Structural And Functional Abnormalities In Patients With Rheumatoid Arthritis Using MRI

Background and purposeRheumatoid arthritis(RA) is a common clinical chronic rheumatic diseases.It may cause several system damage, such as.the respiratory system, digestive system, urinary system, and whether rheumatoid arthritis could cause central nervous system or not, there always has been controversy. Study found that the central nervous system mechanisms such as central sensitization is underlying the rheumatic diseases such as fibromyalgia, and achieved more and more consensus, but whether the central nervous system(CNS) in RA has a similar effect is still not clear, only little research about it. Therefore, this study aims to investigate comparatively the differences between RA patients and normal people in brain function and structure by resting state fMRI(rs-fMRI)and voxel-based morphometry(VBM),in order to find the possible central composition in RA patients in RA patients and discuss the possible mechanism.Materials and methodsThe two matching groups participate in this study and were collected relevant clinical Information: numerical rating scale(NRS),Disease Activity Score in 28 joints using the erythrocyte sedimentation rate(DAS28), disease duration, ets.and all data were acquired by 3T MRI from 35 RA patients and 35 controls. The fMRI data basing on MATLAB platform is pretreated by using SPM8 and DPARSF software and present the results by the REST software.Analysis of two-sample t test was performed to explore the differences of spontaneous brain activities among the two groups, The ALFF results were displayed using REST soft with a threshold of P<0.05 corrected by AlphaSim(a minimum cluster size of 74 voxels), The VBM results were displayed using REST soft with a threshold of P<0.05 corrected by false discovery rate( FDR). Subsequently, the correlation between ALFF values or grey matter volume(GMV) of abnormal regions found in RA group and NRS/DAS28/duration were analyzed.Results1. No significant differences were found between RA group and the control in age,gender and education level(P>0.05).2. compared to controls,ALFF increased in subgenual cingulate(sgACC), medial orbitofrontal cortex(mOFC)and bilateral insula, while ALFF decreased in calcarine, right lingual gyrus, cuneus and left middle occipital gyrus, there has no significant correlation between ALFF values of abnormal regions and NRS/DAS28/duration(P>0.05).3. compared to controls, grey matter volume in the bilateral lenticular nucleus and hypothalamus were higher in RA patients. DAS28 was positively correlated with the GMV of bilateral lenticular nucleus, NRS sores was positively correlated with the GMV of left lenticular nucleusand duration negatively correlated with bilateral lenticular nucleus, there has no significant correlation between hypothalamus and NRS/DAS28/duration(P>0.05).ConclusionSince these observed increased activities and gray matter volume in our present study play an important role in pain processing and in motor decision/control or in modulatin behavior in response to noxious stimuli, we suggest that the changes of these changes may result from central pain modulation or motor control. These decreased ALFF were located at the classical visual processing center, we suggest these changes may represent potential altered visual function. The pattern of gray matter abnormality found in RA may addionally suggests potential somatotopic reorganization in lenticular nucleus and hypothalamus. These changes suggest that the chronic pain states in RA may have its functional and structural foundation.