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Karnam Y, Mut F, Yu AK, Cheng B, Amin-Hanjani S, Charbel FT, Woo HH, Niemelä M, Tulamo R, Jahromi BR, Frösen J, Tobe Y, Robertson AM, Cebral JR. Description of the local hemodynamic environment in intracranial aneurysm wall subdivisions. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2024; 40:e3844. [PMID: 38952068 PMCID: PMC11315625 DOI: 10.1002/cnm.3844] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2024] [Revised: 05/08/2024] [Accepted: 06/18/2024] [Indexed: 07/03/2024]
Abstract
Intracranial aneurysms (IAs) pose severe health risks influenced by hemodynamics. This study focuses on the intricate characterization of hemodynamic conditions within the IA walls and their influence on bleb development, aiming to enhance understanding of aneurysm stability and the risk of rupture. The methods emphasized utilizing a comprehensive dataset of 359 IAs and 213 IA blebs from 268 patients to reconstruct patient-specific vascular models, analyzing blood flow using finite element methods to solve the unsteady Navier-Stokes equations, the segmentation of aneurysm wall subregions and the hemodynamic metrics wall shear stress (WSS), its metrics, and the critical points in WSS fields were computed and analyzed across different aneurysm subregions defined by saccular, streamwise, and topographical divisions. The results revealed significant variations in these metrics, correlating distinct hemodynamic environments with wall features on the aneurysm walls, such as bleb formation. Critical findings indicated that regions with low WSS and high OSI, particularly in the body and central regions of aneurysms, are prone to conditions that promote bleb formation. Conversely, areas exposed to high WSS and positive divergence, like the aneurysm neck, inflow, and outflow regions, exhibited a different but substantial risk profile for bleb development, influenced by flow impingements and convergences. These insights highlight the complexity of aneurysm behavior, suggesting that both high and low-shear environments can contribute to aneurysm pathology through distinct mechanisms.
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Affiliation(s)
- Yogesh Karnam
- Department of Bioengineering, George Mason University, Fairfax, Virginia, USA
| | - Fernando Mut
- Department of Bioengineering, George Mason University, Fairfax, Virginia, USA
| | - Alexander K Yu
- Department of Neurosurgery, Allegheny General Hospital, Pittsburgh, Pennsylvania, USA
| | - Boyle Cheng
- Department of Neurosurgery, Allegheny General Hospital, Pittsburgh, Pennsylvania, USA
| | - Sepideh Amin-Hanjani
- Department of Neurological Surgery, UH Cleveland Medical Center, Cleveland, Ohio, USA
| | - Fady T Charbel
- Department of Neurosurgery, University of Illinois at Chicago, Chicago, Illinois, USA
| | - Henry H Woo
- Department of Neurosurgery, Donald and Barbara Zucker School of Medicine at Hofstra/Northwell, Manhasset, New York, USA
| | - Mika Niemelä
- Neurosurgery Research Group, Helsinki University Hospital, Helsinki, Finland
| | - Riikka Tulamo
- Neurosurgery Research Group, Helsinki University Hospital, Helsinki, Finland
| | | | - Juhana Frösen
- Department of Neurosurgery, University of Tampere, Tampere, Finland
- Hemorrhagic Brain Pathology Research Group, Kuopio University Hospital, Kuopio, Finland
| | - Yasutaka Tobe
- Department of Mechanical Engineering and Material Science, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Anne M Robertson
- Department of Mechanical Engineering and Material Science, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Juan R Cebral
- Department of Bioengineering, George Mason University, Fairfax, Virginia, USA
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Karnam Y, Mut F, Yu AK, Cheng B, Amin-Hanjani S, Charbel FT, Woo HH, Niemelä M, Tulamo R, Jahromi BR, Frösen J, Tobe Y, Robertson AM, Cebral JR. Distribution of rupture sites and blebs on intracranial aneurysm walls suggests distinct rupture patterns in ACom and MCA aneurysms. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2024; 40:e3837. [PMID: 38839043 PMCID: PMC11315635 DOI: 10.1002/cnm.3837] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2024] [Revised: 05/15/2024] [Accepted: 05/18/2024] [Indexed: 06/07/2024]
Abstract
The mechanisms behind intracranial aneurysm formation and rupture are not fully understood, with factors such as location, patient demographics, and hemodynamics playing a role. Additionally, the significance of anatomical features like blebs in ruptures is debated. This highlights the necessity for comprehensive research that combines patient-specific risk factors with a detailed analysis of local hemodynamic characteristics at bleb and rupture sites. Our study analyzed 359 intracranial aneurysms from 268 patients, reconstructing patient-specific models for hemodynamic simulations based on 3D rotational angiographic images and intraoperative videos. We identified aneurysm subregions and delineated rupture sites, characterizing blebs and their regional overlap, employing statistical comparisons across demographics, and other risk factors. This work identifies patterns in aneurysm rupture sites, predominantly at the dome, with variations across patient demographics. Hypertensive and anterior communicating artery (ACom) aneurysms showed specific rupture patterns and bleb associations, indicating two pathways: high-flow in ACom with thin blebs at impingement sites and low-flow, oscillatory conditions in middle cerebral artery (MCA) aneurysms fostering thick blebs. Bleb characteristics varied with gender, age, and smoking, linking rupture risks to hemodynamic factors and patient profiles. These insights enhance understanding of the hemodynamic mechanisms leading to rupture events. This analysis elucidates the role of localized hemodynamics in intracranial aneurysm rupture, challenging the emphasis on location by revealing how flow variations influence stability and risk. We identify two pathways to wall failure-high-flow and low-flow conditions-highlighting the complexity of aneurysm behavior. Additionally, this research advances our knowledge of how inherent patient-specific characteristics impact these processes, which need further investigation.
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Affiliation(s)
- Yogesh Karnam
- Department of Bioengineering, George Mason University, Fairfax, Virginia, USA
| | - Fernando Mut
- Department of Bioengineering, George Mason University, Fairfax, Virginia, USA
| | - Alexander K Yu
- Department of Neurosurgery, Allegheny General Hospital, Pittsburgh, Pennsylvania, USA
| | - Boyle Cheng
- Department of Neurosurgery, Allegheny General Hospital, Pittsburgh, Pennsylvania, USA
| | - Sepideh Amin-Hanjani
- Department of Neurological Surgery, UH Cleveland Medical Center, Cleveland, Ohio, USA
| | - Fady T Charbel
- Department of Neurosurgery, University of Illinois at Chicago, Chicago, Illinois, USA
| | - Henry H Woo
- Department of Neurosurgery, Donald and Barbara Zucker School of Medicine at Hofstra/Northwell, Manhasset, New York, USA
| | - Mika Niemelä
- Neurosurgery Research Group, Helsinki University Hospital, Helsinki, Finland
| | - Riikka Tulamo
- Neurosurgery Research Group, Helsinki University Hospital, Helsinki, Finland
| | | | - Juhana Frösen
- Department of Neurosurgery, University of Tampere, Tampere, Finland
- Hemorrhagic Brain Pathology Research Group, Kuopio University Hospital, Kuopio, Finland
| | - Yasutaka Tobe
- Department of Mechanical Engineering and Material Science, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Anne M Robertson
- Department of Mechanical Engineering and Material Science, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Juan R Cebral
- Department of Bioengineering, George Mason University, Fairfax, Virginia, USA
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Tobe Y, Robertson AM, Ramezanpour M, Cebral JR, Watkins SC, Charbel FT, Amin-Hanjani S, Yu AK, Cheng BC, Woo HH. Comapping Cellular Content and Extracellular Matrix with Hemodynamics in Intact Arterial Tissues Using Scanning Immunofluorescent Multiphoton Microscopy. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2024; 30:342-358. [PMID: 38525887 PMCID: PMC11057816 DOI: 10.1093/mam/ozae025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Revised: 03/01/2024] [Accepted: 03/04/2024] [Indexed: 03/26/2024]
Abstract
Deviation of blood flow from an optimal range is known to be associated with the initiation and progression of vascular pathologies. Important open questions remain about how the abnormal flow drives specific wall changes in pathologies such as cerebral aneurysms where the flow is highly heterogeneous and complex. This knowledge gap precludes the clinical use of readily available flow data to predict outcomes and improve treatment of these diseases. As both flow and the pathological wall changes are spatially heterogeneous, a crucial requirement for progress in this area is a methodology for acquiring and comapping local vascular wall biology data with local hemodynamic data. Here, we developed an imaging pipeline to address this pressing need. A protocol that employs scanning multiphoton microscopy was developed to obtain three-dimensional (3D) datasets for smooth muscle actin, collagen, and elastin in intact vascular specimens. A cluster analysis was introduced to objectively categorize the smooth muscle cells (SMC) across the vascular specimen based on SMC actin density. Finally, direct quantitative comparison of local flow and wall biology in 3D intact specimens was achieved by comapping both heterogeneous SMC data and wall thickness to patient-specific hemodynamic results.
