Brain white matter after pediatric mild traumatic brain injury: a diffusion tensor and neurite orientation and dispersion imaging study

Abstract

Background: Pediatric mild traumatic brain injury (mTBI) affects millions of children annually. Diffusion tensor imaging (DTI) is sensitive to axonal injuries and white matter microstructure and has been used to characterize the brain changes associated with mild traumatic brain injury (mTBI). Neurite orientation dispersion and density imaging (NODDI) is a diffusion model that can provide additional insight beyond traditional DTI metrics, but has not been examined in pediatric mTBI. The goal of this study was to employ DTI and NODDI to gain added insight into white matter alterations in children with mTBI compared to children with mild orthopedic injury (OI). Methods: Children (mTBI n=320, OI n=176) aged 8-16.99 years (12.39 ± 2.32 years) were recruited from emergency departments at five hospitals across Canada and underwent 3T MRI on average 11 days post-injury. DTI and NODDI metrics were calculated for seven major white matter tracts and compared between groups using univariate analysis of covariance controlling for age, sex, and scanner type. False discovery rate (FDR) was used to correct for multiple comparisons. Results: Univariate analysis revealed no significant group main effects or interactions in DTI or NODDI metrics. Fractional anisotropy and neurite density index in all tracts exhibited a significant positive association with age and mean diffusivity in all tracts exhibited a significant negative association with age in the whole sample. Conclusions: Overall, there were no differences between mTBI and OI groups in brain white matter microstructure from either DTI or NODDI in the seven tracts. This indicates that mTBI is associated with only relatively minor white matter differences, if any, at the post-acute stage. Brain differences may evolve at later stages of injury, so longitudinal studies with long-term follow-up are needed.

Machine learning classification of chronic traumatic brain injury using diffusion tensor imaging and NODDI: A replication and extension study

“…While some studies have compared individuals with history of TBI to uninjured participants, such group differences may be moderated by other differences inherent to individuals with TBI, including neurobehavioral characteristics (e.g., impulsivity and rates of PTSD). More recent studies have compared individuals with TBI to individuals with previous orthopedic injury, observing non-significant group differences for FA ( Wilde et al, 2019 ) and NODDI metrics ( Shukla et al, 2021 ). While we ensured that TBI+ and TBI−groups did not significantly differ with respect to multiple variables known to influence WM structural integrity, including psychopathic traits, rates of PTSD and SUDs, and IQ, there exists the possibility that an unmeasured variable may moderate the current results.…”