Study Of Brain Dynamic Functional Network Connectivity In Conventional MRI Negative Children And Juvenile Epilepsy

Objective:To investigate the changes of brain dynamic functional network connectivity in conventional MRI negative children and juvenile idiopathic generalized epilepsy（IGE）based on resting-state functional magnetic resonance imaging（rs-f MRI）,and to explore the correlation between dynamic functional network connectivity indicators（fraction of time,mean dwell time,and number of transitions）and clinical variables（age,duration,and intelligence quotient）,providing imaging evidence for brain function change and cognitive dysfunction in patients with IGE.Methods:Forty patients with IGE were collected,who were negative on routine magnetic resonance imaging（MRI）of the brain from the pediatric outpatient and inpatient department in Affiliated Hospital of Zunyi Medical University from April 2014 to August2021.In addition,thirty-seven healthy subjects were recruited as the control group with matching age,sex and education level.T₂-FLAIR,3D-T₁WI and rs-f MRI images were performed by MRI（3.0THDxt,GE）in all subjects,and all the children in the IGE group were tested by chinese-Wechsler Child Intelligence Scale on the day of examination.Restplus＿v1.24 was used to preprocess rs-f MRI data,and GIFT software was used to perform independent component analysis（ICA）on the pre-processed rs-f MRI data,and 49effective independent components（ICs）were obtained.The d FNC indicators（fraction of time,mean dwell time,and number of transitions）were obtained by using the sliding time window and k-means clustering methods for 49 ICs.Then,based on SPSS18.0 and GIFT software Stats module,the differences of dynamic functional network connections between IGE group and control group in different states were compared,the differences of d FNC indicators between the IGE group and the control group were compared,and further analysis the correlation between d FNC indicators of IGE patients and clinical variables（age,duration,and intelligence quotient）.Finally,the reliability and stability of d FNC results were further verified by changing the size of the sliding window and clustering number.Results:（1）There was no significant difference in clinical information（gender,age and education level）between the IGE group and the control group（P>0.05）.（2）Comparison of d FNC mode between the IGE group and the control group:sliding window width was 30TR and the number of clusters was 6.Six kinds of functional connection states were obtained after clustering,and each state has different functional connection modes and intensities.Among them,state 5 shows large-scale enhancement of functional network connection in resting state brain network（RSN）.state 6 shows"sparse connectivity"within and between RSN,that is,large-scale functional network connectivity of the whole brain is weakened.Compared with the control group,there were significant differences in state 5 and state 6 in the IGE group.In state 5,the functional network connections within the default mode network（DMN）and between the DMN and frontoparietal network（FPN）were enhanced in IGE group,while the functional network connections between the DMN and visual network（VN）were significantly decreased（P<0.001）.In state 6,the functional network connections between DMN and VN and between basal ganglia network（BGN）and sensorimotor network（SMN）were enhanced in IGE group.However,the connection between DMN and attention network（ATTN）and the internal functional network of VN were decreased（P<0.001）.（3）d FNC indicators for groups comparison:there were statistically significant differences of the fraction of time and the mean dwell time in the state 1 and state 4,the fraction of time in the state 6 between the IGE group and the control group（P<0.05）.There were no significant differences in other dynamic functional connectivity indicators between the two groups（P>0.05）.（4）Correlation analysis:There was a negative correlation between duration and the fraction of time of state 1 in the IGE group（r=-0.421,P=0.007,Bonferroni correction）.Age and intelligence quotient had no significant correlation with dynamic functional network connection indicators.Conclusion:The dynamic properties of the whole brain functional network connectivity are abnormal in IGE patients,and the fraction of time of state 1 in IGE patients is correlated with clinical variables,providing a new imaging evidence for cognitive function changes in children and juvenile with IGE.