Comparison of Mechanical Variable Identifiers of Brain Injury

2013 ◽  
Author(s):  
Siddiq M. Qidwai ◽  
Nithyanand Kota ◽  
Alan C. Leung ◽  
Amit Bagchi
Keyword(s):  
Brain Injury ◽  
Ex Vivo ◽  
Computational Simulation ◽  
Region Of Interest ◽  
Human Head ◽  
Critical Value ◽  
Loading Test ◽  
Mechanical Variable ◽  
Location Type ◽  
The Brain

Multiple mechanical variables have been used to describe the occurrence of brain injury in impact modeling of the human head [1, 2]. The validity of these variables for this purpose is usually established separately through the following process. First, a loading test is performed on an animal. Location, type and spatial extent of injury on the brain are measured upon or after loading. Subsequently, computational simulation is performed based on a particular constitutive model of the brain. Mechanical variables such as pressure or effective stress are plotted for the region of interest. The magnitude of the mechanical variable that results in a contour of the same size as the observed extent of experimental injury is declared as the critical value for that type of injury. The choice of mechanical variable itself could be based on conventional wisdom, precedence, or experience of the researcher. Another, much simpler variable-injury correlation process, which does not rely upon simulations, uses the ex vivo failure response of brain tissue as the criterion. For example, the uniaxial failure strain of the tissue may be taken as the critical value for injury.

Traumatic Brain Injury Caused by +Gz Acceleration

2016 ◽  
Author(s):  
Abbas Shafiee ◽  
Mohammad Taghi Ahmadian ◽  
Maryam Hoviattalab
Keyword(s):  
Traumatic Brain Injury ◽  
Brain Injury ◽  
Damage Threshold ◽  
Human Head ◽  
Loss Of Consciousness ◽  
Time Duration ◽  
University Of Technology ◽  
Trauma Model ◽  
The Brain ◽  
Brain Pressure

Traumatic brain injury (TBI) has long been known as one of the most anonymous reasons for death around the world. This phenomenon has been under study for many years and yet it remains a question due to physiological, geometrical and computational complexity. Although the modeling facilities for soft tissue have improved, the precise CT-imaging of human head has revealed novel details of the brain, skull and meninges. In this study a 3D human head including the brain, skull, and meninges is modeled using CT-scan and MRI data of a 30-year old human. This model is named “Sharif University of Technology Head Trauma Model (SUTHTM)”. By validating SUTHTM, the model is then used to study the effect of +Gz acceleration on the human brain. Damage threshold based on loss of consciousness in terms of acceleration and time duration is developed using Maximum Brain Pressure criteria. Results revealed that the Max. Brain Pressure ≥3.1 are representation of loss of consciousness. 3D domains for the loss of consciousness are based on Max. Brain Pressure is developed.

scholarly journals Endogenous protection from ischemic brain injury by preconditioned monocytes

2018 ◽  
Author(s):  
Lidia Garcia-Bonilla ◽  
David Brea ◽  
Corinne Benakis ◽  
Diane Lane ◽  
Michelle Murphy ◽  
...  
Keyword(s):  
Brain Injury ◽  
Cerebral Ischemia ◽  
Low Dose ◽  
Ex Vivo ◽  
Artery Occlusion ◽  
Human Monocytes ◽  
Male Mice ◽  
Lps Preconditioning ◽  
Cerebral Artery Occlusion ◽  
The Brain

AbstractExposure to low dose lipopolysaccharide prior to cerebral ischemia is neuroprotective in stroke models, a phenomenon termed preconditioning. While it is well established that lipopolysaccharide-preconditioning induces central and peripheral immune responses, the cellular mechanisms modulating ischemic injury remain unclear. Here, we investigated the role of immune cells in the brain protection afforded by preconditioning and we tested whether monocytes may be reprogrammed by ex vivo lipopolysaccharide exposure thus modulating the inflammatory injury after cerebral ischemia in male mice. We found that systemic injection of low-dose lipopolysaccharide induces a distinct subclass of CD115+Ly6Chi monocytes that protect the brain after transient middle cerebral artery occlusion in mice. Remarkably, adoptive transfer of monocytes isolated from preconditioned mice into naïve mice 7 hours after transient middle cerebral artery occlusion reduced brain injury. Gene expression and functional studies showed that IL-10, iNOS and CCR2 in monocytes are essential for the neuroprotection. This protective activity was elicited even if mouse or human monocytes were exposed ex vivo to lipopolysaccharide and then injected into male mice after stroke. Cell tracking studies showed that protective monocytes are mobilized from the spleen and reach brain and meninges, wherein they suppressed post-ischemic inflammation and neutrophils influx into the brain parenchyma. Our findings unveil a previously unrecognized subpopulation of splenic monocytes capable to protect the brain with an extended therapeutic window, and provide the rationale for cell therapies based on the delivery of autologous or allogeneic protective monocytes into patients with ischemic stroke.Significance StatementInflammation is a key component of the pathophysiology of the brain in stroke, a leading cause of death and disability with limited therapeutic options. Here, we investigate endogenous mechanisms of protection against cerebral ischemia. Using LPS preconditioning as an approach to induce ischemic tolerance in mice, we found the generation of neuroprotective monocytes within the spleen from where they traffic to the brain and meninges suppressing post-ischemic inflammation. Importantly, systemic LPS preconditioning can be mimicked by adoptive transfer of in vitro-preconditioned mouse or human monocytes at translational relevant time points after stroke. This model of neuroprotection may facilitate clinical efforts to increase the efficacy of bone marrow mononuclear cell treatments in acute neurological diseases such as cerebral ischemia.

