The consequence of fiber orientation downsampling on the computation of white matter tract-related deformation

Incorporating neuroimaging-revealed structural details into finite element (FE) head models opens vast opportunities to understand brain injury mechanisms. Recently, growing efforts have been made to integrate the fiber orientation from diffusion tensor imaging into the FE models to compute white matter (WM) tract-related deformation. Commonly used approaches often downsample the spatially enriched fiber orientation to match the resolution of FE meshes, resulting in an element-wise orientation implementation. However, the validity of downsampling and the consequences on the computed tract-related strains remain elusive. To address this problem, the current study proposed a new voxel-wise approach to integrate fiber orientation into FE models without downsampling. By setting the voxel-wise orientation responses as the reference, we then evaluated the reliability of two existing downsampling approaches on tract-related strains using two FE models with varying element sizes. The results showed that, for a model with a large mesh-image resolution dismatch, the downsampling orientation exhibited an absolute difference over 30 degree across the WM/gray matter interface and pons regions and further negatively affects the computation of tract-related strains with the normalized root-mean-square error up to 20% and peaking tract-related strains underestimated by 5%. This downsampling-induced effect was lower in FE models with finer meshes. Thus, this study yields insights on integrating neuroimaging-revealed fiber orientation into FE models and may better inform the computation of WM tract-related deformation, which are crucial for advancing the etiological understanding and computational predictability of brain injury.

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Age, Sex and Cerebral Microbleed Effects On White Matter Degradation After Traumatic Brain Injury

Innovation in Aging ◽

10.1093/geroni/igaa057.3272 ◽

2020 ◽

Vol 4 (Supplement_1) ◽

pp. 886-887

Author(s):

Andrei Irimia ◽

Ammar Dharani ◽

Van Ngo ◽

David Robles ◽

Kenneth Rostowsky

Keyword(s):

Traumatic Brain Injury ◽

Brain Injury ◽

White Matter ◽

Diffusion Tensor ◽

Diffuse Axonal Injury ◽

Principal Component ◽

Older Age ◽

Analysis Of Covariance ◽

Future Research ◽

Cerebral Microbleed

Abstract Mild traumatic brain injury (mTBI) affects white matter (WM) integrity and accelerates neurodegeneration. This study assesses the effects of age, sex, and cerebral microbleed (CMB) load as predictors of WM integrity in 70 subjects aged 18-77 imaged acutely and ~6 months after mTBI using diffusion tensor imaging (DTI). Two-tensor unscented Kalman tractography was used to segment and cluster 73 WM structures and to map changes in their mean fractional anisotropy (FA), a surrogate measure of WM integrity. Dimensionality reduction of mean FA feature vectors was implemented using principal component (PC) analysis, and two prominent PCs were used as responses in a multivariate analysis of covariance. Acutely and chronically, older age was significantly associated with lower FA (F2,65 = 8.7, p < .001, η2 = 0.2; F2,65 = 12.3, p < .001, η2 = 0.3, respectively), notably in the corpus callosum and in dorsolateral temporal structures, confirming older adults’ WM vulnerability to mTBI. Chronically, sex was associated with mean FA (F2,65 = 5.0, p = 0.01, η2 = 0.1), indicating males’ greater susceptibility to WM degradation. Acutely, a significant association was observed between CMB load and mean FA (F2,65 = 5.1, p = 0.009, η2 = 0.1), suggesting that CMBs reflect the acute severity of diffuse axonal injury. Together, these findings indicate that older age, male sex, and CMB load are risk factors for WM degeneration. Future research should examine how sex- and age-mediated WM degradation lead to cognitive decline and connectome degeneration after mTBI.

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Acute mild traumatic brain injury is not associated with white matter change on diffusion tensor imaging

Brain ◽

10.1093/brain/awu095 ◽

2014 ◽

Vol 137 (7) ◽

pp. 1876-1882 ◽

Cited By ~ 47

Author(s):

Tero Ilvesmäki ◽

Teemu M. Luoto ◽

Ullamari Hakulinen ◽

Antti Brander ◽

Pertti Ryymin ◽

...

Keyword(s):

Traumatic Brain Injury ◽

Diffusion Tensor Imaging ◽

Brain Injury ◽

White Matter ◽

Mild Traumatic Brain Injury ◽

Diffusion Tensor ◽

White Matter Change

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Acute White Matter Tract Damage after Frontal Mild Traumatic Brain Injury

Journal of Neurotrauma ◽

10.1089/neu.2016.4407 ◽

2017 ◽

Vol 34 (2) ◽

pp. 291-299 ◽

Cited By ~ 21

Author(s):

Juan J. Herrera ◽

Kurt Bockhorst ◽

Shakuntala Kondraganti ◽

Laura Stertz ◽

João Quevedo ◽

...

