS was 0.59 Pa. CONCLUSIONS We detected aneurysm regions that were susceptible to further expansion and assessed the rupture risk of each region. The relaxation area could promote aneurysm progression. In addition, the location of the vortex shear force center varied with time. Finally, double vortex streamlines influenced the blood supply through the OA, impairing the vision. Infundibulum might promote thrombus formation and, hence, retard OA blood flow.
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Affiliation(s)
- Dechun Ba
- School of Mechanical Engineering and Automation, Northeastern University, Shenyang 110819, China
| | - Zhipeng Zhu
- School of Mechanical Engineering and Automation, Northeastern University, Shenyang 110819, China
| | - Xiangji Yue
- School of Mechanical Engineering and Automation, Northeastern University, Shenyang 110819, China
| | - Ping Xu
- Department of Neurology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
| | - Pengfei Yan
- Department of Neurosurgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
| | - Dongdong Xiao
- Department of Neurosurgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China.
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Dasenbrock HH, Yan SC, Gross BA, Guttieres D, Gormley WB, Frerichs KU, Ali Aziz-Sultan M, Du R. The impact of aspirin and anticoagulant usage on outcomes after aneurysmal subarachnoid hemorrhage: a Nationwide Inpatient Sample analysis. J Neurosurg 2017; 126:537-547. [DOI: 10.3171/2015.12.jns151107] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
OBJECTIVE
Although aspirin usage may be associated with a decreased risk of rupture of cerebral aneurysms, any potential therapeutic benefit from aspirin must be weighed against the theoretical risk of greater hemorrhage volume if subarachnoid hemorrhage (SAH) occurs. However, few studies have evaluated the association between prehemorrhage aspirin use and outcomes. This is the first nationwide analysis to evaluate the impact of long-term aspirin and anticoagulant use on outcomes after SAH.
METHODS
Data from the Nationwide Inpatient Sample (NIS; 2006–2011) were extracted. Patients with a primary diagnosis of SAH who underwent microsurgical or endovascular aneurysm repair were included; those with a diagnosis of an arteriovenous malformation were excluded. Multivariable logistic regression was performed to calculate the adjusted odds of in-hospital mortality, a nonroutine discharge (any discharge other than to home), or a poor outcome (death, discharge to institutional care, tracheostomy, or gastrostomy) for patients with long-term aspirin or anticoagulant use. Multivariable linear regression was used to evaluate length of hospital stay. Covariates included patient age, sex, comorbidities, primary payer, NIS-SAH severity scale, intracerebral hemorrhage, cerebral edema, herniation, modality of aneurysm repair, hospital bed size, and whether the hospital was a teaching hospital. Subgroup analyses exclusively evaluated patients treated surgically or endovascularly.
RESULTS
The study examined 11,549 hospital admissions. Both aspirin (2.1%, n = 245) and anticoagulant users (0.9%, n = 108) were significantly older and had a greater burden of comorbid disease (p < 0.001); severity of SAH was slightly lower in those with long-term aspirin use (p = 0.03). Neither in-hospital mortality (13.5% vs 12.6%) nor total complication rates (79.6% vs 80.0%) differed significantly by long-term aspirin use. Additionally, aspirin use was associated with decreased odds of a cardiac complication (OR 0.57, 95% CI 0.36%–0.91%, p = 0.02) or of venous thromboembolic events (OR 0.53, 95% CI 0.30%–0.94%, p = 0.03). Length of stay was significantly shorter (15 days vs 17 days [12.73%], 95% CI 5.22%–20.24%, p = 0.001), and the odds of a nonroutine discharge were lower (OR 0.63, 95% CI 0.48%–0.83%, p = 0.001) for aspirin users. In subgroup analyses, the benefits of aspirin were primarily noted in patients who underwent coil embolization; likewise, among patients treated endovascularly, the adjusted odds of a poor outcome were lower among long-term aspirin users (31.8% vs 37.4%, OR 0.63, 95% CI 0.42%–0.94%, p = 0.03). Although the crude rates of in-hospital mortality (19.4% vs 12.6%) and poor outcome (53.6% vs 37.6%) were higher for long-term anticoagulant users, in multivariable logistic regression models these variations were not significantly different (mortality: OR 1.36, 95% CI 0.89%–2.07%, p = 0.16; poor outcome: OR 1.09, 95% CI 0.69%–1.73%, p = 0.72).
