Objective To explore the application value of diffusion tensor imaging and diffusion tensor tractography in the benign lesion of spinal cord.Methods 30 cases with the benign lesions of spinal cord and 10 healthy volunteers underwent MRI and DTI scanning by 1.5T MR.Results Compared with normal control group,ADC values [(1.29±0.24)×10 -3 mm2/s]of extramedullary group-Ⅰwere increased slightly,and FA values (0.46±0.06)were decreased slightly(P <0.05).In extramedullary group-Ⅱ,ADC values [(2.03±0.19)×10-3 mm2/s]were significantly increased and FA values (0.37±0.03)decreased in the lesion level (P <0.05).The ADC values [(1.71±0.24)×10 -3 mm2/s]of intramedullary group was significantly elevated,and the FA values (0.30±0.06)was obviously reduced (P <0.05 ).The fiber tracts showed the abnormality of the white matter,including compression,sparseness, grow downwards,interruption and other changes.Conclusion The changes of the FA and ADC values,diffusion tensor imaging of the bundle can quantitatively evaluate the severity of spinal cord damage and stereo display fiber bundle damage.

【Objective】 To explore the relationship between changes in the entorhinal cortex （EC） of traumatic brain injury （TBI） and cognitive function based on structural magnetic resonance imaging. 【Methods】 MRI was performed in 26 patients with clinically confirmed TBI after admission， and the Mini-mental State Examination （MMSE） was followed up 6 months later. The TBI patients were classified as mild TBI and moderate to severe TBI according to the post-traumatic Glasgow coma scale （GCS）. We compared the differences in age， gender， education level， hypertension， diabetes， TBI operation history， and follow-up MMSE between the two groups. Then the morphology， surface area， volume and thickness of the patient’s EC were evaluated using the visual score and Freesurfer software， and finally the correlation between EC parameters and MMSE was analyzed. 【Results】 The study included 12 cases of mild TBI and 14 cases of moderate to severe TBI. There were no statistical differences in age， gender， years of education， hypertension， diabetes or TBI operation history. However， the two groups differed significantly in follow-up MMSE. Visual evaluation showed statistical difference in the left EC scores. Structural MRI showed that the volume and thickness of left EC were statistically different between the two groups. The correlation analysis showed that there was a positive correlation between the thickness of left EC and MMSE （r=0.430， P<0.05）. 【Conclusion】 Entorhinal cortex atrophy after TBI is related to the severity of trauma， and it can reflect the long-term cognitive level of patients， which can be used as a noninvasive and reliable imaging marker for evaluating cognitive impairment after TBI.