Study On Functional Magnetic Resonance Imaging In Multiple System Atrophy-cerebellar

Part I Quantitative evalution of Multiple system atrophy-cerebellar by diffusion tensor imagingObjective:To determine whether diffusion tensor imaging (DTI) can demonstrate microstructural changes of pons-cerebellar system, the nigrostriatal projection system in MSA-cerebellar patients; Many studies have demonstrated the degeneration of pontine transverse and longitudinal tracts in multiple system atrophy (MSA). One purpose of this study was to assess whether diffusion tensor imaging (DTI) can show microstructural abnormalities in these tracts in patients with MSA cerebellar type (MSA-C). Another purpose was to determine the correlation between cross-sign progress and pontine fiber degeneration in these patients.Methods:Thirty patients with MSA-C and30healthy volunteers underwent conventional magnetic resonance imaging (MRI) and DTI. Regions of interest (ROIs)were placed in both head of caudate nucleus, putamen, globus pallidus, cerebellar peduncle, cerebral peduncles, white matter of cerebellar hemisphere, the posterior limbs of the internal capsule, and pons, and the pontine crossing tract of each subject. Quantitative indexes, such as fractional anisotropy (FA) and mean diffusivity (MD) were compared between groups by ANOVA. Cross sign was divided into three grades as follows:0, no cross sign;1, vertical line only;2, clear cross sign. Spearman rank correlation analysis was used between FA, MD, and the cross grade in patients with MSA-C.Results:The FA and MD values of symmetrical parts of the bilateral brain showed no statistically significant differences; The MSA-C group showed statistically significant changes compared to the normal group, in the following ROIs:increased value of MD and decreased value of FA was found in pons, cerebellar peduncle, and white matter of cerebellar hemisphere; increased value of both MD and FA was found in putamen; FA and MD in the MSA-C group, and each cross grade, showed statistically significant differences compared to control groups;There was a close correlation between all measures. FA decreased and MD increased, and cross grade formed gradually in the patients.Conclusion:DTI quantitative detection can reflect the situation of brain tissue damage in patients with MSA-C and showed the most serious damage regional of the olives-pons-cerebellum and the putamen; DTI can identify micro structural abnormalities in pontine transverse and longitudinal fibers even in patients without abnormalities on conventional MRI; Along with pontine transverse tract degeneration, the cross sign develops accompanied by the start of longitudinal tract degeneration, ultimately resulting in the complete formation of a cross sign. PartⅡ Evalution of Multiple system atrophy-cerebellar by1H-proton magnetic resonance spectroscopyObjective:One purpose was applying’H-proton magnetic resonance spectroscopy (’H-MRS) to investigate the metabolic characteristics of frontal lobe, striatal, cerebellum, and pontine in MSA-C patients. Another purpose was to determine the correlation between the metabolic indexes of pontine and cross-sign progress in these patients.Methods:Thirty patients with MSA-C and30healthy volunteers underwent1H-MRS. Regions of interest (ROIs) were placed in both frontal lobe, striatal, right cerebellum and pontine. Analysis indexes, such as N-acetylaspartate (NAA)/creatine (Cr), choline (Cho)/creatine (Cr), myoinositol (MI)/creatine (Cr) was used to compare between the whole MSA-C group and control groups. Cross sign was divided into three grades as follows:0, no cross sign;1, vertical line only;2, clear cross sign. An analysis of variance (ANOVA) was used to compare each cross grade and the control group in the pontine. Next, spearman’s correlation analysis was used to analyze the correlation between NAA/Cr, Cho/Cr, MI/Cr and each cross grade in the patients’pontine with MSA-C.Results:The NAA/Cr ratio of striatal, cerebellum, and pontine in MSA-C patients was significantly lower than that of normal control group(p<0.05); The MI/Cr ratio of striatal, cerebellum, and pontine in MSA-C patients was significantly higher than that of normal control group(p<0.05); The Cho/Cr ratio of pontine in MSA-C patients was significantly lower than that of normal control group(p<0.05); The Cho/Cr ratio of striatal and cerebellum in MSA-C patients was not statistically different than that of normal control group(p>0.05).However, the NAA/Cr, Cho/Cr, and MI/Cr ratio of frontal lobe in MSA-C patients was not statistically different than that of normal control group(p>0.05). In the analysis of the metabolite concentrations in the pontine, the mean NAA/Cr ratio in each cross grade was significantly lower than that of normal control group(p<0.05). Furthermore, the mean NAA/Cr ratio of the Cross2group was significantly lower than that of the Cross0group (p<0.05). This aside, the comparisons of the mean NAA/Cr ratio in each cross grade showed no significant difference (p>0.05). The mean Cho/Cr ratio in each cross grade was not statistically different than that of normal control group(p>0.05). Apart from this, the comparisons of the mean Cho/Cr ratio in each cross grade showed no significant difference (p>0.05). The mean MI/Cr ratio of the Cross2group was significantly higher than that of normal control group (p<0.05). This aside, the comparisons of the mean MI/Cr ratio in each cross grade showed no significant difference (p>0.05). There was a close correlation between all measures especially the mean NAA/Cr ratio (p<0.05). There was a general trend for NAA/Cr ratio, Cho/Cr ratio reduction and MI/Cr ratio elevation in the pontine as the cross grade gradually formed in patients with MSA-C.Conclusion:’H-MRS detection can detect part of pathological changes in brains of MSA-C patients, such as gliosis and neuronal cell loss, and showed the most serious damage regional of the striatal, cerebellum, and pontine.’H-MRS can demonstrate part of pathological changes in pons in MSA-C patients without abnormalities on conventional MRI. With the abnormal metabolism acceleration of NAA, Cho and MI, cross grade formed gradually in the MSA-C patients. PartⅢ The quantitative study of iron stores in the brain of patients with MSA-C using SWI sequence MRIObjective:To explore whether the phase images of ESWAN has potential for quantifying normal brain iron and quantitative study on the charaeter of iron store in brain with MSA-C patients.Methods:Thirty patients with MSA-C and30healthy volunteers underwent conventional MRI and ESWAN. The correct phase shift value (CP) of substantia nigra(SN), red nucleus(RN), globus pallidus(GP), putamen(PU), caudate nucleus (CA), and thalamus(TH) were measured on the corrected phase images. First, regional CP values were compared with published brain iron concentration by linear correlation analysis. Next, using an independent-sample t-test, regional CP values were compared in corresponding positions of the brain between the MSA-C group and control groups.Results:The SN, RN and GP showed symmetrically homogeneous low intensity both in the CP images and minIP reconstruction images. And their mean CP value were (-0.162,-0.156,-0.125,-0.098, -0.110,-0.033).There was negative linear correlation between CP value and brain iron store(r=-0.86,p=0.029<0.05), Linear regression equation is y=-0.006x-0.0024. The CP values at bilateral putamen of MSA-C group were significantly lower than control group(p<0.05). No significant difference was demonstrated at CP value of caudate, thalamus, substantia nigra, red nucleus, and globus pallidus (p>0.05).Conclusions:The phase images could be used to detect minor iron concentration differences in the brain. There was negative linear correlation between CP value and brain iron store in3.0T MR. The phase images may be useful for estimating the amount of normal brain iron in vivo.The site of pathologic iron store in MSA-C group is putamen excluding caudate, thalamus, substantia nigra, red nueleu and globus pallidus.