CONCLUSIONS
In this nationwide study, neither long-term aspirin nor anticoagulant use were associated with differential mortality or complication rates after SAH. Aspirin use was associated with a shorter hospital stay and lower rates of nonroutine discharge, with these benefits primarily observed in patients treated endovascularly.
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Affiliation(s)
- Hormuzdiyar H. Dasenbrock
- 1Cushing Neurosurgical Outcomes Center,
- 2Department of Neurological Surgery, Brigham and Women's Hospital,
- 3Harvard Medical School, and
- 4H.T. Chan Harvard School of Public Health, Boston, Massachusetts
| | - Sandra C. Yan
- 1Cushing Neurosurgical Outcomes Center,
- 2Department of Neurological Surgery, Brigham and Women's Hospital,
- 5Warren Alpert School of Medicine, Brown University, Providence, Rhode Island; and
| | - Bradley A. Gross
- 6Barrow Neurological Institute, Division of Neurological Surgery, Phoenix, Arizona
| | | | - William B. Gormley
- 1Cushing Neurosurgical Outcomes Center,
- 2Department of Neurological Surgery, Brigham and Women's Hospital,
- 3Harvard Medical School, and
| | - Kai U. Frerichs
- 1Cushing Neurosurgical Outcomes Center,
- 2Department of Neurological Surgery, Brigham and Women's Hospital,
- 3Harvard Medical School, and
| | - M. Ali Aziz-Sultan
- 1Cushing Neurosurgical Outcomes Center,
- 2Department of Neurological Surgery, Brigham and Women's Hospital,
- 3Harvard Medical School, and
| | - Rose Du
- 1Cushing Neurosurgical Outcomes Center,
- 2Department of Neurological Surgery, Brigham and Women's Hospital,
- 3Harvard Medical School, and
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Can A, Du R. Association of Hemodynamic Factors With Intracranial Aneurysm Formation and Rupture: Systematic Review and Meta-analysis. Neurosurgery 2016; 78:510-20. [PMID: 26516819 DOI: 10.1227/neu.0000000000001083] [Citation(s) in RCA: 102] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Recent evidence suggests a link between the magnitude and distribution of hemodynamic factors and the formation and rupture of intracranial aneurysms. However, there are many conflicting results. OBJECTIVE To quantify the effect of hemodynamic factors on aneurysm formation and their association with ruptured aneurysms. METHODS We performed a systematic review and meta-analysis through October 2014. Analysis of the effects of hemodynamic factors on aneurysm formation was performed by pooling the results of studies that compared geometrical models of intracranial aneurysms and "preaneurysm" models where the aneurysm was artificially removed. Furthermore, we calculated pooled standardized mean differences between ruptured and unruptured aneurysms to quantify the association of hemodynamic factors with ruptured aneurysms. Standard PRISMA guidelines were followed. RESULTS The hemodynamic factors that showed high positive correlations with location of aneurysm formation were high wall shear stress (WSS) and high gradient oscillatory number, with pooled proportions of 78.8% and 85.7%, respectively. Positive correlations were largely seen in bifurcation aneurysms, whereas negative correlations were seen in sidewall aneurysms. Mean and normalized WSS were significantly lower and low shear area significantly higher in ruptured aneurysms. CONCLUSION Pooled analyses of computational fluid dynamics models suggest that an increase in WSS and gradient oscillatory number may contribute to aneurysm formation, whereas low WSS is associated with ruptured aneurysms. The location of the aneurysm at the bifurcation or sidewall may influence the correlation of these hemodynamic factors.
