Diffusion Tensor Imaging to Judge the Prognosis of Patients With Diffuse Axonal

The investigators will examine 15 patients who was firstly diagnosed as diffuse axonal injury and 15 patients negative for magnetic resonance examination with no trauma with DTI(diffusion tensor imaging). The investigators then determine the FA（fractional anisotropy）value and the ADC(apparent diffusion coefficient) value of relational interesting area（corpus callosum、brainstem、basal ganglia）to analyse the correlation between the FA（fractional anisotropy）value and ADC(apparent diffusion coefficient) value and GCS(Glasgow Coma Scale) and coma time,so that the investigators can quantify the damage degree of patients' white matter fiber.At the same time the investigators rebuild the white matter fiber tract(corpus callosum 、corticospinal tract、optic radiation) of patients using diffusion tensor tractography so that the investigators can judge intuitively the extent of damage and recovery. The investigators Trace the repair of nerve fibers after treatment and guide the further treatment.This trial can exactly determine the relationship between the FA（fractional anisotropy）value and ADC(apparent diffusion coefficient) value in relational interesting area and the extent of damage in patient of DAI（diffuse axonal injury）.Meanwhile the trial confirms that the DTI(diffusion tensor imaging) can exactly judge the prognosis of DAI（diffuse axonal injury）.Obviously by using fiber tractography the investigators can have the extent of recovery of the patient of DAI（diffuse axonal injury） in real-time detection and give guidance for the clinical decision and the judgement of prognosis).