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Adrienne W. Scott - One of the best experts on this subject based on the ideXlab platform.
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variable practice patterns for management of Sickle Cell Retinopathy
Ophthalmology Retina, 2021Co-Authors: Kapil Mishra, Rohan P Bajaj, Adrienne W. ScottAbstract:Abstract A questionnaire regarding Sickle Cell Retinopathy evaluation and management distributed to retina specialists revealed variable practice patterns and a need for clinical diagnostic and treatment guidelines.
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Artificial intelligence for improving Sickle Cell Retinopathy diagnosis and management
Eye, 2021Co-Authors: Sophie Cai, Ian C. Han, Adrienne W. ScottAbstract:Sickle Cell Retinopathy is often initially asymptomatic even in proliferative stages, but can progress to cause vision loss due to vitreous haemorrhages or tractional retinal detachments. Challenges with access and adherence to screening dilated fundus examinations, particularly in medically underserved areas where the burden of Sickle Cell disease is highest, highlight the need for novel approaches to screening for patients with vision-threatening Sickle Cell Retinopathy. This article reviews the existing literature on and suggests future research directions for coupling artificial intelligence with multimodal retinal imaging to expand access to automated, accurate, imaging-based screening for Sickle Cell Retinopathy. Given the variability in retinal specialist practice patterns with regards to monitoring and treatment of Sickle Cell Retinopathy, we also discuss recent progress toward development of machine learning models that can quantitatively track disease progression over time. These artificial intelligence-based applications have great potential for informing evidence-based and resource-efficient clinical diagnosis and management of Sickle Cell Retinopathy. 镰状细胞性视网膜病变最初甚至在增殖期通常无症状, 但随病情进展, 可由于玻璃体出血或牵拉性视网膜脱离而导致视力丧失。获取广角眼底检查所面临的挑战, 尤其是在医疗资源匮乏、镰状细胞病负担重的地区还面临着挑战, 采用新方法以筛查威胁视力的镰状细胞性视网膜病变患者具有必要性。本文回顾了现有文献, 并提出了未来的研究方向, 将人工智能与多模视网膜成像技术相结合, 以扩大对镰状细胞性视网膜病变的自动化、准确、基于影像的筛查。考虑到视网膜专家在监测和管理镰状细胞性视网膜病变模式的差异性, 我们还讨论了机器学习模型的最新进展, 该模型可以随着时间的推移定量地跟踪疾病进展。这些基于人工智能的应用对于镰状细胞性视网膜病变基于循证及资源有效的临床诊断和管理具有巨大潜力。
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longitudinal assessment of quantitative ultra widefield ischaemic and vascular parameters in Sickle Cell Retinopathy
British Journal of Ophthalmology, 2020Co-Authors: Duriye Damla Sevgi, Adrienne W. Scott, Marguerite O. Linz, Alison Martin, Christopher J Mugnaini, Shaivi Patel, Akosua Nti, Jamie Reese, Justis P EhlersAbstract:Purpose To evaluate longitudinal quantitative ischaemic and vasculature parameters, including ischaemic index, vessel area, length and geodesic distance in Sickle Cell Retinopathy (SCR) on ultra-widefield fluorescein angiography (UWFA). Methods Optimal UWFA images from two longitudinal timepoints of 74 eyes from 45 patients with SCR were aligned and a common region of interest was determined. A deep-learning augmented ischaemia and vascular segmentation platform was used for feature extraction. Geodesic distance maps demonstrating the shortest distance within the vascular masks from the centre of the optic disc were created. Ischaemic index, vessel area, vessel length and geodesic distance were measured. Paired t-test and linear mixed effect model analysis were performed. Results Overall, 25 (44 eyes) patients with HbSS, 14 (19 eyes) with HbSC, 6 (11 eyes) with HbSthal and other genotypes were included. Mean age was 40.1±11.0 years. Mean time interval between two UWFA studies was 23.0±15.1 months (range: 3–71.3). Mean panretinal ischaemic index increased from 10.0±7.2% to 10.9±7.3% (p Conclusion Longitudinal ischaemic index and retinal vascular parameter measurements demonstrate statistically significant progression in SCR. The clinical significance of these relatively small magnitude changes remains unclear but may provide insights into the progression of retinal ischaemia in SCR.