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Affiliation(s)
- Anil Can
- Department of Neurosurgery, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts
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16
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Wall shear stress at the initiation site of cerebral aneurysms. Biomech Model Mechanobiol 2016; 16:97-115. [DOI: 10.1007/s10237-016-0804-3] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Accepted: 06/24/2016] [Indexed: 11/30/2022]
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17
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Dasenbrock HH, Nguyen MO, Frerichs KU, Guttieres D, Gormley WB, Ali Aziz-Sultan M, Du R. The impact of body habitus on outcomes after aneurysmal subarachnoid hemorrhage: a Nationwide Inpatient Sample analysis. J Neurosurg 2016; 127:36-46. [PMID: 27419827 DOI: 10.3171/2016.4.jns152562] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
OBJECTIVE Although the prevalence of obesity is increasing rapidly both nationally and internationally, few studies have analyzed outcomes among obese patients undergoing cranial neurosurgery. The goal of this study, which used a nationwide data set, was to evaluate the association of both obesity and morbid obesity with treatment outcomes among patients with aneurysmal subarachnoid hemorrhage (SAH); in addition, the authors sought to analyze how postoperative complications for obese patients with SAH differ by the treatment modality used for aneurysm repair. METHODS Clinical data for adult patients with SAH who underwent microsurgical or endovascular aneurysm repair were extracted from the Nationwide Inpatient Sample (NIS). The body habitus of patients was classified as nonobese (body mass index [BMI] < 30 kg/m2), obese (BMI ≥ 30 kg/m2 and ≤ 40 kg/m2), or morbidly obese (BMI > 40 kg/m2). Multivariable logistic regression analyzed the association of body habitus with in-hospital mortality rate, complications, discharge disposition, and poor outcome as defined by the composite NIS-SAH outcome measure. Covariates included patient demographics, comorbidities (including hypertension and diabetes), health insurance status, the NIS-SAH severity scale, treatment modality used for aneurysm repair, and hospital characteristics. RESULTS In total, data from 18,281 patients were included in this study; the prevalence of morbid obesity increased from 0.8% in 2002 to 3.5% in 2011. Obese and morbidly obese patients were significantly younger and had a greater number of comorbidities than nonobese patients (p < 0.001). Mortality rates for obese (11.5%) and morbidly obese patients (10.5%) did not significantly differ from those for nonobese patients (13.5%); likewise, no differences in neurological complications or poor outcome were observed among these 3 groups. Morbid obesity was associated with significantly increased odds of several medical complications, including venous thromboembolic (OR 1.52, 95% CI 1.01-2.30, p = 0.046) and renal (OR 1.64, 95% CI: 1.11-2.43, p = 0.01) complications and infections (OR 1.34, 95% CI 1.08-1.67, p = 0.009, attributable to greater odds of urinary tract and surgical site infections). Moreover, morbidly obese patients had higher odds of a nonroutine hospital discharge (OR 1.33, 95% CI 1.03-1.71, p = 0.03). Patients with milder obesity had decreased odds of some medical complications, including cardiac, pulmonary, and infectious complications, primarily among patients who had undergone coil embolization. CONCLUSIONS In this study involving a nationwide administrative database, milder obesity was not significantly associated with increased mortality rates, neurological complications, or poor outcomes after SAH. Morbid obesity, however, was associated with increased odds of venous thromboembolic, renal, and infectious complications, as well as of a nonroutine hospital discharge. Notably, milder obesity was associated with decreased odds of some medical complications, primarily in patients treated with coiling.
