PURPOSE: To analyze the characteristies of traumatic brainstem injury by CT and MR MATERIALS AND METHODS: CT and MR studies of 10 patients with traumatic brainstem lesion in MR were retrospectively reviewed, particularly attended to location, signal intensity and associated lesions. RESULTS: CT failed to depict 8 of 10 brainstem lesions. All lesions were detected in MR images with T2-weighted images showing higher detection rate (n=10) (100%) than Tl-weighted images (n=3) (30%) or CT (n=2) (20%). The brainstem lesions located in the dorsolateral aspects of the rostral brainstem(mid brain and upper pons)in 7 (70%) cases, in ventral aspects of rostral brain in 2 (20%) cases and in median portion of pons in 1 (10%) case. Corpus callosal (n=5), Iobar white matter(n=5) diffuse axonal injury, and 2 hemorrhagic lesions in basal ganglia were the associated findings. CONCLUSION: MR imaging is more helpful than CT in the detection of brainstem injury, especially T2 weighted images. Primary brainstem lesions were typically located in the dorsolateral aspect of rostral brainstem(midbrain and upper pons). Corpus callosum and white matter lesions were frequently associated.