Sensitivity and Specificity of the Optical Coherence Tomography Angiography for Detection of Neovascularization and Evaluation of Peripheral Ischemia in Diabetic Retinopathy

Abstract

Objectives: The purpose of this study was to identify the sensitivity and specificity of optical coherence tomography angiography (OCTA) parameters for the presence of neovascularization elsewhere (NVE) and to investigate the relationship between ischemic areas. Methods: This study included 59 eyes with non-proliferative diabetic retinopathy (NPDR) and 36 eyes with proliferative diabetic retinopathy (PDR). The foveal avascular zone (FAZ), vessel density (VD) for the superficial and the deep capillary plexus (DCP), choriocapillaris flow area (CCP), and non-perfusion area (unit²) were recorded. The area under the curve (AUC) under the receiver operating characteristic curves, sensitivity and specificity were calculated for statistically significant outcomes. Later, based on visual acuity, PDR group was subdivided into group 2A: PDR eyes with VA ≤0.2 logMAR and group 2B: PDR eyes with VA>0.2 logMAR. Non-perfusion area and OCTA features were compared between the subgroups. Results: The VD in DCP was significantly lower, FAZ and non-perfusion area were larger in PDR group (p=0.001, p<0.001, and p<0.001). The AUC for presence of NVE, for the VD, was 0.710 (p=0.012) with sensitivity and specificity of 64% and 65%, for the FAZ was 0.746 (p<0.001) with sensitivity and specificity of 72% and 72.7%. There was a significant positive correlation between the FAZ and non-perfusion area (For NPDR, p=0.025, for PDR p<0.001). There was a significant negative correlation between the VD in DCP and ischemic area in PDR group. (p<0.001) In group 2B, non-perfusion area and FAZ were larger than group 2A. The VD and CCP flow area were also lower in group 2B (All, p<0.05). Conclusion: In cases with decreased VD in DCP and increased FAZ, the probability of PDR increases. Despite the sensitivity and specificity of the OCTA indices for the prediction of NVE being moderate, the OCTA is very useful in evaluating the microvascular structure in DR.