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Affiliation(s)
- Yasutaka Tobe
- Department of Mechanical Engineering and Materials Science, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Anne M Robertson
- Department of Mechanical Engineering and Materials Science, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Mehdi Ramezanpour
- Department of Mechanical Engineering and Materials Science, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Juan R Cebral
- Department of Bioengineering, George Mason University, Fairfax, VA 22030, USA
| | - Simon C Watkins
- Department of Cell Biology, University of Pittsburgh, PA 15261, USA
| | - Fady T Charbel
- Department of Neurosurgery, University of Illinois at Chicago, Chicago, IL 60612, USA
| | - Sepideh Amin-Hanjani
- Department of Neurological Surgery, University Hospital Cleveland Medical Center, Cleveland, OH 44106, USA
| | - Alexander K Yu
- Department of Neurological Surgery, Allegheny Health Network, Pittsburgh, PA 15212, USA
| | - Boyle C Cheng
- Neuroscience and Orthopedic Institutes, Allegheny Health Network, Pittsburgh, PA 15212, USA
| | - Henry H Woo
- Department of Neurosurgery, Donald and Barbara Zucker School of Medicine at Hofstra Northwell, Manhasset, NY 11549, USA
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Liao J, Misaki K, Uno T, Futami K, Nakada M, Sakamoto J. Determination of Significant Three-Dimensional Hemodynamic Features for Postembolization Recanalization in Cerebral Aneurysms Through Explainable Artificial Intelligence. World Neurosurg 2024; 184:e166-e177. [PMID: 38246531 DOI: 10.1016/j.wneu.2024.01.076] [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: 10/10/2023] [Revised: 01/12/2024] [Accepted: 01/13/2024] [Indexed: 01/23/2024]
Abstract
BACKGROUND Recanalization poses challenges after coil embolization in cerebral aneurysms. Establishing predictive models for postembolization recanalization is important for clinical decision making. However, conventional statistical and machine learning (ML) models may overlook critical parameters during the initial selection process. METHODS In this study, we automated the identification of significant hemodynamic parameters using a PointNet-based deep neural network (DNN), leveraging their three-dimensional spatial features. Further feature analysis was conducted using saliency mapping, an explainable artificial intelligence (XAI) technique. The study encompassed the analysis of velocity, pressure, and wall shear stress in both precoiling and postcoiling models derived from computational fluid dynamics simulations for 58 aneurysms. RESULTS Velocity was identified as the most pivotal parameter, supported by the lowest P value from statistical analysis and the highest area under the receiver operating characteristic curves/precision-recall curves values from the DNN model. Moreover, visual XAI analysis showed that robust injection flow zones, with notable impingement points in precoiling models, as well as pronounced interplay between flow dynamics and the coiling plane, were important three-dimensional features in identifying the recanalized aneurysms. CONCLUSIONS The combination of DNN and XAI was found to be an accurate and explainable approach not only at predicting postembolization recanalization but also at discovering unknown features in the future.
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Affiliation(s)
- Jing Liao
- Division of Transdisciplinary Sciences, Graduate School of Frontier Science Initiative, Kanazawa University, Kanazawa, Ishikawa, Japan
| | - Kouichi Misaki
- Department of Neurosurgery, Kanazawa University, Kanazawa, Ishikawa, Japan.
| | - Tekehiro Uno
- Department of Neurosurgery, Kanazawa University, Kanazawa, Ishikawa, Japan
| | - Kazuya Futami
- Department of Neurosurgery, Hokuriku Central Hospital, Oyabe, Toyama, Japan
| | - Mitsutoshi Nakada
- Department of Neurosurgery, Kanazawa University, Kanazawa, Ishikawa, Japan
| | - Jiro Sakamoto
- Division of Mechanical Science and Engineering, Graduate School of Natural Science and Technology, Kanazawa University, Kanazawa, Ishikawa, Japan
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Hadad S, Mut F, Slawski M, Robertson AM, Cebral JR. Evaluation of predictive models of aneurysm focal growth and bleb development using machine learning techniques. J Neurointerv Surg 2024; 16:392-397. [PMID: 37230750 PMCID: PMC10674044 DOI: 10.1136/jnis-2023-020241] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Accepted: 05/15/2023] [Indexed: 05/27/2023]
Abstract
BACKGROUND The presence of blebs increases the rupture risk of intracranial aneurysms (IAs). OBJECTIVE To evaluate whether cross-sectional bleb formation models can identify aneurysms with focalized enlargement in longitudinal series. METHODS Hemodynamic, geometric, and anatomical variables derived from computational fluid dynamics models of 2265 IAs from a cross-sectional dataset were used to train machine learning (ML) models for bleb development. ML algorithms, including logistic regression, random forest, bagging method, support vector machine, and K-nearest neighbors, were validated using an independent cross-sectional dataset of 266 IAs. The models' ability to identify aneurysms with focalized enlargement was evaluated using a separate longitudinal dataset of 174 IAs. Model performance was quantified by the area under the receiving operating characteristic curve (AUC), the sensitivity and specificity, positive predictive value, negative predictive value, F1 score, balanced accuracy, and misclassification error. RESULTS The final model, with three hemodynamic and four geometrical variables, along with aneurysm location and morphology, identified strong inflow jets, non-uniform wall shear stress with high peaks, larger sizes, and elongated shapes as indicators of a higher risk of focal growth over time. The logistic regression model demonstrated the best performance on the longitudinal series, achieving an AUC of 0.9, sensitivity of 85%, specificity of 75%, balanced accuracy of 80%, and a misclassification error of 21%. CONCLUSIONS Models trained with cross-sectional data can identify aneurysms prone to future focalized growth with good accuracy. These models could potentially be used as early indicators of future risk in clinical practice.
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Affiliation(s)
- Sara Hadad
- Department of Bioengineering, George Mason University, Fairfax, Virginia, USA
| | - Fernando Mut
- Department of Bioengineering, George Mason University, Fairfax, Virginia, USA
| | - Martin Slawski
- Statistics Department, George Mason University, Fairfax, Virginia, USA
| | - Anne M Robertson
- Departmnet of Mechanical enginering and Material Science, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Juan R Cebral
- Department of Bioengineering, George Mason University, Fairfax, Virginia, USA
- Department of Mechanical Engineering, George Mason University, Fairfax, Virginia, USA
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Ramezanpour M, Robertson AM, Tobe Y, Jia X, Cebral JR. Phenotyping calcification in vascular tissues using artificial intelligence. ARXIV 2024:arXiv:2401.07825v2. [PMID: 38313202 PMCID: PMC10836085] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 02/06/2024]
Abstract
Vascular calcification is implicated as an important factor in major adverse cardiovascular events (MACE), including heart attack and stroke. A controversy remains over how to integrate the diverse forms of vascular calcification into clinical risk assessment tools. Even the commonly used calcium score for coronary arteries, which assumes risk scales positively with total calcification, has important inconsistencies. Fundamental studies are needed to determine how risk is influenced by the diverse calcification phenotypes. However, studies of these kinds are hindered by the lack of high-throughput, objective, and non-destructive tools for classifying calcification in imaging data sets. Here, we introduce a new classification system for phenotyping calcification along with a semi-automated, non-destructive pipeline that can distinguish these phenotypes in even atherosclerotic tissues. The pipeline includes a deep-learning-based framework for segmenting lipid pools in noisy μ-CT images and an unsupervised clustering framework for categorizing calcification based on size, clustering, and topology. This approach is illustrated for five vascular specimens, providing phenotyping for thousands of calcification particles across as many as 3200 images in less than seven hours. Average Dice Similarity Coefficients of 0.96 and 0.87 could be achieved for tissue and lipid pool, respectively, with training and validation needed on only 13 images despite the high heterogeneity in these tissues. By introducing an efficient and comprehensive approach to phenotyping calcification, this work enables large-scale studies to identify a more reliable indicator of the risk of cardiovascular events, a leading cause of global mortality and morbidity.
