Diffusion tensor imaging of sports-related concussion in adolescents
Virji-Babul N., Borich MR., Makan N., Moore T., Frew K., Emery CA., Boyd LA. Pediatric Neurology. 2013; 48: 24-29.
The impact that a concussion has on an immature adolescent brain is largely unknown. Magnetic resonance imaging advancements such as diffusion tensor imaging may help us understand these changes because it provides quantitative measure of the subtle changes within the white matter tissue in the brain following a concussion. Therefore, the purpose of this study was to use diffusion tensor imaging to investigate the short-term structural differences between 12 adolescents that had sustained a recent concussion (within 2 months) and 10 adolescent athletes with no concussion history. Additionally, the association of diffusion tensor imaging measures and the Sports Concussion Assessment Tool 2 (SCAT2) was assessed. The authors found that the integrity of the white matter differed between the concussed and non-concussed groups. Furthermore, the SCAT2 was associated with two measures of white matter integrity. However, there was no difference in SCAT2 scores between groups.
A concussion is defined as a pathophysiological process that is induced by traumatic biomechanical forces. Thus, when a neuron is stretched many cellular changes take place (known as the neurometabolic cascade; Hovda & Giza). These changes are very subtle and most imaging techniques cannot detect them. These researchers provide preliminary evidence that brains exposed to a recent concussion have differences in the integrity of the white matter compared to healthy brains that can be observed with diffusion tensor imaging. The observed changes in the white matter may be caused by mechanical forces from the concussion that stretch neurons in the white matter and cause ion channels to open. This could lead to an increase in intracellular water and decrease in extracellular water, which may be one reason there is decreased diffusivity. These observed changes could also be associated with the tissue injury itself that induces inflammation. There are several limitations to this study that should be noted. Firstly, the sample size is small, which limits our ability to apply these results to our clinical populations. In addition, there were a varying number of concussions (from 1 to 4 concussions) within the concussed group. Also, there was a varying time for the concussed group to get there diffusion tensor imaging (up to 2 months post injury). These variables could have altered the outcome of their data. This preliminary research will hopefully inspire future research to determine if diffusion tensor imaging has a role in diagnosing concussions, monitoring recovery, and return-to-play decisions. Do you think magnetic resonance imaging, like diffusion tensor imaging, would be a helpful diagnostic tool for concussions?
Written by: Jane McDevitt MS, ATC, CSCS
Reviewed by: Jeffrey Driban
Related Posts:Virji-Babul N, Borich MR, Makan N, Moore T, Frew K, Emery CA, & Boyd LA (2013). Diffusion tensor imaging of sports-related concussion in adolescents. Pediatric Neurology, 48 (1), 24-9 PMID: 23290016