| Objective : To evaluate the ability of measurements of macular microvascular changes using optical coherence tomography angiography(OCTA)to distinguish healthy eyes with diabtetic retinopathy.Methods:In this cross-sectional study,42 eyes with type 2 diabetes were collected from March 2019 to September 2019 in the outpatient and inpatient departments of the first affiliated hospital of Chongqing Medical University.The 28 eyes without diabetes matched the inclusion criteria and exclusion criteria in the same age and sex as diabetes group were selected as healthy group.Both groups were examined by means of a 3mm×3mm OCTA scan,and the superficial retinal region was used as the study object.Five measures were examined: perfusion density,vessel density,the size of the foveal avascular zone,the area under the receiver operating characteristic curve and and circularity index of the foveal avascular zone.Results: 1.Comparison of blood flow density in the macular region of the superficial retina of the diabetic and healthy groups:Theblood flow density in the macular region was compared between the diabetic group and the healthy group.The perfusion density of the superficial retinal layer in the diabetic group in a diameter of 3mm,and the vessel density in a diameter of 1mm,1-3mm and 3mm were smaller than that in the healthy group.(t =-3.042,-3.186,-3.641,-3.892,P <0.05).There was no significant difference in perfusion density between the two groups in the superficial retinal layer in a diameter of 1 mm and a diameter of 1-3 mm compared with the healthy group(t =-1.086,P = 0.282,t =-1.857,P = 0.073).The perimeter of FAZ in the diabetic group was larger than that in the healthy group,and the circularity index was smaller than that in the healthy group(t = 2.679,2.097,P <0.05).There was no significant difference in FAZ area between the two groups(t = 0.442,P =0.659).2.Correlation analysis of OCTA microvessels in macular area in diabetic patients:The severity of diabetes has a negative correlation with the perfusion density of the superficial retina in the range of 1mm diameter,1-3mm diameter,and 3mm diameter,and the vessel density in the region of1-3mm diameter and 3mm diameter.(r=-0.225,-0.495,-0.531,-0.524,-0.563 P <0.05),which is not related to the vessel density of the 1mm diameter region(r =-0.098,P = 0.343).The age of diabetic patients was not related to the vessel density in the superficial macular region of the retina 1mm,1-3mm and 3mm diameter,and perfusion density in a diameterof 1mm,1-3mm and 3mm.(r =-0.051,P = 0.687;r = 0.267,P = 0.069;r =0.248,P = 0.067;r = 0.054,P = 0.672;r = 0.129,P = 0.307;r = 0.177,P =0.158).The best corrected visual acuity of diabetic patients was inversely related to the perfusion density of the superficial retina 1mm diameter,1-3mm diameter,3mm diameter and vessel density of 1mm diameter(r =-0.387,-0.387,-0.428,-0.272 P <0.05),which were not related to the vessel density of the superficial retinal 1-3mm diameter region and 3mm diameter region(r = 0.363,P = 0.073;r = 0.038,P = 0.765).The duration of diabetes was negatively correlated with the vessel density of the superficial retinal diameter of 1mm and 3mm(r = 0.252,0.267 P <0.05).The perfusion density of the superficial retinal diameter of 1mm,1-3mm,and 3mm and the vessel density of 1-3mm diameter region is not correlated with the duration of diabetes.