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Affiliation(s)
- Hormuzdiyar H Dasenbrock
- Cushing Neurosurgical Outcomes Center, Department of Neurosurgery, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts
| | - Michael O Nguyen
- Cushing Neurosurgical Outcomes Center, Department of Neurosurgery, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts
| | - Kai U Frerichs
- Cushing Neurosurgical Outcomes Center, Department of Neurosurgery, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts
| | - Donovan Guttieres
- Cushing Neurosurgical Outcomes Center, Department of Neurosurgery, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts
| | - William B Gormley
- Cushing Neurosurgical Outcomes Center, Department of Neurosurgery, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts
| | - M Ali Aziz-Sultan
- Cushing Neurosurgical Outcomes Center, Department of Neurosurgery, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts
| | - Rose Du
- Cushing Neurosurgical Outcomes Center, Department of Neurosurgery, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts
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18
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Sarrami-Foroushani A, Nasr Esfahany M, Saligheh Rad H, Firouznia K, Shakiba M, Ghanaati H. Effects of Variations of Flow and Heart Rate on Intra-Aneurysmal Hemodynamics in a Ruptured Internal Carotid Artery Aneurysm During Exercise. IRANIAN JOURNAL OF RADIOLOGY 2016; 13:e18217. [PMID: 27110332 PMCID: PMC4837368 DOI: 10.5812/iranjradiol.18217] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/13/2014] [Revised: 06/18/2014] [Accepted: 07/20/2014] [Indexed: 11/16/2022]
Abstract
BACKGROUND Hemodynamics is thought to play an important role in the mechanisms responsible for initiation, growth, and rupture of intracranial aneurysms. Computational fluid dynamic (CFD) analysis is used to assess intra-aneurysmal hemodynamics. OBJECTIVES This study aimed to investigate the effects of variations in heart rate and internal carotid artery (ICA) flow rate on intra-aneurysmal hemodynamics, in an ICA aneurysm, by using computational fluid dynamics. PATIENTS AND METHODS Computed tomography angiography (CTA) was performed in a 55 years old female case, with a saccular ICA aneurysm, to create a patient-specific geometrical anatomic model of the aneurysm. The intra-aneurysmal hemodynamic environments for three states with different flow and heart rates were analyzed using patient-specific image-based CFD modeling. RESULTS Results showed significant changes for the three simulated states. For a proportion of the states examined, results were counterintuitive. Systolic and time-averaged wall shear stress and pressure on the aneurysm wall showed a proportional evolution with the mainstream flow rate. CONCLUSION Results reinforced the pivotal role of vascular geometry, with respect to hemodynamics, together with the importance of performing patient-specific CFD analyses, through which the effect of different blood flow conditions on the aneurysm hemodynamics could be evaluated.
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Affiliation(s)
| | - Mohsen Nasr Esfahany
- Department of Chemical Engineering, Isfahan University of Technology, Isfahan, Iran
- Corresponding author: Mohsen Nasr Esfahany, Department of Chemical Engineering, Isfahan University of Technology, Isfahan, Iran. Tel: +98-3133915631, Fax: +98-3113912677, E-mail:
| | - Hamidreza Saligheh Rad
- Medical Physics and Biomedical Engineering, Tehran University of Medical Sciences, Tehran, Iran
| | - Kavous Firouznia
- Advanced Diagnostic and Interventional Radiology Research Center (ADIR), Tehran University of Medical Sciences, Tehran, Iran
| | - Madjid Shakiba
- Advanced Diagnostic and Interventional Radiology Research Center (ADIR), Tehran University of Medical Sciences, Tehran, Iran
| | - Hossein Ghanaati
- Advanced Diagnostic and Interventional Radiology Research Center (ADIR), Tehran University of Medical Sciences, Tehran, Iran
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20
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Dasenbrock HH, Bartolozzi AR, Gormley WB, Frerichs KU, Aziz-Sultan MA, Du R. Clostridium difficile Infection After Subarachnoid Hemorrhage. Neurosurgery 2016; 78:412-20. [DOI: 10.1227/neu.0000000000001065] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
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Chung B, Cebral JR. CFD for Evaluation and Treatment Planning of Aneurysms: Review of Proposed Clinical Uses and Their Challenges. Ann Biomed Eng 2014; 43:122-38. [DOI: 10.1007/s10439-014-1093-6] [Citation(s) in RCA: 81] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2014] [Accepted: 08/08/2014] [Indexed: 11/29/2022]
