Monitoring mild traumatic brain injury (TBI) presents challenges for conventional MRI and underlying myelin changes are not well understood. Myelin water fraction (MWF) presents an opportunity to examine myelin changes post injury. At 6 months post injury, corpus callosum genu and body MWF decreased from baseline (acute) in 8 out of 9 subjects. Splenium MWF decreased in 7 out of 9 subjects. When averaged across subjects, the average decrease in MWF was 2% for the genu and 5% for the splenium, not significantly different from baseline; the lack of significance was due to large MWF increases in one of the participants.