Intrinsic Functional Connectivity Alterations Of The Primary Visual Cortex In Primary Angle-closure Glaucoma Patients Before And After Surgery: A Resting-state FMRI Study

PurposeTo investigate the altered functional connectivity(FC)of the primary visual cortex(V1)in primary angle-closure glaucoma(PACG)patients before and after surgery with trabeculectomy and peripheral iridectomy using resting-state functional magnetic resonance imaging(rs-fMRI),with an objective to provide functional imaging evidence of the mechanism of the central nervous system injury for PACG patients and to improve the understanding of postoperative functional remodeling.Materials and MethodsPreoperative PACG(pre-PACG)patients confirmed by clinic and well age-and gender-matched healthy controls(HCs)were evaluated by 3T MR using T1 anatomical and resting-state functional magnetic resonance imaging(rs-fMRI)of blood oxygenation level dependent(BOLD),twenty-five PACG patients and 25 HCs were finally included in the analysis of rs-fMRI,and 9 PACG patients were assessed again at 3 months after treatment(post-PACG).After the data preprocessing,the center of the left and right V1 were chosen as the seed point,and its correlation with the time series of the whole brain voxels were calculated and then the differences of the resting state functional connectivity between groups were compared.The difference between pre-PACG patients and HCs was performed with the two sample t test,the paired sample t test was used to analysis the difference between post-PACG and pre-PACG patients.Then,the relationships between the altered FC coefficients and clinical variables were investigated in the pre-PACG patients.Results1.Compared with the HCs,the pre-PACG patients showed decreased FC between the left V1 and right senior visual cortex(V2,covering the right cuneus,calcarine and lingual gyrus),and right posterior cingulate cortex(PCC),increased FC between the left V1 and left temporal-parietal region,left and right operculainsula-basal ganglia region,and right inferior parietal lobule(IPL).2.Compared with the pre-PACG patients,the post-PACG patients showed increased FC between the left V1 and bilateral V2(covering the left precuneus,cuneus,right superior occipital gyrus),left or right postcentral gyrus and IPL,in addition,they showed decreased FC between the left V1 and the left prefrontal cortex and right cerebellum posterior lobe.3.In the pre-PACG patients,visual activity(VA)was positively correlated with increased FC between the left V1 and the left temporal-parietal region or the right inferior parietal lobule.4.Similar patterns of alterations were observed in the right V1-FC in both the pre-and post-PACG patients.Conclusions1.Compared with the HCs,a decrease of the function in visual information integration of the primary-senior visual cortex pathway and VA-related functional compensation were found in the pre-PACG patients.It provides a way to further understand the central damage mechanism of PACG patients.2.Compared with the pre-PACG patients,an increase of the function in visual information integration of the primary-senior visual cortex pathway was found in the post-PACG patients.May be it was the postoperative brain functional remodeling.It provides a clue to explore the outcome of postoperative brain function in PACG patients.