The Study Of Grey And White Matter Microstructure In Ventral And Dorsal Circuit Of Obsessive-complusive Disorder

Objective: Obsessive-compulsive disorder(OCD)is a mental disorder with repeatedly,and interference thoughts,ideas or imagination(obsession)and repeated behaviors(compulsive behavior),which has characteristics of chronic and low remission rates.OCD often makes patients learn,work and communicate difficultly so that it causes great damage to the OCD's social function.Recent year,many neuroimaging studies had shown that OCD displayed structure and functional abnormalities in the classic CSTC(cortico-striato-thalamo-cortical)circuit and further explored the abnormally of ventral circuit in CSTC circuit.But there is few research to explore white and grey matter microstructure abnormalities in dorsal circuit of classic CSTC circuit.So our study combine diffusional Kurtosis Imaging(DKI)and diffusion tensor imaging(DTI)to explore white and grey matter microstructure abnormalities in dorsal circuit of classic CSTC circuit in unmedicated patients of OCD.Methods: 100 drug-na?ve or drug-free(eight weeks or more)patients with OCD and 90 well-matched(gender,age,and education)healthy controls were recruited in our study.We combine DKI and DTI technology to explore white and grey matter microstructure abnormalities in dorsal circuit of classic CSTC circuit in unmedicated patients of OCD.3.0 T Siemens MRI scanner is applied to collect images.By using FSL and DKE software,we get fractional anisotropy(FA),mean kurtosis(MK)and so on parameters that show white and grey matter microstructure.And then we use SPM8 and REST2.0 to conduct twosample t test to explore white and grey matter microstructure abnormalities in dorsal circuit of classic CSTC circuit between OCD patients and healthy controls.At last Pearson correlation is conducted to detect correlation between white and grey matter microstructure in OCD patients and the clinical scores of Yale-Brown Obsessive-Compulsive Scale(Y-BOCS),Hamilton Depression Scale(HAMD24)Hamilton Anxiety Scale(HAMA),and duration of illness.Results: In terms of diffusion tensor,we discover OCD patients have significant decrease FA value in Right Middle Occipital Gyrus,Right Anterior Cingulate and Left Cerebellum Posterior Lobe;significant decrease mean diffusivity(MD)and axial diffusion(AD)values in Right Cerebellum Posterior Lobe and Frotal_Mid_Orb_L and significant decrease radial diffusion(RD)value in Frotal_Mid_Orb_L compared with healthy controls.All above significant results are set P<0.05 with Alphasim correction.In terms of Kurtosis value,we discover OCD patients have significant decrease MK value in Right Anterior Cingulate and Right Sub-lobar,significant increase MK value in Left Middle Temporal Gyru;significant decrease axial kurtosis(AK)value in Right Sub-lobar and significant increase AK value in Left Middle Temporal Gyru;significant decrease radial kurtosis(RK)value in Right Occipital Lobe,Right Sub-lobar and Right Anterior Cingulate;significant increase Kurtosis fractional anisotropy(FAK)value in Posterior Cingulate compared with healthy controls.All above significant results are set P<0.01 with Alphasim correction.At last,we find MK(r=-0.35,P=0.004)and RK(r=-0.26,P=0.013)values in Right Sub-lobar significantly correlate with duration of illness in OCD patients.Conclusions: 1.In general,OCD patients have structural abnormalities displaying decrease complexity of gray matter and white matter fiber structure in dorsal circuit.2.We also find decrease complexity of gray matter and white matter fiber structure in ventral circuit.Besides dorsal and ventral circuit,we also find structural abnormalities in Middle Occipital Lobe and Sub-lobar in OCD patients which support posterior of brain may be also connected with pathological mechanism of OCD patients.