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Interocular asymmetry of foveal avascular zone morphology and parafoveal capillary density in Sickle Cell Retinopathy.
PloS one, 2020Co-Authors: Davis B. Zhou, Adrienne W. Scott, Marguerite O. Linz, Ian C. Han, Maria V. Castanos, Giselle Lynch, Jorge S. Andrade Romo, Rachel E Linderman, Joseph Carroll, Richard B. RosenAbstract:Objectives To examine interocular asymmetry of foveal avascular zone (FAZ) and parafoveal capillary density metrics in Sickle Cell Retinopathy (SCR) using optical coherence tomography angiography (OCT-A). Methods This cross-sectional, retrospective study evaluated SCR patients and unaffected controls who underwent 3x3mm macular OCT-A imaging using a spectral domain-OCT system. FAZ (area, perimeter, and acircularity index) and parafoveal capillary density metrics were computed for both eyes of each participant. In unaffected controls, interocular difference in FAZ and parafoveal capillary density metrics were evaluated using Bland-Altman plots. SCR patients with interocular difference outside the upper 97.5% and lower 2.5% limits of agreement from controls were defined as having interocular asymmetry. Area under receiver operating characteristic curve (AROC) was also performed to determine the ability of the absolute interocular difference to differentiate between subjects with SCR—including non-proliferative SCR (NP-SCR) and proliferative SCR (P-SCR)–and unaffected controls. Results Thirty-one patients with SCR (21 NP-SCR and 10 P-SCR) and 14 race-matched and age-matched controls were included for analysis. Interocular asymmetry was seen for all FAZ and parafoveal capillary density metrics in NP-SCR and P-SCR subjects. SCR subjects showed greater disease severity in the left-eye for FAZ and parafoveal capillary density metrics. Conclusions NP-SCR and P-SCR patients demonstrated quantifiable interocular asymmetry in FAZ and parafoveal capillary density metrics compared to unaffected subjects, with left-eye predominance in disease severity.
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foveal avascular zone morphology and parafoveal capillary perfusion in Sickle Cell Retinopathy
British Journal of Ophthalmology, 2020Co-Authors: Adrienne W. Scott, Marguerite O. Linz, Ian C. Han, Giselle Lynch, Rachel E Linderman, Joseph Carroll, Richard B. Rosen, Jorge Andrade S RomoAbstract:Background/aims To assess foveal avascular zone (FAZ) morphology and parafoveal capillary perfusion in patients with various stages of Sickle Cell Retinopathy (SCR) using optical coherence tomography angiography (OCT-A). Methods This is a multi-institutional retrospective study of patients with various stages of SCR compared with healthy controls. Parafoveal OCT-A images obtained using a commercial spectral domain-OCT system were reviewed. Foveal-centred 3×3 mm full vascular slab OCT-As were used for image processing and data analysis. FAZ area, perimeter, and acircularity index were determined on the OCT-A image after manual delineation of the FAZ border. Quadrant-based parafoveal capillary density and per cent area deviating from normal distribution were also measured. Results Fifty-two patients with SCR (33 non-proliferative and 19 proliferative) and 20 age and race-matched healthy controls were included. One randomly selected eye per study participant was analysed. FAZ perimeter and acircularity index were significantly greater in SCR eyes when compared with the controls. While parafoveal capillary density was significantly lower, per cent area deviated from normal distribution was significantly higher in SCR eyes than that of the control. However, no statistically significant difference between the two SCR stages was observed. In quadrant-based analysis, the temporal quadrant showed greater parafoveal capillary dropout due to SCR, with the most profound effect in patients with proliferative SCR. Conclusions Abnormal FAZ morphology and altered parafoveal capillary perfusion were found in patients with SCR. Our customised OCT-A image analysis method uniquely highlights significant quantitative alterations in perfusion density mapping in a qualitative display, with minimal obscuration of OCT-A image detail.
Ian C. Han - One of the best experts on this subject based on the ideXlab platform.
