Citation

Wu YC, Mustafi SM, Harezlak J, Kodiweera C, Flashman LA, McAllister T. J. Neurotrauma 2018; 35(20): 2377-2390.

Affiliation

Indiana University School of Medicine, Albert E. Sterne Professor and Chair,Department of Psychiatry , 355 W. 16th Street, Suite 4800 , Goodman Hall, Room 4378 , Indianapolis, Indiana, United States , 46202 ; twmcalli@iupui.edu.

Copyright

(Copyright © 2018, Mary Ann Liebert Publishers)

DOI

10.1089/neu.2017.5566

PMID

29786463

Abstract

Mild traumatic brain injury (mTBI) is an important public health problem. Although conventional medical imaging techniques can detect moderate-to-severe injuries, they are relatively insensitive to mTBI. In this study, we used hybrid diffusion imaging (HYDI) to detect white-matter alterations in nineteen patients with mTBI and 23 other trauma-control patients. Within 15 days (SD=10) of brain injury, all subjects underwent magnetic-resonance HYDI and were assessed with battery of neuropsychological tests of sustained attention, memory, and executive function. Tract-based spatial statistics (TBSS) were used for voxelwise statistical analyses within the white-matter skeleton to study between-group differences in diffusion metrics, within-group correlations between diffusion metrics and clinical outcomes, and between group interaction effects. The advanced diffusion imaging techniques including neurite orientation dispersion and density imaging (NODDI) and q-space analyses appeared to be more sensitive then classic diffusion tensor imaging (DTI). Only NODDI-derived intra-axonal volume fraction (V_ic) demonstrated significant group differences (i.e., 5% to 9% lower in the injured brain). Within the mTBI group, V_ic and a q-space measure, P₀, correlated with 6 of 10 neuropsychological tests including measures of attention, memory, and executive function. In addition, the direction of correlations differed significantly between the groups (R² > 0.71 and P_interation < 0.03). Specifically, in the control group, higher V_ic and P₀ were associated with better performances on clinical assessments, whereas in the mTBI group, higher V_ic and P₀ were associated with worse performances with correlation coefficients > 0.83. In summary, the NODDI-derived axonal density index and q-space measure for tissue restriction demonstrated superior sensitivity to white-matter changes shortly after mTBI. These techniques hold promise as a neuroimaging biomarker for mTBI.

Language: en

Keywords

ADULT BRAIN INJURY; AXONAL INJURY; Diffusion Tensor Imaging; MRI; TRAUMATIC BRAIN INJURY