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Fernandes FAO, Silveira CIC. The Significance of Cross-Sectional Shape Accuracy and Non-Linear Elasticity on the Numerical Modelling of Cerebral Veins under Tensile Loading. BIOLOGY 2023; 13:16. [PMID: 38248447 PMCID: PMC10813171 DOI: 10.3390/biology13010016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2023] [Revised: 12/19/2023] [Accepted: 12/22/2023] [Indexed: 01/23/2024]
Abstract
Traumatic brain injury (TBI) is a serious global health issue, leading to serious disabilities. One type of TBI is acute subdural haematoma (ASDH), which occurs when a bridging vein ruptures. Many numerical models of these structures, mainly based on the finite element method, have been developed. However, most rely on linear elasticity (without validation) and others on simplifications at the geometrical level. An example of the latter is the assumption of a regular cylinder with a constant radius, or the geometry of the vein acquired from medical images. Unfortunately, these do not replicate the real conditions of a mechanical tensile test. In this work, the main goal is to evaluate the influence of the vein's geometry in its mechanical behaviour under tensile loading, simulating the real conditions of experimental tests. The second goal is to implement a hyperelastic model of the bridging veins where it would be possible to observe its non-linear elastic behaviour. The results of the developed finite element models were compared to experimental data available in the literature and other models. It was possible to conclude that the geometry of the vein structure influences the tensile stress-strain curve, which means that flattened specimens should be modelled when validating constitutive models for bridging veins. Additionally, the implementation of hyperelastic material models has been verified, highlighting the potential application of the Marlow and reduced polynomial (of fourth and sixth orders) constitutive models.
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Affiliation(s)
- Fábio A. O. Fernandes
- TEMA—Centre for Mechanical Technology and Automation, Department of Mechanical Engineering, University of Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal
- LASI—Intelligent Systems Associate Laboratory, 4800-058 Guimarães, Portugal
| | - Clara I. C. Silveira
- Department of Physics, University of Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal
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2
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Morrison O, Destrade M, Tripathi BB. An atlas of the heterogeneous viscoelastic brain with local power-law attenuation synthesised using Prony-series. Acta Biomater 2023; 169:66-87. [PMID: 37507033 DOI: 10.1016/j.actbio.2023.07.040] [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: 04/04/2023] [Revised: 07/16/2023] [Accepted: 07/24/2023] [Indexed: 07/30/2023]
Abstract
This review addresses the acute need to acknowledge the mechanical heterogeneity of brain matter and to accurately calibrate its local viscoelastic material properties accordingly. Specifically, it is important to compile the existing and disparate literature on attenuation power-laws and dispersion to make progress in wave physics of brain matter, a field of research that has the potential to explain the mechanisms at play in diffuse axonal injury and mild traumatic brain injury in general. Currently, viscous effects in the brain are modelled using Prony-series, i.e., a sum of decaying exponentials at different relaxation times. Here we collect and synthesise the Prony-series coefficients appearing in the literature for twelve regions: brainstem, basal ganglia, cerebellum, corona radiata, corpus callosum, cortex, dentate gyrus, hippocampus, thalamus, grey matter, white matter, homogeneous brain, and for eight different mammals: pig, rat, human, mouse, cow, sheep, monkey and dog. Using this data, we compute the fractional-exponent attenuation power-laws for different tissues of the brain, the corresponding dispersion laws resulting from causality, and the averaged Prony-series coefficients. STATEMENT OF SIGNIFICANCE: Traumatic brain injuries are considered a silent epidemic and finite element methods (FEMs) are used in modelling brain deformation, requiring access to viscoelastic properties of brain. To the best of our knowledge, this work presents 1) the first multi-frequency viscoelastic atlas of the heterogeneous brain, 2) the first review focusing on viscoelastic modelling in both FEMs and experimental works, 3) the first attempt to conglomerate the disparate existing literature on the viscoelastic modelling of the brain and 4) the largest collection of viscoelastic parameters for the brain (212 different Prony-series spanning 12 different tissues and 8 different animal surrogates). Furthermore, this work presents the first brain atlas of attenuation power-laws essential for modelling shear waves in brain.
