Correlation study of DTI in corticospinal tract injury and clinical prognosis of cerebral infarction before and after rehabilitation treatment

Objective: To study the relationship between the corticospinal tract(CST) injury and limb motor function by diffusion tensor imaging(DTI) in patients with cerebral infarction before and after the rehabilitation treatment,and to evaluate the application value of DTI in the assessment of clinical prognosis in patients with cerebral infarction.Methods: Twenty-three cases of chronic cerebral infarction for 23~90 days had DTI inspections respectively before and after rehabilitation.For imaging processing,fractional anisotropy(FA) encoded color maps and 3D tractography of bilateral CST of all patients were performed.The patients were divided into two group(A,B) according to the relationship between the lesions and CST,then measured FA values of the infarctions,ipsilateral cerebral peduncle and corresponding contralateral regions.The Fugl-Meyer motor scale(FM) and the Barthel index(BI) were used to evaluate the neurological function prior to each MRI.Then,the correlation between clinical markers and the changes of FA value were analyzed.Results: Before rehabilitation,FA value of the lesions in 23 cases was 0.221±0.085,and in corresponding contralateral area,the FA value was 0.514±0.071,in ipsilateral cerebral peduncle the FA value was 0.550±0.081,contralateral the FA value was 0.682 ±0.051.By paired t test,the FA values between bilateral brain tissues were statistically significant(P0.001).The ratio between the FA value of ipsilateral cerebral peduncle and corresponding contralateral area of the two groups was statistically significant(t=4.066,P0.01).Before and after rehabilitation,the reduction percent of FA value of CST in the cerebral peduncle of the two groups correlated negatively with the increase percent of FM(r=-0.624,P0.01),but not with the percent change of BI.Conclusion: The measurement of FA values in distal infarction of CST can estimate the degree of degeneration and evaluate the recovery of motor function.The more obvious reduced of FA value,the more serious the nerve degeneration,and the worse recovery of the motor function.