Optic radiation injury in a patient with traumatic brain injury

Primary objective: This study reports on a patient who showed an optic radiation (OR) injury on diffusion tensor imaging (DTI) following head trauma. The patient, who had suffered a traffic accident, underwent conservative management for diffuse axonal injury and contusions in the left midbrain, temporal lobe and anterior to mid-portion of left OR. He complained of right homonymous hemianopsia from the onset of TBI and right bilateral homonymous hemianopsia was detected at the 6-month Humphrey visual field test. Methods and procedures: A 20 year-old man with traumatic brain injury (TBI) and eight age-matched normal subjects were recruited for this study. Main outcomes and results: The left OR of the patient showed a discontinuation around the mid-portion. The FA (fractional anisotropy) values of the posterior portions of left OR decreased over two standard deviations of normal controls, but the ADC (apparent diffusion coefficient) values of these sites increased over two standard deviations of normal controls. Conclusions: Consequently, it was assumed that the main injury site of the left OR was located around the posterior portion of the left OR. This results suggest that DTI may be a useful technique for detection of an OR injury in patients with TBI.