Central Nervous System Changes Induced by Underbody Blast-Induced Hyperacceleration: An in Vivo Diffusion Tensor Imaging and Magnetic Resonance Spectroscopy Study.
Blast-related traumatic brain injury (bTBI) resulting from improvised explosive devices is the hallmark injury of recent wars, and affects many returning veterans who experienced either direct or indirect exposure. Many of these veterans have long-term neurocognitive symptoms. However, there is very little evidence to show whether blast-induced acceleration alone, in the absence of secondary impacts, can cause mild TBI. In this study, we examine the effect of under-vehicle blast-induced hyperacceleration (uBIH) of ∼1700 g on the biochemical and microstrucutral changes in the brain using diffusion tensor imaging (DTI) and magnetic resonance spectroscopy (MRS). Two groups of adult male Sprague-Dawley (SD) rats were subjected to a sham procedure and uBIH, respectively. Axonal and neurochemical alterations were assessed using in vivo DTI and MRS at 2 h, 24 h, and 7 days after uBIH. Significant reduction in mean diffusivity, axial diffusivity, and radial diffusivity were observed in the hippocampus, thalamus, internal capsule, and corpus callosum as early as 2 h, and sustained up to 7 days post-uBIH. Total creatine (Cr) and glutamine (Gln) were reduced in the internal capsule at 24 h post-uBIH. The reductions in DTI parameters, Cr and Gln in vivo suggest potential activation of astrocytes and diffuse axonal injury following a single underbody blast, confirming previous histology reports.
1 Department of Diagnostic Radiology and Nuclear Medicine, University of Maryland , Baltimore, Maryland.|2 Core for Translational Research in Imaging at Maryland, University of Maryland , Baltimore, Maryland.
Shiyu
S
Tang
1 Department of Diagnostic Radiology and Nuclear Medicine, University of Maryland , Baltimore, Maryland.|2 Core for Translational Research in Imaging at Maryland, University of Maryland , Baltimore, Maryland.
Su
S
Xu
3 Department of Mechanical Engineering, University of Maryland , College Park, Maryland.|4 Center of Energetics Concepts Development, University of Maryland , College Park, Maryland.
William L
WL
Fourney
3 Department of Mechanical Engineering, University of Maryland , College Park, Maryland.|4 Center of Energetics Concepts Development, University of Maryland , College Park, Maryland.
Ulrich H
UH
Leiste
5 Department of Anesthesiology, University of Maryland , Baltimore, Maryland.|6 Shock, Trauma, and Anesthesiology Research Center, University of Maryland , Baltimore, Maryland.
Julie L
JL
Proctor
5 Department of Anesthesiology, University of Maryland , Baltimore, Maryland.|6 Shock, Trauma, and Anesthesiology Research Center, University of Maryland , Baltimore, Maryland.
Gary
G
Fiskum
1 Department of Diagnostic Radiology and Nuclear Medicine, University of Maryland , Baltimore, Maryland.|2 Core for Translational Research in Imaging at Maryland, University of Maryland , Baltimore, Maryland.
Rao P
RP
Gullapalli
D000054:Acceleration / Q000009:adverse effects*; D000818:Animals; D001753:Blast Injuries / Q000000981:diagnostic imaging* / Q000378:metabolism; D002490:Central Nervous System / Q000000981:diagnostic imaging / Q000378:metabolism; D056324:Diffusion Tensor Imaging / Q000379:methods / Q000639:trends*; D006624:Hippocampus / Q000000981:diagnostic imaging* / Q000378:metabolism; D020772:Internal Capsule / Q000000981:diagnostic imaging* / Q000378:metabolism; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley
DTI; MRS; hyperacceleration; underbody blast