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Artificial intelligence for improving Sickle Cell Retinopathy diagnosis and management
Eye, 2021Co-Authors: Sophie Cai, Ian C. Han, Adrienne W. ScottAbstract:Sickle Cell Retinopathy is often initially asymptomatic even in proliferative stages, but can progress to cause vision loss due to vitreous haemorrhages or tractional retinal detachments. Challenges with access and adherence to screening dilated fundus examinations, particularly in medically underserved areas where the burden of Sickle Cell disease is highest, highlight the need for novel approaches to screening for patients with vision-threatening Sickle Cell Retinopathy. This article reviews the existing literature on and suggests future research directions for coupling artificial intelligence with multimodal retinal imaging to expand access to automated, accurate, imaging-based screening for Sickle Cell Retinopathy. Given the variability in retinal specialist practice patterns with regards to monitoring and treatment of Sickle Cell Retinopathy, we also discuss recent progress toward development of machine learning models that can quantitatively track disease progression over time. These artificial intelligence-based applications have great potential for informing evidence-based and resource-efficient clinical diagnosis and management of Sickle Cell Retinopathy. 镰状细胞性视网膜病变最初甚至在增殖期通常无症状, 但随病情进展, 可由于玻璃体出血或牵拉性视网膜脱离而导致视力丧失。获取广角眼底检查所面临的挑战, 尤其是在医疗资源匮乏、镰状细胞病负担重的地区还面临着挑战, 采用新方法以筛查威胁视力的镰状细胞性视网膜病变患者具有必要性。本文回顾了现有文献, 并提出了未来的研究方向, 将人工智能与多模视网膜成像技术相结合, 以扩大对镰状细胞性视网膜病变的自动化、准确、基于影像的筛查。考虑到视网膜专家在监测和管理镰状细胞性视网膜病变模式的差异性, 我们还讨论了机器学习模型的最新进展, 该模型可以随着时间的推移定量地跟踪疾病进展。这些基于人工智能的应用对于镰状细胞性视网膜病变基于循证及资源有效的临床诊断和管理具有巨大潜力。
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Interocular asymmetry of foveal avascular zone morphology and parafoveal capillary density in Sickle Cell Retinopathy.
PloS one, 2020Co-Authors: Davis B. Zhou, Adrienne W. Scott, Marguerite O. Linz, Ian C. Han, Maria V. Castanos, Giselle Lynch, Jorge S. Andrade Romo, Rachel E Linderman, Joseph Carroll, Richard B. RosenAbstract:Objectives To examine interocular asymmetry of foveal avascular zone (FAZ) and parafoveal capillary density metrics in Sickle Cell Retinopathy (SCR) using optical coherence tomography angiography (OCT-A). Methods This cross-sectional, retrospective study evaluated SCR patients and unaffected controls who underwent 3x3mm macular OCT-A imaging using a spectral domain-OCT system. FAZ (area, perimeter, and acircularity index) and parafoveal capillary density metrics were computed for both eyes of each participant. In unaffected controls, interocular difference in FAZ and parafoveal capillary density metrics were evaluated using Bland-Altman plots. SCR patients with interocular difference outside the upper 97.5% and lower 2.5% limits of agreement from controls were defined as having interocular asymmetry. Area under receiver operating characteristic curve (AROC) was also performed to determine the ability of the absolute interocular difference to differentiate between subjects with SCR—including non-proliferative SCR (NP-SCR) and proliferative SCR (P-SCR)–and unaffected controls. Results Thirty-one patients with SCR (21 NP-SCR and 10 P-SCR) and 14 race-matched and age-matched controls were included for analysis. Interocular asymmetry was seen for all FAZ and parafoveal capillary density metrics in NP-SCR and P-SCR subjects. SCR subjects showed greater disease severity in the left-eye for FAZ and parafoveal capillary density metrics. Conclusions NP-SCR and P-SCR patients demonstrated quantifiable interocular asymmetry in FAZ and parafoveal capillary density metrics compared to unaffected subjects, with left-eye predominance in disease severity.
