Effect Of Memory Changes After Gastroscopy Under General Anesthesia Based On Multimodal MRI Techniques

Objective:To analyze the spontaneous brain functional activity,brain microstructure and brain volume changes after gastroscopy under general anesthesia,and to analyze the correlation with neuropsychological scale related to memory,so as to provide imaging basis for memory changes after general anesthesia.This study is divided into three parts:Part one:Re Ho and ALFF of rs-f MRI were used to analyze the changes of brain functional activities after gastroscopy under general anesthesia,explore the influence of anesthesia on brain functional activities,and combine neuropsychological scale with in-depth explanation of mechanism of changes in memory after general anesthesia,so as to enrich the research on memory in the field of rs-f MRI.Part two:Based on DKI,differences of brain microstate after general anesthesia was analyzed,and correlation analysis was made between neuroimaging data and neuropsychological scale,so as to provide neuroimaging information for the memory changes after general anesthesia.Part three:Based on u AI-MR brain structure intelligent analysis system,3D-T₁WI data were collected and analyzed before and after gastroscopy under general anesthesia,in order to find the characteristic imaging markers of memory changes after general anesthesia.Part one1.Materials and methodsFrom July 2021 to February 2023,33 cases of rs-f MRI data were prospectively collected before and after gastroscopy under general anesthesia in the Department of Neurology,Cardiovascular Branch of Yan’an University Affiliated Hospital,and 30 cases were eventually included except for 2 patients who could not be processed due to poor image quality and 1 patient who was lost to follow-up.EPI sequences were used to perform rs-f MRI scanning before and after gastroscopy under general anesthesia,and restplus1.2 and SPM8 kits based on Matlab2013b platform were used to calculate and analyze the Re Ho and ALFF before and after general anesthesia.Pearson correlation analysis was performed between Re Ho and ALFF of significantly different brain areas,MMSE score and Wechsler memory scale after general anesthesia.2.ResultsThe region with increased ALFF compared with pre-anesthesia was the right orbitofrontal gyrus（P<0.001,Alphasim correction,cluster size≥1509voxels）.The regions with increased f ALFF compared with pre-anesthesia were the right suproccipital gyrus and right medial superior frontal gyrus（P<0.001,Alphasim correction,cluster size≥134voxels）.There were no areas where ALFF and f ALFF decreased compared with those before anesthesia.The region with increased Re Ho compared with pre-anesthesia was bilateral medial frontal gyrus（P<0.001,Alphasim correction,cluster size≥462voxels）.No areas of decreased Re Ho were found compared to before anesthesia.There was no significant correlation between MMSE and Wechsler memory scale scores and Re Ho and ALFF of different brain regions.3.Brief summary（1）Combined application of Re Ho and ALFF methods showed that spontaneous neuronal activity was abnormal in specific brain regions,and Re Ho increased in bilateral middle frontal gyrus after general anesthesia.ALFF of right orbital superior frontal gyrus increased;f ALFF increased in right medial superior frontalis gyrus and right suproccipital gyrus.（2）The compensatory mechanism represented by increased Re Ho and ALFF may be an important marker of memory changes after general anesthesia,which still needs to be further verified in subsequent studies.Part two1.Materials and methodsThe included object is the same as the first part.DKI images before and after gastroscopy under general anesthesia were collected by Siemens3.0TMR scanner.After pretreatment with DKE software,a circular ROI with an area of no less than 25mm²was described in bilateral hippocampus,bilateral amygdala,bilateral fusiform gyrus,bilateral precuneus,bilateral frontal pole and bilateral thalamus.Mean kurtosis（MK）,mean diffusion（MD）and anisotropy fraction（FA）were measured at the same location at three successive layers.SPSS20.0 statistical analysis software was used to conduct paired T-test for DKI parameters before and after general anesthesia,and Person correlation analysis was conducted between parameter values of different brain regions and MMSE and Wechsler memory scale scores.P<0.05 was considered statistically significant.2.ResultsCompared with before anesthesia,MK in the left amygdala,left frontal pole and bilateral thalamus increased（t=-3.57,-2.594,-2.831,-2.522）,while MK in the left hippocampus decreased（t=2.836）,and MK in the left thalamus were negatively