Abstract
[Truncated abstract] Knowledge of the mechanical properties of the brain-skull interface is important for surgery simulation and injury biomechanics. However, these properties are known only to a limited extent. The goal of this study is to determine the mechanical properties of the brain-skull interface which will lead to the provision of boundary conditions for modelling the brain to predict brain shift during surgery. The most straightforward way to determine the mechanical properties of the brain-skull interface would be to conduct experiments on interface samples. However, the complex anatomical structure of this interface poses difficulties in extracting the interface samples without damaging tissues that form the interface. To overcome this problem, in-situ indentation experiments of the brain were conducted to determine the mechanical properties of the brain-skull interface, and the macroscopic mechanical properties of the brain-skull interface were obtained from the results of these experiments. To the best of my knowledge, this is the first ever analysis of this kind. In this study, the results of in-situ brain indentation experiments are presented and the interface’s mechanical properties were derived by complementing analysis of the results of these experiments with brain modelling usingnon-linear Finite Element (FE) procedures.
Firstly, in-situ brain indentation experiment was conducted and the reaction forces on the indentor were measured. To determine the deformation field within the brain, X-ray opaque markers were implanted inside the brain and two mobile C-arms were used to capture their displacements during in-situ indentation experiments. Subsequently, a cylindrical sample of brain tissue was extracted and uniaxial compression test was conducted to determine the subject specific mechanical properties of the cylindrical tissue sample. The calibration of the X-ray image intensifiers was done to correct any distortion present in the images and the displacement of the markers were obtained from the X-ray images. Finally, a nonlinear model of the in-situ indentation experiment was created in the FE solver ABAQUSTM and the properties of the brain-skull interface models were derived so that the calculated indentor reaction forces matched those measured experimentally. To verify the brain deformation, the 3D displacements of those X-ray opaque markers were also obtained from the nodal displacements predicted by the FE model of in-situ indentation experiment.
Firstly, in-situ brain indentation experiment was conducted and the reaction forces on the indentor were measured. To determine the deformation field within the brain, X-ray opaque markers were implanted inside the brain and two mobile C-arms were used to capture their displacements during in-situ indentation experiments. Subsequently, a cylindrical sample of brain tissue was extracted and uniaxial compression test was conducted to determine the subject specific mechanical properties of the cylindrical tissue sample. The calibration of the X-ray image intensifiers was done to correct any distortion present in the images and the displacement of the markers were obtained from the X-ray images. Finally, a nonlinear model of the in-situ indentation experiment was created in the FE solver ABAQUSTM and the properties of the brain-skull interface models were derived so that the calculated indentor reaction forces matched those measured experimentally. To verify the brain deformation, the 3D displacements of those X-ray opaque markers were also obtained from the nodal displacements predicted by the FE model of in-situ indentation experiment.
| Original language | English |
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| Qualification | Doctor of Philosophy |
| Publication status | Unpublished - 2014 |