(r = 0.121,P = 0.338;r = 0.201,P = 0.108;r= 0.200,P = 0.110;r = 0.210,P = 0.093).Glycated hemoglobin has a negative correlation with the vessel density of the retinal 1-3mm diameter region and 3mm diameter region(r =-0.394,-0.289,P <0.05).There is no correlation between glycated hemoglobin and perfusion density in the 3mm diameter area and the vessel density in the 1mm,1-3mm and 3mm diameter area(r = 0.061,P = 0.631;r =-0.140,P = 0.266;r =-0.102,P = 0.148;r =0.078,P = 0.537).The fasting blood glucose of diabetic patients is not related to the linear density of vascular perfusion density in the superficial macular region of the retina 1mm diameter,1-3mm diameter,3mmdiameter,and 1mm diameter,1-3mm diameter,or 3mm diameter(r =-0.199,P = 0.111;r = 0.161,P = 0.199;r =-0.045,P = 0.719;r =-0.219,P= 0.079;r =-0.169,P = 0.180;r =-0.213,P = 0.089).Uric acid was negatively correlated with the perfusion density of the superficial retinal1-3mm diameter region and the vessel density of the 1-3mm diameter region and the 3mm diameter region(r =-0.302,-0.660,-0.426 P < 0.05),and the perfusion density of the 1mm and 3mm diameter of the retinal layer and the vessel density of the 1mm diameter area were not related(r =-0.033,P = 0.796;r =-0.228,P = 0.068;r =-0.092,P = 0.468).Cystatin C in diabetic patients has a negative correlation with the vessel density of the superficial retinal diameter of 1-3mm and 3mm(r =-0.660,-0.426 P<0.05).The perfusion density in the 1mm,1-3mm,3mm diameter region and the vessel density in the 1mm diameter region were not related(r =0.204,P = 0.104;r =-0.161,P = 0.200;r =-0.131,P = 0.298;r = 0.170,P= 0.175).Creatinine was negatively correlated with the perfusion density of the superficial retinal 1-3mm and 3mm diameter regions,and the vessel density of the 1-3mm and 3mm diameter regions(r =-0.281,-0.278,0.636,-0.519 P <0.05),which is not related to the perfusion density of the superficial retinal diameter of 1mm and the vessel density of the superficial retinal diameter of 1mm(r =-0.006,P = 0.960;r =-0.052,P = 0.681).The severity of diabetes was negatively related to the circularity index of FAZ(r =-0.262,P <0.05),and was not related to the area and perimeterof FAZ(r =-0.140,P = 0.173;r =-0.019,P = 0.856).The age of diabetic patients was positively correlated with the area and perimeter of FAZ(r=0.408,0.446 P <0.05),and negatively correlated with FAZ circularity index(r =-0.306,P = 0.013).The best corrected visual acuity of diabetic patients was not related to the FAZ area,perimeter and circularity index of the superficial retinal layer(r =-0.060,P = 0.633;r =-0.109,P = 0.389;r=-0.122,P = 0.334).The duration of diabetes in patients was positively correlated with their FAZ area(r =-0.373,P <0.05),but not correlated with FAZ perimeter and circularity index(r =-0.240,P = 0.054;r =-0.055,P =0.663).The glycated hemoglobin of patients was positively correlated with FAZ area and perimeter(r = 0.357,0.397 P<0.05),and negatively correlated with FAZ circularity index(r =-0.348,P = 0.004).The fasting blood glucose is negatively correlated with the circularity index of FAZ(r=-0.522,P <0.05),and not related to the area and perimeter of FAZ(r =-0.104,P = 0.441;r = 0.060,P = 0.637).Uric acid had a positive correlation with FAZ area and perimeter(r = 0.275,0.413 P <0.05)and a negative correlation with morphological index(r =-0.430,P = 0.000).Cystatin C was negatively correlated with circularity index in diabetic patients(r = 0.158,P <0.05)and not related to the area and perimeter of FAZ(r =-0.263,P = 0.034;r = 0.238,P = 0.057).Creatinine was positively correlated with FAZ area and perimeter(r = 0.258,0.322 P =0.05)and negatively correlated with circularity index(r =-0.376,P =0.002).3.The vessel density of 3mm in diameter of the superficial retina in diabetic patients has the greatest diagnostic value for diabetic retinopathy(AUC = 0.813,P = 0.000,95% CI,0.698-0.929),and its best diagnostic cutoff is 16.35,sensitivity is 0.742,and specificity is 0.846.Conclusion: Detection of microvascular changes in macular area in diabetic patients is of great significance.OCTA provides a detection method for quantitative analysis of macular area,which can study the severity of diabetic retinopathy and provide a quantitative basis for its diagnosis,treatment and assessment of prognosis. |
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