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Affiliation(s)
- Mehdi Ramezanpour
- Department of Mechanical Engineering and Materials Science, University of Pittsburgh, PA, USA
| | - Anne M. Robertson
- Department of Mechanical Engineering and Materials Science, University of Pittsburgh, PA, USA
| | - Yasutaka Tobe
- Department of Mechanical Engineering and Materials Science, University of Pittsburgh, PA, USA
| | - Xiaowei Jia
- Department of Computer Science, University of Pittsburgh, PA, USA
| | - Juan R. Cebral
- Department of Mechanical Engineering, George Mason University, Fairfax, Virginia, USA
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Niemann A, Tulamo R, Netti E, Preim B, Berg P, Cebral J, Robertson A, Saalfeld S. Multimodal exploration of the intracranial aneurysm wall. Int J Comput Assist Radiol Surg 2023; 18:2243-2252. [PMID: 36877287 PMCID: PMC10480333 DOI: 10.1007/s11548-023-02850-0] [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: 09/21/2022] [Accepted: 02/02/2023] [Indexed: 03/07/2023]
Abstract
PURPOSE Intracranial aneurysms (IAs) are pathological changes of the intracranial vessel wall, although clinical image data can only show the vessel lumen. Histology can provide wall information but is typically restricted to ex vivo 2D slices where the shape of the tissue is altered. METHODS We developed a visual exploration pipeline for a comprehensive view of an IA. We extract multimodal information (like stain classification and segmentation of histologic images) and combine them via 2D to 3D mapping and virtual inflation of deformed tissue. Histological data, including four stains, micro-CT data and segmented calcifications as well as hemodynamic information like wall shear stress (WSS), are combined with the 3D model of the resected aneurysm. RESULTS Calcifications were mostly present in the tissue part with increased WSS. In the 3D model, an area of increased wall thickness was identified and correlated to histology, where the Oil red O (ORO) stained images showed a lipid accumulation and the alpha-smooth muscle actin (aSMA) stained images showed a slight loss of muscle cells. CONCLUSION Our visual exploration pipeline combines multimodal information about the aneurysm wall to improve the understanding of wall changes and IA development. The user can identify regions and correlate how hemodynamic forces, e.g. WSS, are reflected by histological structures of the vessel wall, wall thickness and calcifications.
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Affiliation(s)
- Annika Niemann
- Department of Simulation and Graphics, Otto-von-Guericke University, Magdeburg, Germany
- STIMULATE Research Campus, Magdeburg, Germany
| | - Riikka Tulamo
- Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Eliisa Netti
- Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Bernhard Preim
- Department of Simulation and Graphics, Otto-von-Guericke University, Magdeburg, Germany
- STIMULATE Research Campus, Magdeburg, Germany
| | - Philipp Berg
- STIMULATE Research Campus, Magdeburg, Germany
- Department of Medical Engineering, Otto-von-Guericke University Magdeburg, Magdeburg, Germany
| | - Juan Cebral
- Computational Hemodynamics Lab, Georg Mason University, Fairfax, USA
| | - Anne Robertson
- Department of Mechanical Engineering and Materials Science, University of Pittsburgh, Pittsburgh, USA
| | - Sylvia Saalfeld
- Department of Simulation and Graphics, Otto-von-Guericke University, Magdeburg, Germany.
- STIMULATE Research Campus, Magdeburg, Germany.
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8
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Salimi Ashkezari SF, Mut F, Robertson AM, Cebral JR. Differences Between Ruptured Aneurysms With and Without Blebs: Mechanistic Implications. Cardiovasc Eng Technol 2023; 14:92-103. [PMID: 35819581 PMCID: PMC10029732 DOI: 10.1007/s13239-022-00640-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Accepted: 07/01/2022] [Indexed: 11/26/2022]
Abstract
PURPOSE Blebs are known risk factors for intracranial aneurysm (IA) rupture. We analyzed differences between IAs that ruptured with blebs and those that ruptured without developing blebs to identify distinguishing characteristics among them and suggest possible mechanistic implications. METHODS Using image-based models, 25 hemodynamic and geometric parameters were compared between ruptured IAs with and without blebs (n = 673), stratified by location. Hemodynamic and geometric differences between bifurcation and sidewall aneurysms and for aneurysms at five locations were also analyzed. RESULTS Ruptured aneurysms harboring blebs were exposed to higher flow conditions than aneurysms that ruptured without developing blebs, and this was consistent across locations. Bifurcation aneurysms were exposed to higher flow conditions than sidewall aneurysms. They had larger maximum wall shear stress (WSS), more concentrated WSS distribution, and larger numbers of critical points than sidewall aneurysms. Additionally, bifurcation aneurysms were larger, more elongated, and had more distorted shapes than sidewall aneurysms. Aneurysm morphology was associated with aneurysm location (p < 0.01). Flow conditions were different between aneurysm locations. CONCLUSION Aneurysms at different locations are likely to develop into varying morphologies and thus be exposed to diverse flow conditions that may predispose them to follow distinct pathways towards rupture with or without bleb development. This could explain the diverse rupture rates and bleb presence in aneurysms at different locations.
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Affiliation(s)
- Seyedeh Fatemeh Salimi Ashkezari
- Department of Bioengineering, Volgenau School of Engineering, George Mason University, 4400 University Drive, Fairfax, VA, 22030, USA.
| | - Fernando Mut
- Department of Bioengineering, Volgenau School of Engineering, George Mason University, 4400 University Drive, Fairfax, VA, 22030, USA
| | - Anne M Robertson
- Department of Mechanical Engineering and Material Science, University of Pittsburgh, Pittsburgh, PA, USA
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA
| | - Juan R Cebral
- Department of Bioengineering, Volgenau School of Engineering, George Mason University, 4400 University Drive, Fairfax, VA, 22030, USA
- Department of Mechanical Engineering, George Mason University, Fairfax, VA, USA
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9
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Fan Z, Dong L, Zhang Y, Ye X, Deng X. Hemodynamic impact of proximal anterior cerebral artery aneurysm: Mind the posteriorly projecting ones! Proc Inst Mech Eng H 2022; 236:656-664. [DOI: 10.1177/09544119221082420] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Intracranial aneurysm projected posteriorly is associated with high risk of aneurysm rupture. In order to investigate the biomechanical mechanisms for the adverse event, three-dimension intracranial cerebral aneurysms were constructed based on clinical data, and we numerically compared effect of location, position, size, and shape of aneurysm on hemodynamic conditions including velocity, pressure, and wall shear stress (WSS). The numerical results showed that the aneurysm projected posteriorly even at small sizes led to abnormal hemodynamic environment, which was featured by a local high pressure and stress concentration near aneurysm neck area. Moreover, the one located at the proximal A1 segment and ellipsoidal aneurysm would further worse local hemodynamic environment, causing high local stresses. These findings indicated the potential mechanical mechanism for high rupture rate of the aneurysms projected posteriorly, underscoring importance of early and accurate diagnosis and promptly treatment for improved the clinical outcome, even if these aneurysms are of small sizes.
