Corticospinal tract injury in patients with diffuse axonal injury: a diffusion tensor imaging study

Diffusion tensor imaging (DTI) can be useful in detecting corticospinal tract (CST) injury at the subcortical white matter level. In the current study, we attempted to investigate the incidence and distribution of CST injury in patients with diffuse axonal injury (DAI), using DTI. Fourteen patients who showed motor weakness without any specific lesion along the CST pathway on conventional brain MRI, and twelve age-matched, normal healthy control subjects were recruited. DTI was performed using 1.5 T with a synergy-L Sensitivity Encoding (SENSE) head coil. Fractional anisotropy was measured using the region of interest method. A CST injury was defined as the FA value of a certain area being decreased two standard deviations below that of normal controls. All 14 patients had more than one lesion at the CST injury, and the mean number of CST injuries was 3.6 (range: 2-7). The CSTs were involved at the following locations: the pons (61%), the cerebral peduncle (39%), the corona radiata (21%), the medulla (14%), and the posterior limb (11%). The pons was the most prevalent area of CST injury in patients with weakness caused by DAI at the subcortical level. We found that DTI is a useful technique for detecting a DAI of the CST at the subcortical level.