Changes Of Brain Function In Resting-state In Diabetic Retinopathy Assessed By ReHo,fALFF And FC

Purpose:Diabetic retinopathy（DR）is one of the most common microvascular complications of type 2 diabetes.Previous studies have found structural and functional abnormalities in the brains of DR patients,however functional connectivity changes between the higher visual cortex and the whole brain in DR patients are unknown.The aim of this study was to investigate resting-state brain function changes in DR patients by a variety of resting-state functional magnetic resonance imaging（rs-f MRI）techniques,including region homogeneity（Re Ho）,fractional amplitude of low-frequency fluctuation（f ALFF）and seed-based functional connectivity,were used to investigate resting-state brain function changes in DR patients.Materials and methods:18 cases of DR patients treated the Hospital of Guangzhou Medical University from January 2022 to January 2023 were gathered,and moreover,20 diabetic patients treated the hospital at the same time were collected as the DM group.Meanwhile 18 healthy volunteers were recruited as the HC group.The three groups of subjects were matched for age,sex and education.All subjects were preformed rs-f MRI scanning.DPABI software was applied to preprocess the three groups of data calculated for DR,DM and HC.（1）Re Ho and f ALFF values were calculated for the whole brain,and sz Re Ho and szf ALFF values were extracted for brain regions with differences between groups.（2）ROIs closely related to visual pathways（primary visual cortex,higher visual cortex and superior parietal lobule）were selected to calculate FC values between the whole brain and ROIs,and z FC values of brain regions with differences between groups were extracted.（3）To analyze the correlation between Re Ho,f ALFF and FC brain regions and clinical data and neuropsychological scales between groups.Results:（1）Results of Re Ho comparison among the three groups of DR,DM and HC:Compared with the DM group,DR group showed increased Re Ho values in the left inferior temporal gyrus,left fusiform gyrus,left lingual gyrus,left hippocampus,left cerebellum and right cerebellum;while compared with the HC group,DR group showed decreased Re Ho values in the left middle temporal gyrus,left inferior temporal gyrus,left fusiform gyrus and left parahippocampal gyrus;the Re Ho values in the above different brain regions were negatively correlated with MMSE and Mo CA scores.In addition,DM group compared with the HC group showed decreased Re Ho values in the left middle temporal gyrus,left inferior temporal gyrus,left lingual gyrus,left fusiform gyrus and left middle occipital gyrus.（2）Results of f ALFF comparison among the three groups of DR,DM and HC:Compared with the HC group,DR group showed increased f ALFF values in the left middle occipital gyrus;while DM group showed decreased f ALFF values in the left middle temporal gyrus,the left inferior temporal gyrus,the left lingual gyrus,the left fusiform gyrus and the left cerebellum;and the brain regions with no statistically significant differences were shown in the DR group compared with the DM group.The f ALFF values of the left middle occipital gyrus were negatively correlated with MMSE and Mo CA scores.（3）ROI-based FC comparison results among the three groups:（1）Compared to the HC group,DR group had obviously reduced FC between the ROI₄ and the left precuneus/left postcentral gyrus/left superior parietal lobule/right precuneus;while DM group showed decreased FC values between the ROI₄ and the left precentral gyrus/right postcentral gyrus.No remarkable correlation was observed between the FC results of the above-mentioned intergroup differential brain areas and the MMSE and Mo CA scores of the DR group.The outcome of the comparison between the DR and DM groups revealed no brain regions that were subject to statistical differences.（2）Compared to the DM group,DR group had distinctly augmented FC between the ROI₅ and the left precentral gyrus/left middle frontal gyrus;while compared with the HC group,DM group decreased FC values between the ROI₅ and the right postcentral gyrus/right precentral gyrus.In addition,the brain regions with no statistically significant differences between the DR and HC groups.No significant correlation was found between FC and MMSE and Mo CA scores in DR group.⑸Correlation analysis between brain regions with clinical data of Re Ho,f ALFF and FC value differences between groups:the mean Re Ho value of the left inferior temporal gyrus/left fusiform gyrus/left lingual gyrus/left cerebellum/right cerebellum was positively correlated with age（r=0.577,P=0.015）;the mean Re Ho value of the left middle temporal gyrus/left inferior temporal gyrus/left fusiform gyrus was positively correlated with age（r=0.584,P=0.014）.The mean f ALFF value of the left middle occipital gyrus was positively correlated with age（r=0.603,P=0.01）.The mean FC values between the left precuneus/left postcentral gyrus/left superior parietal lobule/right precuneus and ROI₄were positively correlated with Hb A1c（r=0.879,P<0.001）and FBG（r=0.612,P=0.009）;the mean FC values between the left precuneus/left middle frontal gyrus and ROI₅ were positively correlated with Hb A1c（r=0.951,P<0.001）and FBG（r=0.595,P=0.012）.No significant correlation was found between blood pressure and LDL-L and brain regions between groups（all P>0.05）.Conclusion:The changes of brain function in DR patients mainly focus on default mode network（DMN）,sensorimotor network（SMN）and visual network（VN）,and the results can provide imaging support for the neuropathological mechanisms of cognitive dysfunction,visual impairment,abnormal emotional regulation and sensorimotor dysfunction in DR patients.In further discussion and analysis,it was found that there was a significant correlation between the brain regions with brain function changes and neuropsychological scale scores and clinical characteristics in DR patients,which provided a reference for taking effective clinical preventive measures to delay or reduce the progression of DM to DR.