Keyword(s):

Traumatic Brain Injury ◽

Brain Injury ◽

White Matter ◽

Mild Traumatic Brain Injury ◽

White Matter Tract ◽

Tract Damage

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The Use of a Cellular Strain Injury Criterion and Diffusion Tensor Imaging in a Computational Model of Traumatic Brain Injury

ASME 2010 Summer Bioengineering Conference, Parts A and B ◽

10.1115/sbc2010-19562 ◽

2010 ◽

Author(s):

Rika M. Wright ◽

K. T. Ramesh

Keyword(s):

Traumatic Brain Injury ◽

Brain Injury ◽

Mechanical Loading ◽

Computational Models ◽

Diffusion Tensor ◽

Diffuse Axonal Injury ◽

Element Model ◽

Cellular Level ◽

Cellular Injury ◽

Injury Mechanisms

With the increase in the number of soldiers sustaining traumatic brain injury from military incidents and the recent attention on sports related traumatic brain injury, there has been a focused effort to develop preventative and treatment methods for traumatic brain injury (TBI). Traumatic brain injury is caused by mechanical loading to the head, such as from impacts, sudden accelerations, or blast loading, and the pathology can range from focal damage in the brain to widespread diffuse injury [1]. In this study, we investigate the injury mechanisms of diffuse axonal injury (DAI), which accounts for the second largest percentage of deaths due to brain trauma [2]. DAI is caused by sudden inertial loads to the head, and it is characterized by damage to neural axons. Despite the extensive research on DAI, the coupling between the mechanical loading to the head and the damage at the cellular level is still poorly understood. Unlike previous computational models that use macroscopic stress and strain measures to determine injury, a cellular injury criterion is used in this work as numerous studies have shown that cellular strain can be related to the functional damage of neurons. The effectiveness of using this cellular injury criterion to predict damage in a finite element model of DAI is investigated.

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Diffusion Tensor Imaging (DTI) Based Measures of White Matter Integrity After Traumatic Brain Injury

Archives of Physical Medicine and Rehabilitation ◽

10.1016/j.apmr.2018.08.016 ◽

2018 ◽

Vol 99 (11) ◽

pp. e133

Author(s):

Andrei Vakhtin ◽

Ansgar Furst ◽

Dana Waltzman ◽

J. Ashford ◽

Max Wintermark ◽

...

Keyword(s):

Traumatic Brain Injury ◽

Diffusion Tensor Imaging ◽

Brain Injury ◽

White Matter ◽

Diffusion Tensor ◽

White Matter Integrity ◽

Diffusion Tensor Imaging Dti

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Novel strain analysis informs about injury susceptibility of the corpus callosum to repeated impacts

Brain Communications ◽

10.1093/braincomms/fcz021 ◽

2019 ◽

Vol 1 (1) ◽

Cited By ~ 2

Author(s):

Allen A Champagne ◽

Emile Peponoulas ◽

Itamar Terem ◽

Andrew Ross ◽

Maryam Tayebi ◽

...

Keyword(s):

Magnetic Resonance Imaging ◽

White Matter ◽

Magnetic Resonance ◽

Corpus Callosum ◽

Diffusion Tensor ◽

White Matter Integrity ◽

White Matter Tract ◽

Exposure Group ◽

Resonance Imaging ◽

High Exposure

Abstract Increasing evidence for the cumulative effects of head trauma on structural integrity of the brain has emphasized the need to understand the relationship between tissue mechanic properties and injury susceptibility. Here, diffusion tensor imaging, helmet accelerometers and amplified magnetic resonance imaging were combined to gather insight about the region-specific vulnerability of the corpus callosum to microstructural changes in white-matter integrity upon exposure to sub-concussive impacts. A total of 33 male Canadian football players (meanage = 20.3 ± 1.4 years) were assessed at three time points during a football season (baseline pre-season, mid-season and post-season). The athletes were split into a LOW (N = 16) and HIGH (N = 17) exposure group based on the frequency of sub-concussive impacts sustained on a per-session basis, measured using the helmet-mounted accelerometers. Longitudinal decreases in fractional anisotropy were observed in anterior and posterior regions of the corpus callosum (average cluster size = 40.0 ± 4.4 voxels; P < 0.05, corrected) for athletes from the HIGH exposure group. These results suggest that the white-matter tract may be vulnerable to repetitive sub-concussive collisions sustained over the course of a football season. Using these findings as a basis for further investigation, a novel exploratory analysis of strain derived from sub-voxel motion of brain tissues in response to cardiac impulses was developed using amplified magnetic resonance imaging. This approach revealed specific differences in strain (and thus possibly stiffness) along the white-matter tract (P < 0.0001) suggesting a possible signature relationship between changes in white-matter integrity and tissue mechanical properties. In light of these findings, additional information about the viscoelastic behaviour of white-matter tissues may be imperative in elucidating the mechanisms responsible for region-specific differences in injury susceptibility observed, for instance, through changes in microstructural integrity following exposure to sub-concussive head impacts.

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