Mechanical Response of the Brain Under Blast: The Effect of Blast Direction and the Head Protection

2016 ◽  
Author(s):  
Hesam Sarvghad-Moghaddam ◽  
Asghar Rezaei ◽  
Ashkan Eslaminejad ◽  
Mariusz Ziejewski ◽  
Ghodrat Karami
Keyword(s):  
Brain Injury ◽  
Mechanical Response ◽  
Experimental Studies ◽  
Human Head ◽  
Blast Waves ◽  
Arbitrary Lagrangian Eulerian ◽  
Explosion Pressure ◽  
Head Protection ◽  
Coupling Algorithm ◽  
The Brain

Blast-induced traumatic brain injury (bTBI), is defined as a type of acquired brain injury that occurs upon the interaction of the human head with blast-generated high-pressure shockwaves. Lack of experimental studies due to moral issues, have motivated the researchers to employ computational methods to study the bTBI mechanisms. Accordingly, a nonlinear finite element (FE) analysis was employed to study the interaction of both unprotected and protected head models with explosion pressure waves. The head was exposed to the incoming shockwaves from front, back, and side directions. The main goal was to examine the effects of head protection tools and the direction of blast waves on the tissue and kinematical responses of the brain. Generation, propagation, and interactions of blast waves with the head were modeled using an arbitrary Lagrangian-Eulerian (ALE) method and a fluid-structure interaction (FSI) coupling algorithm. The FE simulations were performed using Ls-Dyna, a transient, nonlinear FE code. Side blast predicted the highest mechanical responses for the brain. Moreover, the protection assemblies showed to significantly alter the blast flow mechanics. Use of faceshield was also observed to be highly effective in the front blast due to hindering of shockwaves.

Simulation of Blast Induced Traumatic Brain Injury using Finite Element Method

2021 ◽  
Vol 13 (2) ◽  
Author(s):  
G. Krishnaveni ◽  
D. Dominic Xavier ◽  
R. Sarathkumar ◽  
G. Kavitha ◽  
M. Senbagan
Keyword(s):  
Traumatic Brain Injury ◽  
Finite Element ◽  
Brain Injury ◽  
Blast Wave ◽  
Ambient Pressure ◽  
Memory Loss ◽  
Human Head ◽  
Head Model ◽  
Stress Concentrations ◽  
The Brain

Because of increase in threat from militant groups and during war exposure to blast wave from improvised explosive devices, Traumatic Brain Injury (TBI), a signature injury is on rise worldwide. During blast, the biological system is exposed to a sudden blast over pressure which is several times higher than the ambient pressure causing the damage in the brain. The severity of TBI due to air blast may vary from brief change in mental status or consciousness (termed as mild) to extended period of unconsciousness or memory loss after injuries (termed as severe). The blast wave induced impact on head propagates as shock wave with the broad spectrum of frequencies and stress concentrations in the brain. The primary blast TBI is directly induced by pressure differentials across the skull/fluid/soft tissue interfaces and is further reinforced by the reflected stress waves within the cranial cavity, leading to stress concentrations in certain regions of the brain. In this paper, an attempt has been made to study the behaviour of a human brain model subjected to blast wave based on finite element model using LSDYNA code. The parts of a typical human head such as skull, scalp, CSF, brain are modelled using finite element with properties assumed based on available literature. The model is subjected to blast from frontal lobe, occipital lobe, temporal lobe of the brain. The interaction of the blast wave with the head and subsequent transformation of various forms of shock energy internally have been demonstrated in the human head model. The brain internal pressure levels and the shear stress distribution in the various lobes of the brain such as frontal, parietal, temporal and occipital are determined and presented.

scholarly journals Brain Injury Differences in Frontal Impact Crash Using Different Simulation Strategies

