Detection of Clinically Unsuspected Retinal Neovascularization With Wide-Field Optical Coherence Tomography Angiography

Abstract

Purpose: To evaluate wide-field optical coherence tomography angiography (OCTA) for detection of clinically unsuspected neovascularization (NV) in diabetic retinopathy (DR). Methods: This prospective observational single-center study included adult patients with a clinical diagnosis of nonproliferative DR. Participants underwent a clinical examination, standard 7-field color photography, and OCTA with commercial and prototype swept-source devices. The wide-field OCTA was achieved by montaging five 6 × 10-mm scans from a prototype device into a 25 × 10-mm image and three 6 × 6-mm scans from a commercial device into a 15 × 6-mm image. A masked grader determined the retinopathy severity from color photographs. Two trained readers examined conventional and wide-field OCTA images for the presence of NV. Results: Of 27 participants, photographic grading found 13 mild, 7 moderate, and 7 severe nonproliferative DR. Conventional 6 × 6-mm OCTA detected NV in 2 eyes (7%) and none with 3 × 3-mm scans. Both prototype and commercial wide-field OCTA detected NV in two additional eyes. The mean area of NV was 0.38 mm2 (range 0.17–0.54 mm2). All eyes with OCTA-detected NV were photographically graded as severe nonproliferative DR. Conclusion: Wide-field OCTA can detect small NV not seen on clinical examination or color photographs and may improve the clinical evaluation of DR.

Widefield optical coherence tomography angiography for early detection and objective evaluation of proliferative diabetic retinopathy

“…According to the authors, clinical examination may have missed these vessels due to previous treatment with anti-VEGF, which may have altered their visibility. (13) In our cohort, none of the patients diagnosed clinically with NPDR were previously treated with anti-VEGF. It is still unclear whether the sensitivity of OCTA in detecting small neovascularisation not visible on clinical examination has clinical significance and if this neovascularization should be treated.…”

“…(4), (12) OCTA may potentially facilitate staging of DR or even detection of early DR changes prior to clinically detectable retinopathy. (13) Thus, it shows promise in supplementing clinical examination by potentially replacing FFA for the diagnosis and monitoring of DR. Until recently, this was not achievable due to the limited field of view of earlier devices. However, a swept-source OCTA (SS-OCTA) device has become available, allowing for montaging of several scans in real-time, thus providing almost 80 degrees field of view in a single scan.…”

Imaging Artifacts and Segmentation Errors With Wide-Field Swept-Source Optical Coherence Tomography Angiography in Diabetic Retinopathy

“…We found that patients with higher severity of DR had a higher MAS and segmentation errors were more frequent in eyes with PDR. Because wide-field SS-OCTA has been used in the diagnosis and follow-up of DR, 2,7,8,12,16 it is necessary to understand the factors that contribute to both segmentation and motion artifacts of montage images in order to ensure meaningful and reliable results. This is particularly important to accurately incorporate wide-field OCTA into our clinical decision making in DR patients as we examine small, quantitative differences in NV and nonperfusion areas.…”

Optical Coherence Tomography Angiography in Diabetes and Diabetic Retinopathy

“…( Figure 5) Tan and co-workers further improved the diagnostic performance of widefield OCTA in detecting nonperfusion areas, by removing the influence of larger retinal vessels from capillaries in OCTA scans [92]. Furthermore, widefield OCTA resulted in the higher detection of retinal neovascularization than on clinical examination, which suggests that widefield OCTA could be considered for the purpose of early detection of neovascularization [94,95]. Of note, the widefield fluorescein angiography remains a vital clinical tool in its ability to detect both peripheral retinal nonperfusion and eventual peripheral active neovascularization, which remains difficult to visualize clinically and is less accurately identified with widefield OCTA.…”