correlated with IMI（r=-0.37,P<0.05）.Compared with before anesthesia,FA in the left amygdala,left fusiform gyrus and left thalamus increased（t=-2.197,-2.575,-3.803）,while FA in the left hippocampus decreased（t=3.581）,and FA in the left hippocampus were negatively correlated with DMI（r=-0.507,P<0.05）.Compared with pre-anesthesia,MD in bilateral hippocampus,left amygdala and left frontal pole increased（t=-3.689,-3.091,-2.303,-3.992）,MD in left hippocampus were negatively correlated with VMI（r=-0.502,P<0.05）,and MD in right hippocampus were negatively correlated with MMSE（r=-0.444,P<0.05）.3.Brief summary（1）DKI was used to observe the changes of brain microstate after general anesthesia.MK in the left amygdala,left frontal pole and bilateral thalamus increased,while MK in the left hippocampus decreased.MK in the left thalamus were negatively correlated with IMI.The FA of left amygdala,left fusiform gyrus and left thalamus increased,and the FA of left hippocampus was negatively correlated with DMI.The MD of bilateral hippocampus,left amygdala and left frontal pole increased,the MD of left hippocampus was negatively correlated with VMI,and the MD of right hippocampus was negatively correlated with MMSE.（2）The changes of kurtosis parameters and diffusion parameters were correlated with memory of different dimensions.MK of the left thalamus,FA and MD of the left hippocampus,and MD of the right hippocampus could provide objective imaging evidence for the changes of memory function after general anesthesia.Part three1.Materials and methodsThe included object is the same as the second part.Siemens Magnetom Verio3.0T MR scanner acquisition 3D-T₁WI sequences,the u AI-MR brain structure intelligent analysis system for measuring the whole brain volume of various brain regions.SPSS20.0 was used to compare the differences in the volume of each brain region before and after gastroscopy under general anesthesia with the paired T-test,and the volume of each brain region was correlated with MMSE and Wechsler memory scale for Person analysis.P<0.05 was considered to be statistically significant.2.ResultsNo brain regions showed significant differences compared with those before anesthesia.3.Brief summaryThe u AI-MR brain structure intelligent analysis system was used to analyze the brain area volume before and after the gastroscopy under general anesthesia,and no obvious abnormal brain area was found.We believe that the clinical control of general anesthesia is accurate and scientific,and will not affect the macro structure of the brain,and speculate that it may be related to the reversible development of brain volume.Conclusions（1）The rs-f MRI was used to study the spontaneous neuronal activity intensity and cooperative changes in patients after general anesthesia,and the combined application of Re Ho and ALFF showed that the spontaneous neuronal activity in the brain of patients after general anesthesia was abnormal,that is,the Re Ho of bilateral middle frontal gyrus was increased.ALFF of right orbital superior frontal gyrus increased,f ALFF of right medial superior frontal gyrus and right supraoccipital gyrus increased.The compensatory mechanism represented by increased Re Ho and ALFF values may be an important marker of memory changes after general anesthesia.（2）DKI was used to observe the changes in brain microstate after general anesthesia,that is,the MK of the left amygdala,the left frontal pole and the bilateral thalamus increased,and the MK of the left hippocampus decreased,and the MK of the left thalamus was negatively correlated with IMI.The FA of left amygdala,left fusiform gyrus and left thalamus increased,and the FA of left hippocampus was negatively correlated with DMI.The MD of bilateral hippocampus,left amygdala and left frontal pole increased,the MD of left hippocampus was negatively correlated with VMI,and the MD of right hippocampus was negatively correlated with MMSE.This indicates that general anesthesia leads to changes in the microstate of brain regions related to memory function,and changes in kurtosis parameters and diffusion parameters are correlated with memory of different dimensions.MK in the left thalamus,FA,MD in the left hippocampus,and MD in the right hippocampus can provide objective imaging evidence for changes in memory after general anesthesia.（3）The u AI-MR brain structure intelligent analysis system was used to analyze the brain area volume before and after the gastroscopy under general anesthesia,and no obvious abnormal brain area was found.We believe that the clinical control of general anesthesia is accurate and scientific,and will not affect the macro structure of the brain.