Diffusion Kurtosis Imaging Of The Effects Of Aging And Hypertension On The Microstructure Of Brain Tissue

Objective: Hypertension and aging are the main risk factors for cer ebrovascular diseases.The purpose of this experiment is to study the eff ects of hypertension and aging on the microstructure of brain tissues,an d to test whether diffusion kurtosis imaging(DKI)can detect microstruc tural changes before significant macrostructural changes occur in the bra in tissue.Methods: In this study,10 W,20W,40 W and 60 W spontaneously h ypertensive rats and control rats were subjected to MRI scanning,includ ing T2 weighted sequence and DKI sequence.The obtained DKI data wa s postprocessed to obtain the corresponding DKI and diffusion tensor im aging(DTI)parameter diagrams,including mean kurtosis(MK),axial ku rtosis(AK),radial kurtosis(RK),kurtosis anisotropy(AFK),fractional a nisotropy(FA),mean diffusivity(MD),axial diffusivity(AD),radial diff usivity(RD).ITK-SNAP,an image processing software,was used to man ually sketch the area of interest,and the software automatically generate d the average parameter value of interest.SPSS was used for statistical analysis of the sample data to compare the differences among the data groups.Results: In the experimental group,DKI parameters were more sensitive than DTI parameters in detecting changes in the microstructure of brain tissue with increasing age,and AK showed relatively stable differences.In the control group,DKI parameters and DTI parameters provided complementary information to show the related changes in the microstructure of brain tissue with increasing age.The study found that in the experimental group and the control group,the average value of most statistically significant parameters increased with increasing age.In the comparison between the experimental group and the control group,it was found that the sensitivity of the DTI parameter was higher than the DKI parameter,and AD and MD showed relatively stable differences between the experimental group and the control group.By comparing the statistically significant parameters,it is found that the average value of most DTI parameters in the experimental group is lower than the control group;the average value of most DKI parameters in the experimental group is higher than the control group.This study also found that there was a significant difference between the left and right cerebral hemispheres in the experimental group and the control group,and the average values of most parameters were higher in the left hemisphere than in the right hemisphere.Conclusion: This study proved the feasibility of using DKI to study the effects of aging and hypertension on the microstructure of brain tissue.Studies have found that aging increases the complexity of brain microstructure.The combination of DTI and DKI parameters can provide more comprehensive structural information for the effect of aging on brain microstructure.The results show that an increase in blood pressure can reduce the rate of tissue diffusion and anisotropy,and increase the complexity of the microstructure of some brain regions.In this study,the difference between the left and right cerebral hemispheres can be considered as a result of the combined action of blood pressure and age,reflecting the different responses of internal structure to blood pressure and age.The combination of DKI parameters and DTI parameters can provide more comprehensive information for the change of brain tissue microstructure.