Artikel
Finite element simulation of brain tissue biomechanics in the controlled cortical contusion model
Simulation der Biomechanik des Gehirns im kortikalen Kontusionsmodell mittels Finite Elemente
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Autoren
Veröffentlicht: | 4. Mai 2005 |
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Gliederung
Text
Objective
The controlled cortical impact model has been used extensively to study focal traumatic brain injury. Although the impact variables can be well defined, little is known about the extent and distribution of the biomechanical trauma as delivered to different brain regions. This knowledge however could be valuable for interpretation of experimental data (immunohistochemistry etc.), especially regarding the comparison of the regional biomechanical severity level to the regional magnitude of the trauma sequel under investigation. We tried to simulate brain tissue biomechanics of trauma with finite element modelling.
Methods
We used finite element (FE) analysis, based on high resolution T2-weighted MRI images of rat brain, to simulate displacement, mean stress, and shear stress of brain during impact. Young’s Modulus E, to describe tissue elasticity, was assigned to each FE in three scenarios: in a constant fashion (E=50kPa), or according to the MRI intensity in a linear (E=[10,100]kPa) and inverse-linear fashion(E=[100,10]kPa).
Results
Between the simulated 3 scenarios tissue displacement did not vary, however mean stress and shear stress were largely different. The linear scenario showed the most likely distribution of stresses in the tissue if general knowledge of a predominantely unilateral injury distribution is taken as reference.
Conclusions
FE analysis seems to be a suitable tool for biomechanical simulation of brain at the time of impact. However, this pilot study clearly shows, that modelling results largely depend on the method by which elastic tissue properties are assigned to the single finite elements. Regional tissue elasticity needs to be determined with a specific approach, e.g. by means of MRI elastography. Only then results can be as close to reality to be used for comparison to e.g. histopathological injury maps.