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Affiliation(s)
- Zhenmin Fan
- School of Mechanical Engineering, Jiangsu University of Technology, Changzhou, Jiangsu, China
| | - Lijun Dong
- School of Mechanical Engineering, Jiangsu University of Technology, Changzhou, Jiangsu, China
| | - Yingying Zhang
- Beijing Key Laboratory of Rehabilitation Technical Aids for Old-Age Disability, National Research Center for Rehabilitation Technical Aids, Beijing, China
| | - Xia Ye
- School of Mechanical Engineering, Jiangsu University of Technology, Changzhou, Jiangsu, China
| | - Xiaoyan Deng
- Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, Beijing, China
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10
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Salimi Ashkezari SF, Mut F, Slawski M, Jimenez CM, Robertson AM, Cebral JR. Identification of Small, Regularly Shaped Cerebral Aneurysms Prone to Rupture. AJNR Am J Neuroradiol 2022; 43:547-553. [PMID: 35332023 PMCID: PMC8993208 DOI: 10.3174/ajnr.a7470] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Accepted: 01/20/2022] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE Many small, regularly shaped cerebral aneurysms rupture; however, they usually receive a low score based on current risk-assessment methods. Our goal was to identify patient and aneurysm characteristics associated with rupture of small, regularly shaped aneurysms and to develop and validate predictive models of rupture in this aneurysm subpopulation. MATERIALS AND METHODS Cross-sectional data from 1079 aneurysms smaller than 7 mm with regular shapes (without blebs) were used to train predictive models for aneurysm rupture using machine learning methods. These models were based on the patient population, aneurysm location, and hemodynamic and geometric characteristics derived from image-based computational fluid dynamics models. An independent data set with 102 small, regularly shaped aneurysms was used for validation. RESULTS Adverse hemodynamic environments characterized by strong, concentrated inflow jets, high speed, complex and unstable flow patterns, and concentrated, oscillatory, and heterogeneous wall shear stress patterns were associated with rupture in small, regularly shaped aneurysms. Additionally, ruptured aneurysms were larger and more elongated than unruptured aneurysms in this subset. A total of 5 hemodynamic and 6 geometric parameters along with aneurysm location, multiplicity, and morphology, were used as predictive variables. The best machine learning rupture prediction-model achieved a good performance with an area under the curve of 0.84 on the external validation data set. CONCLUSIONS This study demonstrated the potential of using predictive machine learning models based on aneurysm-specific hemodynamic, geometric, and anatomic characteristics for identifying small, regularly shaped aneurysms prone to rupture.
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Affiliation(s)
| | - F Mut
- From the Departments of Bioengineering (S.F.S.A., F.M., J.R.C.)
| | | | - C M Jimenez
- Neurosurgery Department (C.M.J.), University of Antioquia, Medellin, Colombia
| | - A M Robertson
- Departments of Mechanical Engineering and Material Science (A.M.R.)
- Bioengineering (A.M.R.), University of Pittsburgh, Pittsburgh, Pennsylvania
| | - J R Cebral
- From the Departments of Bioengineering (S.F.S.A., F.M., J.R.C.)
- Mechanical Engineering (J.R.C.), George Mason University, Fairfax, Virginia
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11
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Williamson PN, Docherty PD, Yazdi SG, Khanafer A, Kabaliuk N, Jermy M, Geoghegan PH. Review of the Development of Hemodynamic Modeling Techniques to Capture Flow Behavior in Arteries Affected by Aneurysm, Atherosclerosis, and Stenting. J Biomech Eng 2022; 144:1128816. [PMID: 34802061 DOI: 10.1115/1.4053082] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Indexed: 02/05/2023]
Abstract
Cardiovascular diseases (CVDs) are the leading cause of death in the developed world. CVD can include atherosclerosis, aneurysm, dissection, or occlusion of the main arteries. Many CVDs are caused by unhealthy hemodynamics. Some CVDs can be treated with the implantation of stents and stent grafts. Investigations have been carried out to understand the effects of stents and stent grafts have on arteries and the hemodynamic changes post-treatment. Numerous studies on stent hemodynamics have been carried out using computational fluid dynamics (CFD) which has yielded significant insight into the effect of stent mesh design on near-wall blood flow and improving hemodynamics. Particle image velocimetry (PIV) has also been used to capture behavior of fluids that mimic physiological hemodynamics. However, PIV studies have largely been restricted to unstented models or intra-aneurysmal flow rather than peri or distal stent flow behaviors. PIV has been used both as a standalone measurement method and as a comparison to validate the CFD studies. This article reviews the successes and limitations of CFD and PIV-based modeling methods used to investigate the hemodynamic effects of stents. The review includes an overview of physiology and relevant mechanics of arteries as well as consideration of boundary conditions and the working fluids used to simulate blood for each modeling method along with the benefits and limitations introduced.
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Affiliation(s)
- Petra N Williamson
- Department of Mechanical Engineering, University of Canterbury, Private Bag 4800, Christchurch 8140, New Zealand
| | - Paul D Docherty
- Department of Mechanical Engineering, University of Canterbury, Private Bag 4800, Christchurch 8140, New Zealand
| | - Sina G Yazdi
- Department of Mechanical Engineering, University of Canterbury, Private Bag 4800, Christchurch 8140, New Zealand
| | - Adib Khanafer
- Vascular, Endovascular, and Renal Transplant Unit, Christchurch Hospital, Canterbury District Health Board, Riccarton Avenue, Christchurch 8053, New Zealand; Christchurch School of Medicine, University of Otago, Dunedin 9016, New Zealand
| | - Natalia Kabaliuk
- Department of Mechanical Engineering, University of Canterbury, Private Bag 4800, Christchurch 8140, New Zealand
| | - Mark Jermy
- Department of Mechanical Engineering, University of Canterbury, Private Bag 4800, Christchurch 8140, New Zealand
| | - Patrick H Geoghegan
- School of Life and Health Sciences, Aston University, Birmingham B4 7ET, UK; Department of Mechanical and Industrial Engineering, University of South Africa, Johannesburg 2006, South Africa
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12
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Salimi Ashkezari SF, Mut F, Slawski M, Cheng B, Yu AK, White TG, Woo HH, Koch MJ, Amin-Hanjani S, Charbel FT, Rezai Jahromi B, Niemelä M, Koivisto T, Frosen J, Tobe Y, Maiti S, Robertson AM, Cebral JR. Prediction of bleb formation in intracranial aneurysms using machine learning models based on aneurysm hemodynamics, geometry, location, and patient population. J Neurointerv Surg 2021; 14:1002-1007. [PMID: 34686573 PMCID: PMC9023610 DOI: 10.1136/neurintsurg-2021-017976] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Accepted: 10/08/2021] [Indexed: 11/04/2022]
Abstract
BACKGROUND Bleb presence in intracranial aneurysms (IAs) is a known indication of instability and vulnerability. OBJECTIVE To develop and evaluate predictive models of bleb development in IAs based on hemodynamics, geometry, anatomical location, and patient population. METHODS Cross-sectional data (one time point) of 2395 IAs were used for training bleb formation models using machine learning (random forest, support vector machine, logistic regression, k-nearest neighbor, and bagging). Aneurysm hemodynamics and geometry were characterized using image-based computational fluid dynamics. A separate dataset with 266 aneurysms was used for model evaluation. Model performance was quantified by the area under the receiving operating characteristic curve (AUC), true positive rate (TPR), false positive rate (FPR), precision, and balanced accuracy. RESULTS The final model retained 18 variables, including hemodynamic, geometrical, location, multiplicity, and morphology parameters, and patient population. Generally, strong and concentrated inflow jets, high speed, complex and unstable flow patterns, and concentrated, oscillatory, and heterogeneous wall shear stress patterns together with larger, more elongated, and more distorted shapes were associated with bleb formation. The best performance on the validation set was achieved by the random forest model (AUC=0.82, TPR=91%, FPR=36%, misclassification error=27%). CONCLUSIONS Based on the premise that aneurysm characteristics prior to bleb formation resemble those derived from vascular reconstructions with their blebs virtually removed, machine learning models can identify aneurysms prone to bleb development with good accuracy. Pending further validation with longitudinal data, these models may prove valuable for assessing the propensity of IAs to progress to vulnerable states and potentially rupturing.
