Johnson Ho

Can sulci protect the brain from traumatic injury

The influence of sulci in dynamic finite element simulations of the human head has been investigated. First, a detailed 3D FE model was constructed based on an MRI scan of a human head. A second model with a smoothed brain surface was created based on the same MRI scan as the first FE model. These models were validated against experimental data to confirm their human-like dynamic responses during impact. The validated FE models were subjected to several acceleration impulses and the maximum principle strain and strain rate in the brain were analyzed. The results suggested that the inclusion of sulci should be considered for future FE head models as it alters the strain and strain distribution in an FE model.

Automatic generation and validation of patient-specific finite element head models suitable for crashworthiness analysis

A method to automatically generate finite element (FE) head models is presented in this paper. Individual variation in geometry of the head should be taken into consideration in future injury-prediction research. To avoid inter- and intra-operator variation due to manual segmentation, a robust and accurate algorithm is suggested. The current approach utilises expectation maximisation classification and skull stripping. The whole process from geometry extraction to model generation is converted into an automatic scheme. The models that are generated from the proposed method are validated in terms of segmentation accuracy, element quality and injury-prediction ability. The segmentations of the white matter and grey matter are about 90% accurate and the models have good element quality, with 94% of the elements having a Jacobian above 0.5. Using the experimental data from post-mortem human subject heads, nodal displacements were compared with the data collected from the simulations with the FE head models. The results are promising, indicating that the proposed method is good enough to generate patient-specific model for brain injury prediction. Further improvement can be made in terms of geometry accuracy and element quality.

Three Dimensional Poroelastic Simulation of Brain Edema : Initial studies on intracranial pressure

Three Dimensional Poroelastic Simulation of Brain Edema : Initial Studies on Intracranial Pressure Using Comsol Multiphysics

The peculiar properties of the falx and tentorium in brain injury biomechanics

The influence of the falx and tentorium on brain injury biomechanics during impact was studied with finite element (FE) analysis. Three detailed 3D FE head models were created based on the images of a healthy, normal size head. Two of the models contained the addition of falx and tentorium with material properties from previously published experiments. Impact loadings from a reconstructed concussive case in a sport accident were applied to the two players involved. The results suggested that the falx and tentorium could induce large strains to the surrounding brain tissues, especially to the corpus callosum and brainstem. The tentorium seemed to constrain the motion of the cerebellum while inducing large strain in the brainstem in both players involved in the accident (one player had mainly coronal head rotation and the other had both coronal and transversal rotations). Since changed strain levels were observed in the brainstem and corpus callosum, which are classical sites for diffuse axonal injuries (DAI), we confirmed the importance of using accurate material properties for falx and tentorium in a FE head model when studying traumatic brain injuries.

Learning through a virtual patient vs. recorded lecture : a comparison of knowledge retention in a trauma case

Objectives To compare medical students’ and residents’ knowledge retention of assessment, diagnosis and treatment procedures, as well as a learning experience, of patients with spinal trauma after training with either a Virtual Patient case or a video-recorded traditional lecture. Methods A total of 170 volunteers (85 medical students and 85 residents in orthopedic surgery) were randomly allocated (stratified for student/resident and gender) to either a video-recorded standard lecture or a Virtual Patient-based training session where they interactively assessed a clinical case portraying a motorcycle accident. The knowledge retention was assessed by a test immediately following the educational intervention and repeated after a minimum of 2 months. Participants’ learning experiences were evaluated with exit questionnaires. A repeated-measures analysis of variance was applied on knowledge scores. A total of 81% (n = 138) of the participants completed both tests. Results There was a small but significant decline in first and second test results for both groups (F(1, 135) = 18.154, p = 0.00). However, no significant differences in short-term and long-term knowledge retention were observed between the two teaching methods. The Virtual Patient group reported higher learning experience levels in engagement, stimulation, general perception, and expectations. Conclusions Participants’ levels engagement were reported in favor of the VP format. Similar knowledge retention was achieved through either a Virtual Patient or a recorded lecture.

Investigation of the dynamic response contribution of vascular in a 3D finite element head model

Investigation of the Dynamic Response Contribution of Vasculature in a 3D Finite Element Head Model