The Study Of Multimodal Magnetic Resonance Imaging In Patients With Post-stroke Aphasia

Post-stroke aphasia(PSA)results from brain network disorders caused by focal stroke lesions.The symptoms are attributed to the damage of structural network composed of local gray matter and white matter fibers and functional network damage based on it.Language activity is an advanced and complex function of human beings,which involves a wide range of networks,complex components,and diversified manifestations of language barriers.The mechanism of aphasia after stroke is not clear.Resting state functional magnetic resonance imaging(rs-f MRI)and diffusion tensor imaging(DTI)are important methods in the study of aphasia in recent years.Previous studies have shown that aphasia caused by local stroke can lead to structural remodeling and functional reorganization of the brain network.In this study,rs-f MRI and DTI techniques were used to explore the characteristics of brain changes in aphasia after stroke.ObjectiveIn this study,the resting fractional low frequency amplitude(f ALFF)was used to analyze the characteristics of cortical spontaneous neuronal activity in patients with subacute PSA,and to explore the pathogenesis and recovery mechanism,and then regions of interest were selected based on the results of f ALFF,and functional connections(FC)were used to analyze the characteristics of brain network in subacute PSA patients.Finally,DTI technique was used to study the changes of nerve fibers in bilateral Broca,BA44,BA45,Wernicke,BA41,BA42,and arcuate fiber tract in patients with subacute PSA,and to explore the characteristics of brain structural changes in patients with PSA.Through this study,it is hoped that it can provide scientific basis for clinical diagnosis and rehabilitation treatment of subacute PSA and provide clinical reference.MethodsUsing a case-control study.In the study of PSA by f ALFF and FC,there were 18post-stroke aphasia patients in the PSA group and 18 healthy volunteers in normal group.The clinical data and WAB score were collected.The T1WI3 D and resting f MRI image data were collected,and the data were preprocessed by DPARSF.The zf ALFF encephalogram was calculated and corrected by two-sample t-test and GRF multiple comparison.The statistically significant f ALFF encephalogram was obtained,and the statistically significant brain regions were observed.The data of brain regions were extracted and correlated with clinical data.Then,according to the results of f ALFF brain region,locate the region of interest,use DPARSF to calculate z FC brain map and carry out two-sample t-test and GRF multiple comparison correction to get statistically significant FC brain map.The brain regions with statistical significance were observed and analyzed.From the PSA group,13 cases were enrolled in the case group of DTI study,and another 13 healthy volunteers were selected as control group.The clinical data and WAB scores were collected.The T1WI3 D and DTI image data were collected.In our work,the FSL software was used to analyze the data,we first defined region of interest,and then extracted the average FA values of bilateral BA41 area,BA42 area,BA44 area,BA45 area,BA41/42 combination area,BA44/45 combination area and arcuate fiber tract.Two-sample t-test was used for statistical analysis,and the statistically significant brain region data and clinical data were analyzed.Results1.Compared with HC,f ALFF increased in PSA group: left: Precentral Gyrus(BA4/6),Angular Gyrus(BA39),Superior Marginal Gyrus(BA40),Dorsolateral Superior Frontal Gyrus(BA8/9),Medial Superior Frontal Gyrus(BA9),Middle Temporal Gyrus;right:Precentral gyrus(BA4/6),dorsolateral superior frontal gyrus(BA8/9),postcentral gyrus(BA3/4/5),operculum(BA44).2.Compared with HC group,f ALFF decreased in PSA group: left: Trigone(BA45/48),operculum(BA44),medial superior frontal gyrus(BA10/32),orbital middle frontal gyrus(BA47),insula(BA48),middle frontal gyrus(BA9/46),dorsal Lateral superior frontal gyrus(BA9),cingulate gyrus(BA10).3.In PSA group,compared with HC group,the brain areas with enhanced connectivity to the right precentral gyrus: right: Lingual gyrus(BA17/18/19),peri-Talar fissure cortex(BA17),fusiform gyrus(BA19/37),angular gyrus(BA39),supramarginal gyrus(BA40),middle frontal gyrus(BA9/46);left: Lingual gyrus(BA17/18),peri-taloid fissure cortex(BA17),cerebellar area 6.4.In PSA group,compared with HC group,the brain areas with enhanced connectivity to the posterior part of the left inferior frontal gyrus: Bilateral caudate nucleus,bilateral medial superior frontal gyrus(BA10),bilateral dorsolateral superior frontal gyrus(BA10),left insular(BA48),right middle temporal gyrus(BA21),right inferior temporal gyrus(BA20).5.Compared with HC(DTI)group,the average FA value of region of interest in PSA(DTI)group had statistically significant ROI: right Broca,right Wernicke area,right BA44 area,right BA41 area,left Wernicke area,left BA41 area.6.The average FA value of the left arcuate fiber tract in the PSA(DTI)group was significantly higher than that in the HC(DTI)group.7.The correlation analysis between the mean FA value of ROI and clinical data in two samples t-test showed that the right Broca area was positively correlated with the course of disease;the right Wernicke was positively correlated with spontaneous speech,comprehension,retelling and aphasia quotient;the left BA41 area was positively correlated with spontaneous speech,retelling and aphasia quotient;and the right BA41 was positively correlated with spontaneous speech,retelling and aphasia quotient.Conclusion1.The decrease of fALFF in the left Broca area of PSA patients may be a pathogenesis of aphasia after stroke2.The activation of the right Broca area in patients with subacute PSA may be the compensation of the right hemisphere to the left hemisphere.3.When the right hemisphere of patients with subacute PSA participates in the compensation of language function,the non-classical language area may be dominant.4.The right precentral gyrus may be part of the brain’s language network.5.Patients with aphasia caused by left hemispheric stroke may have microstructural abnormalities of white matter fibers in the Broca and Wernicke areas on the right.