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Affiliation(s)
- Oisín Morrison
- School of Mathematical and Statistical Sciences, University of Galway, University Road, Galway, Ireland
| | - Michel Destrade
- School of Mathematical and Statistical Sciences, University of Galway, University Road, Galway, Ireland
| | - Bharat B Tripathi
- School of Mathematical and Statistical Sciences, University of Galway, University Road, Galway, Ireland.
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3
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Age effects on the mechanical behavior of human cerebral bridging veins. Clin Biomech (Bristol, Avon) 2022; 100:105792. [PMID: 36327547 DOI: 10.1016/j.clinbiomech.2022.105792] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Revised: 09/26/2022] [Accepted: 10/02/2022] [Indexed: 02/07/2023]
Abstract
BACKGROUND It is well established that the probability of occurrence of acute subdural hematomas in traumatic situations increases with age, since the main cause of such hematomas is the mechanical failure of cerebral blood vessels known as bridging veins. This research aims to determine whether there is an effect of age on the mechanical properties of these cerebral vessels, because previous reported studies were conflicting. METHODS This study used mechanical tests blue of cerebral bridging veins from post-mortem human subjects. In particular, a series of in vitro tensile tests were performed on a balanced sample of bridging veins from different human subjects. FINDINGS The mechanical parameters measured from the tests were analyzed by means of regression analysis looking for age related effects. The results show that there is a significant effect on both the ultimate strength, maximum stress and strain that the specimens can withstand. The quantitative analysis shows reductions of nearly 50% in ultimate stress, and almost 35% in ultimate strain. INTERPRETATION Mechanical deterioration of the mechanical strength of cerebral blood vessels seems to be a major factor involved in the increase of frequency of acute subdural hematoma in elderly people in a wide range of life-threatening traumatic situations.
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4
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Rubio JE, Subramaniam DR, Unnikrishnan G, Sajja VSSS, Van Albert S, Rossetti F, Frock A, Nguyen G, Sundaramurthy A, Long JB, Reifman J. A biomechanical-based approach to scale blast-induced molecular changes in the brain. Sci Rep 2022; 12:14605. [PMID: 36028539 PMCID: PMC9418170 DOI: 10.1038/s41598-022-17967-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Accepted: 08/03/2022] [Indexed: 11/09/2022] Open
Abstract
Animal studies provide valuable insights on how the interaction of blast waves with the head may injure the brain. However, there is no acceptable methodology to scale the findings from animals to humans. Here, we propose an experimental/computational approach to project observed blast-induced molecular changes in the rat brain to the human brain. Using a shock tube, we exposed rats to a range of blast overpressures (BOPs) and used a high-fidelity computational model of a rat head to correlate predicted biomechanical responses with measured changes in glial fibrillary acidic protein (GFAP) in rat brain tissues. Our analyses revealed correlates between model-predicted strain rate and measured GFAP changes in three brain regions. Using these correlates and a high-fidelity computational model of a human head, we determined the equivalent BOPs in rats and in humans that induced similar strain rates across the two species. We used the equivalent BOPs to project the measured GFAP changes in the rat brain to the human. Our results suggest that, relative to the rat, the human requires an exposure to a blast wave of a higher magnitude to elicit similar brain-tissue responses. Our proposed methodology could assist in the development of safety guidelines for blast exposure.
