Research Progress Of Multimodal Magnetic Resonance Imagin In Evaluating The Efficacy Of Repetitive Transcranial Magnetic Stimulation In Obsessive-Compulsive Disorder

Background and purposeObsessive-compulsive disorder(OCD)is a kind of disabling mental disorder with different clinical features.The lifetime prevalence rate is 2%-3%.The core symptoms of OCD are invasive repetitive thoughts or repetitive behaviors that can be disturbed by difficulty anticipating and controlling the onset of obsessive-compulsive symptoms in advance,causing severe personal distress or social dysfunction.However,at present,the neural mechanism of OCD occurrence is still unclear,and previous studies have confirmed the existence of abnormalities in the cortico-striato-thalamus-cortical(CSTC)loop,since then,more and more researches have begun to explore the neural mechanism of OCD from the perspective of brain imaging.Previous brain imaging studies of OCD patients have focused on local spontaneous neural activity,recent studies have also suggested that the neural mechanisms of OCD may be related to more widespread brain networks.The emergence of resting-state functional magnetic resonance imaging(rs-f MRI)provides a way for researchers to explore abnormal connections between large-scale functional brain networks in patients with obsessive-compulsive disorder.At present,the effect of medication and cognitive behavior therapy for patients with OCD is limited,and a small number of patients will continue to have OCD symptoms after treatment,rTMS is a new therapeutic method with good safety and tolerability and low probability of adverse reactions,has been widely used in the treatment of obsessive-compulsive disorder,depression and other mental disorders.However,the neural mechanism of rTMS in the treatment of obsessive-compulsive disorder is not clear.In this paper,the functional network connectivity(FNC)analysis,method based on independent component analysis(ICA)is adopted,to explore the neuroimaging mechanism of OCD,we compared the functional connectivity(FC)between OCD patients and healthy controls,and analyzed the correlation between FC values and Y-BOCS between different brain networks.By comparing the changes of FC in OCD patients before and after treatment with rTMS,and analyzing the correlation between the changes of FC difference in specific brain networks and the changes of difference in Y-BOCS,to provide a more comprehensive and longitudinal brain imaging mechanism for the treatment of OCD with rTMS.Materials and methodsA total of 17 patients with OCD who did not respond to the first or inpatient use of psychoactive drugs were enrolled in the outpatient and inpatient departments of our hospital.At Baseline,17 patients underwent rs-f MRI scanning,14 patients underwent 3-week rTMS,and 14 patients underwent rs-f MRI(rTMS group),and clinical data is collected for all subjects: general data collection includes the participant’s age,gender,years of education etc.;clinical information collection includes the patient’s personal history,past history and family history,and at the same time,19 healthy controls matched with the rTMS group in terms of age,sex and years of education were collected.Rs-f MRI scans and Yale-Brown Obsessive-Compulsive Scale(Y-BOCS),Hamilton Depression-17 item Scale(HAMD)and Hamilton Anxiety Scale(HAMA)were performed in the healthy control group as well as the rTMS group before and after treatment.The age,years of education and scores of Y-BOCS,HAMD,HAMA between the two groups were analyzed by two sample t test,and the differences were statistically significant(p<0.05).The scores of Y-BOCS,HAMD,HAMA before and after treatment in rTMS group were analyzed by paired sample t test,and the differences were statistically significant(p<0.05).The collected image data is pre-processed by Spm12 software under the MATLAB 2019 b operating platform: culling time point,head movement correction,time correction,registration,segmentation,spatial standardization,and smoothing;independent component analysis of pre-processed image data on the software GIFT(group ICA of f MRI toolbox),selecting the most relevant independent components(IC)as the intrinsic functional connection indicators;using the FNC method for functional connection analysis,and get the difference in functional connections.To analyze the correlation between FC value and Y-BOCS between OCD patients and healthy control group,the correlation between the difference of FC between specific brain network of OCD patients before and after rTMS treatment and the difference of Y-BOCS.Results1.The age,years of education of rTMS group and healthy control group were analyzed by two sample t test,the results showed no significant difference(p>0.05).The scores of Y-BOCS,HAMD and HAMA at baseline were analyzed by two sample t test,the results showed that there was significant difference between the two groups(p<0.05).The scores of Y-BOCS,HAMD and HAMA in the rTMS group were analyzed by paired sample t test before and after treatment,the results showed that the scores of Y-BOCS,HAMD and HAMA in the rTMS group were significantly different before and after treatment(p<0.05).2.Compared with the healthy control group,the functional connectivity in the rTMS Group was significantly lower(p<0.05,both FDR adjusted).The networks included the default mode network(DMN)and the salience network(SN),and there was a significant negative correlation between FC value and scale score(r=-0.718,p=0.004);between DMN and the visual network(VSN),FC value was negatively correlated with scale score(r=-0.878,p<0.001);between DMN and the attention network(ATN),FC value was negatively correlated with scale score(r=-0.968,p<0.001);within DMN,FC was negatively correlated with the scale score(r=-0.822,p<0.001);within the sensorimotor network(SMN),FC was negatively correlated with Y-BOCS(r=-0.907,p<0.001);between SMN and DMN,FC was negatively correlated with the score(r=-0.656,p=0.011).3.Compared with before treatment,the functional connectivity of rTMS group was significantly enhanced after treatment(p<0.05,both FDR adjusted),including the network between SN and VSN,between VSN and SMN,between the central executive network(CEN)and VSN,between SMN and DMN,and the difference of FC between SMN and DMN was negatively correlated with the difference of Y-BOCS(r=-0.584,p=0.028).ConclusionsCompared with the healthy control group,OCD patients showed abnormalities of FC between or in brain networks,which may be the neuroimaging mechanism of OCD.After treatment with rTMS,the FC between brain networks of OCD patients changed and the clinical symptoms improved.Therefore,the improvement of clinical symptoms in OCD patients might be related to the FC between brain networks related to the selective regulation of rTMS.