To determine the prevalence and severity of white matter T2 hyperintensities (WMHs) in young healthy adults and those with recent mild traumatic brain injury (mTBI).

WMHs on T2-weighted (T2W) MRI are common. Normative data on their prevalence in young healthy adults and in the setting of mTBI is not well characterized, and dependent upon classification system, MRI field strength, scan resolution and imaging parameters.

High-resolution 3-Tesla 3D T2W FLAIR and SWI images were retrospectively reviewed from 602 mTBI and control patients who participated in a larger multicenter study of advanced neuroimaging biomarkers. All scans were independently reviewed by 2 board-certified blinded neuroradiologists. All patients with WMHs were identified; patients with excessive WMHs were also identified if ≥5 objective, punctate, white matter foci were present or lesions were >3 mm or atypical in location.

413 patients with documented mTBI and 189 controls were analyzed. 32% (134/413) of the mTBI patients and 40% (76/189) of the control patients demonstrated at least 1 WMH on high-resolution T2W-FLAIR imaging. Of these patients, 34% (45/134) of the mTBI group and 34% (26/76) of the control group demonstrated ≥5 lesions, one >3 mm lesion, or lesions in atypical locations. There was no significant difference in number of patients with at least 1 WMH (p=0.064) or excessive WMHs (p=0.313) between mTBI and control groups.

This represents the largest study cohort of mTBI patients and healthy controls assessing the prevalence of WMHs on high-resolution 3-Telsa 3D T2W-FLAIR. Prevalence of WMHs did not differ between groups and were observed at higher rates than reported in the current literature. These results reflect an evidence-based need to reassess our understanding and clinical interpretation of WMHs in normal healthy adults and patients with mTBI.