Assessment of the DTI-ALPS Index in Adolescents With Sport-Related Concussion

Background: Sport-related concussion (SRC) can be associated with glymphatic system dysfunction that may be assessed using the diffusion tensor imaging along the perivascular space (DTI-ALPS) index. Here, DTI-ALPS between adolescent athletes within 10 days of SRC and after recovery with control adolescents are compared, and associations between the DTI-ALPS and clinical outcomes are explored. Study Type: Prospective case control. Population: Thirty-five SRC participants (diagnosed according to the 5th International Conference on Concussion in Sport guidelines; 42.9% female, mean age 15.31 years) and 34 controls (44.1% female, mean age 15.79 years). Field Strength/Sequence: 3D DTI using an echo-planar imaging sequence at 3T. Assessment: MRI, self-report questionnaires, and a physical examination were conducted within 10 days of SRC (at recruitment for controls) and 2 weeks after clinical recovery (1 month for controls). The physical examination consisted of balance and vision assessments, including near-point convergence. Mean, left, and right DTI-ALPS were calculated and compared between groups and visits. Statistical Tests: Independent and paired t-tests assessed group DTI-ALPS indices at Visit 1 and Visit 2 and between visits, respectively. A p value of < 0.05 was significant. Linear regressions assessed associations between DTI-ALPS and demographic/clinical variables. A Bonferroni-corrected p value of < 0.0167 was significant. Groups did not differ significantly at Visit 1 for mean, left, or right (p = 0.843, 0.533, 0.744) DTI-ALPS or at Visit 2 (mean p = 0.827, left p = 0.706, right p = 0.992). There were no significant changes between visits for the SRC (mean p = 0.946, left p = 0.787, right p = 0.888) or control groups (mean p = 0.777, left p = 0.791, right p = 0.813). Near-point convergence and right DTI-ALPS were significantly associated in the SRC group at Visit 1, but significance was not retained after correction (p = 0.040, beta = 0.111, R² = 0.137). Data Conclusion: The DTI-ALPS index may not be an indicator of glymphatic dysfunction in adolescent athletes within 10 days of SRC. Evidence Level: 2. Technical Efficacy: Stage 2.