| Part One Study on Abnormality of Dynamic Regional Homogeneity in Patients with Trigeminal Neuralgia.Objective:In order to explore spontaneous brain activity in patients with Trigeminal Neuralgia(TN)under resting state,Dynamic Regional Homogeneity(dReHo)algorithm was used to study abnormal alterations of brain function characteriscticsin TN patients.Methods and Materials:In this study,28 TN patients and 28 health controls(HC)matched by gender,age and education level were included.Two independent sample t-tests were performedto compare the dReHo differences between the two groups.Pearson’s correlation was adoptedto explore the correlation of abnormal dRreHo with clinical data and duration of pain.Results:The dReHo value of bilateral thalamus in the TN group was higher than that in the HC group,while dReHo values in the left middle temporal gyrus(MTG),superior parietal lobule(SPL)and prcentral gyrus(PCG)were lower in the TN group than those in the HC group.Correlation analysis showed that the average dReHo value of thalamus was significantly and positively correlated with TN duration(r=0.485,p=0.012),while the average dReHo value of other brain regions was not significantly,positively or negatively correlated with TN duration.In addition,no significant association was found between the average dReHo value of significant brain areas and the score of Self-Rating Anxiety Scale(SAS)or Self-Rating Depression Scale(SDS).Conclusion:We found that dReHochanges in TN patientsmainly appearsin the thalamus,temporal lobe and parietal lobe.These areas are involved in pain perception and regulation.Meanwhile we also revealed that the increaseddReHo value in thalamus was positively correlated,with pain intensity.These results provide important information for the currently limited studies onbrain function changes in patients with TN.Part Two Study on Abnormal Functional Connectivity in Patients with Trigeminal NeuralgiaObjective:In this study,we aimed to understand the abnormal functionalconnectivityat the whole brain level in TN patients and to analyze the distribution of these abnormal functional connections in the whole brain.In addition,we also attempted toexplore whether the dynamic functional connections of the thalamus can be used as an imaging marker of TN to effectively identify TN patients.Methods and Materials:28 patients with primary TN and 28 control subjects matched by gender,age and education level were included in the study.The thalamus was used as aseed point for functional connectivity calculation.The functional connectivity differences between the two groups were analyzed by constructing a general linear model and by using two independent samples t-tests.In addition,the gray matter probability template included in the SPM software was used as amask,and the functional connectivity in the template was used as characteristics,multi-voxel pattern recognition was performedby the linear support vector machine and the dimensionality reduction method of principal component analysis.Results:The thalamus was used as aseed point for functional connectionof the whole brain,and enhanced connectivity was found in the right superior frontal superior gyrus(FSG)of TN patients compared to HC group.In terms of identification performace of TN patients based on the functional connectionof thalamus as a seed point,the accuracy was0.70±0.21,sensitivity was0.70±0.30,specificity was0.76±0.24,and area under the curve(AUC)was0.75± 0.33.the AUC of recevier operating characteristic curve(ROC)for identifying TN patients was 0.75,indicating good recognition performance of the model.Brain regions with a higher classification weight in functional connectivity were mainly bilateral thalamus(extending to the left putamen),anterior cingulate gyrus,central cingulate gyrus,bilateral temporal poles,and auxiliary motor areas.Conclusion:In this study,we explored the abnormal functional connectivity of the whole brian in TN patients by using the thalamus as a seed point.In addition,the SVM-based MVPA analysis revealded that the effectivefunctional connectivity of the bilateral thalmus,a key node of TN,could accurately distinguish TN patients form normal controls,which could also detect the difference of effcitve functional connectivity in the relevant brian areas between TN patients and NC group.Our results suggest that effective functional connectivity between the bilateral thalamus and related brain regions is a potential biological marker for TN.Additonally,through this method we gained further understanding of the neurological change mechanism inTN.Part Three Analysis of Abnormal Brain Structure in Patients with Trigeminal NeuralgiaObjective:CAT12 and TBSS methods were used to investigate the structural changes of gray and white matter in TN patients.Materials and Methods:30 TN patients and 30 control subjects matched by gender,age and education level were included in the study.The cortical feature analysis was performed using CAT 12.All images were automatically segmentedinto gray matter,white matter and cerebrospinal fluid and the cortical thickness was measured.Tissue segmentation was used to estimate the white matterdistance.Newly generated images were smoothedby the Gaussian moothing kernel FWHM.For white matter TBSS data processing,PANDA was used to calculate the anisotropy fraction(FA)diagram of all subjects based on the DTI data after eddy current correction.Then the FA diagram was registered to the standard MNI152 space,and the average FA diagram was created by using the registered FA diagram,followed by exraction of the fiber skeleton.Finally,the FA diagram of each subject was projected onto the average skeleton.Two independent sample t-testswere used to analyze the differences in gray-white matter characteristics of the two groups.Results:(1)Compared with the control group,patients in the TN group had thinner cortical thickness in the left orbitofrontal cortex and subfrontal cortex(extending to the anterior central gyrus),and decreased cortical gyri index in the left superior frontal gyrus.Meanwhile the bilateral groove depth from frontal epithelium to anterior cingulate sulcus decreased.(2)There was a significant negative correlation between the average thickness of the left orbitofrontal cortex and pain intensity in TN patients,and there was also a significant negative correlation between the average gyri index of the left orbitofrontal cortex and pain intensity.(3)No significant difference in white matter fiber skeleton FA was found between TN group and HC group.Conclusion:There were abnormal changes in cortical thickness,gyri index and groove depth in TN patients,these brain areas are mainly involved in pain perception and management.In the present study,we also found a correlation between reduced cortical morphological indicators and increased pain intensity.However,the TBSS analysis showed no significant differences in the white matter fiber skeleton FA between the TN and HC groups,and these results may provide important indications to reveal the mechanisms of pain related neurophysiology. |
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