OCT angiography and visible-light OCT in diabetic retinopathy.
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ABSTRACT:
SUBMITTER: Nesper PL
PROVIDER: S-EPMC5723235 | biostudies-literature | 2017 Oct
REPOSITORIES: biostudies-literature
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OCT angiography and visible-light OCT in diabetic retinopathy.
Nesper Peter L PL Soetikno Brian T BT Zhang Hao F HF Fawzi Amani A AA
Vision research 20170621
In recent years, advances in optical coherence tomography (OCT) techniques have increased our understanding of diabetic retinopathy, an important microvascular complication of diabetes. OCT angiography is a non-invasive method that visualizes the retinal vasculature by detecting motion contrast from flowing blood. Visible-light OCT shows promise as a novel technique for quantifying retinal hypoxia by measuring the retinal oxygen delivery and metabolic rates. In this article, we discuss recent in ...[more]
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Project description:BACKGROUND:Varying degrees of macular ischemia generally occur in diabetic retinopathy (DR). This study aims to evaluate the effect of conbercept with 3+ pro re nata (PRN) on macular perfusion status in patients with diabetic macular edema (DME) and quantitatively assess changes in foveal avascular zone (FAZ) areas and capillary density in macular regions by applying optical coherence tomography angiography (OCTA). METHODS:Fifty patients were divided into ischemic (n =?31) and non-ischemic (n =?19) groups according to the presence of ischemia on OCTA at baseline. All patients received intravitreal injections of 0.5?mg of conbercept with 3+ PRN principle. The FAZ areas and macular vessel density measured using OCTA were evaluated at baseline, 3?months, and 6?months after treatment in both groups. RESULTS:At months 3 and 6, the FAZ area in the ischemic group changed from 0.510?±?0.171?mm2 to 0.441?±?0.158?mm2 then to 0.427?±?0.153?mm2 (p =?0.003, p =?0.296); in the non-ischemic group, it remained stable (p =?0.269, p =?0.926). The superficial vessel density changed from 41.1?±?4.1 to 42.5%?±?4.7% then to 42.6%?±?4.6% (p =?0.043, p =?0.812), and the deep vessel density changed from 40.7?±?4.4 to 42.3%?±?3.6% then to 42.3%?±?4.7% (p =?0.072, p =?0.961) in the ischemic group. In the non-ischemic group, the superficial vessel density changed from 44.8?±?3.2 to 46.0%?±?3.5% then to 45.7%?±?3.3% (p =?0.108, p =?0.666), whereas the deep vessel density changed from 43.6?±?3.6 to 43.8%?±?3.2% then to 43.5%?±?4.5% (p =?0.882, p =?0.736). Reperfusion in macular nonperfusion areas was observed. CONCLUSION:Anti-vascular endothelial growth factor treatment may have a positive effect on macular perfusion status. Furthermore, OCTA had advantages in quantifying and calculating blood flow index in the study of macular perfusion status.
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Project description:Diabetic retinopathy, the most serious ocular complication of diabetes, imposes a serious economic burden on society. Automatic and objective assessment of vessel changes can effectively manage diabetic retinopathy and prevent blindness. Optical coherence tomography angiography (OCTA) metrics have been confirmed to be used to assess vessel changes. The accuracy and reliability of OCTA metrics are restricted by vessel segmentation methods. In this study, a multi-branch retinal vessel segmentation method is proposed, which is comparable to the segmentation results obtained from the manual segmentation, effectively extracting vessels in low contrast areas and improving the integrity of the extracted vessels. OCTA metrics based on the proposed segmentation method were validated to be reliable for further analysis of the relationship between OCTA metrics and diabetes and the severity of diabetic retinopathy. Changes in vessel morphology are influenced by systemic risk factors. However, there is a lack of analysis of the relationship between OCTA metrics and systemic risk factors. We conducted a cross-sectional study that included 362 eyes of 221 diabetic patients and 1,151 eyes of 587 healthy people. Eight systemic risk factors were confirmed to be closely related to diabetes. After controlling these systemic risk factors, significant OCTA metrics (such as vessel complexity index, vessel diameter index, and mean thickness of retinal nerve fiber layer centered in the macular) were found to be related to diabetic retinopathy and severe diabetic retinopathy. This study provides evidence to support the potential value of OCTA metrics as biomarkers of diabetic retinopathy.
| S-EPMC8702651 | biostudies-literature
Project description:As the prevalence of diabetes increases, millions of people need to be screened for diabetic retinopathy (DR). Remarkable advances in technology have made it possible to use artificial intelligence to screen DR from retinal images with high accuracy and reliability, resulting in reducing human labor by processing large amounts of data in a shorter time. We developed a fully automated classification algorithm to diagnose DR and identify referable status using optical coherence tomography angiography (OCTA) images with convolutional neural network (CNN) model and verified its feasibility by comparing its performance with that of conventional machine learning model. Ground truths for classifications were made based on ultra-widefield fluorescein angiography to increase the accuracy of data annotation. The proposed CNN classifier achieved an accuracy of 91-98%, a sensitivity of 86-97%, a specificity of 94-99%, and an area under the curve of 0.919-0.976. In the external validation, overall similar performances were also achieved. The results were similar regardless of the size and depth of the OCTA images, indicating that DR could be satisfactorily classified even with images comprising narrow area of the macular region and a single image slab of retina. The CNN-based classification using OCTA is expected to create a novel diagnostic workflow for DR detection and referral.
| S-EPMC8626435 | biostudies-literature
Project description:PurposeThe purpose of this study was to evaluate specifically in type 1 diabetes mellitus (DM) individuals the relationship between perifoveal superficial capillary plexus (SCP) parameters assessed by optical coherence tomography angiography (OCTA) and diabetic retinopathy (DR) grade.MethodsCross-sectional analysis of a large scale prospective OCTA trial cohort (ClinicalTrials.gov NCT03422965). A total of 1186 eyes (593 individuals), 956 type 1 DM eyes (478 patients), and 230 control eyes (115 healthy volunteers) were included in this study. DR stage was graded according to the International Classification. OCTA imaging was performed with a commercially available device (Cirrus HD-OCT). Vessel density (VD), perfusion density (PD), and foveal avascular zone (FAZ) area, perimeter and circularity measurements were quantified in the SCP and receiver operating characteristic (ROC) curves were constructed for each OCTA parameter.ResultsVD and PD (in both 3 × 3 and 6 × 6 mm captures) were inversely associated with DR stage (P < 0.001 in all cases) in a multiple regression analysis after controlling by age, gender, signal strength index, axial length, and DM duration. Greater FAZ area and perimeter and conversely lower circularity measurements were observed as DR severity increased in both scanning protocols (P < 0.05 in all cases).ConclusionsIn type 1 DM individuals, OCTA provides an objective, continuous, and reliable method for accurate quantification of VD, PD, and FAZ parameters in the SCP, which ultimately correlate with DR stages.Translational relevanceObjective OCTA measurements of the retinal microvasculature could substitute the clinical DR classification in patients with type 1 DM, identify patients at risk of DR progression, and inform treatment decisions to modify the evolution of the disease.
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