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foveal avascular zone morphology and parafoveal capillary perfusion in Sickle Cell Retinopathy
British Journal of Ophthalmology, 2020Co-Authors: Adrienne W. Scott, Marguerite O. Linz, Ian C. Han, Giselle Lynch, Rachel E Linderman, Joseph Carroll, Richard B. Rosen, Jorge Andrade S RomoAbstract:Background/aims To assess foveal avascular zone (FAZ) morphology and parafoveal capillary perfusion in patients with various stages of Sickle Cell Retinopathy (SCR) using optical coherence tomography angiography (OCT-A). Methods This is a multi-institutional retrospective study of patients with various stages of SCR compared with healthy controls. Parafoveal OCT-A images obtained using a commercial spectral domain-OCT system were reviewed. Foveal-centred 3×3 mm full vascular slab OCT-As were used for image processing and data analysis. FAZ area, perimeter, and acircularity index were determined on the OCT-A image after manual delineation of the FAZ border. Quadrant-based parafoveal capillary density and per cent area deviating from normal distribution were also measured. Results Fifty-two patients with SCR (33 non-proliferative and 19 proliferative) and 20 age and race-matched healthy controls were included. One randomly selected eye per study participant was analysed. FAZ perimeter and acircularity index were significantly greater in SCR eyes when compared with the controls. While parafoveal capillary density was significantly lower, per cent area deviated from normal distribution was significantly higher in SCR eyes than that of the control. However, no statistically significant difference between the two SCR stages was observed. In quadrant-based analysis, the temporal quadrant showed greater parafoveal capillary dropout due to SCR, with the most profound effect in patients with proliferative SCR. Conclusions Abnormal FAZ morphology and altered parafoveal capillary perfusion were found in patients with SCR. Our customised OCT-A image analysis method uniquely highlights significant quantitative alterations in perfusion density mapping in a qualitative display, with minimal obscuration of OCT-A image detail.
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utility of ultra widefield retinal imaging for the staging and management of Sickle Cell Retinopathy
Retina-the Journal of Retinal and Vitreous Diseases, 2019Co-Authors: Ian C. Han, Marguerite O. Linz, Alice Yang Zhang, Tin Yan Alvin Liu, Adrienne W. ScottAbstract:Purpose To determine whether ultra-widefield (UWF) retinal imaging changes the staging or management of Sickle Cell Retinopathy compared with clinical examination. Methods Prospective, observational study including patients with Sickle Cell disease. All patients underwent dilated fundus examination by a fellowship-trained retina specialist, as well as UWF fundus photography (FF) and fluorescein angiography (FA). Sickle Retinopathy stage and treatment recommendation per eye were determined after clinical examination, UWF-FF, and UWF-FA, respectively, and differences in Retinopathy stage and treatment recommendation were compared. Results A total of 70 eyes from 35 patients (17 women, 48.6%), mean age 30.4 years, were included. Sickle genotypes included 26 patients with Sickle SS (74.3%), 7 SC (20.0%), and 2 β(+)thalassemia (5.7%). Based on examination, most eyes (42/70; 60.0%) had no visible Retinopathy. Based on UWF-FF, about half of the eyes were found to be Goldberg Stage 2 or above (36/70; 51.4%). Based on UWF-FA, nearly all eyes were Goldberg Stage 2 or above (63/70; 90%). However, clinical examination reliably detected neovascularization, and in no case did the addition of UWF imaging change management relative to examination alone. Conclusion Ultra-widefield imaging detects a higher stage of Sickle Cell Retinopathy compared with clinical examination alone, but these differences may not be clinically significant.
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progressive retinal thinning in Sickle Cell Retinopathy
Ophthalmology Retina, 2018Co-Authors: Cindy X Cai, Ian C. Han, Marguerite O. Linz, Jing Tian, Adrienne W. ScottAbstract:Purpose To determine the rate of retinal thinning on spectral-domain (SD) OCT in patients with Sickle Cell compared with controls. Design Retrospective, longitudinal study. Participants Patients with Sickle Cell and age-similar control patients with SD-OCT macula volume scans at least 10 months apart were reviewed. Methods Automated segmentation of the SD-OCT macula volume scans was performed using the Iowa Reference Algorithms to divide the retina into 3 combined retina layers: superficial (retinal nerve fiber layer and ganglion Cell layer), middle (inner plexiform layer and inner nuclear layer), and outer (outer plexiform layer to retinal pigment epithelium). The mean retinal thickness in each Early Treatment Diabetic Retinopathy Study (ETDRS) subfield was recorded. The rate of retinal thickness change was calculated using a multilevel mixed-effects model. Main Outcome Measures The rate of retinal thickness change in the superficial, middle, and outer retina. Results Thirty-eight eyes of 24 patients with Sickle Cell (age: mean 40 years, range 18–67 years; genotype: 12 hemoglobin SS, 11 hemoglobin SC, 1 not available) and 30 eyes of 30 control patients were followed on average for 25.5 months. The mean initial retinal thickness was thinner in the Sickle Cell group compared with the control group (superficial: 69.95 vs. 72.22 μm; middle: 65.24 vs. 71.22 μm; outer: 171.37 vs. 175.55 μm). The mean rate of retinal thinning was greater for the Sickle Cell group than the control group (superficial: −0.89 vs. −0.41 μm/year; middle: −0.45 vs. +0.18 μm/year; outer: −0.50 vs. −0.02 μm/year). The rate of thinning in patients with Sickle Cell was statistically significant (P Conclusions Patients with Sickle Cell exhibit a progressive retinal thinning predominantly affecting the superficial and middle retina that may represent chronic microvascular insult.
