Micromechanical analysis of brain's diffuse axonal injury

Area of Science:

• Biomedical Engineering
• Neuroscience
• Computational Mechanics

Background:

• Traumatic brain injury (TBI) is a significant health concern.
• Diffuse axonal injury (DAI) is a primary mechanism of TBI.
• Existing models often rely on statistical analysis of accident data.

Purpose of the Study:

• To develop a mechanistic, multi-scale numerical model to quantify DAI.
• To analyze the percentage of injured axons at the micro-level.
• To create a methodology independent of statistical injury risk curves.

Main Methods:

• A 2D micro-level lattice method was implemented using single axon properties and a viscoelastic constitutive relation.
• The model analyzes axon injury under biaxial stretches in white matter voxels.
• Micro-injury maps were generated based on principal strain values and direction.

Main Results:

• The numerical approach quantifies DAI by calculating the percentage of injured axons within a voxel.
• The methodology provides direct output of injured axon percentages based on mechanical inputs.
• Reference micro-injury maps were developed for specific strain conditions.

Conclusions:

• The proposed micro-mechanical approach offers a novel way to analyze DAI.
• This method considers the anatomical structure and mechanical properties of neural axons.
• The work has potential applications in developing advanced TBI prevention and diagnosis tools.