Deformation of the human brain induced by mild angular head acceleration

Area of Science:

• Biomechanics
• Neuroimaging
• Medical Physics

Background:

• Traumatic brain injury (TBI) mechanics are not fully understood.
• Quantitative data on brain deformation during acceleration is lacking.
• Previous studies often rely on computational models or animal experiments.

Purpose of the Study:

• To quantitatively measure human brain deformation during angular acceleration.
• To provide experimental data illuminating the mechanics of TBI.
• To correlate observed strain patterns with known TBI mechanisms.

Main Methods:

• Utilized tagged magnetic resonance imaging (MRI) with spatial modulation of magnetization (SPAMM).
• Acquired dynamic images synchronized with head motion during mild angular acceleration.
• Employed a custom MR-compatible device for controlled head motion within the scanner.
• Characterized brain deformation using Lagrangian strain analysis.

Main Results:

• Observed consistent patterns of radial-circumferential shear strain in the brain.
• Strain patterns showed similarities to those in viscoelastic gel models under angular acceleration.
• Brain strain fields were influenced by regional heterogeneity and anatomical structures (e.g., central fissure).
• The brain's suspension system (dura mater, falx cerebri, tentorium) affected strain distribution.

Conclusions:

• Experimental measurement of human brain deformation during angular acceleration is feasible using dynamic tagged MRI.
• Observed shear strain patterns provide direct evidence for mechanical responses during head acceleration.
• Brain deformation is modulated by its complex internal structure and surrounding membranes, impacting TBI mechanics.