A Preliminary Study On The Application Value Of Diffusion Kurtosis Imaging In Assessing Olfactory Brain Regions In Patients With Parkinson’s Disease

Objective:In this study,DKI(Diffusion Kurtosis Imaging)sequence was used to scan,measure and analyze the olfactory related brain regions of patients with PD(Parkinson’s Disease)and HC(Healthy control)to explore the microstructural changes of the corresponding brain regions in patients with PD complicated with olfactory disorders.The diagnostic value of DKI in PD olfactory disorder was also sought.Methods:A total of 28 PD patients diagnosed in the Department of Neurology of the Affiliated Hospital of Guizhou Medical University from July 2020 to February 2021 were tested and collected by using the "Soul show" olsmell test developed by the Institute of Psychology,Chinese Academy of Sciences.Meanwhile,20 healthy middle-aged and elderly people with matched age and gender were collected.In PD group,there were 13 females and 15 males,aged 44-76 years old,with an average age of 64.36±9.07 years old.The HC group consisted of 10 females and 10 males,aged51-69 years,with an average age of 61.50±5.19 years.All subjects underwent MMSE(Mini-Mental State Examination)and MOCA(Montreal Cognitive Assessment Scale)tests to exclude the influence of Cognitive impairment on the olfactory test results3D-T1 WI and DKI scans were performed on all the subjects’ heads using the3.0T MR imaging system,and the original DKI image data was transferred to GE AW4.6 image post-processing workstation,and the Functool 9.4.05 software was applied for post-processing of the images.Mk,FA,MD,Da and Dr Values of olfactory related brain regions(bilateral caudate head,putamen,globus pallidus,amygdala,hippocampus,substantia nigra,red nucleus)in PD group and HC group were measured.Independent sample t test was used to compare the differences in DKI parameters between PD group and HC group and above,and Pearson test of bivariate analysis was used to compare the relationship between the length of disease and olfaction score and the statistically significant DKI change parameters between PD group and HC group.In addition,Pearson test of bivariate analysis was used to compare the correlation of H&Y stage,disease duration and age with olfactory threshold score,olfactory discrimination score and olfactory recognition score,respectively.(All the above statistical methods take α=0.05 as the standard,that is,when P < 0.05,the difference is considered to be statistically significant)Results:The olfactory test threshold,discrimination and recognition scores in PD group were all lower than those in HC group,and the differences were statistically significant.After correlation analysis,it was found that there was no significant correlation between olfactory test scores and H&Y stage,i.e.,length of disease course.Only the negative correlation between age and olfactory threshold was statistically significant.Compared with HC group,the MK(t=5.248,P < 0.001)and MD(t=2.530,P=0.013)values of the nigra in PD group were increased,the FA(t=-2.771,P= 0.007)values were decreased,and the DA(t=3.228,P= 0.002)values of the red nucleus were increased.The MK(t=2.642,P =0.010),MD(t=2.384,P =0.019)and DA(t=3.094,P=0.003)values of the caudate head were increased,and the MK(t=3.241,P =0.002),MD(t=4.018,P < 0.001)and DA(t=4.306,P < 0.001)were increased,and FA(t=-2.122,P =0.036)and amygdala(t=-2.185,P =0.031)were decreased.Correlation analysis showed that the length of disease in PD patients was positively correlate with the increase of the MK value in the substantia nigra(t=0.488,P =0.008),and the threshold score in PD patients was positively correlated with the FA value in the amygdala(t=0.413,P =0.029).Conclusions:The changes of DKI parameters can be used to evaluate the microstructural changes of olfactory brain regions in patients with PD complicated with osmia.The MK value of the nigra can be used to evaluate the course of the disease,and the FA value of the amygdala can be used to evaluate the course of the olfactory dysfunction in PD.The changes of MD,DA and DR values indicate the pathological changes of neuronal axons in the corresponding brain regions in PD patients.The change of the MK value in the substantia nigra has high sensitivity and specificity in the diagnosis of PD patients with olfactory disorder.