Multiparametric MRI changes persist beyond recovery in concussed adolescent hockey players

Abstract

Objective:To determine whether multiparametric MRI data can provide insight into the acute and long-lasting neuronal sequelae after a concussion in adolescent athletes.Methods:Players were recruited from Bantam hockey leagues in which body checking is first introduced (male, age 11–14 years). Clinical measures, diffusion metrics, resting-state network and region-to-region functional connectivity patterns, and magnetic resonance spectroscopy absolute metabolite concentrations were analyzed from an independent, age-matched control group of hockey players (n = 26) and longitudinally in concussed athletes within 24 to 72 hours (n = 17) and 3 months (n = 14) after a diagnosed concussion.Results:There were diffusion abnormalities within multiple white matter tracts, functional hyperconnectivity, and decreases in choline 3 months after concussion. Tract-specific spatial statistics revealed a large region along the superior longitudinal fasciculus with the largest decreases in diffusivity measures, which significantly correlated with clinical deficits. This region also spatially intersected with probabilistic tracts connecting cortical regions where we found acute functional connectivity changes. Hyperconnectivity patterns at 3 months after concussion were present only in players with relatively less severe clinical outcomes, higher choline concentrations, and diffusivity indicative of relatively less axonal disruption.Conclusions:Changes persisted well after players' clinical scores had returned to normal and they had been cleared to return to play. Ongoing white matter maturation may make adolescent athletes particularly vulnerable to brain injury, and they may require extended recovery periods. The consequences of early brain injury for ongoing brain development and risk of more serious conditions such as second impact syndrome or neural degenerative processes need to be elucidated.

Reduced brain glutamine in female varsity rugby athletes after concussion and in non‐concussed athletes after a season of play

“…The decrease in Gln and Gln/ Cr observed in the days and months post-concussion in the current study is consistent with studies of rodent models using Carbon-13 spectroscopy that have found reduced Gln labeling up to 24-hr postinjury (Bartnik, Lee, Hovda, & Sutton, 2007). A previous cross-sectional study of 13-14 year old hockey players using the same methodology as the current study also found a statistical trend toward reduced glutamine levels in the concussed athletes three months after concussion (Manning et al, 2017). Since Gln is a by-product of glucose metabolism these results suggest that the reduction in Gln may be the result of reduced glucose metabolism (Bartnik et al, 2007).…”

Resting‐state functional connectivity after concussion is associated with clinical recovery

“…Whether hyperconnectivity is adaptive or maladaptive is difficult to establish, as the relationship between hyperconnectivity and clinical measures has varied across studies of mTBI. Some have associated hyperconnectivity with less severe injury (Manning et al, ; Yan et al, ). Others have reported hyperconnectivity associated with more symptoms or longer recovery time, consistent with current findings (Churchill, Hutchison, Richards, et al, ; van der Horn et al, ).…”

“…In fact, our observation of similar time course of recovery for physiological effects and clinical symptoms following SRC runs contrary to recent work suggesting physiological effects extend beyond clinical recovery. For example, group differences in rs-FC have been reported in clinically recovered athletes after clearance for complete RTP (Churchill, Hutchison, Richards, et al, 2017), at approximately 10 days postinjury (Johnson et al, 2012), after 3 months postconcussion (Manning et al, 2017), and even within 6 months postconcussion (Czerniak et al, 2015). As highlighted in a recent systematic review, much of the prior work has included single postinjury visits and/or has included relatively small numbers of injured athletes.…”

“…Several studies have investigated the sensitivity of resting‐state functional connectivity (rs‐FC), the most common rs‐fMRI technique, to mTBI and SRC during the acute and sub‐acute phase of the injury (Mayer, Bellgowan, & Hanlon, ; McCrea et al, ). Yet, few studies have evaluated the effects of SRC on rs‐FC longitudinally across the acute (i.e., days) and sub‐acute phases (i.e., weeks), the period in which clinical recovery is observed in most athletes (Churchill et al, ; Manning et al, ; Meier, Bellgowan, & Mayer, ; Zhu et al, ). The majority of these studies have focused on specific resting‐state networks or seed‐regions or have included a relatively limited number of injured athletes.…”

Posttraumatic Headache: Basic Mechanisms and Therapeutic Targets

“…35 In humans, however, direct cellular and metabolic monitoring has occurred primarily in the ICU settings for more severe brain injuries. 37 At this stage, none of these acute or sustained changes have been specifically correlated with headache in a manner that could guide therapeutic intervention. 36 Imaging and serum biomarkers confirm that metabolic and cerebral blood flow derangements typically last up to 30 days post injury.…”