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Chien A, Sayre J. Morphologic and hemodynamic risk factors in ruptured aneurysms imaged before and after rupture. AJNR Am J Neuroradiol 2014; 35:2130-5. [PMID: 24970547 DOI: 10.3174/ajnr.a4016] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE Due to limited information about aneurysm natural history, choosing the appropriate management strategy for an unruptured aneurysm is challenging. By comparing unruptured and ruptured cases, studies have identified a variety of aneurysm morphologic and hemodynamic properties as risk factors for rupture. In this study, we investigated changes in 4 ruptured aneurysms before and after rupture and tested whether previously published risk factors identified a risk before rupture. MATERIALS AND METHODS A retrospective review of ruptured aneurysms based on the inclusion criteria of documenting angiographic images before and after rupture was performed. Such cases are extremely rare. To minimize hemodynamic influence due to location, we selected 4 cases at the posterior communicating artery. 3D morphologic and hemodynamic analyses were applied to examine qualitative and quantitative risk factors in aneurysms before and after rupture. RESULTS When we compared aneurysms before and after rupture, all increased in size. Volume, surface area, and morphology changed in both high and low wall shear stress areas. Aneurysm surface ratio, nonsphericity index, and pulsatility index were the only risk factors to consistently identify risk before and after aneurysm rupture for all aneurysms. CONCLUSIONS Although changes in shape and flow properties were found before and after aneurysm rupture, in this small study, we found that some risk factors were evident as early as 2 years before rupture.
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Affiliation(s)
- A Chien
- From the Division of Interventional Neuroradiology (A.C.), David Geffen School of Medicine
| | - J Sayre
- Department of Biostatistics (J.S.), School of Public Health, University of California, Los Angeles, Los Angeles, California
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Contrast Agent Bolus Dispersion in a Realistic Coronary Artery Geometry: Influence of Outlet Boundary Conditions. Ann Biomed Eng 2013; 42:787-96. [DOI: 10.1007/s10439-013-0950-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2013] [Accepted: 11/19/2013] [Indexed: 01/02/2023]
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First demonstration of resolution of an infundibulum by direct treatment of the arterial wall with Pipeline flow-diverting stent. Neuroradiology 2013; 56:35-9. [PMID: 24221534 DOI: 10.1007/s00234-013-1295-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2013] [Accepted: 10/17/2013] [Indexed: 10/26/2022]
Abstract
INTRODUCTION Infundibula are symmetrical funnel-shaped widening, measuring more than 3 mm at its base with the branch artery arising from its apex. The pathological significance of this entity remains controversial. Although a relatively common appearance in otherwise normal angiograms, they have occasionally been described to progress into saccular aneurysms or directly rupture. METHODS/RESULTS We describe the first case of a disappearing infundibulum after a flow diverting stent was deployed across the infundibulum during the treatment of an adjacent aneurysm. CONCLUSIONS We concur in the view that infundibula are at least pre-pathological lesions that may in certain circumstances require consideration for treatment. Our case for the first time offers a potential treatment option for such situations.
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Chen H, Selimovic A, Thompson H, Chiarini A, Penrose J, Ventikos Y, Watton PN. Investigating the influence of haemodynamic stimuli on intracranial aneurysm inception. Ann Biomed Eng 2013; 41:1492-504. [PMID: 23553330 DOI: 10.1007/s10439-013-0794-6] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2012] [Accepted: 03/15/2013] [Indexed: 10/27/2022]
Abstract
We propose a novel method to reconstruct the hypothetical geometry of the healthy vasculature prior to intracranial aneurysm (IA) formation: a Frenet frame is calculated along the skeletonization of the arterial geometry; upstream and downstream boundaries of the aneurysmal segment are expressed in terms of the local Frenet frame basis vectors; the hypothetical healthy geometry is then reconstructed by propagating a closed curve along the skeleton using the local Frenet frames so that the upstream boundary is smoothly morphed into the downstream boundary. This methodology takes into account the tortuosity of the arterial vasculature and requires minimal user subjectivity. The method is applied to 22 clinical cases depicting IAs. Computational fluid dynamic simulations of the vasculature without IA are performed and the haemodynamic stimuli in the location of IA formation are examined. We observe that locally elevated wall shear stress (WSS) and gradient oscillatory number (GON) are highly correlated (20/22 for WSS and 19/22 for GON) with regions susceptible to sidewall IA formation whilst haemodynamic indices associated with the oscillation of the WSS vectors have much lower correlations.