Szilard Kiss - One of the best experts on this subject based on the ideXlab platform.
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ultra wide field fluorescein angiography in retinal disease
Current Opinion in Ophthalmology, 2014Co-Authors: Mrinali Patel, Szilard KissAbstract:PURPOSE OF REVIEW Ultra-wide-field fluorescein angiography (UWFA), which captures up to 200° of retina in a single image, now affords us the ability to angiographically examine the parts of the retina previously not photographable. Here, we review the role of UWFA in the management of retinal disease. RECENT FINDINGS UWFA effectively images the abnormality in a variety of retinal conditions, including diabetic Retinopathy, retinal vein occlusion, Sickle Cell Retinopathy, uveitis, and pediatric retinal disease, in turn guiding both diagnosis and management of these conditions. SUMMARY UWFA is a useful imaging modality that is expected to become increasingly incorporated into the practice of retina. This will likely fuel the studies to determine how to reconcile the findings from UWFA with practice guidelines based on the studies conducted prior to the development of UWFA.
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detection and monitoring of Sickle Cell Retinopathy using ultra wide field color photography and fluorescein angiography
Retina-the Journal of Retinal and Vitreous Diseases, 2011Co-Authors: Minhee Cho, Szilard KissAbstract:Purpose:In this study, we demonstrate the use of wide-field photography and fluorescein angiography to visualize the peripheral vascular changes and to identify patients with risk factors for developing proliferative Sickle Cell Retinopathy.Methods:This is a retrospective case series of 12 eyes of 6
Jennifer I Lim - One of the best experts on this subject based on the ideXlab platform.
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longitudinal assessment of retinal thinning in adults with and without Sickle Cell Retinopathy using spectral domain optical coherence tomography
JAMA Ophthalmology, 2021Co-Authors: Jennifer I Lim, Marcia Niec, Jie Sun, Dingcai CaoAbstract:Importance Determination of retinal thinning rates may help to identify patients who are at risk of progression of Sickle Cell Retinopathy. Objective To assess the rates of macular thinning in adults with and without Sickle Cell Retinopathy using spectral-domain optical coherence tomography (OCT) and to identify ocular and systemic risk factors associated with retinal thinning. Design, setting, and participants This longitudinal prospective case-control study enrolled adult participants from a university-based retina subspecialty clinic between February 11, 2009, and July 3, 2019. The study was designed in autumn 2008 and conducted from February 2, 2009, to July 3, 2020. Participants with Sickle Cell Retinopathy (Sickle Cell group) were matched by age and race with participants without Sickle Cell Retinopathy (control group). Participants received annual spectral-domain OCT and clinical examinations. Those with at least 1 year of follow-up by July 3, 2020, were included in the analysis. Data were analyzed from February 2, 2009, to July 3, 2020. Main outcomes and measures The primary outcome was comparison of spectral-domain OCT measurements from early-treatment diabetic Retinopathy study subfield rates of retinal thinning between eyes with and without Sickle Cell Retinopathy and between different Sickle Cell hemoglobin subtypes. The secondary outcome was identification of ocular and systemic risk factors associated with rates of retinal thinning. Results Among 370 adults (711 eyes) enrolled in the study, 310 participants (606 eyes) had Sickle Cell Retinopathy, and 60 participants (105 eyes) did not. Of those, 175 of 310 participants (56.5%; 344 of 606 eyes [56.8%]; mean [SD] age, 37.8 [12.8] years; 126 women [72.0%]) in the Sickle Cell group and 31 of 60 participants (51.7%; 46 of 105 eyes [43.8%]; mean [SD] age, 59 [15.4] years; 22 women [71.0%]) in the control group had at least 1 year of clinical and spectral-domain OCT follow-up data from baseline. The mean (SD) follow-up was 53.7 (32.6) months for the Sickle Cell group and 54.6 (34.9) months for the control group. Rates of macular thinning in the Sickle Cell group were significantly higher than those in the control group for the inner nasal (difference, -1.18 μm per year; 95% CI, -1.71 to -0.65 μm per year), inner superior (difference, -1.03 μm per year; 95% CI, -1.78 to -0.29 μm per year), inner temporal (difference, -0.61 μm per year; 95% CI, -1.16 to -0.07 μm per year), and outer nasal (difference, -0.41 μm per year; 95% CI, -0.80 to -0.03 μm per year) quadrants. Patients with Sickle Cell hemoglobin SC and Sickle Cell hemoglobin β-thalassemia subtypes had higher rates of retinal thinning than those with the Sickle Cell hemoglobin SS subtype. Risk factors associated with greater rates of retinal thinning included participant age, stage of Retinopathy, previous stroke, and presence of hypertension, acute chest syndrome, or diabetes. Hydroxyurea therapy was associated with decreased rates of retinal thinning and may be a protective factor. Conclusions and relevance In this study, rates of retinal thinning were higher among participants with Sickle Cell Retinopathy compared with those without Sickle Cell Retinopathy, and thinning rates increased with participant age and stage of Retinopathy. These findings suggest that identifying anatomic worsening of Sickle Cell maculopathy through spectral-domain OCT may be a useful parameter to evaluate the progression of Sickle Cell Retinopathy.
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relating retinal blood flow and vessel morphology in Sickle Cell Retinopathy
Eye, 2020Co-Authors: Jennifer Cano, Jennifer I Lim, Shayan Farzad, Maziyar M Khansari, Ou Tan, David Huang, Mahnaz ShahidiAbstract:The purpose of the current study was to determine associations between retinal blood flow and vessel morphology metrics in Sickle Cell Retinopathy (SCR) and healthy normal control (NC) subjects. Optical coherence tomography angiography (OCTA) and Doppler OCT imaging were performed in 12 SCR (15 eyes) and 19 NC (26 eyes) subjects. Vessel tortuosity was measured using a dedicated image analysis algorithm applied to OCTA images. Vessel density and spacing between vessels were determined from OCTA images by a fractal dimension analysis method. Retinal blood flow was quantified using a phase-resolved technique applied to en face Doppler OCT images. There was a significant association between increased retinal blood flow and increased vessel tortuosity (P = 0.03). Furthermore, increased retinal blood flow was associated with increased vessel density (P = 0.03) and decreased spacing between small vessels (P = 0.01). There was no significant association between retinal blood flow and spacing between large vessels (P = 0.11). Vessel tortuosity and blood flow were increased, whereas spacing between small vessels was decreased in SCR compared to NC group (P ≤ 0.03). There were no significant differences in vessel density or spacing between large vessels between the SCR and NC groups (P ≥ 0.31). Associations between retinal hemodynamics and vessel morphology were reported, providing better understanding of retinal pathophysiology and insight into potential quantitative biomarkers to evaluate SCR.
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Sickle Cell Retinopathy
2020Co-Authors: Ruik Chee, Sarwar Zahid, Jennifer I LimAbstract:Sickle Cell disease refers to a group of inherited hemoglobinopathies characterized by abnormal hemoglobin genes. The resulting abnormal hemoglobin protein results in sickling of erythrocytes, intravascular hemolysis, defective oxygen transport, and tissue damage due to ischemia and necrosis. Sickle Cell disease manifests systemically in many organs such as the brain, lungs, heart, liver, spleen, kidneys, joints, bones, and skin (Yawn et al. 2014).
