Traumatic axonal injury of the corticospinal tract in the subcortical white matter in patients with mild traumatic brain injury

Abstract

Background: Little is known about injury of the corticospinal tract (CST) in patients with mild traumatic brain injury (TBI). This study reports on patients with mild TBI who showed traumatic axonal injury of the CST in the sub-cortical white matter, as demonstrated by diffusion tensor tractography (DTT).

Methods: Four patients with mild TBI who complained of motor weakness and had DTT parameters within the normal range, including fractional anisotropy, apparent diffusion coefficient and fibre number of the CST, and 10 normal control subjects were recruited for this study.

Results: All four patients showed partial tearing of the CSTs in a portion of the sub-cortical white matter in both hemispheres on DTT. However, three patients showed low amplitude on motor evoked potential obtained from both hand muscles by transcranial magnetic stimulation and two patients revealed abnormality of hand motor function in terms of grip strength or Purdue Pegboard score.

Conclusions: This study demonstrated traumatic axonal injury of the CST using configurational evaluation of DTT in patients with mild TBI. It is believed that configurational evaluation using DTT would be a useful technique for detection of localized traumatic axonal injury in patients with mild TBI.

• Axonal injury
• corticospinal tract
• diffusion tensor imaging
• mild traumatic brain injury

Declaration of interest

This research was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology (2012R1A1A4A01001873).