Diffusion Kurtosis Imaging Study Of Brain Microstructure Change In Gray Matter Nucleus Parkinson’s Disease With Depression

Objective: To explore the value of diffusion kurtosis imaging（DKI）for diagnosing the microstructure changes of deep brain nuclei in patients with Parkinson’s disease with depression（DPD）.Methods: Routine MRI sequence and DKI were performed in 30 patients with DPD,30 patients with non Parkinson’s disease（NDPD）and 30 healthy controls（HC）.Clinical data was collected and motor and cognitive symptoms were assessed.After post-processing,the original MRI scanning data were processed to obtain the quantitative parameter values of DKI,including fractional anisotropy（FA）,mean diffusivity（MD）,axial diffusivity（DA）,radial diffusivity（DR）,mean kurtosis（MK）,axial kurtosis（KA）and radial kurtosis（KR）.The above parameters were measured in bilateral red nucleus,substantia nigra pars reticula,substantia nigra pars compacta,putamen,globus pallidus,thalamus and caudate nucleus.The parameters and clinical data were statistically analyzed among the three groups to evaluate the microstructure changes of deep gray matter nuclei in patients with DPD and NDPD.Results:1.There was no significant difference in age,gender,years of education and mini mental state examination（MMSE）scores among the three groups（DPD,NDPD and HC）（P>0.05）.There was no significant difference between DPD group and NDPD group in MMSE score,course of disease,onset side and Hoehn Yahr stage（H ＆Y stage）（P>0.05）,and there was significant difference in Hamilton Depression Scale（HAMD）（P<0.05）.The HAMD score of DPD patients was significantly higher than that of NDPD patients.2.Comparison between NDPD group and HC group: the FA value of globus pallidus in NDPD patients decreased（P<0.05）;The MD values of substantia nigra pars reticula,substantia nigra pars compacta,globus pallidus and head of caudate nucleus decreased（P<0.05）;The DA values of putamen,globus pallidus and head of caudate nucleus decreased（P<0.05）;The MK value in the substantia nigra pars reticula increased（P<0.05）;The Ka values of substantia nigra pars reticula,substantia nigra pars compacta,putamen,globus pallidus and head of caudate nucleus increased（P<0.05）;There was no significant difference in Dr and Kr between the two groups.3.Comparison between DPD group and HC group: the MD values of DPD patients in red nucleus,substantia nigra pars reticula,substantia nigra pars compacta,putamen,globus pallidus,thalamus and head of caudate nucleus decreased（P<0.05）;In the substantia nigra pars reticula,substantia nigra pars compacta,putamen,globus pallidus,thalamus and head of caudate nucleus,the values of Da and Dr decreased（P<0.05）,and the values of DR in red nucleus decreased（P<0.05）;The Ka values of red nucleus,substantia nigra pars reticula,substantia nigra pars compacta,putamen,globus pallidus,thalamus and head of caudate nucleus increased（P<0.05）;KR values of putamen and globus pallidus decreased（P<0.05）.4.Comparison between DPD group and NDPD group: the FA value in putamen and globus pallidus in DPD patients increased（P<0.05）,and the Kr value in globus pallidus decreased（P<0.05）;There was no significant difference in MD,Da,Dr,MK and Ka values.5.Correlation analysis showed that in DPD group,only the Ka value of substantia nigra pars reticula（r= 0.417,P= 0.022）was positively correlated with HAMD score,and there was no correlation between the remaining FA,MD,Da,Dr,MK and Kr values and HAMD score.Conclusion:1.The gray matter nuclei of both PD patients with depression group and patients non-depression group had changes of microstructure.2.DPD patients had more pronounced diffusion heterogeneity in the putamen and globus pallidus,and the integrity of Globus Pallidus Myelin was reduced.3.The severity of depression in patients with Parkinson’s disease with depression was correlated with axonal injury in the substantia nigra pars reticula,but not with the rest of the grey matter nuclei.