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Affiliation(s)
- Haoyu Chen
- Institute of Biomedical Engineering Department of Engineering Science, University of Oxford, Oxford, UK.
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Quantitative comparison of the dynamic flow waveform changes in 12 ruptured and 29 unruptured ICA-ophthalmic artery aneurysms. Neuroradiology 2013; 55:313-20. [PMID: 23443738 PMCID: PMC3582813 DOI: 10.1007/s00234-012-1108-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2012] [Accepted: 10/17/2012] [Indexed: 11/30/2022]
Abstract
Introduction Studies have reported a correlation between blood flow dynamics in the cardiac cycle and vascular diseases, but research to analyze the dynamic changes of flow in cerebral aneurysms is limited. This quantitative study investigates the temporal changes in flow during a cardiac cycle (flow waveform) in different regions of aneurysms and their association with aneurysm rupture. Methods Twelve ruptured and 29 unruptured aneurysms from the internal carotid artery–ophthalmic artery segment were studied. Patient-specific aneurysm data were implemented to simulate blood flow. The temporal flow changes at different regions of the aneurysm were recorded to compare the flow waveforms. Results In more than 60 % of the cases, peak flow in the aneurysm sac occurred after peak flow in the artery. Flow rate varied among cases and no correlation with rupture, aneurysm flow rate, and aneurysm size was found. Higher pulsatility within aneurysm sacs was found when comparing with the parent artery (P < 0.001). Pulsatility was high throughout ruptured aneurysms, but increased from neck to dome in unruptured ones (P = 0.021). Significant changes between inflow and outflow flow profile were found in unruptured aneurysms (P = 0.023), but not in ruptured aneurysms. Conclusion Quantitative analysis which considers temporal blood flow changes appears to provide additional information which is not apparent from aneurysmal flow at a single time point (i.e., peak of systole). By considering the flow waveform throughout the cardiac cycle, statistically significant differences were found between ruptured and unruptured cases — for flow profile, pulsatility and timing of peak flow.
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Yagi T, Sato A, Shinke M, Takahashi S, Tobe Y, Takao H, Murayama Y, Umezu M. Experimental insights into flow impingement in cerebral aneurysm by stereoscopic particle image velocimetry: transition from a laminar regime. J R Soc Interface 2013; 10:20121031. [PMID: 23427094 DOI: 10.1098/rsif.2012.1031] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
This study experimentally investigated the instability of flow impingement in a cerebral aneurysm, which was speculated to promote the degradation of aneurysmal wall. A patient-specific, full-scale and elastic-wall replica of cerebral artery was fabricated from transparent silicone rubber. The geometry of the aneurysm corresponded to that found at 9 days before rupture. The flow in a replica was analysed by quantitative flow visualization (stereoscopic particle image velocimetry) in a three-dimensional, high-resolution and time-resolved manner. The mid-systolic and late-diastolic flows with a Reynolds number of 450 and 230 were compared. The temporal and spatial variations of near-wall velocity at flow impingement delineated its inherent instability at a low Reynolds number. Wall shear stress (WSS) at that site exhibited a combination of temporal fluctuation and spatial divergence. The frequency range of fluctuation was found to exceed significantly that of the heart rate. The high-frequency-fluctuating WSS appeared only during mid-systole and disappeared during late diastole. These results suggested that the flow impingement induced a transition from a laminar regime. This study demonstrated that the hydrodynamic instability of shear layer could not be neglected even at a low Reynolds number. No assumption was found to justify treating the aneurysmal haemodynamics as a fully viscous laminar flow.
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Affiliation(s)
- Takanobu Yagi
- Center for Advanced Biomedical Sciences, Waseda University, Tokyo, Japan.