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Affiliation(s)
- Jose E Rubio
- Department of Defense Biotechnology High Performance Computing Software Applications Institute, Telemedicine and Advanced Technology Research Center, United States Army Medical Research and Development Command, ATTN: FCMR-TT, 504 Scott Street, Fort Detrick, MD, 21702-5012, USA.,The Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc., 6720-A Rockledge Drive, Bethesda, MD, 20817, USA
| | - Dhananjay Radhakrishnan Subramaniam
- Department of Defense Biotechnology High Performance Computing Software Applications Institute, Telemedicine and Advanced Technology Research Center, United States Army Medical Research and Development Command, ATTN: FCMR-TT, 504 Scott Street, Fort Detrick, MD, 21702-5012, USA.,The Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc., 6720-A Rockledge Drive, Bethesda, MD, 20817, USA
| | - Ginu Unnikrishnan
- Department of Defense Biotechnology High Performance Computing Software Applications Institute, Telemedicine and Advanced Technology Research Center, United States Army Medical Research and Development Command, ATTN: FCMR-TT, 504 Scott Street, Fort Detrick, MD, 21702-5012, USA.,The Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc., 6720-A Rockledge Drive, Bethesda, MD, 20817, USA
| | - Venkata Siva Sai Sujith Sajja
- Blast Induced Neurotrauma Branch, Center for Military Psychiatry and Neurosciences, Walter Reed Army Institute of Research, 503 Robert Grant Ave, Silver Spring, MD, 20910, USA
| | - Stephen Van Albert
- Blast Induced Neurotrauma Branch, Center for Military Psychiatry and Neurosciences, Walter Reed Army Institute of Research, 503 Robert Grant Ave, Silver Spring, MD, 20910, USA
| | - Franco Rossetti
- Blast Induced Neurotrauma Branch, Center for Military Psychiatry and Neurosciences, Walter Reed Army Institute of Research, 503 Robert Grant Ave, Silver Spring, MD, 20910, USA
| | - Andrew Frock
- Department of Defense Biotechnology High Performance Computing Software Applications Institute, Telemedicine and Advanced Technology Research Center, United States Army Medical Research and Development Command, ATTN: FCMR-TT, 504 Scott Street, Fort Detrick, MD, 21702-5012, USA.,The Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc., 6720-A Rockledge Drive, Bethesda, MD, 20817, USA
| | - Giang Nguyen
- Department of Defense Biotechnology High Performance Computing Software Applications Institute, Telemedicine and Advanced Technology Research Center, United States Army Medical Research and Development Command, ATTN: FCMR-TT, 504 Scott Street, Fort Detrick, MD, 21702-5012, USA.,The Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc., 6720-A Rockledge Drive, Bethesda, MD, 20817, USA
| | - Aravind Sundaramurthy
- Department of Defense Biotechnology High Performance Computing Software Applications Institute, Telemedicine and Advanced Technology Research Center, United States Army Medical Research and Development Command, ATTN: FCMR-TT, 504 Scott Street, Fort Detrick, MD, 21702-5012, USA.,The Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc., 6720-A Rockledge Drive, Bethesda, MD, 20817, USA
| | - Joseph B Long
- Blast Induced Neurotrauma Branch, Center for Military Psychiatry and Neurosciences, Walter Reed Army Institute of Research, 503 Robert Grant Ave, Silver Spring, MD, 20910, USA
| | - Jaques Reifman
- Department of Defense Biotechnology High Performance Computing Software Applications Institute, Telemedicine and Advanced Technology Research Center, United States Army Medical Research and Development Command, ATTN: FCMR-TT, 504 Scott Street, Fort Detrick, MD, 21702-5012, USA.
