Optic radiation injury following traumatic epidural hematoma: Diffusion tensor imaging study.

Little is known about optic radiation (OR) injury in patients with traumatic brain injury (TBI). We report on a patient who showed an OR injury on diffusion tensor imaging (DTI) following traumatic epidural hematoma (EDH). A 38 year-old man with TBI and 7 age-matched normal subjects were enrolled in this study. The patient had fallen down stairs while in an alcohol intoxicated state. He underwent a craniotomy following diagnosis of traumatic EDH in the left temporo-parietal lobe on brain CT. He complained of right bilateral homonymous hemianopsia, which was confirmed on the Humphrey visual field test. No lesion on the left OR was observed during brain MRI. We were not able to reconstruct the fiber tractography for the left OR in this patient. We found that the left OR had been injured most severely around the midportion between the lateral geniculate body and occipital pole. We determined that DTI would be a useful technique for detection of an OR injury in patients with TBI. Therefore, we believe that DTI should be performed along with conventional brain MRI for patients with visual field defects following TBI.