| Objective:The purpose of this study were:(1)to use dynamic amplitude low-frequency fluctuation(dALFF)method to explore the characteristics of dynamic changes of local spontaneous brain activity in PACG patients based on sliding time windows;(2)to compare with static ALFF(sALFF)results to deepen the understanding of the pathogenesis of PACG.Methods:Eighty-three patients with PACG diagnosed and healthy controls between July2015 and October 2022 were retrospectively analyzed.Thirty-three PACG patients and thirty-three healthy controls who meeting the enrollment criteria and matched for age and sex were included.Patients in the PACG group were diagnosed by senior attending physicians from the ophthalmology department of the First Affiliated Hospital of Nanchang University according to the clinical diagnostic criteria proposed in the Chinese Glaucoma Guidelines(2020)in PACG,ranging age from 40 to 69.All subjects underwent 3.0T resting-state functional brain MRI data acquisition,and PACG patients underwent ophthalmic parameter acquisition.Afterwards,the functional MRI data were processed using the dALFF and sALFF algorithms respectively,and the results were subjected to a two-sample t-test with Gaussian random field(GRF)correction to obtain statistically different brain areas.Finally,the mean dALFF and sALFF values of different brain regions were extracted,based on which the PACG and HC groups were distinguished by SVM,while the correlation with clinical ophthalmic parameters was also analyzed.Results:(1)Compared with the HC group,PACG patients had reduced dALFF variability in spontaneous neurons in the right lingual gyrus,left fusiform gyrus,right inferior occipital gyrus,left calcarine fissure and surrounding cortex,bilateral cuneus gyrus and right postcentral gyrus;and increased sALFF values in the left inferior cerebellum,right parahippocampal gyrus and right thalamus,and reduced sALFF values in the left middle occipital gyrus,right inferior occipital gyrus,left postcentral gyrus and right superior parietal gyrus.(2)The dALFF variability in the right inferior occipital gyrus of PACG patients was positively correlated with the left RNFL and negatively correlated with the left ACDR and left V-CDR,the dALFF variability in the left cuneus was negatively correlated with the right IOP,and the dALFF variability in the right postcentral gyrus was negatively correlated with the right A-CDR and right V-CDR;the sALFF values in the right inferior occipital gyrus were negatively correlated with the right RNFL and positively correlated with the right V-CDR.(3)The accuracy of the classifier featuring dALFF data was 81.54%,the precision was 77.78%,the sensitivity was 87.50%,and the specificity was 75.76%;the accuracy of the classifier featuring sALFF data was 84.85%,the precision was 87.10%,the sensitivity was 81.82%,and the specificity was 87.88%.Conclusions:(1)patients with PACG have both altered intensity and stability of spontaneous neural activity involving visual cortex,ventral-dorsal visual pathway,default mode network and cerebellum;suboccipital gyrus and cuneus may be important brain regions for altered brain function in PACG.(2)The brain areas with altered spontaneous neural activity in PACG patients relative to the HC group were correlated with clinical ophthalmic parameters,suggesting that altered spontaneous neural activity in PACG patients may be related to the severity of PACG.(3)dALFF values and sALFF values may be potential neuroimaging disease markers in PACG patients,and sALFF may provide additional information for PACG neuroimaging diagnosis. |
