Study on the Application of DTI to the Relativity between Impairment of Corticospinal Tract and Motor Function Recovery after Cerebral Infarction

Objective To study the characteristics of anisotropy of cerebral infarction by diffusion tensor imaging(DTI) and to evaluate the relativity between impairment of cortical spinal tract and motor recovery after cerebral infarction by diffusion tensor tractography(DTT).Methods Conventional MRI and DTI were performed to ten healthy volunteers and fifty-seven patients with cerebral infarction.The fractional anisotropy(FA) values of bilateral cerebral peduncles,posterior limbs of internal capsule,infarction focus and its contralateral side were measured,compared and analyzed;Diffusion tensor tractogeaphy(DTT) were performed to the cortical spinal tract(CST).The changes of CST were classified.Those patients were evaluated by the National Institutes of Health Stroke Scale(NIHSS) and the Fugl-Meyer Motor Scale(FMS) before DTI and after treatment.Pearson correlation analysis was performed to the FA reduction ratio of infarction focus,the DTT classification of CST,NIHSS and FMS after treatment.Results The average FA values of bilateral cerebral peduncles,posterior limbs of internal capsule and centrum semiovale of volunteers were not have statistical differences(P0.05);the average FA values of infarction focus and its contralateral side had statistical differences,no mater in acute stage,subacute stage or chronic stage(P 0.05),and the FA reduction ratio of infarction focus had positive correlation with the NIHSS(Pearson's correlation coefficient was 0.500,p=0.001);the FA values of bilateral cerebral peduncles and posterior limbs of internal capsule of patients with cerebral infarction were not have statistic differences in acute stage(P0.05),but had statistic differences in subacute stage and chronic stage(P0.05).DTT showed that the grades of CST had negative correlation with FMS after treatment(Pearson's correlation coefficient was-0.899,p=0.000).Conclusion The injury of white matter fiber bundles after cerebral infarction could be well evaluated by DTI;the motor function recovery had significant correlation with the degree of injury of cortical spinal tract.