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5
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Fiber orientation downsampling compromises the computation of white matter tract-related deformation. J Mech Behav Biomed Mater 2022; 132:105294. [DOI: 10.1016/j.jmbbm.2022.105294] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Revised: 04/13/2022] [Accepted: 05/21/2022] [Indexed: 11/18/2022]
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6
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Duckworth H, Azor A, Wischmann N, Zimmerman KA, Tanini I, Sharp DJ, Ghajari M. A Finite Element Model of Cerebral Vascular Injury for Predicting Microbleeds Location. Front Bioeng Biotechnol 2022; 10:860112. [PMID: 35519616 PMCID: PMC9065595 DOI: 10.3389/fbioe.2022.860112] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2022] [Accepted: 03/31/2022] [Indexed: 11/22/2022] Open
Abstract
Finite Element (FE) models of brain mechanics have improved our understanding of the brain response to rapid mechanical loads that produce traumatic brain injuries. However, these models have rarely incorporated vasculature, which limits their ability to predict the response of vessels to head impacts. To address this shortcoming, here we used high-resolution MRI scans to map the venous system anatomy at a submillimetre resolution. We then used this map to develop an FE model of veins and incorporated it in an anatomically detailed FE model of the brain. The model prediction of brain displacement at different locations was compared to controlled experiments on post-mortem human subject heads, yielding over 3,100 displacement curve comparisons, which showed fair to excellent correlation between them. We then used the model to predict the distribution of axial strains and strain rates in the veins of a rugby player who had small blood deposits in his white matter, known as microbleeds, after sustaining a head collision. We hypothesised that the distribution of axial strain and strain rate in veins can predict the pattern of microbleeds. We reconstructed the head collision using video footage and multi-body dynamics modelling and used the predicted head accelerations to load the FE model of vascular injury. The model predicted large axial strains in veins where microbleeds were detected. A region of interest analysis using white matter tracts showed that the tract group with microbleeds had 95th percentile peak axial strain and strain rate of 0.197 and 64.9 s−1 respectively, which were significantly larger than those of the group of tracts without microbleeds (0.163 and 57.0 s−1). This study does not derive a threshold for the onset of microbleeds as it investigated a single case, but it provides evidence for a link between strain and strain rate applied to veins during head impacts and structural damage and allows for future work to generate threshold values. Moreover, our results suggest that the FE model has the potential to be used to predict intracranial vascular injuries after TBI, providing a more objective tool for TBI assessment and improving protection against it.
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Affiliation(s)
- Harry Duckworth
- HEAD Lab, Dyson School of Design Engineering, Imperial College London, London, United Kingdom
- The Computational, Cognitive and Clinical Neuroimaging Laboratory, Imperial College London, London, United Kingdom
| | - Adriana Azor
- HEAD Lab, Dyson School of Design Engineering, Imperial College London, London, United Kingdom
- The Computational, Cognitive and Clinical Neuroimaging Laboratory, Imperial College London, London, United Kingdom
| | - Nikolaus Wischmann
- HEAD Lab, Dyson School of Design Engineering, Imperial College London, London, United Kingdom
| | - Karl A. Zimmerman
- HEAD Lab, Dyson School of Design Engineering, Imperial College London, London, United Kingdom
- The Computational, Cognitive and Clinical Neuroimaging Laboratory, Imperial College London, London, United Kingdom
| | - Ilaria Tanini
- HEAD Lab, Dyson School of Design Engineering, Imperial College London, London, United Kingdom
- Industrial Engineering Department, University of Florence, Florence, Italy
| | - David J. Sharp
- The Computational, Cognitive and Clinical Neuroimaging Laboratory, Imperial College London, London, United Kingdom
- Care Research and Technology Centre, Dementia Research Institute, London, United Kingdom
| | - Mazdak Ghajari
- HEAD Lab, Dyson School of Design Engineering, Imperial College London, London, United Kingdom
- *Correspondence: Mazdak Ghajari,
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7
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Sundaramurthy A, Kote VB, Pearson N, Boiczyk GM, McNeil EM, Nelson AJ, Subramaniam DR, Rubio JE, Monson K, Hardy WN, VandeVord PJ, Unnikrishnan G, Reifman J. A 3-D Finite-Element Minipig Model to Assess Brain Biomechanical Responses to Blast Exposure. Front Bioeng Biotechnol 2022; 9:757755. [PMID: 34976963 PMCID: PMC8719465 DOI: 10.3389/fbioe.2021.757755] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Accepted: 11/17/2021] [Indexed: 12/05/2022] Open
Abstract
