Brain Injury Assessment And Prognostic Value Research Of Diffusion Tensor Imaging In Patients With Acute Cerebral Infarction

Objective:To investigate the relationship between changes in the parameters of magnetic resonance diffusion tensor imaging in the lesion area of patients with acute cerebral infarction and the clinical course of the disease,the assessment of the disease at admission,and the clinical outcome after 3 months.It is hoped to provide help for early diagnosis and treatment and prognosis prediction of patients with acute cerebral infarction.Methods:Twenty-eight patients with acute cerebral infarction were selected for emergency treatment of stroke and proved.（1）Brain injury assessment in patients with acute cerebral infarction,i.e.DTI correlation study with clinical disease progression and condition assessment at admission:Magnetic resonance diffusion tensor imaging（DTI）scanning was performed at admission,and the area of interest was placed in the lesion area after post-processing.Calculate the anisotropy index（FA）,volume ratio anisotropy（VRA）,average diffusion coefficient（DCavg）,exponential attenuation（Exat）and relative values（rFA,rVRA,rDCavg,rExat）formed by bilateral（sick/health）comparisons.Patients were divided into hyperacute phase（5 cases）and acute phase（24 cases）according to the time of onset.And clinical severity scales:National Institutes of Health Stroke Scale（NIHSS）and Modified Rankin Scale（mRS）.Analyze the changes of DTI parameters in the hyperacute and acute lesion areas;differences between the relative values of DTI parameters in hyperacute and acute phases;correlation between relative values of patient DTI parameters;correlation between the relative value of each parameter of the patient’s DTI and the NIHSS and mRS scores at admission.（2）Evaluation of prognosis in patients with acute cerebral infarction,i.e.DTI correlation with prognosis:Follow-up with the mRS score was performed 3 months later,and 22 patients were successfully followed up.According to the mRS score after 3 months,they were divided into the group with good prognosis（12 cases）and the group with poor prognosis（10 cases）.Analyze the correlation between the relative values of the DTI parameters at admission and the mRS score after 3 months;differences in relative values of DTI parameters at admission between different prognostic groups.Results:1.Brain injury assessment in patients with acute cerebral infarction,i.e.DTI correlation study with clinical disease progression and condition assessment at admission:In the hyperacute phase,the DCavg value on the lesion side is lower than that on the corresponding healthy side[（3.498±1.349）×e^-10vs.（7.648±0.287）×e^-10m²/s,P=0.002],and the Exat value is higher than that on the corresponding healthy side[（0.468±0.013）vs.（0.468±0.013）,P=0.004].The difference between FA value and VRA value is not statistically significant（P>0.05）.In the acute phase,the FA value,VRA value,and DCavg value of the lesion side are lower than those of the corresponding healthy side[respectively（0.350±0.157）vs.（0.426±0.137）,P=0.013;0.133 vs.0.191（Rank sum test:using median）,P=0.024;（3.164±1.191）×e^-10vs.（7.829±0.821）×e^-10m²/s,P<0.001],and the Exat value is higher than that of the corresponding healthy side[（0.735±0.085）vs.（0.461±0.036）,P<0.001].The rFA value and rVRA value in the hyperacute phase are higher than those in the acute phase[1.059 vs.0.817（Rank sum test:using median）,P=0.021;1.143vs.0.684（Rank sum test:using median）,P=0.018].The rFA value of the patient’s lesion area has a strong positive correlation with the rVRA value（r=0.989,P<0.001）;there is a strong negative correlation between the rDCavg value and the rExat value（r=-0.895,P<0.001）;There is a moderate negative correlation between rFA value and rDCavg value,rVRA value and rDCavg value（respectively r=-0.468,P=0.010;r=-0.438,P=0.017）.The rFA value,rVRA value,rDCavg value,and rExat value in the patient’s DTI were not significantly correlated with the NIHSS and mRS scores at admission（P>0.05）.2.Evaluation of prognosis in patients with acute cerebral infarction,i.e.DTI correlation with prognosis:There was no significant correlation between the relative values of the DTI parameters at admission and the mRS score after 3 months（P>0.05）.There was no significant difference in the relative values of DTI parameters at admission between the different prognostic groups（P>0.05）.Conclusion:1.The changes of DTI parameters of lesions in different periods can reflect the brain tissue damage of patients with cerebral infarction in different periods.Values representing diffusion in hyperacute and acute lesions:DCavg decreases and Exat increases.However,only in the acute phase are the lesions manifested as decreased FA and VRA,which represent the condition of the nerve fiber bundles.2.There is a difference between the hyperacute phase and the acute phase in the lesion area rFA and rVRA.It is expected that rFA and rVRA will assist in the diagnosis of onset time.This can provide an imaging basis for the clinical staging and treatment options of patients with cerebral infarction.3.The relative values of DTI parameters at admission for patients with acute cerebral infarction cannot reflect the clinical severity at admission,and cannot predict the prognosis after 3 months.This suggests that DTI may need to include more periods（Subacute phase,Chronic period）,larger sample sizes,or more comprehensive factor analyses when used to assess the condition and prognosis of patients with non-lacunar infarction.