Headaches are frequently reported by patients with traumatic brain injury (TBI). The relationship between TBI and headaches is poorly understood. Disruption of the glymphatic pathway, a brain-wide network of perivascular spaces, could explain this link. The glymphatic pathway allows the exchange of fluid, solutes, and wastes between the cerebrospinal fluid and the brain interstitium. MRI-visible enlarged perivascular spaces (ePVS) may be putative surrogates of glymphatic function. The purpose of this study is to: a) characterize the ePVS burden in a cohort of healthy adolescents; b) determine if ePVS burden is increased in individuals with post-concussive symptoms.