Despite years of research, it is still unknown whether the interaction of explosion-induced blast waves with the head causes injury to the human brain. One way to fill this gap is to use animal models to establish “scaling laws” that project observed brain injuries in animals to humans. This requires laboratory experiments and high-fidelity mathematical models of the animal head to establish correlates between experimentally observed blast-induced brain injuries and model-predicted biomechanical responses. To this end, we performed laboratory experiments on Göttingen minipigs to develop and validate a three-dimensional (3-D) high-fidelity finite-element (FE) model of the minipig head. First, we performed laboratory experiments on Göttingen minipigs to obtain the geometry of the cerebral vasculature network and to characterize brain-tissue and vasculature material properties in response to high strain rates typical of blast exposures. Next, we used the detailed cerebral vasculature information and species-specific brain tissue and vasculature material properties to develop the 3-D high-fidelity FE model of the minipig head. Then, to validate the model predictions, we performed laboratory shock-tube experiments, where we exposed Göttingen minipigs to a blast overpressure of 210 kPa in a laboratory shock tube and compared brain pressures at two locations. We observed a good agreement between the model-predicted pressures and the experimental measurements, with differences in maximum pressure of less than 6%. Finally, to evaluate the influence of the cerebral vascular network on the biomechanical predictions, we performed simulations where we compared results of FE models with and without the vasculature. As expected, incorporation of the vasculature decreased brain strain but did not affect the predictions of brain pressure. However, we observed that inclusion of the cerebral vasculature in the model changed the strain distribution by as much as 100% in regions near the interface between the vasculature and the brain tissue, suggesting that the vasculature does not merely decrease the strain but causes drastic redistributions. This work will help establish correlates between observed brain injuries and predicted biomechanical responses in minipigs and facilitate the creation of scaling laws to infer potential injuries in the human brain due to exposure to blast waves.
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Affiliation(s)
- Aravind Sundaramurthy
- Department of Defense Biotechnology High Performance Computing Software Applications Institute, Telemedicine and Advanced Technology Research Center, United States Army Medical Research and Development Command, Fort Detrick, MD, United States.,The Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc., Bethesda, MD, United States
| | - Vivek Bhaskar Kote
- Department of Defense Biotechnology High Performance Computing Software Applications Institute, Telemedicine and Advanced Technology Research Center, United States Army Medical Research and Development Command, Fort Detrick, MD, United States.,The Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc., Bethesda, MD, United States
| | - Noah Pearson
- Department of Mechanical Engineering, The University of Utah, Salt Lake City, UT, United States
| | - Gregory M Boiczyk
- Department of Biomedical Engineering, The University of Utah, Salt Lake City, UT, United States
| | - Elizabeth M McNeil
- Department of Biomedical Engineering and Mechanics, Virginia Tech, Blacksburg, VA, United States
| | - Allison J Nelson
- Department of Biomedical Engineering and Mechanics, Virginia Tech, Blacksburg, VA, United States.,Center for Injury Biomechanics, Virginia Tech, Blacksburg, VA, United States
| | - Dhananjay Radhakrishnan Subramaniam
- Department of Defense Biotechnology High Performance Computing Software Applications Institute, Telemedicine and Advanced Technology Research Center, United States Army Medical Research and Development Command, Fort Detrick, MD, United States.,The Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc., Bethesda, MD, United States
| | - Jose E Rubio
- Department of Defense Biotechnology High Performance Computing Software Applications Institute, Telemedicine and Advanced Technology Research Center, United States Army Medical Research and Development Command, Fort Detrick, MD, United States.,The Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc., Bethesda, MD, United States
| | - Kenneth Monson
- Department of Mechanical Engineering, The University of Utah, Salt Lake City, UT, United States.,Department of Biomedical Engineering, The University of Utah, Salt Lake City, UT, United States
| | - Warren N Hardy
- Center for Injury Biomechanics, Virginia Tech, Blacksburg, VA, United States
| | - Pamela J VandeVord
- Department of Biomedical Engineering and Mechanics, Virginia Tech, Blacksburg, VA, United States.,Center for Injury Biomechanics, Virginia Tech, Blacksburg, VA, United States
| | - Ginu Unnikrishnan
- Department of Defense Biotechnology High Performance Computing Software Applications Institute, Telemedicine and Advanced Technology Research Center, United States Army Medical Research and Development Command, Fort Detrick, MD, United States.,The Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc., Bethesda, MD, United States
| | - Jaques Reifman
- Department of Defense Biotechnology High Performance Computing Software Applications Institute, Telemedicine and Advanced Technology Research Center, United States Army Medical Research and Development Command, Fort Detrick, MD, United States
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8
