Study On Neurovascular Coupling In Chronic Stroke Based On FMRI

Objective:Ischemic stroke is a common disease of the central nervous system.It is a blood supply disorder caused by various causes,leading to brain tissue ischemia and hypoxic necrosis,resulting in motor dysfunction and cognitive dysfunction.Although there are many neuroimaging studies on the structure and function of chronic ischemic stroke,the effect of neuronal activity with cerebral blood flow perfusion after chronic ischemic stroke is unclear.Neurovascular coupling represents the metabolic activity of neurons that matches cerebral blood flow perfusion in the brain,providing a new concept for the study of central nervous system diseases.This study enrolled a large sample of patients with chronic ischemic stroke.Based on the theory of neurovascular coupling,CBF-fALFF coupling analysis and CBF/ fALFF ratio calculation were performed to investigate the changes of neurovascular coupling and clinical significance of chronic basal ganglia ischemic stroke.Methods:A total of 66 chronic stroke of basal ganglia(46 women and 20 men)were included and divided into two groups based on the lesion side,namely the left-sided patients group(40 patients)and the right-sided patients(26 patients).At the same time,58(female 33,male 25)healthy volunteers whose age,gender and education level were matched were selected as the control group.MR imaging data were acquired using a Siemens 3.0 T scanner,including rsfMRI and ASL.The standardized fractional Amplitude of low-frequency fluctuation was calculated from fMRI and CBF was computed from ASL.We calculated across-voxel CBF-fALFF correlations and CBF/fALFF ratio of each voxel to evaluate the global neurovascular coupling and the regional neurovascular coupling respectively.The CBF /fALFF ratio of each voxel in the template was then compared between groups using the two-sample t-test.The two-sample t-test for CBF and fALFF was used to compare the voxel-based groups.Then,the chronic basal ganglia stroke patients from different sides were divided into three groups according to the onset time,which were 6-12 months,12-24 months,>24 months,respectively,and compared with the normal control group.Results:1.There was a significant positive correlation between CBF and fALFF in the normal control group.2.Compared with the normal control group,the CBF-fALFF coupling of the whole brain level in the left lesion group and the right lesion group ware lower.3.Compared with the normal control group,the ratio of CBF/fALFF in the right frontal gyrus,the right middle anterior cingulate gyrus,the right anterior cingulate gyrus and the right supplementary motor area increased in the left lesion group.4.Compared with the normal control group,the ratio of CBF/fALFF in the left inferior frontal gyrus,left superior frontal gyrus and left frontal gyrus was increased in the right lesion group(P<0.05,Alphasim correction).5.In the left lesion group and the right lesion group,the CBF/fALFF ratio increased in the brain region at different time points,but the range of the damaged brain region was different.Conclusions:1.The level of neuronal activity in the healthy control group matched the perfusion of blood,proving the presence of neurovascular coupling in the normal human brain.2.There is impaired neurovascular coupling in the chronic stroke patients of basal ganglia,and neurovascular unit may become a potential therapeutic target for patients with chronic ischemic stroke.3.In the chronic stroke patients of basal ganglia,although the brain regions damaged by neurovascular coupling are the same at different time points,the range of damaged brain regions gradually shrinks with the onset of onset,and it is basically becoming steady after 2 years.