TBI-induced vessel softening increases brain susceptibility to injury with repeated head trauma

Farshid Shojaeianforoud¹, Alexander M. Venezie¹, Jose E. Rubio^2,3, Jaques Reifman², Brittany Coats^1,4, Kenneth L. Monson^1,4

¹Department of Mechanical Engineering, University of Utah, Salt Lake City, UT, USA; ²Department of Defense Biotechnology High Performance Computing Software Applications Institute, Defense Health Agency Research & Development, Medical Research and Development Command, Fort Detrick, MD, USA; ³The Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc., Bethesda, MD, USA; ⁴Department of Biomedical Engineering, University of Utah, Salt Lake City, UT, USA

Repeated traumatic brain injury (TBI) is a significant concern among military personnel, athletes, and abuse victims, but little is known about the mechanisms that drive the brain's apparent increase in injury susceptibility with repeated loading. One critical factor may be the softening of cerebral blood vessels, which are significantly stiffer than brain tissue and influence its mechanical response during trauma. In this study, we employed a finite element model of a Göttingen minipig head to investigate how progressive vascular softening influences strain changes in brain tissue during both repeated blast and rapid rotation (coronal and sagittal directions). For a more detailed description, please refer to the publication in the Journal of the Mechanical Behavior of Biomedical Materials.

All simulations were conducted using Abaqus/Explicit 2022 at the Center for High Performance Computing (CHPC) at the University of Utah. We used 64 CPU cores in an MPI-based parallel computing setup and in double-precision mode for efficient and accurate multi-node processing. Each blast simulation required 40–44 h, while the rotation simulations took 25–49 h. Post-processing was performed using the CAE module in Abaqus (2022) and custom scripts in the Abaqus Python module.

Finite-element model of minipig head with vasculature — Components of the 3-D FE model of a Göttingen minipig head, integrating the head and vasculature using the embedded elements method in Abaqus (recreated from Sundaramurthy et al., 2021).

Plot of increase in vessel average strain relative to the first exposure as a function of repetitions (possitive correlation)

Percent increase in vessel average strain relative to the first exposure (S0), in coronal (C) and sagittal (S) rotations across three severity levels for repetitions S1–S5 (exposures 2-6). The plots demonstrate progressive strain accumulation with repeated exposures, although the rate of increase diminishes with higher number of repetitions. Fitted curves are quadratic (R² > 0.99 for all cases).

Strain contours in brain tissue during severe coronal and sagittal rotations. For coronal rotations, results are shown on three coronal cross-sections (C1, C2 – mid-coronal, and C3), and for sagittal rotations, on three sagittal cross-sections (S1, S2 – mid-sagittal, and S3), with cross-section positions illustrated above the figure. Contours are presented following the second, fourth, and sixth repetitions, as well as for the no-vasculature cases. Black regions indicate intersections of blood vessels with the cross sections, with vessels filled in black to enhance visual distinction. For more detailed information, please refer to the publication.

Attribution: This content was provided by researchers involved with the project and edited by staff at the CHPC to fit this format.