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Subramaniam DR, Unnikrishnan G, Sundaramurthy A, Rubio JE, Kote VB, Reifman J. Cerebral Vasculature Influences Blast-Induced Biomechanical Responses of Human Brain Tissue. Front Bioeng Biotechnol 2021; 9:744808. [PMID: 34805106 PMCID: PMC8599150 DOI: 10.3389/fbioe.2021.744808] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Accepted: 10/18/2021] [Indexed: 11/13/2022] Open
Abstract
Multiple finite-element (FE) models to predict the biomechanical responses in the human brain resulting from the interaction with blast waves have established the importance of including the brain-surface convolutions, the major cerebral veins, and using non-linear brain-tissue properties to improve model accuracy. We hypothesize that inclusion of a more detailed network of cerebral veins and arteries can further enhance the model-predicted biomechanical responses and help identify correlates of blast-induced brain injury. To more comprehensively capture the biomechanical responses of human brain tissues to blast-wave exposure, we coupled a three-dimensional (3-D) detailed-vasculature human-head FE model, previously validated for blunt impact, with a 3-D shock-tube FE model. Using the coupled model, we computed the biomechanical responses of a human head facing an incoming blast wave for blast overpressures (BOPs) equivalent to 68, 83, and 104 kPa. We validated our FE model, which includes the detailed network of cerebral veins and arteries, the gyri and the sulci, and hyper-viscoelastic brain-tissue properties, by comparing the model-predicted intracranial pressure (ICP) values with previously collected data from shock-tube experiments performed on cadaver heads. In addition, to quantify the influence of including a more comprehensive network of brain vessels, we compared the biomechanical responses of our detailed-vasculature model with those of a reduced-vasculature model and a no-vasculature model for the same blast-loading conditions. For the three BOPs, the predicted ICP values matched well with the experimental results in the frontal lobe, with peak-pressure differences of 4-11% and phase-shift differences of 9-13%. As expected, incorporating the detailed cerebral vasculature did not influence the ICP, however, it redistributed the peak brain-tissue strains by as much as 30% and yielded peak strain differences of up to 7%. When compared to existing reduced-vasculature FE models that only include the major cerebral veins, our high-fidelity model redistributed the brain-tissue strains in most of the brain, highlighting the importance of including a detailed cerebral vessel network in human-head FE models to more comprehensively account for the biomechanical responses induced by blast exposure.
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Affiliation(s)
- Dhananjay Radhakrishnan Subramaniam
- Department of Defense Biotechnology High Performance Computing Software Applications Institute, Telemedicine and Advanced Technology Research Center, United States Army Medical Research and Development Command, Fort Detrick, MD, United States
- The Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc., Bethesda, MD, United States
| | - Ginu Unnikrishnan
- Department of Defense Biotechnology High Performance Computing Software Applications Institute, Telemedicine and Advanced Technology Research Center, United States Army Medical Research and Development Command, Fort Detrick, MD, United States
- The Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc., Bethesda, MD, United States
| | - Aravind Sundaramurthy
- Department of Defense Biotechnology High Performance Computing Software Applications Institute, Telemedicine and Advanced Technology Research Center, United States Army Medical Research and Development Command, Fort Detrick, MD, United States
- The Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc., Bethesda, MD, United States
| | - Jose E. Rubio
- Department of Defense Biotechnology High Performance Computing Software Applications Institute, Telemedicine and Advanced Technology Research Center, United States Army Medical Research and Development Command, Fort Detrick, MD, United States
- The Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc., Bethesda, MD, United States
| | - Vivek Bhaskar Kote
- Department of Defense Biotechnology High Performance Computing Software Applications Institute, Telemedicine and Advanced Technology Research Center, United States Army Medical Research and Development Command, Fort Detrick, MD, United States
- The Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc., Bethesda, MD, United States
| | - Jaques Reifman
- Department of Defense Biotechnology High Performance Computing Software Applications Institute, Telemedicine and Advanced Technology Research Center, United States Army Medical Research and Development Command, Fort Detrick, MD, United States
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9
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Bigler ED, Allder S. Earliest Marker of Brain Injury in Repetitive Sports-Related Concussion: Canary in the Midline? Neurology 2021; 97:567-569. [PMID: 34433677 DOI: 10.1212/wnl.0000000000012589] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Accepted: 07/23/2021] [Indexed: 11/15/2022] Open
Affiliation(s)
- Erin D Bigler
- From the Departments of Neurology and Psychiatry (E.D.B.), University of Utah, Salt Lake City; Department of Psychology and Neuroscience Center (E.D.B.), Brigham Young University, Provo, UT; Department of Neurology (E.D.B.), University of California-Davis, Sacramento; and Re:Cognition Health (S.A.), London, UK.
