Morphometry and diffusion MR imaging years after childhood traumatic brain injury

ObjectiveOur goal was to detect possible unrecognized injury in cerebral white matter (WM) in adult survivors of traumatic brain injury (TBI) during childhood, who showed no detectable axonal injury or chronic contusion on late conventional MRI.Material and methodsWe used voxel-based morphometry (VBM) to detect subtle structural changes in brain morphology and diffusion-tensor imaging (DTI) to non-invasively probe WM integrity. By means of VBM and DTI we examined a group of 12 adult patients who suffered from childhood closed head injury without axonal injury on late conventional MRI.ResultsPatients sustained complicated mild or moderate-to-severe TBI with a mean of 7 points based on the Glasgow Coma Scale. The mean time after trauma was 19 years (range 7–31 years). For VBM, group comparisons of segmented T1-weighted grey matter and WM images were performed, while for DTI we compared the fractional anisotropy and mean diffusivity (MD) between the groups. Patients presented with higher MD in the right cerebral white matter, bilaterally in the forceps major and in the body and splenium of the corpus callosum. These findings were supported by VBM, which showed reduced WM volume bilaterally, mainly along the callosal splenium.ConclusionOur results indicate that persistent focal long-term volume reduction and underlying WM structural changes may occur after TBI during childhood and that their effects extend into adulthood. Normal late conventional MR findings after childhood TBI do not rule out non-apparent axonal injury.

► VBM is used to detect subtle structural changes in brain morphology.
► DTI probe non-invasively WM integrity.
► We examined with VBM and DTI 12 adult patients who suffered from childhood TBI without axonal injury on late conventional MRI.
► VBM and DTI showed persistent focal long-term volume reduction and underlying WM structural changes.
► The effects of TBI during childhood may extend into adulthood.