Search

Diffuse axonal injury (DAI) disrupts the integrity of white matter microstructure and affects brain functional connectivity, resulting in persistent cognitive, behavioral and affective deficits. Mounting evidence suggests that altered cortical-subcortical connectivity is a major contributor to cognitive dysfunction. The functional integrity of the striatum is particularly vulnerable to DAI, but has received less attention. This study aimed to investigate the alteration patterns of striatal subdivision functional connectivity. Twenty-six patients with DAI and 27 healthy controls underwent resting-state fMRI scans on a 3.0 T scanner. We assessed striatal subdivision functional connectivity using a seed-based analysis in DAI. Furthermore, a partial correlation was used to measure its clinical association. Compared to controls, patients with DAI showed decreased functional connectivity between the right inferior ventral striatum and right inferior frontal gyrus, as well as the right inferior parietal lobule, between the left inferior ventral striatum and right inferior frontal gyrus, between the right superior ventral striatum and bilateral cerebellar posterior lobe, between the bilateral dorsal caudal putamen and right anterior cingulate gyrus, and between the right dorsal caudal putamen and right inferior parietal lobule. Moreover, decreased functional connectivity was observed between the left dorsal caudate and the right cerebellar posterior lobe, while increased functional connectivity was found between the left dorsal caudate and right inferior parietal lobule. Correlation analyses showed that regions with functional connectivity differences in the DAI group correlated with multiple clinical scoring scales, including cognition, motor function, agitated behavior, and anxiety disorders. These findings suggest that abnormalities in cortico-striatal and cerebellar-striatal functional connectivity are observed in patients with DAI, enriching our understanding of the neuropathological mechanisms of post-injury cognitive disorders and providing potential neuroimaging markers for the diagnosis and treatment of DAI., (Copyright © 2023 The Author(s). Published by Wolters Kluwer Health, Inc.)

A better understanding of white matter tract damage in patients with diffuse axonal injury (DAI) and mild traumatic brain injury (MTBI) is important to obtain an objective basis for sequelae. The purpose of this study was to clarify the characteristics of white matter tract degeneration in DAI and MTBI using automated tractography. T1-weighted and diffusion tensor imaging (DTI) was performed on seven DAI and seven MTBI patients as well as on nine healthy subjects. Automated probabilistic tractography analysis was performed using FreeSurfer and TRACULA (tracts constrained by underlying anatomy) for the reconstruction of major nerve fibers. We investigated the difference between DTI quantitative values in each white matter nerve fiber between groups and attempted to evaluate the classification accuracy of DAI and MTBI using receiver operator curve analysis. Both DAI and MTBI appeared to exhibit axonal degeneration along the nerve fiber tract in a scattered manner. The mean diffusivity of the ampulla of the corpus callosum was significantly higher in DAI than that in MTBI patients, suggesting axonal degeneration of the corpus callosum in DAI patients. Using mean diffusivity of the right cingulum-angular bundle, DAI and MTBI could be discriminated with an area under the curve of 94%. Both DAI and MTBI exhibited scattered axonal degeneration; however, DAI appeared to exhibit more pronounced axonal degeneration in the ampulla of the corpus callosum than MTBI. Our results suggest that DAI and MTBI can be accurately distinguished using DTI., (Copyright © 2021 Wolters Kluwer Health, Inc. All rights reserved.)

Objective: Diffuse axonal injury (DAI) is a common pathological process after traumatic brain injury, which may cause survivors severe functional disorders, including cognitive impairment and physical disability. Recent literature indicated lateral hypothalamus and medial hypothalamus damage during DAI. Thus, we aim to investigate whether there is imaging evidence of hypothalamic injury in patients with DAI and its clinical association., Methods: Twenty-four patients with diagnosed DAI and 26 age and sex-matched healthy controls underwent resting-state functional MRI. We assessed the lateral hypothalamus and medial hypothalamus functional connectivity with seed-based analysis in DAI. Furthermore, a partial correlation was used to measure its clinical association. The prediction of the severity of DAI from the altered lateral hypothalamus and medial hypothalamus connectivity was conducted using a general linear model., Results: Compared with healthy control, the DAI group showed significantly decreased lateral hypothalamus functional connectivity with the basal ganglia and cingulate gyrus, which was positively correlated with mini-mental state examination scores (Bonferroni correction at P < 0.0125). Importantly, this disrupted functional connectivity can be used to predict the patients' cognitive state reliably (P = 0.006; P = 0.009, respectively) in DAI. Moreover, we also observed increased connectivity of medial hypothalamus with the superior temporal gyrus and the regions around the operculum. Furthermore, there was a trend of negative correlation between the medial hypothalamus functional connectivity changes to the right superior temporal gyrus and the disability rating scale scores in the DAI group., Conclusion: Our results suggest that there are alterations of medial hypothalamus and lateral hypothalamus connectivity in DAI and further understand its clinical symptoms, including related cognitive impairment., (Copyright © 2021 Wolters Kluwer Health, Inc. All rights reserved.)

Disrupted white matter structure has been established in patients with diffuse axonal injury (DAI), but morphological changes in gray matter and local intrinsic activity in the short and midterm (before 6 months) have not been documented in DAI patients. We hypothesized that regionally selective atrophy observed in deep gray matter in the short-term and mid-term periods in patients with mild-to-moderate DAI, local atrophy, and/or dysfunction would be related to clinical characteristics. We evaluated the changes in regional density and synchronization in 18 DAI patients separately using Diffeomorphic Anatomical Registration through Exponentiated Lie algebra-enhanced voxel-based morphometry and regional homogeneity (ReHo). Compared with the controls, DAI patients showed a decreased density in the bilateral thalami and decreased ReHo values in the ventral anterior and ventral lateral nuclei of the bilateral thalami. Pearson's correlation analysis showed that decreased density in the bilateral thalami was correlated negatively with time since injury and decreased ReHo values in the ventral anterior and ventral lateral nuclei of the bilateral thalami were associated with a worsened motor assessment scale. These findings suggest that mild-to-moderate traumatic DAI within the short and midterm could lead to thalamic atrophy and that dysfunction in the bilateral thalami is associated with declining motor function. This study could potentially provide complementary evidence as an important element in longitudinal studies.