Evidence for white matter disruption in traumatic brain injury without macroscopic lesions

TLDR

Non‑missile traumatic brain injury without visible lesions frequently causes cognitive deficits that impair daily functioning. The study aimed to detect abnormal white matter tracts in cognitively impaired nmTBI patients via diffusion tensor imaging. DTI was performed on 23 cognitively impaired nmTBI patients and healthy controls, using voxel‑based and ROI fractional anisotropy analyses plus tractography of the corpus callosum and fornix. Patients showed reduced fractional anisotropy in the corpus callosum and fornix and coarser tractography, indicating disrupted white matter that DTI can detect in nmTBI without macroscopic lesions.

Abstract

<b>Background:</b> Non-missile traumatic brain injury (nmTBI) without macroscopically detectable lesions often results in cognitive impairments that negatively affect daily life. <b>Aim:</b> To identify abnormal white matter projections in patients with nmTBI with cognitive impairments using diffusion tensor magnetic resonance imaging (DTI). <b>Methods:</b> DTI scans of healthy controls were compared with those of 23 patients with nmTBI who manifested cognitive impairments but no obvious neuroradiological lesions. DTI was comprised of fractional anisotropy analysis, which included voxel-based analysis and confirmatory study using regions of interest (ROI) techniques, and magnetic resonance tractography of the corpus callosum and fornix. <b>Results:</b> A decline in fractional anisotropy around the genu, stem and splenium of the corpus callosum was shown by voxel-based analysis. Fractional anisotropy values of the genu (0.47), stem (0.48), and splenium of the corpus callosum (0.52), and the column of the fornix (0.51) were lower in patients with nmTBI than in healthy controls (0.58, 0.61, 0.62 and 0.61, respectively) according to the confirmatory study of ROIs. The white matter architecture in the corpus callosum and fornix of patients with nmTBI were seen to be coarser than in the controls in the individual magnetic resonance tractography. <b>Conclusions:</b> Disruption of the corpus callosum and fornix in patients with nmTBI without macroscopically detectable lesions is shown. DTI is sensitive enough to detect abnormal neural fibres related to cognitive dysfunction after nmTBI.