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28
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Cebral JR, Raschi M. Suggested connections between risk factors of intracranial aneurysms: a review. Ann Biomed Eng 2012; 41:1366-83. [PMID: 23242844 DOI: 10.1007/s10439-012-0723-0] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2012] [Accepted: 12/07/2012] [Indexed: 12/01/2022]
Abstract
The purpose of this article is to review studies of aneurysm risk factors and the suggested hypotheses that connect the different risk factors and the underlying mechanisms governing the aneurysm natural history. The result of this work suggests that at the center of aneurysm evolution there is a cycle of wall degeneration and weakening in response to changing hemodynamic loading and biomechanic stress. This progressive wall degradation drives the geometrical evolution of the aneurysm until it stabilizes or ruptures. Risk factors such as location, genetics, smoking, co-morbidities, and hypertension seem to affect different components of this cycle. However, details of these interactions or their relative importance are still not clearly understood.
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Affiliation(s)
- Juan R Cebral
- Center for Computational Fluid Dynamics, George Mason University, Fairfax, VA, USA.
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29
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Jamison RA, Siu KKW, Dubsky S, Armitage JA, Fouras A. X-ray velocimetry within the ex vivo carotid artery. JOURNAL OF SYNCHROTRON RADIATION 2012; 19:1050-1055. [PMID: 23093769 DOI: 10.1107/s0909049512033912] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2012] [Accepted: 07/29/2012] [Indexed: 06/01/2023]
Abstract
X-ray velocimetry offers a non-invasive method by which blood flow, blood velocity and wall shear stress can be measured in arteries prone to atherosclerosis. Analytical tools for measuring haemodynamics in artificial arteries have previously been developed and here the first quantification of haemodynamics using X-ray velocimetry in a living mammalian artery under physiologically relevant conditions is demonstrated. Whole blood seeded with a clinically used ultrasound contrast agent was pumped with a steady flow through live carotid arterial tissue from a rat, which was kept alive in a physiological salt solution. Pharmacological agents were then used to produce vascular relaxation. Velocity measurements were acquired with a spatial resolution of 14 µm × 14 µm and at a rate of 5000 acquisitions per second. Subtle velocity changes that occur are readily measurable, demonstrating the ability of X-ray velocimetry to sensitively and accurately measure haemodynamics ex vivo. Future applications and possible limitations of the technique are discussed, which allows for detailed living tissue investigations to be carried out for various disease models, including atherosclerosis and diabetic vasculopathy.
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Affiliation(s)
- R A Jamison
- Division of Biological Engineering, Monash University, Victoria 3800, Australia
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30
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Sforza DM, Putman CM, Cebral JR. Computational fluid dynamics in brain aneurysms. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2012; 28:801-808. [PMID: 25364852 PMCID: PMC4221804 DOI: 10.1002/cnm.1481] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2011] [Revised: 10/04/2011] [Accepted: 10/05/2011] [Indexed: 05/30/2023]
Abstract
Because of its ability to deal with any geometry, image-based computational fluid dynamics (CFD) has been progressively used to investigate the role of hemodynamics in the underlying mechanisms governing the natural history of cerebral aneurysms. Despite great progress in methodological developments and many studies using patient-specific data, there are still significant controversies about the precise governing processes and divergent conclusions from apparently contradictory results. Sorting out these issues requires a global vision of the state of the art and a unified approach to solving this important scientific problem. Towards this end, this paper reviews the contributions made using patient-specific CFD models to further the understanding of these mechanisms, and highlights the great potential of patient-specific computational models for clinical use in the assessment of aneurysm rupture risk and patient management.
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Affiliation(s)
- Daniel M Sforza
- Center for Computational Fluid Dynamics, School of Physics, Astronomy and Computational Sciences, George Mason University, 4400 University Drive, MSN 6A2, Fairfax, VA 22030, USA.