2015 ◽  
Vol 2015 ◽  
pp. 1-8
Author(s):  
Dao Li ◽  
Chunsheng Ma ◽  
Ming Shen ◽  
Peiyu Li ◽  
Jinhuan Zhang
Keyword(s):  
Brain Injury ◽  
Human Body ◽  
Human Head ◽  
Von Mises Stress ◽  
Head Model ◽  
Fe Model ◽  
Human Body Model ◽  
Body Model ◽  
Cumulative Strain ◽  
The Brain

In the real world crashes, brain injury is one of the leading causes of deaths. Using isolated human head finite element (FE) model to study the brain injury patterns and metrics has been a simplified methodology widely adopted, since it costs significantly lower computation resources than a whole human body model does. However, the degree of precision of this simplification remains questionable. This study compared these two kinds of methods: (1) using a whole human body model carried on the sled model and (2) using an isolated head model with prescribed head motions, to study the brain injury. The distribution of the von Mises stress (VMS), maximum principal strain (MPS), and cumulative strain damage measure (CSDM) was used to compare the two methods. The results showed that the VMS of brain mainly concentrated at the lower cerebrum and occipitotemporal region close to the cerebellum. The isolated head modelling strategy predicted higher levels of MPS and CSDM 5%, while the difference is small in CSDM 10% comparison. It suggests that isolated head model may not equivalently reflect the strain levels below the 10% compared to the whole human body model.

Modelling and Analysis of the Effect of Angular Velocity and Acceleration on Brain Strain Field in Traumatic Brain Injury

2013 ◽  
Author(s):  
Hesam Hoursan ◽  
Mohammad Taghi Ahmadian ◽  
Ahmad Barari ◽  
Hamid Naghibi Beidokhti
Keyword(s):  
Traumatic Brain Injury ◽  
Brain Injury ◽  
Angular Velocity ◽  
Strain Field ◽  
Damage Threshold ◽  
Human Head ◽  
Geometrical Model ◽  
Fe Method ◽  
Soft Tissue Modeling ◽  
The Brain

Traumatic brain injury (TBI) has long been known as one of the most anonymous reasons for death around the world. A presentation of a model of what happens in the process has been under study for many years; and yet it remains a question due to physiological, geometrical and computational complications. Although the facilities for soft tissue modeling have improved and the precise CT-imaging of human head has revealed novel details of brain, skull and the interface (the meninges), a comprehensive FEM model of TBI is still being studied. This study aims to present an optimized model of human head including the brain, skull, and the meninges after a comprehensive study of the previous models. The model is then used to investigate the effects of various sudden velocity-acceleration impulses on the strain field of the brain by using FE method. Next, the results are summed up and compared with an existing criterion on damage threshold in the brain during trauma. To reach this aim, a full geometrical model of a 30-year-old patient’s head has been generated from CT-scan and MR data. The model has been exposed to 20 angular velocity-acceleration pulses. Subsequently, the changes in the strain field have been compared with the results obtained in the previous studies yielding acceptable accordance with a major previous criterion. The results also show that certain criteria can be generated on the threshold of damage in the brain.

Response of Post-Mortem Human Head Under Primary Blast Loading Conditions: Effect of Blast Overpressures

2013 ◽  
Author(s):  
Shailesh Ganpule ◽  
Robert Salzar ◽  
Namas Chandra
Keyword(s):  
Brain Injury ◽  
Blast Loading ◽  
Human Head ◽  
Severe Injury ◽  
Post Mortem ◽  
Loading Conditions ◽  
Primary Blast ◽  
Blast Overpressure ◽  
Moderate Traumatic Brain Injury ◽  
The Brain

Blast induced neurotrauma (BINT), and posttraumatic stress disorder (PTSD) are identified as the “signature injuries” of recent conflicts in Iraq and Afghanistan. The occurrence of mild to moderate traumatic brain injury (TBI) in blasts is controversial in the medical and scientific communities because the manifesting symptoms occur without visible injuries. Whether the primary blast waves alone can cause TBI is still an open question, and this work is aimed to address this issue. We hypothesize that if a significant level of intracranial pressure (ICP) pulse occurs within the brain parenchyma when the head is subjected to pure primary blast, then blast induced TBI is likely to occur. In order to test this hypothesis, three post mortem human heads are subjected to simulated primary blast loading conditions of varying intensities (70 kPa, 140 kPa and 200 kPa) at the Trauma Mechanics Research Facility (TMRF), University of Nebraska-Lincoln. The specimens are placed inside the 711 mm × 711 mm square shock tube at a section where known profiles of incident primary blast (Friedlander waveform in this case) are obtained. These profiles correspond to specific field conditions (explosive strength and stand-off distance). The specimen is filled with a brain simulant prior to experiments. ICPs, surface pressures, and surface strains are measured at 11 different locations on each post mortem human head. A total of 27 experiments are included in the analysis. Experimental results show that significant levels of ICP occur throughout the brain simulant. The maximum peak ICP is measured at the coup site (nearest to the blast) and gradually decreases towards the countercoup site. When the incident blast intensity is increased, there is a statistically significant increase in the peak ICP and total impulse (p<0.05). Even after five decades of research, the brain injury threshold values for blunt impact cases are based on limited experiments and extensive numerical simulations; these are still evolving for sports-related concussion injuries. Ward in 1980 suggested that no brain injury will occur when the ICP<173 kPa, moderate to severe injury will occur when 173 kPa<ICP<235 kPa and severe injury will occur when ICP>235 kPa for blunt impacts. Based on these criteria, no injury will occur at incident blast overpressure level of 70 kPa, moderate to severe injuries will occur at 140 kPa and severe head injury will occur at the incident blast overpressure intensity of 200 kPa. However, more work is needed to confirm this finding since peak ICP alone may not be sufficient to predict the injury outcome.

