SWI And DKIStudy Of Brain Iron Deposition And Microstructure Change In Gray Matter Nucleus In Parkinson’ S Disease

Objective: To initially exploit the clinical application value of susceptibility weighted imaging(SWI) and diffusion kurtosis imaging(DKI) on brain microstrusture damage in Parkinson’s disease(PD) by measuring the diffusion kurtosis data and the phase value of six gray matter nucleus.Materials and Methods: This prospective study was approved by the hospital ethics committee.The subjects were divided into two groups, PD group and healthy control(HC) group. Thirty-five cases of clinically confirmed PD patients were participated into this study, including 18 males and 17 females(mean age 67.00±8.76years). Twenty-three healthy volunteers whose age and gender matched with PD group were as control group(12 males, 11 females, mean age 66.48 ± 5.2 years).The clinical data of all the subjects were collected,and the mental status was also evaluated for every case through MMSE table by one neurologist.All patients performed conventional MRI scan, DKI and SWI sequence. Bilateral MK value, Ka value, Kr value, MD value, Da value, Dr value, FA value and Phase value of the head of caudate nuclei, putamen, globus pallidus, thalamus, red nucleus,substantia nigrawere measured. Two independent samples t-test was used to compare the mean values of parameters in all brain regions between the PD and HC groups.Receiver operating characteristic(ROC) test was used to assess the ability of each DKI or SWI parameterin every regionin distinguishing thetwo groups. The correlations of between DKI 、 SWI parameters and MMSE score,the SWI parameters between each different two nucleus, and the DKI and SWI parameter of each nuclei of PD group wereall tested using Spearmans correlation. All measurement dataswereshown as mean value and standard deviation.All statistical results were P≤0.05 as statistically significant.Results:1.Compared to the HC group, the mean value of MK in PD group significantly decreased in substantia nigra, while markedly increased in globus pallidus; Ka value decreased in thalamus, red nucleus, substantia nigra;Krvalue decreased in putamen, red nucleus whileincreased inglobus pallidus and substantia nigra(all P<0.05).2.Compared to the HC group, MDvalue in PD group significantly increased in putamen, globus pallidus, thalamus, red nucleus and substantia nigra;Da value increased inglobus pallidus, thalamus, red nucleus and substantia nigra;Dr value increased inglobus pallidus and substantia nigra(all P<0.05).3. Compared to the HC group, FA value in PD group significantly decreased in putamen while increased in globus pallidus and red nucleus(all P<0.05).4. The biggest area under ROC curve(AUC) value of 0.830 belongs to Dr value in the globus pallidus. In turn, the AUC of 0.811, 0.796, 0.775, 0.763, 0.742, 0.724, 0.716 and 0.701 was attributed to the MD value in globus pallidus, the Da value in red nucleus,the MD value in substantia nigra, the Da value in globus pallidus, the Da and Dr value in substantia nigra, the Kr value in globus pallidus, and the MD value in putamen.5.In all regions, most of the diffusion kurtosis parameters(MK, Ka and Kr values)showed positive correlation with MMSE score, among which, the Ka value in globus pallidus has the best correlation with MMSE score(r=0.458, P=0.006). Simultaneously,the diffusivity parameters exhibited the several negative correlations with MMSE score,among which, the MD value in thalamus showed the best correlation with the MMSE score(r=-0.408, P=0.019).6. Compared to the HC group, the Phase value decreased in substantia nigra, red nucleus, globus pallidus and the head of caudate nuclei while increased in putamen(all P<0.05).7. The biggest area under ROC curve(AUC) value of 0.887 belongs to Phase value in substantia nigra. In turn, the AUC of0.702, 0.698 and 0.664 was attributed to thePhase value in the head of caudate nuclei, globus pallidus and red nucleus.8. The Phase value in substantia nigra showed significant positive correlation with it of red nucleus, globus pallidus, the head of caudate nuclei and thalamus, among which, the phase value between substantia nigra and red nucleus has the best correlation(r=0.451, P=0.000).9. It showed positive correlation between the Phase value and Kr value in substantia nigra(r=0.349, P=0.030) and the Phase value and Da value in red nucleus(r=0.414, P=0.009); meanwhile, negative correlation between the Phase value and FA value in left putamen.10. Correlation analysis founded that the Phase value in substantia nigra and globus pallidus has kind of positive correlation with MMSE score, in which the substantia nigra has the better correlation(r=0.349, P=0.030).Conclusion:1. As a new MRI technique, DKIcanqualitatively diagnose Parkinson Disease; the DKI parameters also can quantitatively evaluate the change of microstructure in extrapyramidal system gray matter nucleus of PD patients.2. The iron overload exists in every gray matter nucleus of the extrapyramidal system in PD patients, and there are some effects among them.3. The ROC analysis found that the Phase value in substantia nigra and Dr value inglobus pallidus could be asthebestindividual biomarkers of differentiation PDpatient to control.4. There are some relation between the iron overload and the change of microstructure in substantia nigra, red nucleus and putamen of PD patients.