Quantitative Imaging Analysis Of Central Serous Chorioretinopathy:A Swept-Source Optical Coherence Tomography Based Study

Objectives:To develop a Central Serous Chorioretinopathy(CSC)imaging features,subretinal fluid(SRF)and choroidal vessels(CV),quantitative analysis tool based on U-net Convolution Neural Network(CNN)deep learning system.Comparing the baseline risk factors of acute and chronic CSC with risk factor rating scales.Evaluating the SS-OCT imaging features,SRF and quantitative analysis parameters.Comparing the differences of the changing patterns of choroid flow parameters of the acute and chronic CSC groups during follow-ups.Discussing the mechanisms of CSC.Materials and Methods:35 OCT volumetric scans were selected for the U-net CNN artificial intelligence,10 B-scans were chosen from each OCT volumetric scan.All pictures were labeled with Labelme software for deep learning in order to build the SRF volume,area,CVI,and CVV measuring tool.A total of 65 eyes of 65 CSC patients were enrolled in this cross-sectional study,which was conducted in West China Hospital of Sichuan University,Chengdu,China from May 2019 to December 2020.Scoring scales were used for the comparison of the baseline information and risk factors of the acute and chronic CSC groups.Recorded and compared the presence of featured imaging findings in the two groups,including general outer plexiform(OPL)layer hyperreflectivity,OPL thickening with variable reflectivity,subretinal exudates,thickening of the ellipsoid zone,variable reflectivity of the ellipsoid zone,Retinal Pigment Epithelium(RPE)irregularity,and Pigment Epithelial Detachment(PED).Compared the Choriocapillaris flow,Choriocapillaris density,CVV,and CVI in the 3mm × 3mm and 6mm×6mm area of the acute and chronic CSC group.Follow-up 30 CSC patients at the initial visit,one month,two months,and three months post-visit.Compare the changes of the Choriocapillaris flow,Choriocapillaris density,CVV,and CVI in the 3×3mm circular area,1-3 mm ring superior,temporal,inferior,and nasal,and 6mm×6mm circular area,3-6 mm ring superior,temporal,inferior,and nasal of the acute and chronic CSC group and the correlations between different parameters.Results:The accuracy,sensitivity,and specificity of the SRF model were 99.9836%,90.4039%,and 99.9886% respectively.The accuracy,sensitivity,and specificity of the CV model were 97.6739%,89.1545%,98.2483%.Regarding the gender distribution,the contribution of male patients was more significant in the acute group than the chronic group(P=0.003).The NEI-VEQ-25 score of the acute group was higher than the chronic group(P<0.0001).The difference in the blood pressure,Body Mass Index(BMI),log MAR BCVA,Intraocular Pressure(IOP),antidepressants use,corticosteroids use,pregnancy,alcohol use,and sleeping quality score was not statistically significant between the two groups.The FTND score of the acute group was higher than that of the chronic group.The logistic multivariable analysis shows male is an independent risk factor of acute CSC.The analysis of the imaging features reveals the presence of general OPL hyperreflectivity,subretinal exudates,thicknening of the ellipsoid zone,variable reflectivity of the ellipsoid zone,RPE irregularity in the two groups was statistically different(P<0.05),however,OPL thickening with variable reflectivity and PED was not statistically significant in the univariate analysis.Multivariable analysis shows OPL thickening with variable reflectivity is an independent protecting factor for chronic CSC.Variable reflectivity of the ellipsoid zone and RPE irregularity are independent risk factors for chronic CSC.The SRF area and volume,Choroidal thickness,Choriocapillaris flow of the acute group were significantly higher than that of the chronic group.The CVI and CVV in the 3mm × 3mm and 6mm×6mm area were not statistically different between the acute and chronic CSC group.Pearson correlation analysis showed the choroidal thickness and CVV was moderately positively relevant(3mm×3mm: R=0.566,6mm×6mm: R=0.733).In the chronic CSC group,SRF is negatively related to the Choriocapillaris flow in the 3mm × 3mm and6 mm × 6mm area.In the repeated measurement analysis of variance,the changing pattern of Choriocapillaris flow in the 3mm × 3mm area was statistically different during followups.However,the difference between the CVI and CVV was not statistically significant.Conclusion1.Through combing with U-net CNN deep learning network,we generated a measuring tool of SRF,CVI,and CVV with relevantly ideal accuracy,sensitivity and specificity,which provides quantitative parameters of the features of SRF and choroid circulation in CSC follow-up.2.The baseline features,SS-OCT imaging features,and quantitative parameters of acute CSC and chronic CSC were significantly different.The chronic group showed lower Choriocapillaris flow,which is also negatively correlated to SRF.3.Through follow-ups of the acute and chronic CSC group,we found the acute and chronic group showed different changing patterns of Choriocapillaris flow,which provides a new parameter to CSC staging and monitoring.