Volumetric Three-Dimensional Optical Coherence Tomography Angiography of Retinal Neovascularization in Proliferative Diabetic Retinopathy

Purpose To evaluate structural and angiographic neovascularization in patients with proliferative diabetic retinopathy (PDR) using volumetric three-dimensional optical coherence tomography angiography (OCTA). Methods This prospective, observational cross-sectional study included 29 eyes of 27 patients with PDR. The angiogenic structure, feeding vessel (epicenter), flow volume, and flow volume density (FVD) of the neovasculatures were evaluated using three-dimensional OCTA imaging. The flow area and the flow area density (FAD) were also measured using en face OCTA imaging. Results Sites of neovascularization were imaged successfully in 17 of the 29 eyes (58.6%). Three proposed types of neovascularization were identified on the basis of structural features seen on the three-dimensional OCTA images. Neovascularization of the adhesion type (9 of 17, 52.9%) adhered to the retinal vasculature. Those of the traction type (5 of 17, 29.4%) were partially separated from the retinal vascular plexus. Those of the mushroom type (3 of 17, 17.6%) were connected to the retinal vasculature via several epicenters. There was a significant difference between highly leaky (active) and faintly leaky (inactive) neovascularization for FVD, but not for flow area, flow volume, or FAD (P=0.01, 0.9, 0.6, and 0.1, respectively). Conclusions Volumetric three-dimensional OCTA revealed three types of neovascularization in PDR, and may be useful for assessing neovascular activity and planning vitrectomies.