The Study About Diffusion Tensor Imaging Characters In Children With Tic Disorders

BackgroundTic disorder(TD)is a common developmental neuropsychiatric disorder in childhood,which is mainly manifested as involuntary vocalization tics and/or motor tics.The age of onset is most common between 5 and 10.There are significantly more male than female.Combining the clinical manifestations and duration of the disease,tic disorder can be divided into three types,respectively for Tourette syndrome(also called multiple tic syndrome,Tourene syndrome,TS),transient and chronic tic disorders.Compared with the other two,TS has more complex symptoms,longer course of disease,and greater impact on children's lives,often as the main research object.The etiology of tic disorder is complex,and its research involves many fields such as neuropsychology,neuroimaging,neurobiochemistry and other fields.In recent years,MRI research has provided more evidence for the etiology of TD.There is considerable evidence from some autopsy and functional imaging studies that the cortico-striato-thalamo-cortex pathway is involved in the pathophysiology of tics,and that the basal ganglia may have structural and functional abnormalities,which can result in tics.Diffusion tensor imaging(DTI)is a magnetic resonance imaging sequence that visualizes the white matter of the brain.The principle is based on the diffusion of water molecules,while physiologically the diffusion of water molecules in the brain is limited to the long axis of white matter.Therefore,it reflects the integrity and spatial directivity of the white matter bundles in the brain.It is highly sensitive and can directly reflect the movement,absence,and density of white matter bundles.Two parameters are commonly used to quantify fiber bundles,one of which is the apparent diffusion coefficient(Apparent diffusion coefficient,ADC)value,and the other is the fractional anisotropy(Fractional anisotropy,FA)value.FA is a parameter used to quantify the direction of water molecules in tissues.The range of FA value is 0-1.When the tissue is intact,water is forced to move in a specific direction,and the FA value is close to 1.When the tissue is damaged by micro or macro structures,water molecules move in multiple directions,and the FA value approaches 0.ADC describes the diffusion amount of water molecules,reflects the strength of water molecules diffusion ability,the signal level is proportional to the overall diffusion rate of water molecules,and reflects the microstructure information inside and outside the cell.Therefore,DTI technology can be used to observe whether the CSTC microstructure of TD patients is complete.At present,the diagnosis of TD is mainly based on medical history and clinical symptoms,and there is no objective standard.When the clinical manifestations of children are atypical or combined with other diseases,the diagnosis just based on clinical manifestations may be misdiagnosed and missed.Therefore,reliable imaging diagnosis can help its early diagnosis,treatment evaluation,and research on pathogenesis.ObjectiveDiffusion tensor imaging(DTI)was used to compare the microscopic lesions of basal ganglia,thalamus,and frontal white matter lesions in children between Tourette syndrome(TS)and healthy volunteers,and explore the pathological mechanism of TS,to provide possible imaging basis for the diagnosis and differentiation of TS.MethodsIn this study,30 right-handed TS children(case group)and 30 right-handed healthy children(control group)were selected for cranial magnetic resonance diffusion tensor imaging(DTI)scanning.Using hand-drawn regions of interest(ROI),draw the bilateral frontal cortex,caudate nucleus,putamen,paleosphere,and thalamus region of interest at the maximum level of the basal ganglia in the DTI image,and measure their apparent diffusion coefficients(ADC)value and fractional anisotropy(FA)value.The independent sample t test was used to compare and analyze the differences in the FA values and ADC values of the brain structures corresponding to the case group and the control group.Then,the statistically significant regions of interest measured in the case group were selected and Pearson correlation was used to analyze the correlation between ADC values of FA values and YGTSS(the Yale Global Tic Severity Scale)scores respectively.ResultsCompared with the healthy control group,in the TS case group,decreased FA and increased ADC value in the right frontal lobe,bilateral caudate nucleus,and bilateral thalamus were of statistical significance(P<0.05);The increase of ADC value in the left thalamus was correlated with the increase of YGTSS score(r=0.746,P<0.05).Conclusions1.The results of the cranial DTI study of children in the case group showed abnormal parameter values in the bilateral caudate nucleus,thalamus and white matter of the right frontal lobe,suggesting abnormal pathological changes in these areas in TS patients2.DTI technology provides possible imaging basis for the diagnosis and differentiation of children with TS.