Effects Of Hypertension On White Matter Integrity In The Middleaged Measured By Diffusion Tensor Imaging

Objective: To explor the differences of white matter integrity between hypertensive and non-hypertensive healthy middle-aged adults,to evaluate the correlation between the fractional anisotropy(FA)in regions of reduced white matter integrity with multiple elements including systolic blood pressure,duration of hypertension,age,sex and so on,and to investigate the correlation of effects of age and hypertension on white matter integrity in middle-aged with a voxel-based analysis of diffusion tensor imaging(DTI)data.Methods: Forty-four middle aged(45-59 years old)subjects including twenty-five hypertensive patients and nineteen healthy individuals,recruited from the cardiology clinic and Medical Center of The Second Hospital of Hebei Medical University since October 2015 to January 2016,were underwent conventional MRI?T1-FFE and DTI EPI sequence.FA maps were compared by voxel-based analysis of diffusion tensor imaging(DTI)data to identify the regional brain area of difference peak between two groups,and then FA values of the peak area including left middle occipital gyrus,right sub-Gyral of frontal lobe scilicet in front of head of caudate nucleus and left sub-Gyral of frontal lobe namely the anterior corona radiate white matter were determined by region-of-interest analysis.The relationship between FA and SBP,duration of hypertension,age,sex and so on were estimated by bivariate correlation analysis and multiple linear regression analysis with a significance level ?0.05.Results:1 Compared with non-hypertensive group,the hypertensive group showed significant FA decline though bilaterally but mostly in left white matter area where peak value lay in the sub-gyral of bilateral frontal lobe,left supramarginal gyrus,left middle occipital gyrus and left postcentral gyrus,expanding to right extra-nuclear,right caudate,right putamen,left superior occipital gyrus,cuneus,inferior parietal lobule(including inferior parietal supramarginal and angular gyri and angular gyrus)and left precentral gyrus,as well as regions in middle and inferior frontal gyrus,middle temporal gyrus,cingulate gyrus and brodmann area 40,6,18 and 44(P <0.005).2 In left middle occipital gyrus,the multiple linear regression analysis of FA,SBP,duration of hypertension,age and BMI suggested that FA had a significantly negative linear regression correlation(R~2=0.621,P<0.000)with SBP and the duration of hypertension while the latter contributed more to the regression.No statistically significant regression association was seen between FA and age or BMI.3 In the right sub-Gyral of frontal white matter,the multiple linear regression analysis of FA,SBP,duration of hypertension and sex suggested that FA had a significantly negative linear regression correlation with SBP and sex(R~2=0.292,P<0.01).FA value was less among women than man for this region,but no statistically significance existed(P>0.05).No statistically significant regression association was seen between FA and duration of hypertension.4 In the left anterior corona radiate white matter,the multiple linear regression analysis of FA,SBP and duration of hypertension indicated that FA had a significantly negative linear regression correlation with SBP(R~2=0.252,P<0.01).No statistically significant regression association existed between FA and duration of hypertension.Conclusion:1 SBP is associated with injury to white matter microstructure in healthy middle-aged(45-59 years old)adults.Injury worsened continuously as SBP increased and was significantly different between hypertensive and nonhypertensive individuals in several peak regions including the sub-gyral white matter of bilateral frontal lobe,left supramarginal gyrus,left middle occipital gyrus and left postcentral gyrus.2 Duration of hypertension show a negative linear correlation with white matter integrity,with preferential susceptibility to the left middle occipital gyrus where FA values declines with the extending of duration of hypertension.The effect of duration of hypertension on white matter microstructure is a little more notable than SBP.3 Age-related degeneration of white matter integrity is not significant in middle-aged(45-59 years old)adults and SBP matters more than age for degeneration of white matter integrity.