title: Quantitative analysis of brain microstructure following mild blunt and blast trauma.
abstract: We induced mild blunt and blast injuries in rats using a custom-built device and utilized in-house diffusion tensor imaging (DTI) software to reconstruct 3-D fiber tracts in brains before and after injury (1, 4, and 7 days). DTI measures such as fiber count, fiber length, and fractional anisotropy (FA) were selected to characterize axonal integrity. In-house image analysis software also showed changes in parameters including the area fraction (AF) and nearest neighbor distance (NND), which corresponded to variations in the microstructure of Hematoxylin and Eosin (H&E) brain sections. Both blunt and blast injuries produced lower fiber counts, but neither injury case significantly changed the fiber length. Compared to controls, blunt injury produced a lower FA, which may correspond to an early onset of diffuse axonal injury (DAI). However, blast injury generated a higher FA compared to controls. This increase in FA has been linked previously to various phenomena including edema, neuroplasticity, and even recovery. Subsequent image analysis revealed that both blunt and blast injuries produced a significantly higher AF and significantly lower NND, which correlated to voids formed by the reduced fluid retention within injured axons. In conclusion, DTI can detect subtle pathophysiological changes in axonal fiber structure after mild blunt and blast trauma. Our injury model and DTI method provide a practical basis for studying mild traumatic brain injury (mTBI) in a controllable manner and for tracking injury progression. Knowledge gained from our approach could lead to enhanced mTBI diagnoses, biofidelic constitutive brain models, and specialized pharmaceutical treatments.
authors.affiliation: Department of Agricultural and Biological Engineering, Mississippi State University, Mississippi State, MS 39762, United States.
authors.forename: M T
authors.initials: MT
authors.lastname: Begonia
authors.affiliation: Department of Agricultural and Biological Engineering, Mississippi State University, Mississippi State, MS 39762, United States; Center for Advanced Vehicular Systems (CAVS), Starkville, MS 39759, United States.
authors.forename: R
authors.initials: R
authors.lastname: Prabhu
authors.affiliation: Department of Agricultural and Biological Engineering, Mississippi State University, Mississippi State, MS 39762, United States; Center for Advanced Vehicular Systems (CAVS), Starkville, MS 39759, United States.
authors.forename: J
authors.initials: J
authors.lastname: Liao
authors.affiliation: Center for Advanced Vehicular Systems (CAVS), Starkville, MS 39759, United States.
authors.forename: W R
authors.initials: WR
authors.lastname: Whittington
authors.affiliation: College of Veterinary Medicine, Mississippi State University, Mississippi State, MS 39762, United States.
authors.forename: A
authors.initials: A
authors.lastname: Claude
authors.affiliation: College of Veterinary Medicine, Mississippi State University, Mississippi State, MS 39762, United States.
authors.forename: B
authors.initials: B
authors.lastname: Willeford
authors.affiliation: Gateway Veterinary Surgery, St. Louis, MO 63131, United States.
authors.forename: J
authors.initials: J
authors.lastname: Wardlaw
authors.affiliation: Department of Computer Science and Engineering, Mississippi State University, Mississippi State, MS 39762, United States.
authors.forename: R
authors.initials: R
authors.lastname: Wu
authors.affiliation: Department of Computer Science and Engineering, Mississippi State University, Mississippi State, MS 39762, United States.
authors.forename: S
authors.initials: S
authors.lastname: Zhang
authors.affiliation: Department of Agricultural and Biological Engineering, Mississippi State University, Mississippi State, MS 39762, United States; Center for Advanced Vehicular Systems (CAVS), Starkville, MS 39759, United States. Electronic address: lwilliams@abe.msstate.edu.
authors.forename: L N
authors.initials: LN
authors.lastname: Williams
mesh_terms: D000818:Animals; D016880:Anisotropy; D001369:Axons / Q000473:pathology*; D001753:Blast Injuries / Q000473:pathology*; D001921:Brain / Q000473:pathology*; D001930:Brain Injuries / Q000473:pathology*; D056324:Diffusion Tensor Imaging; D008297:Male; D017207:Rats, Sprague-Dawley
keywords: Blast trauma; Blunt trauma; Diffusion tensor imaging; Image analysis; Mild traumatic brain injury