Characterizing Flow and Structure of Diabetic Retinal Neovascularization after Intravitreal Anti-VEGF Using Optical Coherence Tomography Angiography: A Pilot Study

Figure 3

(a–d) Visualizing changes of area size and flow density of neovascularization (NV) for the flow and the angio area for every NV separately (data series NV 1–9). Bullet points represent time points of antivascular endothelial growth factor (anti-VEGF) injections in the respective eyes (data series IVT 1–9). It is indicated that in en face imaging, the structural framework (NV-structure) is at least partly remaining despite the fact that perfusion area (NV-angio) and flow density within the structural area (FD-structure) are regressing, while flow density within the angio area (FD-angio) is relatively stable. The two NV from the case presentation (NV 1 with vitreous hemorrhage and NV 2) are represented in dotted lines for better recognition. (a) Relative change of NV-structure from baseline (=1). The graph shows that the structural areas of the NV decrease only slightly. (b) Relative change of NV-angio from baseline (=1). The graph shows that in most NV, the angio area en face is decreasing after treatment with anti-VEGF. Two NV are growing back to a significant proportion after a long treatment-free interval. In one of these eyes, a new vitreous hemorrhage occurred before retreatment. (c) Flow density within the structural NV-area (FD-structure) in %. The graph indicates the consistent decrease of flow density within the structural areas of the NVs after treatment, as well as a new increase of the two NVs with recurrent proliferative diabetic retinopathy (PDR) activity. (d) Flow density within the angio NV-area (FD-angio) in %. The graph indicates the lesser decrease of flow density within the structural areas of the NVs after treatment. Also, in the case of the two NVs with recurrent PDR activity, it cannot be determined by the flow density of the NV measured on the OCTA angio image.

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