NVCs had been identified through clinical examination and at least 2 types of multimodal imaging such as structural OCT, FA, color fundus photography, multicolor imaging, near-infrared reflectance, or red-free fundus photography, as in previous studies. Subjects have given their written informed consent and the study was approved by Hospital de Santa Maria local ethics committee (Lisbon, Portugal) and by the Western Institutional Review Board (Olympia, WA) and adheres to the tenets of the Declaration of Helsinki.Ī database search was performed and eyes from patients with PDR and OCTA imaging of NVCs acquired as part of routine clinical examination were included. This was a retrospective case series conducted in 2 retinal clinics, based in Lisbon and New York, from 2015 to 2018. These findings have clinical utility in estimating the activity of specific neovascular complexes, monitoring treatment response, surgical planning, and reducing the need for dye-based imaging during busy clinics, all the more important now with the impact of the COVID-19 pandemic. Herein, we aim to describe features of neovascularization in PDR using OCTA, complementing previous observations. 24, 25 In PDR, OCTA can be useful to visualize retinal nonperfusion areas (NPAs) and the presence of blood flow in NVCs and IRMAs. 19 – 25 OCTA provides two and three-dimensional noninvasive vascular mapping at the microcirculation level. 16 OCT angiography (OCTA) is a more recent technique that identifies vascular structures by detecting the change in backscattering between consecutive B-scans and then attributing the differences to the flow of erythrocytes through retinal blood vessels. 15, 17, 18 One study described the use of spectral-domain OCT to distinguish quiescent from active NVCs, since active NVCs had a higher presence of vitreous hyperreflective dots whereas quiescent NVCs were associated with features more suggestive of fibrotic changes, including adjacent epiretinal membrane, inner retinal tissue contracture, protrusion towards the vitreous and frank vitreous invasion. 12, 13, 16, 18 Also, NVCs can be differentiated from intraretinal microvascular abnormalities (IRMA) since the neovascularization breaches the internal limiting membrane (ILM) and grows into the posterior hyaloid. 13, 14, 16 – 18 Prior reports describe NVD as hyperreflective lesions over the optic disc with NVE appearing as flat vessels arising from the inner retina which then grow as hyperreflective loops. 12 – 18 With OCT, it is possible to evaluate neovascular complexes (NVCs) in their earliest stages and to identify associated vitreoretinal interface changes. OCT is used routinely in diabetic retinopathy to evaluate macular edema, 7 – 11 but can also be helpful in evaluating morphologic changes in PDR related to neovascularization. 6 OCT is a noninvasive technique that provides images of the retinal structure typically displayed as cross-sections. 4 – 6 Also, since fluorescent signals originating in both the superficial and deep capillary networks are projected onto a single plane, it is impossible to identify in which of these retinal layers the vascular abnormalities exist. While FA is considered the gold standard, it is an invasive technique. There are several established imaging techniques to evaluate PDR, with fluorescein angiography (FA) and optical coherence tomography (OCT) being the most relevant. Proliferative diabetic retinopathy (PDR) is characterized by the presence of neovascularization, which can lead to severe visual loss resulting from hemorrhagic and/or tractional complications.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |