Cerebral Blood Flow Alterations in Acute Sport-Related Concussion

Abstract

Sport-related concussion (SRC) is a major health problem, affecting millions of athletes each year. While the clinical effects of SRC (e.g., symptoms and functional impairments) typically resolve within several days, increasing evidence suggests persistent neurophysiological abnormalities beyond the point of clinical recovery after injury. This study aimed to evaluate cerebral blood flow (CBF) changes in acute SRC, as measured using advanced arterial spin labeling (ASL) magnetic resonance imaging (MRI). We compared CBF maps assessed in 18 concussed football players (age, 17.8 -1.5 years) obtained within 24 h and at 8 days after injury with a control group of 19 matched non-concussed football players. While the control group did not show any changes in CBF between the two time-points, concussed athletes demonstrated a significant decrease in CBF at 8 days relative to within 24 h. Scores on the clinical symptom (Sport Concussion Assessment Tool 3, SCAT3) and cognitive measures (Standardized Assessment of Concussion [SAC]) demonstrated significant impairment (vs. pre-season baseline levels) at 24 h (SCAT, p < 0.0001; SAC, p < 0.01) but returned to baseline levels at 8 days. Two additional computerized neurocognitive tests, the Automated Neuropsychological Assessment Metrics and Immediate Post-Concussion and Cognitive Testing, showed a similar pattern of changes. These data support the hypothesis that physiological changes persist beyond the point of clinical recovery after SRC. Our results also indicate that advanced ASL MRI methods might be useful for detecting and tracking the longitudinal course of underlying neurophysiological recovery from concussion.

The Pathophysiology of Concussion

“…There was further decrease at 8 days post-injury both when compared to preseason baselines and matched controls. This did not correlate with recovery of symptoms and neurocognitive testing similar to what has been seen in other studies, indicating that physiological disturbances may still be present even after symptoms have perceptibly resolved [43,44].…”

Cerebral amyloid angiopathy: a long-term consequence of traumatic brain injury?

“…How these vascular changes may relate to TBI has not been established, although a blood-brain barrier disturbance is observed in up to 50 % of patients many years after moderate-to-severe TBI [14]. Injury to the neurovascular system has been observed chronically both after moderate-to-severe TBI and following sports-related concussions, suggesting that cerebrovascular abnormalities may persist following TBI, which may be related to the vascular pathologies observed in the present CAA case [15,16].…”

Sports Concussion: A Clinical Overview

“…Altered functional connectivity has also been observed relative to executive function, visual, and motor networks [57][58][59][60]. Reduced cerebral blood flow (CBF) has been reported during the acute and sub-acute phases (days to weeks) post-concussion [61][62][63], as well as at more chronic time points (approximately 5 months) [64].…”