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Affiliation(s)
| | - Fernando Mut
- Department of Bioengineering, George Mason University, Fairfax, Virginia, USA
| | - Martin Slawski
- Department of Statistics, George Mason University, Fairfax, Virginia, USA
| | - Boyle Cheng
- Department of Neurosurgery, Allegheny General Hospital, Pittsburgh, Pennsylvania, USA
| | - Alexander K Yu
- Department of Neurosurgery, Allegheny General Hospital, Pittsburgh, Pennsylvania, USA
| | - Tim G White
- Department of Neurosurgery, Donald and Barbara Zucker School of Medicine at Hofstra/Northwell, Manhasset, New York, USA
| | - Henry H Woo
- Department of Neurosurgery, Donald and Barbara Zucker School of Medicine at Hofstra/Northwell, Manhasset, New York, USA
| | - Matthew J Koch
- Department of Neurosurgery, University of Illinois at Chicago, Chicago, Illinois, USA
| | - Sepideh Amin-Hanjani
- Department of Neurosurgery, University of Illinois at Chicago, Chicago, Illinois, USA
| | - Fady T Charbel
- Department of Neurosurgery, University of Illinois at Chicago, Chicago, Illinois, USA
| | - Behnam Rezai Jahromi
- Neurosurgery Research Group, Biomedicum Helsinki, University of Helsinki, Helsinki, Uusimaa, Finland
| | - Mika Niemelä
- Department of Neurosurgery, Töölö Hospital, University of Helsinki, Helsinki, Finland
| | - Timo Koivisto
- Department of Neurosurgery, Kuopio University Hospital, Kuopio, Pohjois-Savo, Finland
| | - Juhana Frosen
- Department of Neurosurgery, Tampere University Hospital, Tampere, Finland.,Hemorrhagic Brain Pathology Research Group, NeuroCenter, Kuopio University Hospital, Kuopio, Pohjois-Savo, Finland
| | - Yasutaka Tobe
- Department of Mechanical Engineering and Material Science, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.,Department of Bioengineering, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Spandan Maiti
- Department of Mechanical Engineering and Material Science, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Anne M Robertson
- Department of Mechanical Engineering and Material Science, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.,Department of Bioengineering, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Juan R Cebral
- Department of Bioengineering, George Mason University, Fairfax, Virginia, USA.,Department of Mechanical Engineering, George Mason University, Fairfax, Virginia, USA
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13
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The association between hemodynamics and wall characteristics in human intracranial aneurysms: a review. Neurosurg Rev 2021; 45:49-61. [PMID: 33913050 DOI: 10.1007/s10143-021-01554-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Revised: 04/02/2021] [Accepted: 04/20/2021] [Indexed: 12/28/2022]
Abstract
Hemodynamics plays a key role in the natural history of intracranial aneurysms (IAs). However, studies exploring the association between aneurysmal hemodynamics and the biological and mechanical characteristics of the IA wall in humans are sparse. In this review, we survey the current body of literature, summarize the studies' methodologies and findings, and assess the degree of consensus among them. We used PubMed to perform a systematic review of studies that explored the association between hemodynamics and human IA wall features using different sources. We identified 28 publications characterizing aneurysmal flow and the IA wall: 4 using resected tissues, 17 using intraoperative images, and 7 using vessel wall magnetic resonance imaging (MRI). Based on correlation to IA tissue, higher flow conditions, such as high wall shear stress (WSS) with complex pattern and elevated pressure, were associated with degenerated walls and collagens with unphysiological orientation and faster synthesis. MRI studies strongly supported that low flow, characterized by low WSS and high blood residence time, was associated with thicker walls and post-contrast enhancement. While significant discrepancies were found among those utilized intraoperative images, they generally supported that thicker walls coexist at regions with prolonged residence time and that thinner regions are mainly exposed to higher pressure with complex WSS patterns. The current body of literature supports a theory of two general hemodynamic-biologic mechanisms for IA development. One, where low flow conditions are associated with thickening and atherosclerotic-like remodeling, and the other where high and impinging flow conditions are related to wall degeneration, thinning, and collagen remodeling.
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14
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Zárate-Méndez AM, Ramos-Delgado JM, Lujan-Guerra JC, Rio-Olivares CD, Moreira-Ponce LE, Aceves-Chimal JL. Three-Dimensional Virtual Reality Simulation to Safe Planning Neurosurgical Procedure in Brain Aneurysms, Latin American Single-Center Experience: Advantages and Limitations. INDIAN JOURNAL OF NEUROSURGERY 2021. [DOI: 10.1055/s-0041-1725233] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
Abstract
Abstract
Background The neurosurgical approach to clipping cerebral aneurysms has been a complex challenge for all neurosurgeon experts in cerebrovascular surgery. The three-dimensional computed tomography angiography (3D-CTA) allows identifying bone and vascular structures close to an aneurysm to simulate in virtual 3D images, the appropriate and safest approach to cerebral aneurysm clipping.
Objectives This study aims to share our experience using 3D simulation as a support to the safe planning for cerebrovascular disease surgery.
Materials and Methods We reviewed the surgical outcomes from a cerebrovascular neurosurgeon using the 3D-CTA images in 360-degree reconstruction in the planning of the preoperative surgical procedure for the treatment of brain aneurysm. In all patients, the virtual surgical approach was replicated in real-time surgery.
Results We analyzed 34 patients around 51 ± 8 years of age. Of these, 76.5% (n = 26) and 23.5% (n = 8) were males and females, respectively. Saccular aneurysms were the most frequent (85%), the Arteries affected by aneurysms were middle cerebral artery (n = 6), basilar tip (n = 6), vertebral artery in V3 and V4 (n = 6), and posterior cerebral artery (n = 5). The virtual surgical pterional approach was the most frequently used (50%), followed by fronto-orbito-zigomático (29%) and far lateral (15%) approaches. There were no intraoperative complications in any patient.
Conclusion Preoperative 3D virtual reality simulation is a great support tool to perform a safe surgical procedure in real-time for the treatment of simple and complex brain aneurysms.