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differential artery vein analysis improves the performance of octa staging of Sickle Cell Retinopathy
Translational Vision Science & Technology, 2019Co-Authors: Minhaj Alam, Jennifer I Lim, Devrim Toslak, Xincheng YaoAbstract:Purpose We test if differential artery-vein analysis can increase the performance of optical coherence tomography angiography (OCTA) detection and classification of Sickle Cell Retinopathy (SCR). Method This observational case series was conducted in a tertiary-retina practice. Color fundus and OCTA images were collected from 20 control and 48 SCR subjects. Fundus data were collected from fundus imaging devices, and SD-OCT and corresponding OCTA data were acquired using a spectral-domain OCT (SD-OCT) angiography system. For each patient, color fundus image-guided artery-vein classification was conducted in the OCTA image. Traditional mean blood vessel tortuosity (m-BVT) and mean blood vessel caliber (m-BVC) in OCTA images were quantified for control and SCR groups. Artery BVC (a-BVC), vein BVC (v-BVC), artery BVT (a-BVT), and vein BVT (v-BVT) were calculated; and then the artery-vein ratio of BVC (AVR-BVC) and artery-vein ratio of BVT (AVR-BVT) were quantified for comparative analysis. Results We evaluated 40 control and 85 SCR images in this study. The color fundus image-guided artery-vein classification had 97.02% accuracy for differentiating arteries and veins in OCTA. Differential artery-vein analysis provided significant improvement (P < 0.05) in detecting and classifying SCR stages compared to traditional mean blood vessel analysis. AVR-BVT and AVR-BVC showed significant (P < 0.001) correlation with SCR severity. Conclusions Differential artery-vein analysis can significantly improve the performance of OCTA detection and classification of SCR. AVR-BVT is the most sensitive feature that can classify control and mild SCR. Translational Relevance SCR and other retinovascular diseases result in changes to the caliber and tortuosity appearance of arteries and veins separately. Differential artery-vein analysis can improve the performance of SCR detection and stage classification.
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analysis of retinal thinning using spectral domain optical coherence tomography imaging of Sickle Cell Retinopathy eyes compared to age and race matched control eyes
American Journal of Ophthalmology, 2018Co-Authors: Jennifer I Lim, Dingcai CaoAbstract:Purpose To determine whether the retina is thinner in Sickle Cell patients than in race- and age-matched controls, and, if it is thinner, whether there is any association with systemic diseases. Methods Sickle Cell and control (age- and race-matched) patients were prospectively enrolled from a university retina clinic into this observational study. Participants underwent visual acuity testing, slit-lamp biomicroscopy, dilated ophthalmoscopy, and spectral-domain optical coherence tomography imaging. Sickle Cell retinal lesions, degree of vascular tortuosity, caliber of arteriovenous anastomosis, and stage of Retinopathy were noted. Early Treatment Diabetic Retinopathy Study (ETDRS) subfield measurements were compared between Sickle Cell and control subjects and also among Sickle Cell hemoglobin subtypes. Associations between ETDRS subfield measurements and hemoglobin subtype, Retinopathy stage, and systemic diseases were assessed. Results A total of 513 Sickle Cell eyes (260 patients) and 75 control eyes (39 patients) had median visual acuities of 20/20. ETDRS central ( P = .002), inner (nasal P = .009, superior P = .021, temporal P P = .017), and temporal outer ( P = .012) subfield measurements were thinner in Sickle Cell eyes compared to control eyes. Hemoglobin SS eyes had significantly thinner inner ETDRS subfield measurements compared to SC and SThal eyes. Retinal thinning in all subfields was associated with age ( P = .017) for Sickle Cell and control eyes. No association was found between retinal thinning and hydroxyurea use or arteriovenous anastomosis caliber. Conclusions The macula is thinner in Sickle Cell eyes compared to control eyes; retinal thickness decreases with increasing age and Sickle Cell Retinopathy stage and is most severe in hemoglobin SS subtypes.
Marguerite O. Linz - One of the best experts on this subject based on the ideXlab platform.
