scholarly journals Optical Coherence Tomography Angiography in Diabetes and Diabetic Retinopathy

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.

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.


2019 ◽  
Vol 6 (1) ◽  
Author(s):  
Kai Yuan Tey ◽  
Kelvin Teo ◽  
Anna C. S. Tan ◽  
Kavya Devarajan ◽  
Bingyao Tan ◽  
...  

Abstract Background Diabetic retinopathy (DR) is a leading cause of vision loss in adults. Currently, the standard imaging technique to monitor and prognosticate DR and diabetic maculopathy is dye-based angiography. With the introduction of optical coherence tomography angiography (OCTA), it may serve as a potential rapid, non-invasive imaging modality as an adjunct. Main text Recent studies on the role of OCTA in DR include the use of vascular parameters e.g., vessel density, intercapillary spacing, vessel diameter index, length of vessels based on skeletonised OCTA, the total length of vessels, vascular architecture and area of the foveal avascular zone. These quantitative measures may be able to detect changes with the severity and progress of DR for clinical research. OCTA may also serve as a non-invasive imaging method to detect diabetic macula ischemia, which may help predict visual prognosis. However, there are many limitations of OCTA in DR, such as difficulty in segmentation between superficial and deep capillary plexus; and its use in diabetic macula edema where the presence of cystic spaces may affect image results. Future applications of OCTA in the anterior segment include detection of anterior segment ischemia and iris neovascularisation associated with proliferative DR and risk of neovascular glaucoma. Conclusion OCTA may potentially serve as a useful non-invasive imaging tool in the diagnosis and monitoring of diabetic retinopathy and maculopathy in the future. Future studies may demonstrate how quantitative OCTA measures may have a role in detecting early retinal changes in patients with diabetes.


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.


Author(s):  
Felipe F. Conti ◽  
Weilin Song ◽  
Eduardo B. Rodrigues ◽  
Rishi P. Singh

Abstract Background Optical coherence tomography angiography (OCTA) enables detailed, non-invasive assessment of ocular vasculature. This study uses OCTA imaging to evaluate choriocapillaris and retinal capillary perfusion density (CPD) changes in diabetic retinopathy following anti-vascular endothelial growth factor (VEGF) treatment. Methods Records of 38 eyes at a single institution were reviewed, grouped as non-diabetic controls (19 eyes), diabetes mellitus patients with diabetic retinopathy (DR, 19 eyes) and macular edema (DME). DR eyes were imaged at baseline, 6-months and 12-months after anti-VEGF treatment. Quantitative analyses assessed CPD of the choriocapillaris and retinal plexus. Results DR eyes showed decreased choriocapillaris whole-image CPD (62.6 ± 6.1 vs. 68.4 ± 5.1, p < 0.003), foveal CPD (61.2 ± 7.4 vs. 66.3 ± 9.8, p < 0.014), and parafoveal CPD (61.9 ± 6.6 vs. 68.2 ± 4.8, p < 0.002) at baseline. DR eyes also showed decreased retinal density, including whole-image CPD (46.9 ± 5.1 vs. 50.7 ± 5.6, p < 0.04), foveal CPD (27.6 ± 5.9 vs. 34.1 ± 6.1, p < 0.002), and parafoveal CPD (49.0 ± 5.6 vs. 53.1 ± 6.0, p < 0.011). Following 12 months of anti-VEGF treatment, no changes to retinal or choriocapillaris or CPD were observed. Retinal central subfield thickness decreased (397.1 ± 93.2 µm vs. 294.2 ± 71.5 µm, p < 0.005). Lastly, FAZ area (0.307 ± 0.133 mm2 vs. 0.184 ± 0.058 mm2, p = 0.008) and perimeter (2.415 ± 0.692 mm2 vs. 1.753 ± 0.408 mm2, p = 0.002) were increased in DR eyes at baseline. No changes to FAZ area or perimeter were seen with anti-VEGF treatment in DR eyes. Conclusions Compared to control, choriocapillaris and retinal CPD are reduced in DR, while FAZ area and perimeter are increased. No retinal capillary or choriocapillaris CPD changes were observed in DR eyes following anti-VEGF treatment.


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.


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