Magnetic Resonance Spectroscopy And Diffusion Tensor Imaging In The Assessment Of Motor Subtypes In Parkinson’s Disease

Background and PurposeParkinson’s Disease(PD)can be divided into different motor subtypes according to different clinical manifestations.Accurate identification of subtypes is of great significance for clinical decision,but the understanding of the pathophysiological mechanisms of the different subtypes is still insufficient.Diffusion tensor imaging(DTI)and magnetic resonance spectroscopy(MRS)were used to analyze microstructure alterations of brain nucleus between two subtypes of Parkinson’s Disease(PD).It is expected to find a imaging biomaker to distinguish them,then assist the early identification of individuals in clinical practice and formulate intervention measures.Materials and MethodsPD patients were recruited from the society.After evaluation by neurologists,37 patients with TD type and 41 patients with PIGD type were finally diagnosed and included,and 47 volunteers at same stage were included in the control group.The H-Y grading scale for PD patients was used to evaluate the severity of the disease,and evaluate the patient’s non-motor symptoms by RBDQ-HK,AHRS and PDQ-39.The MRS and DTI images of all enrolled subjects were acquired by Siemens Magnetom Prisma 3.0T magnetic resonance scanner.The frequency,phase and baseline of the MRS data were corrected by the post-processing analysis platform of Syngo.via Frontier to obtain the MRS spectrum and concentration of the bilateral putamen and substantia nigra of the three groups of subjects.Convert DTI data,then the head movement,eddy current and gradient direction were corrected by the post-processing platform of FSL.The region of interest(ROI)was drawn on the B0image: putamen,substantia nigra and dentate nucleus.Then the ROI was matched to FA,MD,AD and RD images to automatically analyze and calculate their DTI parameter values.At the level of p<0.05,SPSS 22.0 was used to statistically analyze the values of MRS and DTI parameters and clinical scale scores of all subjects in the three groups.Results1.Compared with the HC group,the TD group and the PIGD group had significantlylower Cr levels in the putamen(p<0.001),and obviously lower NAA and m Ins levels.The TD group had a mainly decrease in m Ins(p=0.020),but in PIGD group,NAA reduced more clearly(p=0.010).The ratio of NAA/Cho in the substantia nigra in the TD and PIGD groups was significantly lower than that in the HC group(p<0.01),and the values of NAA/Cr and m Ins/Cr in the PIGD group had dropped off compared with the HC group(p<0.05),while there was no statistically significant difference in the TD group.2.The results of DTI parameter analysis in the substantia nigra region showed that the FA values of PD groups were decreased visibly,while the MD,AD and RD values all increased.At the same time,Intra-group analysis showed that AD value in PIGD group was clearly higher than that in TD group(p=0.036).In addition,FA value in dentate nucleus of TD group was reduced compared to HC group,but no such difference was observed between the other two groups.There were no statistical distinctions of DTI values in putamen among the three groups(p>0.05).3.The average score of RBDQ-HK scale in the TD group was 24.52±10.05,and that in the PIGD group was 31.74±15.31.The RBD in the PIGD group was higher than that in the TD patients(p=0.040).There were no findings in AHRS and PDQ-39 scores between the two groups(p=0.162,p=0.343).4.The ratio of NAA/ Cho in the substantia nigra was negatively correlated with the motor function(Ⅲ)score of MDS-UPDRS in the TD group and strongly correlated with the PIGD group.There was a negative correlation between the FA value of the substantia nigra and the tremor score of the MDS-UPDRS in the TD group(r=-0.645,p=0.001),but no significant correlation was found in the PIGD group.In addition,the ratio of NAA/Cr in the substantia nigra of PIGD group was correlated with the score of RBDQ-HK(r=-0.540,p=0.003).The more severe the reduction of NAA/Cr ratio was,the higher the RBDQ-HK score was.5.Cr in putamen and NAA/Cho in substantia nigra have good diagnostic performance in the differentiation of PD from normal groups,with AUC of 0.812 and0.805 respectively.Among them,NAA/Cho of substantia nigra has a higher sensitivity(79.7%),and Cr of putamen has a higher specificity(84.8%).AD value of the substantia nigra played a good diagnostic efficiency in the identification of TD and PIGD subtypes,with an AUC of 0.809 and a sensitivity of 92.7%.Conclusion1.NAA,Cr and mIns in Putamen,NAA/Cho ratio and FA value in substantia nigra all can be used as non-invasive biomarkers of PD to assist clinical diagnosis;2.AD value has the potential to distinguish TD and PIGD subtypes,and can be used as an imaging index for clinical evaluation of TD and PIGD subtypes;3.TD and PIGD subtypes have heterogeneity in the pathologic development process and disease progression pattern.Meanwhile,indicators of medical imaging play an important role in revealing the pathogenesis of clinical symptoms in PD patients.