Retinal Microvasculature in Nonproliferative Diabetic Retinopathy: Automated Quantitative Optical Coherence Tomography Angiography Assessment

2017 ◽  
Vol 58 (3) ◽  
pp. 131-141 ◽  
Author(s):  
Marco Lupidi ◽  
Gabriel Coscas ◽  
Florence Coscas ◽  
Tito Fiore ◽  
Elisa Spaccini ◽  
...  
2021 ◽  
Author(s):  
Yanhui Ma ◽  
Matthew Ohr ◽  
Cynthia Roberts

Abstract Quantitative imaging using optical coherence tomography angiography (OCTA) could provide objective tools for the detection and characterization of diabetic retinopathy (DR). In this study, we developed a novel quantitative approach using OCTA images to delineate the vessel orientation pattern of a specific region of interest, which is an orientation distribution curve depicting the probability of vessels at each angle from 0 to 360 degrees. Three quantitative metrics including vessel preferred orientation, vessel anisotropy and vessel mass were extracted from the orientation pattern and analyzed in each of eight 45° sectors at the macula. Differential retinal microvascular orientation patterns were observed between three healthy subjects and three subjects with DR. Greater variability of vessel preferred orientation (p<0.001) and vessel mass (p<0.001) was exhibited among subjects with DR than healthy in eight sectors. In the nasal-superior sector, there was a significant difference between healthy and DR subjects in preferred orientation and vessel anisotropy. The vessel mass characterized from the vascular orientation pattern was shown to be strongly correlated with the traditionally reported vessel density (p<0.00001). These preliminary results suggest the feasibility and advantage of our vessel orientation-based quantitative approach using OCTA to characterize DR-associated changes in retinal microvasculature.


2017 ◽  
Vol 27 (6) ◽  
pp. 716-729 ◽  
Author(s):  
Kumar Sambhav ◽  
Khaled K. Abu-Amero ◽  
Kakarla V. Chalam

Purpose To evaluate the integrity of macular and temporomacular vasculature in nonproliferative diabetic retinopathy (NPDR) with noninvasive optical coherence tomography angiography (OCTA) and correlate perfusion indices with degree of NPDR. Methods In this prospective observational cross-sectional study, 102 eyes with newly diagnosed NPDR (mild NPDR, 36; moderate NPDR, 21; severe NPDR, 13; NPDR with diabetic macular edema [DME], 32) underwent OCTA. Sixty eyes of normal subjects served as control. Degree of NPDR (based on Early Treatment Diabetic Retinopathy Study criteria) was confirmed with fluorescein angiography. Automated OCTA/split-spectrum amplitude decorrelation angiography software generated perfusion indices (vessel density and flow index) from images of the retina. The perfusion index of superficial and deep retinal plexuses was obtained in both perifoveal (central 1-3 mm) and parafoveal (3-6 mm) areas. Results Deep plexus parafoveal vessel density was 25.23% (±6.1) in mild NPDR, 20.16% (±6.16) in moderate NPDR, 11.16% (±4.16) in severe NPDR, and 17.91% (±4.42) in NPDR + DME compared to normal subjects (36.93% [±8.1]; (p<0.01). Spearman correlation coefficient (rs) between vessel density and level of NPDR severity in the parafoveal region showed inverse correlation for both superficial (rs -0.87; p = 0.083) and deep (rs -0.96; p = 0.017) plexus. Similarly, when vessel density of the perifoveal region was compared with level of NPDR severity, inverse correlation was noted in both superficial (rs -0.85; p = 0.08) and deep (rs -0.98; p = 0.011) plexus. Conclusions Optical coherence tomography angiography clearly delineated the retinal microcirculation and allowed quantification of vascular perfusion of each layer. As diabetic retinopathy progressed, a decrease in perfusion index is more pronounced in the deep retinal plexus and precedes changes in superficial plexus.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yanhui Ma ◽  
Matthew P. Ohr ◽  
Xueliang Pan ◽  
Cynthia J. Roberts

