Electronic Thesis and Dissertation Repository

Thesis Format

Integrated Article

Degree

Master of Engineering Science

Program

Mechanical and Materials Engineering

Supervisor

Mao, Haojie

Abstract

To better understand traumatic brain injury (TBI), various laboratory animal experiments have been developed. However, there lacks an effective scaling to connect animal TBI models with human brain injuries. With the help of the finite element (FE) model, brain mechanical responses such as strains can be predicted, and hence can serve as a parameter to facilitate animal to human scaling, as these tissue-level strains directly link to neuronal damage. In this thesis, first, a comprehensive comparison of brain strains between animal TBI models and human TBI cases was conducted. Then, a brain-strain-based scaling law between mouse and human was developed, which could serve as a guideline for closed head neurotrauma model design. Lastly, a novel and high mesh quality marmoset brain FE model was developed, which was used to enrich scaling law to non-human primates. In summary, the comparison method, scaling law, and new marmoset FE model, all together could help better represent human real-world TBI using laboratory mouse and marmoset TBI models, hence improving prevention, diagnostics, and therapeutics.

Summary for Lay Audience

Traumatic brain injury (TBI) posed serious threats to social and economic development. Effective prevention, diagnostics and therapeutics need to be discovered. TBI is mostly caused by rapid linear and rotational acceleration, induced by direct blunt impact to the head or neck-involved inertia loading. One of the most common pathologies is axonal injury. During the event, brain tissues experience stretch, which causes axon fibers to be damaged when exceeding their elongation limit. From the perspective of biomechanics, the strain could serve as an effective evaluator of potential brain injury severity and risk. However, the challenge is that the in vivo observation of brain strain was almost impossible due to the skull and short impact duration. Though animal TBI experiments in the laboratory offered huge amounts of data of brain response, brain strains of these animal TBI models usually remain unknown and their comparison to brain strain in human TBI needs to be investigated. The main contribution of this thesis is to look into both human and animal brain strains among both real-world impacts and laboratory settings, and then developed codes and methods to compare and scale animal head kinematics, to better understand available animal TBI and design future animal TBI that is more relevant to human TBI. By doing so, better prevention, diagnostics, and therapeutics of TBI could be developed.

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