To assess the prevalence and location of white matter hyperintensities (WMH), and their link to clinical outcomes, among patients with traumatic brain injury (TBI).

Although WMHs are commonly seen after TBI, little is known about their relationship with pathology and long-term outcomes. We hypothesized that distinctions exist between the prevalence and location of WMHs in TBI participants compared with healthy controls, and are related to outcomes after TBI.

Participants with TBI were studied at 2 weeks and 6 months post-injury. Healthy controls were also enrolled. WMHs were manually segmented then using tools available in FreeSurfer, were categorized into periventricular (adjacent to a ventricle), subcortical (>4mm from the gray-white junction), or juxtacortical (<4mm from the gray-white junction).

Thirty-five participants with TBI (mean[SD] age: 44.7[16.6], 74% male, median GCS: 15 (IQR:14-15)) and 15 control subjects (mean[SD] age: 33.2[11.8], 60% male) were enrolled. TBI patients had a significantly higher burden of WMHs at 2 weeks (20.8±25.3) compared with controls (5.27±4.2; p=0.023). When TBI participants were re-scanned 6 months later, the number of WMHs over time did not change (21.38+33.29, p=0.24). The large majority of WMH were found in the juxtacortical area (controls: 49.4% vs. TBI at 2 weeks: 67.4% (p=0.02); TBI at 6 months: 66.8% (p=0.05)). There was no relationship between WMH burden and functional outcome, assessed by Glasgow Outcome Scale-Extended. There was a significant relationship between WMH burden at 2 weeks and the cognitive component of the Rivermead Post-Concussion Symptom Questionnaire at 2 weeks (r=-0.414, p=0.021).

WMHs are common after predominantly mild TBI and are more prevalent than age- and gender-matched healthy controls. WMHs are primarily juxtacortical, a distribution distinct from what is found in demyelinating disease and aging. While non-specific, WMHs are common in TBI, and in appropriate clinical settings may be helpful diagnostically and prognostically.