The Preliminary Study Of IVIM In Different Regions Of DKI In Patients With Ischemic Stroke

Objective: To investigate the feasibility of using IVIM to explain the microcirculation perfusion and spread of different regions of the lesion in the DKI parameter map,so as to provide further evidence for the accurate division of infarct core and ischemic penumbra by DKI.Methods: This study retrospectively analyzed the results of magnetic resonance imaging of DWI,DKI,and IVIM in 24 patients with clinically diagnosed ischemic stroke and 24 normal controls without neurological disease.The raw data is processed by the GE aw4.6 post-processing workstation to obtain DKI and IVIM parameter maps.According to whether the MD parameter map and the MK parameter map showed the same range of lesions(with a difference of 5 mm),31 lesions of 24 patients with cerebral infarction were divided into MD/MK matching group(<5mm)and MD/MK mismatch group.(?5mm).The brain tissues showing abnormal signals in both MD and MK maps were named as the central area of the lesion;the brain tissues with normal MK maps and abnormal MD maps were named as the mismatch area;the normal brain tissues with 2cm periphery of abnormal MD maps were named as the marginal area.The region of interest(ROI)was drawn from the largest section of the lesion,and the DKI parameter values and IVIM parameters of each region of the lesion were obtained.The healthy control group chose to plot ROI in the basal ganglia and thalamic area to obtain various parameter values.Statistical analysis was performed using SPSS 22.0.The paired t-test was used to compare the difference between the parameter values of the matching group and the mismatch group.The independent sample t test was used to compare the differences in the values of the same ischemic regions between the MD/MK matched group and the MD/MK mismatch group.One-way ANOVA was used to compare the differences of IVIM values in different regions of the matching group and the mismatch group.The difference between the two IVIM parameters in the mismatch group in different ischemic regions was compared by LSD method.The independent sample t test was used to compare the difference in parameter values between the mirror image area and the healthy group.P < 0.05 indicates statistical significance.Results: Of the 31 independent lesions in 24 patients with cerebral infarction,17 were in the MD/MK matched group and 14 in the MD/MK mismatch group.1 The MK,Ka,and Kr values of the mismatched area in the lesion center and mismatch group were higher than those in the mirror area.MD,Standerd ADC,Slow ADC,and f values were lower than the mirror area.,and the values of each parameter were statistically significant(P < 0.05).The values of Standerd ADC and Slow ADC in the marginal area of the lesion were lower than those on the contralateral side,and the f value was higher than that in the mirror area.The difference was statistically significant.Fast ADC decreased in the central area of the lesion compared with the mirror area,and the difference was statistically significant.There was no significant difference in the value of Fast ADC between the mismatched area and the marginal area and the mirror area(P>0.05).There was no significant difference between the matching group and the mismatch group in the same ischemic area(P>0.05).3 The parameter values of the central and marginal regions in the mismatched group and the matching group were not statistically significant except for the Fast ADC value(P=0.25),and the other parameters were statistically significant.The values of MK,Ka,and Kr in the center of each group are higher than those in the edge area,and the MD,standerd ADC,Slow ADC,and f values are reduced.4 There was no statistically significant difference in the parameters between the mirror area of the stroke patient and the normal healthy person group.(P>0.05)Conclusion: The derived parameters of IVIM,Standerd ADC,Slow ADC,and f,are able to distinguish the differences in diffusion and perfusion between the infarct core and the ischemic penumbra as judged by DKI.IVIM provides further evidence to confirm that DKI can accurately assess infarct core and ischemic penumbra.