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Affiliation(s)
- Antonio M. Zárate-Méndez
- Department of Neurosurgery, Centro Médico Nacional “20 de Noviembre” Instituto de Seguridad y Servicios Sociales de los Trabajadores del Estado (ISSSTE), Mexico City, Mexico
| | - José M. Ramos-Delgado
- Department of Neurosurgery, Centro Médico Nacional “20 de Noviembre” Instituto de Seguridad y Servicios Sociales de los Trabajadores del Estado (ISSSTE), Mexico City, Mexico
| | - Juan C. Lujan-Guerra
- Department of Neurosurgery, Centro Médico Nacional “20 de Noviembre” Instituto de Seguridad y Servicios Sociales de los Trabajadores del Estado (ISSSTE), Mexico City, Mexico
| | - Carlos D. Rio-Olivares
- Department of Neurosurgery, Centro Médico Nacional “20 de Noviembre” Instituto de Seguridad y Servicios Sociales de los Trabajadores del Estado (ISSSTE), Mexico City, Mexico
| | - Luis E. Moreira-Ponce
- Department of Neurosurgery, Centro Médico Nacional “20 de Noviembre” Instituto de Seguridad y Servicios Sociales de los Trabajadores del Estado (ISSSTE), Mexico City, Mexico
| | - José L. Aceves-Chimal
- Department of Neurosurgery, Centro Médico Nacional “20 de Noviembre” Instituto de Seguridad y Servicios Sociales de los Trabajadores del Estado (ISSSTE), Mexico City, Mexico
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15
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Niemann A, Voß S, Tulamo R, Weigand S, Preim B, Berg P, Saalfeld S. Complex wall modeling for hemodynamic simulations of intracranial aneurysms based on histologic images. Int J Comput Assist Radiol Surg 2021; 16:597-607. [PMID: 33715047 PMCID: PMC8052238 DOI: 10.1007/s11548-021-02334-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Accepted: 02/25/2021] [Indexed: 12/04/2022]
Abstract
Purpose For the evaluation and rupture risk assessment of intracranial aneurysms, clinical, morphological and hemodynamic parameters are analyzed. The reliability of intracranial hemodynamic simulations strongly depends on the underlying models. Due to the missing information about the intracranial vessel wall, the patient-specific wall thickness is often neglected as well as the specific physiological and pathological properties of the vessel wall. Methods In this work, we present a model for structural simulations with patient-specific wall thickness including different tissue types based on postmortem histologic image data. Images of histologic 2D slices from intracranial aneurysms were manually segmented in nine tissue classes. After virtual inflation, they were combined into 3D models. This approach yields multiple 3D models of the inner and outer wall and different tissue parts as a prerequisite for subsequent simulations. Result We presented a pipeline to generate 3D models of aneurysms with respect to the different tissue textures occurring in the wall. First experiments show that including the variance of the tissue in the structural simulation affect the simulation result. Especially at the interfaces between neighboring tissue classes, the larger influence of stiffer components on the stability equilibrium became obvious. Conclusion The presented approach enables the creation of a geometric model with differentiated wall tissue. This information can be used for different applications, like hemodynamic simulations, to increase the modeling accuracy.
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Affiliation(s)
- Annika Niemann
- Faculty of Computer Science, Otto-von-Guericke University Magdeburg, Universitätsplatz 2, D-39106, Magdeburg, Germany.
| | - Samuel Voß
- Laboratory of Fluid Dynamics and Technical Flows, Otto-von-Guericke University Magdeburg, Magdeburg, Germany
| | - Riikka Tulamo
- Department of Vascular Surgery, and Neurosurgery Research Group, Helsinki University Hospital and University of Helsinki, Helsinki, Finland
| | - Simon Weigand
- Department of General, Visceral and Transplantation Surgery, Hospital of the University of Munich, Campus Grosshadern, Munich, Germany
| | - Bernhard Preim
- Faculty of Computer Science, Otto-von-Guericke University Magdeburg, Universitätsplatz 2, D-39106, Magdeburg, Germany
| | - Philipp Berg
- Laboratory of Fluid Dynamics and Technical Flows, Otto-von-Guericke University Magdeburg, Magdeburg, Germany.,Forschungscampus STIMULATE, Magdeburg, Germany
| | - Sylvia Saalfeld
- Faculty of Computer Science, Otto-von-Guericke University Magdeburg, Universitätsplatz 2, D-39106, Magdeburg, Germany.,Forschungscampus STIMULATE, Magdeburg, Germany
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16
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Teixeira FS, Neufeld E, Kuster N, Watton PN. Modeling intracranial aneurysm stability and growth: an integrative mechanobiological framework for clinical cases. Biomech Model Mechanobiol 2020; 19:2413-2431. [PMID: 32533497 PMCID: PMC7603456 DOI: 10.1007/s10237-020-01351-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2019] [Accepted: 05/12/2020] [Indexed: 11/03/2022]
Abstract
We present a novel patient-specific fluid-solid-growth framework to model the mechanobiological state of clinically detected intracranial aneurysms (IAs) and their evolution. The artery and IA sac are modeled as thick-walled, non-linear elastic fiber-reinforced composites. We represent the undulation distribution of collagen fibers: the adventitia of the healthy artery is modeled as a protective sheath whereas the aneurysm sac is modeled to bear load within physiological range of pressures. Initially, we assume the detected IA is stable and then consider two flow-related mechanisms to drive enlargement: (1) low wall shear stress; (2) dysfunctional endothelium which is associated with regions of high oscillatory flow. Localized collagen degradation and remodelling gives rise to formation of secondary blebs on the aneurysm dome. Restabilization of blebs is achieved by remodelling of the homeostatic collagen fiber stretch distribution. This integrative mechanobiological modelling workflow provides a step towards a personalized risk-assessment and treatment of clinically detected IAs.
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Affiliation(s)
| | - Esra Neufeld
- IT’IS Foundation & ETH Zürich, Zürich, Switzerland
| | - Niels Kuster
- IT’IS Foundation & ETH Zürich, Zürich, Switzerland
| | - Paul N. Watton
- Department of Computer Science, Insigneo Institute for in silico Medicine, University of Sheffield, Sheffield, UK
- Department of Mechanical Engineering and Materials Science, University of Pittsburgh, Pittsburgh, USA
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17
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Salimi Ashkezari SF, Detmer FJ, Mut F, Chung BJ, Yu AK, Stapleton CJ, See AP, Amin-Hanjani S, Charbel FT, Rezai Jahromi B, Niemelä M, Frösen J, Zhou J, Maiti S, Robertson AM, Cebral JR. Blebs in intracranial aneurysms: prevalence and general characteristics. J Neurointerv Surg 2020; 13:226-230. [PMID: 32680877 PMCID: PMC8294207 DOI: 10.1136/neurintsurg-2020-016274] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Revised: 06/16/2020] [Accepted: 06/18/2020] [Indexed: 12/14/2022]
Abstract
BACKGROUND Blebs are rupture risk factors in intracranial aneurysms (IAs), but their prevalence, distribution, and associations with clinical factors as well as their causes and effects on aneurysm vulnerability remain unclear. METHODS A total of 122 blebs in 270 IAs selected for surgery were studied using patient-specific vascular reconstructions from 3D angiographic images. Bleb geometry, location on the aneurysm, and frequency of occurrence in aneurysms at different locations were analyzed. Associations between gender, age, smoking, hypertension, hormone therapy, dental infection, and presence of blebs were investigated. RESULTS Of all aneurysms with blebs, 77% had a single bleb and 23% had multiple blebs. Only 6% of blebs were at the neck, while 46% were in the body and 48% in the dome. Aneurysms with blebs were larger (p<0.0001), more elongated (p=0.0002), and with wider necks than aneurysms without blebs. Bleb presence was associated with dental infection (p=0.0426) and negatively associated with hormone therapy (p=0.0426) in women. Anterior and posterior communicating arteries had larger percentages of aneurysms with blebs than internal carotid arteries. Patients with a history of hypertension tended to have a larger percentage of aneurysms with blebs. However, these trends did not reach significance in this sample. CONCLUSIONS Blebs are common in IAs, and most aneurysms harboring blebs have a single bleb. Blebs in the aneurysm neck are rare, but they are equally common in the body and dome. The presence of blebs in IAs was associated with dental infection, and negatively associated with hormone replacement therapy.
