<p>Optical Coherence Tomography Angiography Features of Neovascularization in Proliferative Diabetic Retinopathy</p>

Abstract

To describe features of neovascularization in proliferative diabetic retinopathy (PDR) using optical coherence tomography angiography (OCTA). Methods: A retrospective case series was performed in 23 eyes from 21 patients who underwent OCTA of neovascular complexes (NVCs) due to PDR. Eyes were imaged with the DRI Triton swept-source OCTA, Avanti RTVue XR or Cirrus HD-OCT 5000 as part of routine clinical examination. Segmentation was adjusted to include vasculature between the vitreous cavity and the internal limiting membrane (ILM). The presence of NVCs was confirmed by clinical examination and multimodal imaging such as color or red-free fundus photography, fluorescein angiography, multicolor imaging or near-infrared reflectance. Results: Thirty-five NVCs were imaged, of which, 34% were neovascularization of the disc (NVD) and 66% were neovascularization elsewhere (NVE). On structural OCT B-scans, NVE appeared as medium to highly reflective tissue that breached the ILM, while NVD showed highly reflective tissue protruding from the disc in a sea fan configuration. Flow signal was seen on OCTA in all cases of NVE and in 67% of NVD lesions. Areas with minimal or absent retinal flow signal identified retinal nonperfusion areas and were found adjacent to 87% of NVE. Intraretinal microvascular abnormalities (IRMAs) were noted next to 70% of NVE. Absent flow signal was seen in 4 NVD cases showing posterior shadowing and were considered inactive. Conclusion: OCTA appears useful for imaging NVCs, IRMAs, and retinal nonperfusion areas in eyes with diabetic retinopathy. This imaging modality enables noninvasive screening and monitoring of PDR and can obviate the need for additional testing in certain clinical settings.

An optimized segmentation and quantification approach in microvascular imaging for OCTA-based neovascular regression monitoring

“…The latter observation, we believe, may due to the fact that some of the smaller vessels have disappeared after treatment and only the larger vessels/larger vasculature persisted, resulting in an increased average width of vascularity as shown in OCTA images. This finding may share a common ground with the regression of exuberant vascular proliferation (EVP) after treatment in OCT images as per previous reports [ 21 , 22 ]. The quantified results from our image analysis are consistent with the clinical medical observation and diagnosis, which have strongly proved the effectiveness of the proposed VCA improvement.…”

An optimized segmentation and quantification approach in microvascular imaging for OCTA-based neovascular regression monitoring

“…The latter observation, we believe, may due to the fact that some of the smaller vessels have disappeared after treatment and only the larger vessels/larger vasculature persisted, resulting in an increased average width of vascularity as shown in OCTA images. This nding may share a common ground with the regression of exuberant vascular proliferation (EVP) after treatment in OCT images as per previous reports 21,22 . The quanti ed results from our image analysis are consistent with the clinical medical observation and diagnosis, which have strongly proved the effectiveness of the proposed VCA improvement.…”

Update on Optical Coherence Tomography and Optical Coherence Tomography Angiography Imaging in Proliferative Diabetic Retinopathy

“…NVEs can develop at different levels of the inner retina, penetrate the ILM and can assume different morphologic patterns in relation to the retina (Figures 3 and 4) [21][22][23]25,27,47,48]. Using OCTA, NVEs can be observed as irregular vessels with a positive flow signal above the ILM, which distinguishes them from other vascular lesions such as IRMA and microaneurysms (Figures 3 and 4) [6,15,26,[36][37][38][39][40][41][42][43][44][45]50,52,54,56,[62][63][64][68][69][70][71][72][73][74][75].…”

“…It was developed as an extension of OCT technology, without the necessity for dye injection, as in FA [29], and allows a twoand three-dimensional noninvasive visualization of the retinal microvasculature by detecting the movement of the red blood cells within the vessels in consecutive B-scans [30][31][32][33][34][35]. Thus, OCTA is able to show the NVCs' vascular structure and flow [6,[36][37][38][39][40][41][42], and widefield OCTA (WF-OCTA) has been shown to diagnose PDR with high accuracy [6,[43][44][45][46].…”