Cerebral Perfusion Changes in Post-Concussion Syndrome: A Prospective Controlled Cohort Study

Abstract

The biology of post-concussive symptoms is unclear. Symptoms are often increased during activities, and have been linked to decreased cerebrovascular reactivity and perfusion. The aim of this study was to examine cerebral blood flow (CBF) in children with different clinical recovery patterns following mild traumatic brain injury (mTBI). This was a prospective controlled cohort study of children with mTBI (ages 8 to 18 years) who were symptomatic with post-concussive symptoms at one month post-injury (symptomatic, n = 27) and children who had recovered quickly (asymptomatic, n = 24). Pseudo continuous arterial spin labeling magnetic resonance imaging (MRI) was used to quantify CBF. The mTBI groups were imaged at 40 days post-injury. Global and regional CBF were compared with healthy controls of similar age and sex but without a history of mTBI (n = 21). Seventy-two participants (mean age: 14.1 years) underwent neuroimaging. Significant differences in CBF were found: global CBF was higher in the symptomatic group and lower in the asymptomatic group compared with controls, (F(2,69) 9.734; p < 0.001). Post-injury symptom score could be predicted by pre-injury symptoms and CBF in presence of mTBI (adjusted R² = 0.424; p < 0.001). Altered patterns of cerebral perfusion are seen following mTBI and are associated with the recovery trajectory. Symptomatic children have higher CBF. Children who "recovered" quickly, have decreased CBF suggesting that clinical recovery precedes the cerebral recovery. Further longitudinal studies are required to determine if these perfusion patterns continue to change over time.

Keywords: arterial spin labeling; cerebral blood flow; pediatric brain injury; recovery; traumatic brain injury.

FIG. 1.

Consort diagram depicting enrollment through to analysis: Children with mTBI were identified in the ED (n = 244) and enrolled at 3 to 4 weeks post-injury (n = 84). ED, emergency department; mTBI, mild traumatic brain injury.

FIG. 2.

A scatterplot demonstrating the correlation between cognitive function (Neurocognition Index) and global CBF. Cognitive function was predicted by CBF only in the mTBI group (significant interaction effect between CBF and mTBI; beta = –2.16, p = 0.028), R² = 0.165, p = 0.008. CBF, cerebral blood flow; mTBI, mild traumatic brain injury.

FIG. 3.

The regions where cerebral perfusion is significantly greater in children who remained symptomatic at 40 days following an mTBI when compared with healthy controls are shown. The cluster size and coordinates of these areas are reported in the table. MNI, Montreal Neurological Institute; mTBI, mild traumatic brain injury.

FIG. 4.

The regions where perfusion in the symptomatic group is significantly greater than the asymptomatic group at 40 days post-injury are shown. The cluster size and coordinates of these areas are given in the table. MNI, Montreal Neurological Institute.

FIG. 5.

The regions where cerebral perfusion is significantly decreased in children who were asymptomatic at 40 days following an mTBI when compared with healthy controls are shown. The cluster size and coordinates of the areas are reported in the table (overall pcrit <0.05, voxel cluster-level >100). MNI, Montreal Neurological Institute; mTBI, mild traumatic brain injury.