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Affiliation(s)
| | - Felicitas J Detmer
- Gordon Center for Medical Imaging, Massachusetts General Hospital, Boston, Massachusetts, USA.,Harvard Medical School, Boston, Massachusetts, USA
| | - Fernando Mut
- Department of Bioengineering, George Mason University, Fairfax, Virginia, USA
| | - Bong Jae Chung
- Department of Mathematical Sciences, Montclair State University, Montclair, New Jersey, USA
| | - Alexander K Yu
- Neurosurgery, Allegheny General Hospital, Pittsburgh, Pennsylvania, USA
| | | | - Alfred P See
- Department of Neurosurgery, University of Illinois at Chicago, Chicago, Illinois, USA
| | - Sepideh Amin-Hanjani
- Department of Neurosurgery, University of Illinois at Chicago, Chicago, Illinois, USA
| | - Fady T Charbel
- Department of Neurosurgery, University of Illinois at Chicago, Chicago, Illinois, USA
| | - Behnam Rezai Jahromi
- Neurosurgery Research Group, Biomedicum Helsinki, University of Helsinki, Helsinki, Uusimaa, Finland
| | - Mika Niemelä
- Neurosurgery Research Group, Biomedicum Helsinki, University of Helsinki, Helsinki, Uusimaa, Finland
| | - Juhana Frösen
- Department of Neurosurgery, University of Tampere, Tampere, Pirkanmaa, Finland.,Department of Neurosurgery, Tampere University Hospital, Tampere, Finland
| | - Ji Zhou
- Department of Mechanical Engineering and Material Science, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Spandan Maiti
- Department of Mechanical Engineering and Material Science, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Anne M Robertson
- Department of Mechanical Engineering and Material Science, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.,Department of Bioengineering, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Juan R Cebral
- Department of Bioengineering, George Mason University, Fairfax, Virginia, USA.,Department of Mechanical Engineering, George Mason University, Fairfax, Virginia, USA
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18
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Rayz VL, Cohen-Gadol AA. Hemodynamics of Cerebral Aneurysms: Connecting Medical Imaging and Biomechanical Analysis. Annu Rev Biomed Eng 2020; 22:231-256. [PMID: 32212833 DOI: 10.1146/annurev-bioeng-092419-061429] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
In the last two decades, numerous studies have conducted patient-specific computations of blood flow dynamics in cerebral aneurysms and reported correlations between various hemodynamic metrics and aneurysmal disease progression or treatment outcomes. Nevertheless, intra-aneurysmal flow analysis has not been adopted in current clinical practice, and hemodynamic factors usually are not considered in clinical decision making. This review presents the state of the art in cerebral aneurysm imaging and image-based modeling, discussing the advantages and limitations of each approach and focusing on the translational value of hemodynamic analysis. Combining imaging and modeling data obtained from different flow modalities can improve the accuracy and fidelity of resulting velocity fields and flow-derived factors that are thought to affect aneurysmal disease progression. It is expected that predictive models utilizing hemodynamic factors in combination with patient medical history and morphological data will outperform current risk scores and treatment guidelines. Possible future directions include novel approaches enabling data assimilation and multimodality analysis of cerebral aneurysm hemodynamics.
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Affiliation(s)
- Vitaliy L Rayz
- Weldon School of Biomedical Engineering and School of Mechanical Engineering, Purdue University, West Lafayette, Indiana 47907, USA;
| | - Aaron A Cohen-Gadol
- Department of Neurosurgery, Indiana University School of Medicine, Indianapolis, Indiana 46202, USA.,Goodman Campbell Brain and Spine, Carmel, Indiana 46032, USA
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19
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Gade PS, Tulamo R, Lee KW, Mut F, Ollikainen E, Chuang CY, Jae Chung B, Niemelä M, Rezai Jahromi B, Aziz K, Yu A, Charbel FT, Amin-Hanjani S, Frösen J, Cebral JR, Robertson AM. Calcification in Human Intracranial Aneurysms Is Highly Prevalent and Displays Both Atherosclerotic and Nonatherosclerotic Types. Arterioscler Thromb Vasc Biol 2019; 39:2157-2167. [PMID: 31462093 PMCID: PMC6911659 DOI: 10.1161/atvbaha.119.312922] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVE Although the clinical and biological importance of calcification is well recognized for the extracerebral vasculature, its role in cerebral vascular disease, particularly, intracranial aneurysms (IAs), remains poorly understood. Extracerebrally, 2 distinct mechanisms drive calcification, a nonatherosclerotic, rapid mineralization in the media and a slower, inflammation driven, atherosclerotic mechanism in the intima. This study aims to determine the prevalence, distribution, and type (atherosclerotic, nonatherosclerotic) of calcification in IAs and assess differences in occurrence between ruptured and unruptured IAs. Approach and Results: Sixty-five 65 IA specimens (48 unruptured, 17 ruptured) were resected perioperatively. Calcification and lipid pools were analyzed nondestructively in intact samples using high resolution (0.35 μm) microcomputed tomography. Calcification is highly prevalent (78%) appearing as micro (<500 µm), meso (500 µm-1 mm), and macro (>1 mm) calcifications. Calcification manifests in IAs as both nonatherosclerotic (calcification distinct from lipid pools) and atherosclerotic (calcification in the presence of lipid pools) with 3 wall types: Type I-only calcification, no lipid pools (20/51, 39%), Type II-calcification and lipid pools, not colocalized (19/51, 37%), Type III-calcification colocalized with lipid pools (12/51, 24%). Ruptured IAs either had no calcifications or had nonatherosclerotic micro- or meso-calcifications (Type I or II), without macro-calcifications. CONCLUSIONS Calcification in IAs is substantially more prevalent than previously reported and presents as both nonatherosclerotic and atherosclerotic types. Notably, ruptured aneurysms had only nonatherosclerotic calcification, had significantly lower calcification fraction, and did not contain macrocalcifications. Improved understanding of the role of calcification in IA pathology should lead to new therapeutic targets.
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Affiliation(s)
- Piyusha S Gade
- From the Department of Bioengineering (P.S.G., K.L., A.M.R.), University of Pittsburgh, PA
| | - Riikka Tulamo
- Department of Vascular Surgery (R.T.), Helsinki University Hospital, University of Helsinki, Finland
| | - Kee-Won Lee
- From the Department of Bioengineering (P.S.G., K.L., A.M.R.), University of Pittsburgh, PA
| | - Fernando Mut
- Department of Bioengineering, George Mason University, Fairfax, VA (F.M., J.R.C.)
| | - Eliisa Ollikainen
- Department of Mechanical Engineering and Materials Science (E.O., C.-Y.C., A.M.R.), University of Pittsburgh, PA.,Department of Neurosurgery (E.O., M.N., B.R.J.), Helsinki University Hospital, University of Helsinki, Finland
| | - Chih-Yuan Chuang
- Department of Mechanical Engineering and Materials Science (E.O., C.-Y.C., A.M.R.), University of Pittsburgh, PA
| | - Bong Jae Chung
- Department of Mathematical Sciences, Montclair State University, NJ (B.J.C.)
| | - Mika Niemelä
- Department of Neurosurgery (E.O., M.N., B.R.J.), Helsinki University Hospital, University of Helsinki, Finland
| | - Behnam Rezai Jahromi
- Department of Neurosurgery (E.O., M.N., B.R.J.), Helsinki University Hospital, University of Helsinki, Finland
| | - Khaled Aziz
- Department of Neurosurgery, Allegheny General Hospital, Pittsburgh, PA (K.A., A.Y.)
| | - Alexander Yu
- Department of Neurosurgery, Allegheny General Hospital, Pittsburgh, PA (K.A., A.Y.)
| | - Fady T Charbel
- Department of Neurosurgery, University of Illinois at Chicago (F.T.C., S.A.-H.)
| | | | - Juhana Frösen
- Department of Neurosurgery, Kuopio University Hospital, Finland (J.F.)
| | - Juan R Cebral
- Department of Bioengineering, George Mason University, Fairfax, VA (F.M., J.R.C.)
| | - Anne M Robertson
- From the Department of Bioengineering (P.S.G., K.L., A.M.R.), University of Pittsburgh, PA.,Department of Mechanical Engineering and Materials Science (E.O., C.-Y.C., A.M.R.), University of Pittsburgh, PA
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20
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Abstract
The region where the vascular lumen meets the surrounding endothelium cell layer, hence the interface region between haemodynamics and cell tissue, is of primary importance in the physiological functions of the cardiovascular system. The functions include mass transport to/from the blood and tissue, and signalling via mechanotransduction, which are primary functions of the cardiovascular system and abnormalities in these functions are known to affect disease formation and vascular remodelling. This region is denoted by the near-wall region in the present work, and we outline simple yet effective numerical recipes to analyse the near-wall flow field. Computational haemodynamics solutions are presented for six patient specific cerebral aneurysms, at three instances in the cardiac cycle: peak systole, end systole (taken as dicrotic notch) and end diastole. A sensitivity study, based on Newtonian and non-Newtonian rheological models, and different flow rate profiles, is effected for a selection of aneurysm cases. The near-wall flow field is described by the wall shear stress (WSS) and the divergence of wall shear stress (WSSdiv), as descriptors of tangential and normal velocity components, respectively, as well as the wall shear stress critical points. Relations between near-wall and free-stream flow fields are discussed.