A Study on the Impact of Helmet Padding Materials on the Brain Pressure Under Shock Loads

2012 ◽  
Author(s):  
Mehdi Salimi Jazi ◽  
Asghar Rezaei ◽  
Ghodrat Karami ◽  
Fardad Azarmi ◽  
Mariusz Ziejewski
Keyword(s):  
Traumatic Brain Injury ◽  
Brain Injury ◽  
Motor Vehicle ◽  
Human Head ◽  
Motor Vehicle Crashes ◽  
Ballistic Impacts ◽  
Common Causes ◽  
The Impact ◽  
The Brain ◽  
Brain Pressure

A traumatic brain injury (TBI) can occur from a sharp strain, or acceleration, to the human head. Based on the level of injury, TBIs are classified as mild, moderate, or severe, with the most common causes being motor vehicle crashes; violence related injuries; collisions in sports; and falls are the most common causes of TBIs for the general public. Many soldiers experience a TBI in combat zones when they are exposed to the shock waves from blasts, or to ballistic impacts.

scholarly journals Aerosolized In Vivo 3D Localization of Nose-to-Brain Nanocarrier Delivery Using Multimodality Neuroimaging in a Rat Model—Protocol Development

Pharmaceutics ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 391
Author(s):  
Michael C. Veronesi ◽  
Brian D. Graner ◽  
Shih-Hsun Cheng ◽  
Marta Zamora ◽  
Hamideh Zarrinmayeh ◽  
...  
Keyword(s):  
Rat Model ◽  
Ex Vivo ◽  
Region Of Interest ◽  
Ct Imaging ◽  
Pet Tracer ◽  
Positron Emission ◽  
Pet Ct ◽  
Activity Measurements ◽  
The Brain

The fate of intranasal aerosolized radiolabeled polymeric micellar nanoparticles (LPNPs) was tracked with positron emission tomography/computer tomography (PET/CT) imaging in a rat model to measure nose-to-brain delivery. A quantitative temporal and spatial testing protocol for new radio-nanotheranostic agents was sought in vivo. LPNPs labeled with a zirconium 89 (89Zr) PET tracer were administered via intranasal or intravenous delivery, followed by serial PET/CT imaging. After 2 h of continuous imaging, the animals were sacrificed, and the brain substructures (olfactory bulb, forebrain, and brainstem) were isolated. The activity in each brain region was measured for comparison with the corresponding PET/CT region of interest via activity measurements. Serial imaging of the LPNPs (100 nm PLA–PEG–DSPE+89Zr) delivered intranasally via nasal tubing demonstrated increased activity in the brain after 1 and 2 h following intranasal drug delivery (INDD) compared to intravenous administration, which correlated with ex vivo gamma counting and autoradiography. Although assessment of delivery from nose to brain is a promising approach, the technology has several limitations that require further development. An experimental protocol for aerosolized intranasal delivery is presented herein, which may provide a platform for better targeting the olfactory epithelium.

Confronting the grey zone after severe brain injury

2019 ◽  
Vol 3 (6) ◽  
pp. 707-711 ◽  
Author(s):  
Andrew Peterson ◽  
Adrian M. Owen
Keyword(s):  
Brain Injury ◽  
Ethical Issues ◽  
Vegetative State ◽  
Clinical Care ◽  
Grey Zone ◽  
Severe Brain Injury ◽  
New Methods ◽  
Legal Decision Making ◽  
Technological Developments ◽  
The Brain

In recent years, rapid technological developments in the field of neuroimaging have provided several new methods for revealing thoughts, actions and intentions based solely on the pattern of activity that is observed in the brain. In specialized centres, these methods are now being employed routinely to assess residual cognition, detect consciousness and even communicate with some behaviorally non-responsive patients who clinically appear to be comatose or in a vegetative state. In this article, we consider some of the ethical issues raised by these developments and the profound implications they have for clinical care, diagnosis, prognosis and medical-legal decision-making after severe brain injury.

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