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Characterization of Closed Head Impact Injury in Rat.

Hua Y, Akula P, Kelso M, Gu L - Biomed Res Int (2015)

Bottom Line: Results revealed that impact depth and impactor shape were the two leading factors affecting intracranial responses.An indentation depth instead of impact depth would be appropriate to characterize the influence of a large deformed rubber impactor.This work could be used to better design or compare CHI experiments.

View Article: PubMed Central - PubMed

Affiliation: Department of Mechanical and Materials Engineering, University of Nebraska-Lincoln, Lincoln, NE 68588-0656, USA.

ABSTRACT
The closed head impact (CHI) rat models are commonly used for studying the traumatic brain injury. The impact parameters vary considerably among different laboratories, making the comparison of research findings difficult. In this work, numerical CHI experiments were conducted to investigate the sensitivities of intracranial responses to various impact parameters (e.g., impact depth, velocity, and position; impactor diameter, material, and shape). A three-dimensional finite element rat head model with anatomical details was subjected to impact loadings. Results revealed that impact depth and impactor shape were the two leading factors affecting intracranial responses. The influence of impactor diameter was region-specific and an increase in impactor diameter could substantially increase tissue strains in the region which located directly beneath the impactor. The lateral impact could induce higher strains in the brain than the central impact. An indentation depth instead of impact depth would be appropriate to characterize the influence of a large deformed rubber impactor. The experimentally observed velocity-dependent injury severity could be attributed to the "overshoot" phenomenon. This work could be used to better design or compare CHI experiments.

No MeSH data available.


Related in: MedlinePlus

Finite element discretization of the adult male Sprague-Dawley rat head.
© Copyright Policy - open-access
Related In: Results  -  Collection


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fig1: Finite element discretization of the adult male Sprague-Dawley rat head.

Mentions: A 3D FE rat head model was generated from the high-resolution magnetic resonance imaging (MRI) datasets of an adult male Sprague-Dawley rat weighing about 360 g, as shown in Figure 1. The brain MRI has an isotropic resolution of 256 × 256 × 256 pixels, for a field view of 30 mm in all three directions. The image data were segmented into three main brain regions: cerebrum, hippocampus, and cerebellum. The segmentation was realized using the 3D image analysis algorithm implemented in Mimics (Materialise, Inc., Leuven, Belgium). The segmented brain model was then imported into HyperMesh (Altair Engineering, Inc., MI, USA) and meshed as a triangular surface mesh (S3R). A volume mesh with 4-noded tetrahedral elements (C3D4) was generated from this surface mesh. The rat skull was created by offsetting a layer of wedge elements (C3D6) above the outer surface of the brain by 0.16 mm [12]. A mesh convergence test was conducted and the minimum mesh size of 0.4 mm was chosen. At this resolution, the rat head model consisted of a total of 1,107,183 tetrahedral elements and 14,898 prism elements for the brain and skull, respectively.


Characterization of Closed Head Impact Injury in Rat.

Hua Y, Akula P, Kelso M, Gu L - Biomed Res Int (2015)

Finite element discretization of the adult male Sprague-Dawley rat head.
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4588353&req=5

fig1: Finite element discretization of the adult male Sprague-Dawley rat head.
Mentions: A 3D FE rat head model was generated from the high-resolution magnetic resonance imaging (MRI) datasets of an adult male Sprague-Dawley rat weighing about 360 g, as shown in Figure 1. The brain MRI has an isotropic resolution of 256 × 256 × 256 pixels, for a field view of 30 mm in all three directions. The image data were segmented into three main brain regions: cerebrum, hippocampus, and cerebellum. The segmentation was realized using the 3D image analysis algorithm implemented in Mimics (Materialise, Inc., Leuven, Belgium). The segmented brain model was then imported into HyperMesh (Altair Engineering, Inc., MI, USA) and meshed as a triangular surface mesh (S3R). A volume mesh with 4-noded tetrahedral elements (C3D4) was generated from this surface mesh. The rat skull was created by offsetting a layer of wedge elements (C3D6) above the outer surface of the brain by 0.16 mm [12]. A mesh convergence test was conducted and the minimum mesh size of 0.4 mm was chosen. At this resolution, the rat head model consisted of a total of 1,107,183 tetrahedral elements and 14,898 prism elements for the brain and skull, respectively.

Bottom Line: Results revealed that impact depth and impactor shape were the two leading factors affecting intracranial responses.An indentation depth instead of impact depth would be appropriate to characterize the influence of a large deformed rubber impactor.This work could be used to better design or compare CHI experiments.

View Article: PubMed Central - PubMed

Affiliation: Department of Mechanical and Materials Engineering, University of Nebraska-Lincoln, Lincoln, NE 68588-0656, USA.

ABSTRACT
The closed head impact (CHI) rat models are commonly used for studying the traumatic brain injury. The impact parameters vary considerably among different laboratories, making the comparison of research findings difficult. In this work, numerical CHI experiments were conducted to investigate the sensitivities of intracranial responses to various impact parameters (e.g., impact depth, velocity, and position; impactor diameter, material, and shape). A three-dimensional finite element rat head model with anatomical details was subjected to impact loadings. Results revealed that impact depth and impactor shape were the two leading factors affecting intracranial responses. The influence of impactor diameter was region-specific and an increase in impactor diameter could substantially increase tissue strains in the region which located directly beneath the impactor. The lateral impact could induce higher strains in the brain than the central impact. An indentation depth instead of impact depth would be appropriate to characterize the influence of a large deformed rubber impactor. The experimentally observed velocity-dependent injury severity could be attributed to the "overshoot" phenomenon. This work could be used to better design or compare CHI experiments.

No MeSH data available.


Related in: MedlinePlus