| | - Steven Allder
- From the Departments of Neurology and Psychiatry (E.D.B.), University of Utah, Salt Lake City; Department of Psychology and Neuroscience Center (E.D.B.), Brigham Young University, Provo, UT; Department of Neurology (E.D.B.), University of California-Davis, Sacramento; and Re:Cognition Health (S.A.), London, UK
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10
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Sánchez-Molina D, García-Vilana S, Llumà J, Galtés I, Velázquez-Ameijide J, Rebollo-Soria MC, Arregui-Dalmases C. Mechanical Behavior of Blood Vessels: Elastic and Viscoelastic Contributions. BIOLOGY 2021; 10:831. [PMID: 34571709 PMCID: PMC8472519 DOI: 10.3390/biology10090831] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Revised: 08/19/2021] [Accepted: 08/23/2021] [Indexed: 11/16/2022]
Abstract
The mechanical properties of the cerebral bridging veins (CBVs) were studied using advanced microtensile equipment. Detailed high-quality curves were obtained at different strain rates, showing a clearly nonlinear stress-strain response. In addition, the tissue of the CBVs exhibits stress relaxation and a preconditioning effect under cyclic loading, unequivocal indications of viscoelastic behavior. Interestingly, most previous literature that conducts uniaxial tensile tests had not found significant viscoelastic effects in CBVs, but the use of more sensitive tests allowed to observe the viscoelastic effects. For that reason, a careful mathematical analysis is presented, clarifying why in uniaxial tests with moderate strain rates, it is difficult to observe any viscoelastic effect. The analysis provides a theoretical explanation as to why many recent studies that investigated mechanical properties did not find a significant viscoelastic effect, even though in other circumstances, the CBV tissue would clearly exhibit viscoelastic behavior. Finally, this study provides reference values for the usual mechanical properties, as well as calculations of constitutive parameters for nonlinear elastic and viscoelastic models that would allow more accurate numerical simulation of CBVs in Finite Element-based computational models in future works.
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Affiliation(s)
- David Sánchez-Molina
- Escola d’Enginyeria de Barcelona Est, Universitat Politècnica de Catalunya, Av. Eduard Maristany, 16, 08019 Barcelona, Spain; (S.G.-V.); (J.L.); (J.V.-A.)
| | - Silvia García-Vilana
- Escola d’Enginyeria de Barcelona Est, Universitat Politècnica de Catalunya, Av. Eduard Maristany, 16, 08019 Barcelona, Spain; (S.G.-V.); (J.L.); (J.V.-A.)
| | - Jordi Llumà
- Escola d’Enginyeria de Barcelona Est, Universitat Politècnica de Catalunya, Av. Eduard Maristany, 16, 08019 Barcelona, Spain; (S.G.-V.); (J.L.); (J.V.-A.)
| | - Ignasi Galtés
- Institut de Medicina Legal i Ciències Forenses de Catalunya, G.V. Corts Catalanes, 111, 08014 Barcelona, Spain;
- Departament de Psiquiatria i de Medicina Legal, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, 08193 Barcelona, Spain
| | - Juan Velázquez-Ameijide
- Escola d’Enginyeria de Barcelona Est, Universitat Politècnica de Catalunya, Av. Eduard Maristany, 16, 08019 Barcelona, Spain; (S.G.-V.); (J.L.); (J.V.-A.)
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