Study On The Diffusion Tensors Of Pyramidal Tract And Resting State Functional Connectivity After Internal Capsule Ischaemi

Objectives The study aimed to identify the brain FC and the diffusion tensors of the bilateral PT changes in patients with unilateral internal capsule ischaemic,and study the relationship between motor function assessent and the diffusion tensors of PT,FC using DTI and the resting-state fMRI.MethodsNineteen stroke patients with hemiplegia hospitalized in the Neurology Department,the First Affiliated Hospital of Guangxi Medical University from January 2015 to December 2016 and ten healthy controls were recruited in this study.The FA,MD,AD,and RD values of the bilateral PT in stroke patients as well as motor function assessent including the National Institutes of Health stroke scale(NIHSS),Barthel index(BI),Fugl-Meyer Assessment(FM)at the 3 time points(on the 7th day,30th day,90th day after onset)were measured.The motor related networks of stroke patients on the 7th day,30th day,90th day after onset and the healthy volunteers were identified usingindependentcomponentanalysis.Comparedthemotorrelated networks(MRN)between stroke patients and healthy controls on the 7th day after onset,and the different brain regions were identified.The futional conennectivity beween the different brain regions were calculated in all the subjects on the 7~thh day,30~thh day,90~thh day after onset.Two sample t-test was used to analyze the differece of the diffusion tensors and FC between the stroke patients and the controls.Repeated measures ANOVA was used to analyze the changes of the functional assesment,functional connectivity and the diffusion tensors of the pyramidal tracts in patients at different time.LSD was used to compared the the functional assesment,functional connectivity and the diffusion tensors among different time poits in patients.The correlations between the changes of the functional score,the functional connectivity and the diffusion tensors,between the changes of FA and the AD,RD,between the changes of FA and the FC were analyzed by the Spearman method.Results(1)The NIHSS score of the stroke patients was decreased,while FM,BI score were increased within three time points.(2)The FAs of the ipsilesional PT adjacent to lesion,above lesion,below lesion and the contralesional PT were smaller than the controls on the 7~thh day after onset,and were consistly increased from the 7~thh day to 90~thh day after onset.Accordingly,the RD ofthe contralesional PT was decreased after the onset;while the MD、AD of the bilateral PT had no changes.(3)The brain regions of stroke patiets on th 7~thh day after onset with enhancement functional connectivity were the right precentral gyrus,the right paracentral_lobule and so on,the brain regions with decreased functional connectivity were the left paracentral lobule,the left precuneus,the left middle cingulum and so on,compared with the controls.(4)The functional connectivity between the different brain regions was decreased within 7 days of onset,then was increased during the period from the 7~thh day to the 30~thh day,and returned to the normal level at the end of the 30~thh day.(5)There was a significant negative correlation between the increased percentage of FA of the ipsilesional PT adjacent to lesion and the decreased percentage of NIHSS score,the increased percentages of FA of the ipsilesional PT above the lesion and below the lesion were significantly positively correlated with the FM score.There was a significant positive correlation between the increased percentages of FA of the contralesional pyramidal tract and the BI score.(6)There was a significant positive correlation between the increased percentages of functional connectivity and BI score.(7)The increased percentage of FA was positively correlated with the increased percentage of the FC in the contralesional PT.(8)The increased percentage of functional connectivity was positively correlated with the increased percentage of FA of the ipsilesional PT above the lesion and the contralesional PT.ConclusionsIt was suggested that proliferating reorganization after an unilateral internal capsule infarct would exist not only in ipsilesional but in contralesional PT,and the FC between the motor relate regions of the left and right hemisphere showed a devastating decline at the early stage,and then recovery gradually to normal.The FC between the left and right hemisphere motor related brain areas was related to the reconstruction of the bilateral PT,which promoted the functional recovery of stroke patients in common.