Study On The Plasticity Of The White Matter During Motor Recovery Of Stroke Patients By Diffusion Tensor Imaging

Stroke is an acute cerebrovascular disease of high morbidity and disability,and patients often have varying degrees of motor dysfunction.Motor function recovery after stroke has been the focus of clinical attention.However it is very difficult to judge the recovery of motor function using conventional imaging data after initial onset.Thus it is necessary to find a radiographic marker to estimate the prognosis of motor function.Motor imagery which has been increasingly used in recovery of motor function in stroke patients,combined with conventional therapy can improve motor function recovery in stroke patients,but its neurophysiological mechanism is still unclear.Diffusion tensor imaging(DTI)is the only non-invasive imaging technique that can reveal white matter fiber tracts,thus it has unique advantages in the study of white matter.We used a variety of methods based on DTI technology to study the change of white matter structure and cerebral structural network in stroke patients with hemiplegia and found parameters of recovery marker of motor function.We compared the changes of white matter structure and cerebral structural network in conventional treatment group and motor imagery group to explore the effect of motor imagery on white matter structure and cerebral structural network in stroke patients with hemiplegia.Part ?ObjectiveTo research the damage of the cerebral white matter and the change of the cerebral structural network in the stroke patients,and to explore the correlation between the white matter damage and the motor dysfunction.MethodsSeventeen stroke patients and twenty-one healthy controls(HCs)were recruited to collect the DTI data.Fractional anisotropy(FA),axial diffusivity(?1)and radial diffusivity(?23)were analyzed for differences between two groups using Tract-Based Spatial Statistics(TBSS).The regions of interest(ROI)were defined based on Johns Hopkins white matter partition atlas.The correlations between the parameters of ROI and the Fugl-Meyer assessment(FMA)score of the stroke patients were also analyzed.Reconstruct corticospinal tract of stroke patients,and the correlations between the parameters of corticospinal tract and the FMA score of the stroke patients were also analyzed.At last,the differences between the cerebral structural network of the two groups were calculated.ResultsCompared with the HCs,the FA of the white matter fiber bundles were reduced in ipsilesional corticospinal tract,inferior fronto-occipital fasciculus,uncinate fasciculus,anterior thalamic radiation,superior longitudinal fasciculus,forceps minor and bilateral forceps major(p<0.005).The ?1 of the white matter fiber bundles were reduced in ipsilesional corticospinal tract(p<0.05).The ?2 of the white matter fiber bundles were increased in ipsilesional corticospinal tract,inferior fronto-occipital fasciculus,uncinate fasciculus,anterior thalamic radiation,forceps minor,bilateral forceps major and superior longitudinal fasciculus(p<0.01).A positive correlation was found between ?1 value of ipsilesional corticospinal tract and the FMA score of stroke patients(p<0.05).A negative correlation was found between rV value of corticospinal tract and the FMA score of stroke patients(p<0.05).Compared with the HCs,there were 15 pairs of structural connectivity significantly reduced(P<0.005)and 2 pairs of structural connectivity significantly increased(P<0.005).The significantly reduced degree of nodes including(P<0.01): left thalamus,left supplementary motor area,left posterior central gyrus,right supramarginal gyrus,left olfactory cortex,left inferior parietal gyrus,left middle occipital gyrus.ConclusionDTI is a powerful tool for studying the white matter and brain network.Abnormal white matter structure were found in the stroke patients and the cerebral structural network were significantly changed.The value of ?1 in ipsilesional corticospinal tract could reflect the motor dysfunction and thus predict the recovery of motor function.Part ?ObjectiveTo research the effect of motor imagery on the white matter and cerebral structural network in stroke patients.Methodsnineteen stroke patients were randomly divided into motor imagery group(nine patients)and conventional treatment group(ten patients).They were recruited to collect the DTI data twice before and after the treatment period of one month.Fractional anisotropy(FA),axial diffusivity(?1)and radial diffusivity(?23)were analyzed for differences between two times of each group using Tract-Based Spatial Statistics(TBSS).The changes of parameters pre and post treatment were compared.The differences between the cerebal structural network pre and post treatment of each group were also calculated.ResultsThe FMA score of motor imagery treatment group increased greater than that of conventional treatment group.Compared with pre treatment in motor imagery group,the FA of the white matter fiber bundles post treatment were increased in ipsilesional corticospinal tract,inferior fronto-occipital fasciculus and superior longitudinal fasciculus(P<0.05,uncorrected).The ?1 of the white matter fiber bundles were increased in ipsilesional corticospinal tract,inferior longitudinal fasciculus,inferior fronto-occipital fasciculus and anterior thalamic radiation(p<0.05,uncorrected).There were no significantly changes between two times in conventional treatment group.Compared with pre treatment in conventional treatment group,there were 8 pairs of structural connectivity significantly increased(P<0.05)and 4 pairs of structural connectivity significantly reduced(P<0.05)post treatment.Compared with pre treatment in motor imagery group,there were 13 pairs of structural connectivity significantly increased(P<0.05)and 6 pairs of structural connectivity significantly reduced(P<0.05)post treatment.Compared with pre treatment in conventional treatment group,the significantly increased degree of nodes post treatment including(P<0.05): left middle frontal gyrus,left Superior frontal gyrus,orbital part,left inferior occipital gyrus.The significantly reduced degree of nodes including(P<0.05): left Inferior parietal,supramarginal and angular gyri,left fusiform gyrus,left thalamus,left superior temporal.Compared with pre treatment in motor imagery group,the significantly increased degree of nodes post treatment including(P<0.05): left pallidum,left parahippocampal gyrus,right Inferior frontal gyrus,triangular part.ConclusionMotor imagery combined with conventional therapy can significantly improve motor function in stroke patients with hemiplegia,and it has greater impact on the plasticity of white matter.