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31
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Jamison RA, Dubsky S, Siu KKW, Hourigan K, Fouras A. X-ray Velocimetry and Haemodynamic Forces Within a Stenosed Femoral Model at Physiological Flow Rates. Ann Biomed Eng 2011; 39:1643-53. [PMID: 21293973 DOI: 10.1007/s10439-011-0260-2] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2010] [Accepted: 01/22/2011] [Indexed: 11/27/2022]
Affiliation(s)
- R Aidan Jamison
- Division of Biological Engineering, Monash University, Victoria, 3800, Australia
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32
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Cao RY, Amand T, Ford MD, Piomelli U, Funk CD. The Murine Angiotensin II-Induced Abdominal Aortic Aneurysm Model: Rupture Risk and Inflammatory Progression Patterns. Front Pharmacol 2010; 1:9. [PMID: 21713101 PMCID: PMC3112241 DOI: 10.3389/fphar.2010.00009] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2010] [Accepted: 06/22/2010] [Indexed: 01/22/2023] Open
Abstract
An abdominal aortic aneurysm (AAA) is an enlargement of the greatest artery in the body defined as an increase in diameter of 1.5-fold. AAAs are common in the elderly population and thousands die each year from their complications. The most commonly used mouse model to study the pathogenesis of AAA is the angiotensin II (Ang II) infusion method delivered via osmotic mini-pump for 28 days. Here, we studied the site-specificity and onset of aortic rupture, characterized three-dimensional (3D) images and flow patterns in developing AAAs by ultrasound imaging, and examined macrophage infiltration in the Ang II model using 65 apolipoprotein E-deficient mice. Aortic rupture occurred in 16 mice (25%) and was nearly as prevalent at the aortic arch (44%) as it was in the suprarenal region (56%) and was most common within the first 7 days after Ang II infusion (12 of 16; 75%). Longitudinal ultrasound screening was found to correlate nicely with histological analysis and AAA volume renderings showed a significant relationship with AAA severity index. Aortic dissection preceded altered flow patterns and macrophage infiltration was a prominent characteristic of developing AAAs. Targeting the inflammatory component of AAA disease with novel therapeutics will hopefully lead to new strategies to attenuate aneurysm growth and aortic rupture.
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Affiliation(s)
- Richard Y Cao
- Department of Physiology, Queen's University Kingston, ON, Canada
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Yu J, Wang H, Xu K, Wang B, Luo Q. Endovascular embolization of ruptured infundibular dilation of posterior communicating artery: a case report. Case Rep Med 2010; 2010:210397. [PMID: 21209803 PMCID: PMC3014759 DOI: 10.1155/2010/210397] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2010] [Revised: 11/11/2010] [Accepted: 12/11/2010] [Indexed: 11/30/2022] Open
Abstract
Hemorrhage due to the rupture of the infundibular dilatation of the posterior communicating artery (ID of the PCo-A) occurs infrequently. The preferred treatment of such hemorrhages is surgical clipping through craniotomy. There are few reports about endovascular coil embolization in such cases. We report such a case treated by endovascular embolization. A 35-year-old man, who had experienced 2 episodes of subarachnoid hemorrhage (SAH), was found to have a ruptured ID of the PCo-A by head computed tomography angiography (CTA) and digital subtraction angiography (DSA). We performed stent-assisted endovascular coil embolization through a combined anterior and posterior circulation approach. Postembolization angiography showed absence of contrast filling of the ID of the PCo-A and nonleakage of the contrast agent. The patient recovered well with no complications. SAH recurrence was not recorded during the 1-year followup. The postoperative angiographic result was good. To our knowledge, this is the first case of hemorrhage due to ruptured ID of the PCo-A that was treated by such a technique.
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Affiliation(s)
- Jinlu Yu
- Department of Neurosurgery, First Hospital of Jilin University, Changchun 130021, China
| | - Honglei Wang
- Department of Neurosurgery, First Hospital of Jilin University, Changchun 130021, China
| | - Kan Xu
- Department of Neurosurgery, First Hospital of Jilin University, Changchun 130021, China
| | - Bai Wang
- Department of Radiology, First Hospital of Jilin University, Changchun 130021, China
| | - Qi Luo
- Department of Neurosurgery, First Hospital of Jilin University, Changchun 130021, China
- *Qi Luo:
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