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21
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Cebral JR, Detmer F, Chung BJ, Choque-Velasquez J, Rezai B, Lehto H, Tulamo R, Hernesniemi J, Niemela M, Yu A, Williamson R, Aziz K, Shakur S, Amin-Hanjani S, Charbel F, Tobe Y, Robertson A, Frösen J. Local Hemodynamic Conditions Associated with Focal Changes in the Intracranial Aneurysm Wall. AJNR. AMERICAN JOURNAL OF NEURORADIOLOGY 2019; 40:510-516. [PMID: 30733253 DOI: 10.3174/ajnr.a5970] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Received: 09/14/2018] [Accepted: 12/25/2018] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE Aneurysm hemodynamics has been associated with wall histology and inflammation. We investigated associations between local hemodynamics and focal wall changes visible intraoperatively. MATERIALS AND METHODS Computational fluid dynamics models were constructed from 3D images of 65 aneurysms treated surgically. Aneurysm regions with different visual appearances were identified in intraoperative videos: 1) "atherosclerotic" (yellow), 2) "hyperplastic" (white), 3) "thin" (red), 4) rupture site, and 5) "normal" (similar to parent artery), They were marked on 3D reconstructions. Regional hemodynamics was characterized by the following: wall shear stress, oscillatory shear index, relative residence time, wall shear stress gradient and divergence, gradient oscillatory number, and dynamic pressure; these were compared using the Mann-Whitney test. RESULTS Hyperplastic regions had lower average wall shear stress (P = .005) and pressure (P = .009) than normal regions. Flow conditions in atherosclerotic and hyperplastic regions were similar but had higher average relative residence time (P = .03) and oscillatory shear index (P = .04) than thin regions. Hyperplastic regions also had a higher average gradient oscillatory number (P = .002) than thin regions. Thin regions had lower average relative residence time (P < .001), oscillatory shear index (P = .006), and gradient oscillatory number (P < .001) than normal regions, and higher average wall shear stress (P = .006) and pressure (P = .009) than hyperplastic regions. Thin regions tended to be aligned with the flow stream, while atherosclerotic and hyperplastic regions tended to be aligned with recirculation zones. CONCLUSIONS Local hemodynamics is associated with visible focal wall changes. Slow swirling flow with low and oscillatory wall shear stress was associated with atherosclerotic and hyperplastic changes. High flow conditions prevalent in regions near the flow impingement site characterized by higher and less oscillatory wall shear stress were associated with local "thinning" of the wall.
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Affiliation(s)
- J R Cebral
- From the Department of Bioengineering (J.R.C., F.D., B.J.C.), Volgenau School of Engineering, George Mason University, Fairfax, Virginia
| | - F Detmer
- From the Department of Bioengineering (J.R.C., F.D., B.J.C.), Volgenau School of Engineering, George Mason University, Fairfax, Virginia
| | - B J Chung
- From the Department of Bioengineering (J.R.C., F.D., B.J.C.), Volgenau School of Engineering, George Mason University, Fairfax, Virginia
| | - J Choque-Velasquez
- Neurosurgery Research Group (J.C.-V., B.R., H.L., R.T., J.H., M.N.), Biomedicum Helsinki and Helsinki University Central Hospital, Helsinki, Finland
| | - B Rezai
- Neurosurgery Research Group (J.C.-V., B.R., H.L., R.T., J.H., M.N.), Biomedicum Helsinki and Helsinki University Central Hospital, Helsinki, Finland
| | - H Lehto
- Neurosurgery Research Group (J.C.-V., B.R., H.L., R.T., J.H., M.N.), Biomedicum Helsinki and Helsinki University Central Hospital, Helsinki, Finland
| | - R Tulamo
- Neurosurgery Research Group (J.C.-V., B.R., H.L., R.T., J.H., M.N.), Biomedicum Helsinki and Helsinki University Central Hospital, Helsinki, Finland.,Department of Vascular Surgery (R.T.), Helsinki University Central Hospital, Helsinki, Finland
| | - J Hernesniemi
- Neurosurgery Research Group (J.C.-V., B.R., H.L., R.T., J.H., M.N.), Biomedicum Helsinki and Helsinki University Central Hospital, Helsinki, Finland
| | - M Niemela
- Neurosurgery Research Group (J.C.-V., B.R., H.L., R.T., J.H., M.N.), Biomedicum Helsinki and Helsinki University Central Hospital, Helsinki, Finland
| | - A Yu
- Department of Neurosurgery (A.Y., R.W., K.A.), Allegheny General Hospital, Pittsburgh, Pennsylvania
| | - R Williamson
- Department of Neurosurgery (A.Y., R.W., K.A.), Allegheny General Hospital, Pittsburgh, Pennsylvania
| | - K Aziz
- Department of Neurosurgery (A.Y., R.W., K.A.), Allegheny General Hospital, Pittsburgh, Pennsylvania
| | - S Shakur
- Department of Neurosurgery (S.S., S.A.-H., F.C.), University of Illinois at Chicago, Chicago, Illinois
| | - S Amin-Hanjani
- Department of Neurosurgery (S.S., S.A.-H., F.C.), University of Illinois at Chicago, Chicago, Illinois
| | - F Charbel
- Department of Neurosurgery (S.S., S.A.-H., F.C.), University of Illinois at Chicago, Chicago, Illinois
| | - Y Tobe
- Mechanical Engineering and Materials Science and Department of Bioengineering (Y.T., A.R.), Swanson School of Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - A Robertson
- Mechanical Engineering and Materials Science and Department of Bioengineering (Y.T., A.R.), Swanson School of Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - J Frösen
- Hemorrhagic Brain Pathology Research Group (J.F.), Neurocenter, Kuopio University Hospital, Kuopio, Finland
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22
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Gade PS, Robertson AM, Chuang CY. Multiphoton Imaging of Collagen, Elastin, and Calcification in Intact Soft-Tissue Samples. CURRENT PROTOCOLS IN CYTOMETRY 2019; 87:e51. [PMID: 30379412 PMCID: PMC6314890 DOI: 10.1002/cpcy.51] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Multiphoton-induced second-harmonic generation and two-photon excitation enable imaging of collagen and elastin fibers at micron-level resolution to depths of hundreds of microns, without the use of exogenous stains. These attributes can be leveraged for quantitative analysis of the 3D architecture of collagen and elastin fibers within intact, soft tissue specimens such as the artery and bladder wall. This architecture influences the function of intramural cells and also plays a primary role in determining tissue passive mechanical properties. Calcification deposition in soft tissues is a highly prevalent pathology in both older and diseased populations that can alter tissue properties. In this unit, we provide a protocol for simultaneous multiphoton microscopy (MPM) imaging and analysis of 3D collagen and elastin structures with calcification, which is effective for fixed and fresh intact samples. We also provide an associated micro-CT protocol to identify regions of interest in the samples as a means to target the MPM imaging. © 2018 by John Wiley & Sons, Inc.
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Affiliation(s)
- Piyusha S. Gade
- Department of Bioengineerin, University of Pittsburgh Pittsburgh, PA
| | - Anne M. Robertson
- Department of Bioengineerin, University of Pittsburgh Pittsburgh, PA
- Department of Mechanical Engineering and Materials Science, University of Pittsburgh Pittsburgh, PA
| | - Chih-Yuan Chuang
- Department of Mechanical Engineering and Materials Science, University of Pittsburgh Pittsburgh, PA
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