Case Report: An MRI Traumatic Brain Injury Longitudinal Case Study at 7 Tesla: Pre- and Post-injury Structural Network and Volumetric Reorganization and Recovery

Relationship Between Structural and Functional Network Connectivity Changes for Patients With Traumatic Brain Injury and Chronic Health Symptoms

Combination of structural and functional brain connectivity methods provides a more complete and effective avenue into the investigation of cortical network responses to traumatic brain injury (TBI) and subtle alterations in brain connectivity associated with TBI. Structural connectivity (SC) can be measured using diffusion tensor imaging to evaluate white matter integrity, whereas functional connectivity (FC) can be studied by examining functional correlations within or between functional networks. In this study, the alterations of SC and FC were assessed for TBI patients, with and without chronic symptoms (TBIcs/TBIncs), compared with a healthy control group (CG). The correlation between global SC and FC was significantly increased for both TBI groups compared with CG. SC was significantly lower in the TBIcs group compared with CG, and FC changes were seen in the TBIncs group compared with CG. When comparing TBI groups, FC differences were observed in the TBIcs group compared with the TBIncs group. These observations show that the presence of chronic symptoms is associated with a distinct pattern of SC and FC changes including the atrophy of the SC and a mixture of functional hypoconnectivity and hyperconnectivity, as well as loss of segregation of functional networks.

Characteristics of the Structural Connectivity in Patients with Brain Injury and Chronic Health Symptoms: A Pilot Study

Diffusion properties from diffusion tensor imaging (DTI) are exquisitely sensitive to white matter abnormalities incurred during traumatic brain injury (TBI), especially for those patients with chronic post-TBI symptoms such as headaches, dizziness, fatigue, etc. The evaluation of structural and functional connectivity using DTI has become a promising method for identifying subtle alterations in brain connectivity associated with TBI that are otherwise not visible with conventional imaging. This study assessed whether TBI patients with (n = 17) or without (n = 16) chronic symptoms (TBIcs/TBIncs) exhibit any changes in structural connectivity (SC) and mean fractional anisotropy (mFA) of intra- and inter-hemispheric connections when compared to a control group (CG) (n = 13). Reductions in SC and mFA were observed for TBIcs compared to CG, but not for TBIncs. More connections were found to have mFA reductions than SC reductions. On the whole, SC is dominated by ipsilateral connections for all the groups after the comparison of contralateral and ipsilateral connections. More contra-ipsi reductions of mFA were found for TBIcs than TBIncs compared to CG. These findings suggest that TBI patients with chronic symptoms not only demonstrate decreased global and regional mFA but also reduced structural network connectivity.

PREFACE to what traditional neuropsychological assessment got wrong about mild traumatic brain injury. A four-part opinion review

This Preface overviews a four-part opinion series on the role of tradtional neuropsychological tests in evaluating mild traumatic brain injury (mTBI), juxtaposed to all of the progress that has occurred with advanced neuroimaging and allied technologies. The four areas of review and critique are: I. Neuropathology; II: Limitations in Test Development, Statistical and Psychometric Issues; III. Implications of Advanced Neuroimaging Findings inn the Neuropsychological Assessment of the mTBI Patient, and IV: Clinical Applications and Future Directions. The example is made that since their inception in the early to mid-20th Century, traditional neuropsychological measures mostly have remained invariant, have been used as omnibus measures for assessing all types of neurological and neuropsychiatric conditions, and were never specifically designed to asses the effects of mTBI. Extensive discussion is provided across all four parts concerning the limits of traditional neuropsychological methods, especially in the absences of any integration with advanced neuroimaging and biomarker findings. Part IV provides an outline for future research and clinical application in the development of novel neuropsychological assessment mesasures specific to mTBI.

Updates on Improving Imaging Modalities for Traumatic Brain Injury

The Center for Disease Control and Prevention reports that traumatic brain injury (TBI) was related to over 64,000 deaths in the United States in 2020, equating to more than 611 TBI-related hospitalizations and 176 TBI-related deaths per day. There are both long- and short-term sequelae involved with the pathophysiology of TBI that can range from mild to severe. Recently, more effort has been devoted to understanding the long-term consequences of TBI and how early detection of these injuries can prevent late clinical manifestations. Obtaining proper, detailed imaging is key to guiding the direction of intervention, but there is a gap in the understanding of how TBI imaging can be used to predict and prevent the long-term morbidities seen with even mild forms of TBI. There have been significant strides in the advancement of TBI imaging that allows for quicker, more affordable, and more effective imaging of intracranial bleeds, axonal injury, tissue damage, and more. Despite this, there is still room for improved standardization and more data supporting the justification of using certain imaging modalities. This review aims to outline recent advancements in TBI imaging and areas that require further investigation to improve patient outcomes and minimize the acute and chronic comorbidities associated with TBI.