Cross-sectional Study Of Early Changes Of Brain Fiber Tracts In Patients With Ischemic Stroke:A Fixel-based Analysis Of Diffusion Kurtosis Imaging

Objective: We use fixel-based analysis(FBA)based on diffusion kurtosis imaging(DKI)data to laterally study the macro and micro changes in nerve fibers in the infarcted focus of patients with ischemic stroke within three weeks.Methods: 83 patients with ischemic stroke were examined by Philips Achieva 3.0T magnetic resonance scanner,They were grouped according to the course and location of the disease.Scanning sequence includes structure image sequence 3D T1 WI,T2MV,3D T2WI-FLAIR and 3-b value,15-direction DKI sequence.MRtrix3 software is used to post-process the obtained DKI original map,and then MRIcron software is used to outline the infarct focus on the registered FLAIR sequence.As the mirror area generated,the FC value,FD value and the product of the two areas FDC value are measured.And the parameter ratios of the infarct side and the control side △FC,△FD,△FDC indicate the degree and direction of parameter change.SPSS 23.0 software is used to process the obtained data and perform statistical analysis.P<0.05 indicates statistical significance.Results:The values of FC,FD and FDC in the acute and subacute phases of the infarct side were higher than those of the control side,the FC value in the chronic phase was higher than that of the control side,and the FD value was lower than that of the control side.△FC,△FD,△FDC showed a decrease in the chronic phase compared with the acute phase,and △FDC was also reduced in the subacute phase compared with the acute phase.Without grouping,the △FC,△FD and△FDC of the infarct side were significantly negative with the onset time Related.The FC and FDC values of the infarcted side of the basal ganglia group were higher than those of the control side.The FC,FD and FDC values of the infarcted side of the pons and thalamus group were higher than those of the control side.Only the FC value of the semi-oval center group was higher than that of the control Lateral enlargement.The average △FD of the basal ganglia group was significantly smaller than that of the pons.Only the △FC,△FD and△FDC of the basal ganglia group were negatively correlated with time.The above differences and correlations are statistically significant.There was no significant correlation between △FC,△FD,△FDC and infarct volume in the four groups.Conclusion:Within three weeks after the onset of ischemic stroke,the fiber bundles in the infarct area show a process from macroscopic compensation to microscopic decompensation.The cross-sectional area of the fiber bundles in the infarct area basically presents within three weeks after the onset In the compensated state,the average density begins to appear decompensated after about two weeks.The fiber density is more sensitive to the degeneration of nerve fibers than the fiber cross-sectional area.