Regional Blood Flow Alterations Following Pediatric Concussion: A PedCARE+MRI Substudy

Abstract

Background: This study examined whether cerebral blood flow (CBF) differed between children with concussion and orthopedic injury (OI) controls at 72 hours and 4 weeks post-injury. It also examined whether psychological resilience and acute CBF improved prediction of 2-and 4-week concussion symptoms beyond the existing 5P score prediction tool.Methods: Concussed and OI participants, aged 10-18 years, were enrolled from CHEO's Emergency Department. Arterial spin labelling was used to measure CBF at 72 hours and 4 weeks post-injury. Symptoms were assessed using the Health and Behaviour Inventory at 2 and 4 weeks. Self-reported psychological resilience was measured with the Connor-Davidson Resilience Scale. Crude and adjusted mixed model analyses were conducted to assess absolute CBF (aCBF) and normalized aCBF in both groups over time. Multiple regression analyses assessed whether the 5P score, regional CBF, and resilience combined predicted 2-and 4-week symptoms for the concussion group.Results: A total of 70 participants with concussion (Mage=13.05±2.02, 47% female) and 29 with OI (Mage=12.59±1.97, 41% female) were included. For aCBF, a significant group*time interaction was found in the left anterior cingulate/medial frontal cortex (L_ACC_MFC) and right middle frontal gyrus (R_MFG). In the L_ACC_MFC, the concussion group showed increased CBF compared to OIs both time points (p<.001). In the R_MFG, CBF was increased compared to OIs at 4 weeks (p<.001), but not 72 hours. In both regions, CBF increased over time in the concussion group (p≤.001), but did not differ between time points for OIs. Concussed participants also had increased CBF in the left angular gyrus (L_angular) that did not differ between time points. For normalized aCBF, the concussion group displayed significantly iii increased CBF in the L_ACC_MFC, R_MFG, and L_angular, and significantly decreased CBF in the right superior temporal gyrus (R_STG), right fusiform gyrus (R_fusiform), and bilateral lingual gyri. The multiple regression model revealed that the 5P score, L_ACC_MFC or R_MFG CBF, and resilience combined did not significantly predict 2-or 4-week symptoms for the concussion group.Conclusion: Though clinical significance remains unclear, these results are an important contribution to the pediatric concussion literature, as they indicate clear CBF alterations in pediatric concussion with some regional CBF varying in time. These results are important for understanding persistent neurobiological deficits after concussion.