AbstractQuantitative imaging using optical coherence tomography angiography (OCTA) could provide objective tools for the detection and characterization of diabetic retinopathy (DR). In this study, an operator combining the second derivative and Gaussian multiscale convolution is applied to identify the retinal orientation at each pixel in the OCTA image. We quantified the pattern of retinal vascular orientation and developed three novel quantitative metrics including vessel preferred orientation, vessel anisotropy, and vessel area. Each of eight 45º sectors of the circular disk centered at the macular region was defined as the region of interest. Significant sectoral differences were observed in the preferred orientation (p < 0.0001) and vessel area (p < 0.0001) in the 34 healthy subjects, whereas vessel anisotropy did not demonstrate a significant difference among the eight sectors (p = 0.054). Differential retinal microvascular orientation patterns were observed between healthy controls (n = 34) and the DR subjects (n = 7). The vessel area characterized from the vascular orientation pattern was shown to be strongly correlated with the traditionally reported vessel density (Pearson R > 0.97, p < 0.0001). With three metrics calculated from the vascular orientation pattern simultaneously and sectorally, our quantitative assessment for retinal microvasculature provides more information than vessel density alone and thereby may enhance the detection of DR. These preliminary results suggest the feasibility and advantage of our vessel orientation-based quantitative approach using OCTA to characterize DR-associated changes in retinal microvasculature.


2018 ◽  
Vol 159 (8) ◽  
pp. 320-326
Author(s):  
Cecília Czakó ◽  
Gábor László Sándor ◽  
Mónika Ecsedy ◽  
Zsuzsanna Szepessy ◽  
Ágnes Borbándy ◽  
...  

Abstract: Introduction: Optical coherence tomography angiography is a non-invasive imaging technique that is able to visualize the different retinal vascular layers using motion contrast to detect blood flow without intravenous dye injection. This method might help to assess microangiopathy in diabetic retinopathy during screening and follow-up. Aim: To quantify retinal microvasculature alterations in both eyes of diabetic patients in relation to systemic risk factors using optical coherence tomography angiography. Method: Both eyes of 36 diabetic patients and 45 individuals without diabetes were examined. Duration of diabetes, insulin therapy, blood pressure, HbA1c, dyslipidemia, axial length and the presence of diabetic retinopathy were recorded. Retinal vessel density was measured by optical coherence tomography angiography. The effect of risk factors on vessel density and between-eye asymmetry was assessed using multivariable regression analysis. Results: Vessel density was significantly lower and between-eye difference was significantly higher in diabetic patients compared to controls (p<0.05). Both vessel density and between-eye asymmetry significantly correlated with diabetes duration (p<0.05) after controlling for the effect of risk factors. The between-eye asymmetry in vessel density was significantly higher in patients without clinically detectable diabetic retinopathy compared to control subjects (p<0.001). Conclusions: There is a decrease in retinal vessel density and an increase in between-eye asymmetry in patients with diabetes compared to healthy subjects. By using optical coherence tomography angiography, the detection of these microvascular alterations is possible before clinically detectable diabetic retinopathy and might serve as a useful tool in both screening and timing of treatment. Orv Hetil. 2018; 159(8): 320–326.


2016 ◽  
Vol 57 (9) ◽  
pp. OCT519 ◽  
Author(s):  
Devanshi Bhanushali ◽  
Neha Anegondi ◽  
Santosh G. K. Gadde ◽  
Priya Srinivasan ◽  
Lavanya Chidambara ◽  
...  

2020 ◽  
Vol 9 (6) ◽  
pp. 1723 ◽  
Author(s):  
Jacqueline Chua ◽  
Ralene Sim ◽  
Bingyao Tan ◽  
Damon Wong ◽  
Xinwen Yao ◽  
...  

Diabetic retinopathy (DR) is a common complication of diabetes mellitus that disrupts the retinal microvasculature and is a leading cause of vision loss globally. Recently, optical coherence tomography angiography (OCTA) has been developed to image the retinal microvasculature, by generating 3-dimensional images based on the motion contrast of circulating blood cells. OCTA offers numerous benefits over traditional fluorescein angiography in visualizing the retinal vasculature in that it is non-invasive and safer; while its depth-resolved ability makes it possible to visualize the finer capillaries of the retinal capillary plexuses and choriocapillaris. High-quality OCTA images have also enabled the visualization of features associated with DR, including microaneurysms and neovascularization and the quantification of alterations in retinal capillary and choriocapillaris, thereby suggesting a promising role for OCTA as an objective technology for accurate DR classification. Of interest is the potential of OCTA to examine the effect of DR on individual retinal layers, and to detect DR even before it is clinically detectable on fundus examination. We will focus the review on the clinical applicability of OCTA derived quantitative metrics that appear to be clinically relevant to the diagnosis, classification, and management of patients with diabetes or DR. Future studies with longitudinal design of multiethnic multicenter populations, as well as the inclusion of pertinent systemic information that may affect vascular changes, will improve our understanding on the benefit of OCTA biomarkers in the detection and progression of DR.


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