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longitudinal assessment of quantitative ultra widefield ischaemic and vascular parameters in Sickle Cell Retinopathy
British Journal of Ophthalmology, 2020Co-Authors: Duriye Damla Sevgi, Adrienne W. Scott, Marguerite O. Linz, Alison Martin, Christopher J Mugnaini, Shaivi Patel, Akosua Nti, Jamie Reese, Justis P EhlersAbstract:Purpose To evaluate longitudinal quantitative ischaemic and vasculature parameters, including ischaemic index, vessel area, length and geodesic distance in Sickle Cell Retinopathy (SCR) on ultra-widefield fluorescein angiography (UWFA). Methods Optimal UWFA images from two longitudinal timepoints of 74 eyes from 45 patients with SCR were aligned and a common region of interest was determined. A deep-learning augmented ischaemia and vascular segmentation platform was used for feature extraction. Geodesic distance maps demonstrating the shortest distance within the vascular masks from the centre of the optic disc were created. Ischaemic index, vessel area, vessel length and geodesic distance were measured. Paired t-test and linear mixed effect model analysis were performed. Results Overall, 25 (44 eyes) patients with HbSS, 14 (19 eyes) with HbSC, 6 (11 eyes) with HbSthal and other genotypes were included. Mean age was 40.1±11.0 years. Mean time interval between two UWFA studies was 23.0±15.1 months (range: 3–71.3). Mean panretinal ischaemic index increased from 10.0±7.2% to 10.9±7.3% (p Conclusion Longitudinal ischaemic index and retinal vascular parameter measurements demonstrate statistically significant progression in SCR. The clinical significance of these relatively small magnitude changes remains unclear but may provide insights into the progression of retinal ischaemia in SCR.
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Interocular asymmetry of foveal avascular zone morphology and parafoveal capillary density in Sickle Cell Retinopathy.
PloS one, 2020Co-Authors: Davis B. Zhou, Adrienne W. Scott, Marguerite O. Linz, Ian C. Han, Maria V. Castanos, Giselle Lynch, Jorge S. Andrade Romo, Rachel E Linderman, Joseph Carroll, Richard B. RosenAbstract:Objectives To examine interocular asymmetry of foveal avascular zone (FAZ) and parafoveal capillary density metrics in Sickle Cell Retinopathy (SCR) using optical coherence tomography angiography (OCT-A). Methods This cross-sectional, retrospective study evaluated SCR patients and unaffected controls who underwent 3x3mm macular OCT-A imaging using a spectral domain-OCT system. FAZ (area, perimeter, and acircularity index) and parafoveal capillary density metrics were computed for both eyes of each participant. In unaffected controls, interocular difference in FAZ and parafoveal capillary density metrics were evaluated using Bland-Altman plots. SCR patients with interocular difference outside the upper 97.5% and lower 2.5% limits of agreement from controls were defined as having interocular asymmetry. Area under receiver operating characteristic curve (AROC) was also performed to determine the ability of the absolute interocular difference to differentiate between subjects with SCR—including non-proliferative SCR (NP-SCR) and proliferative SCR (P-SCR)–and unaffected controls. Results Thirty-one patients with SCR (21 NP-SCR and 10 P-SCR) and 14 race-matched and age-matched controls were included for analysis. Interocular asymmetry was seen for all FAZ and parafoveal capillary density metrics in NP-SCR and P-SCR subjects. SCR subjects showed greater disease severity in the left-eye for FAZ and parafoveal capillary density metrics. Conclusions NP-SCR and P-SCR patients demonstrated quantifiable interocular asymmetry in FAZ and parafoveal capillary density metrics compared to unaffected subjects, with left-eye predominance in disease severity.
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foveal avascular zone morphology and parafoveal capillary perfusion in Sickle Cell Retinopathy
British Journal of Ophthalmology, 2020Co-Authors: Adrienne W. Scott, Marguerite O. Linz, Ian C. Han, Giselle Lynch, Rachel E Linderman, Joseph Carroll, Richard B. Rosen, Jorge Andrade S RomoAbstract:Background/aims To assess foveal avascular zone (FAZ) morphology and parafoveal capillary perfusion in patients with various stages of Sickle Cell Retinopathy (SCR) using optical coherence tomography angiography (OCT-A). Methods This is a multi-institutional retrospective study of patients with various stages of SCR compared with healthy controls. Parafoveal OCT-A images obtained using a commercial spectral domain-OCT system were reviewed. Foveal-centred 3×3 mm full vascular slab OCT-As were used for image processing and data analysis. FAZ area, perimeter, and acircularity index were determined on the OCT-A image after manual delineation of the FAZ border. Quadrant-based parafoveal capillary density and per cent area deviating from normal distribution were also measured. Results Fifty-two patients with SCR (33 non-proliferative and 19 proliferative) and 20 age and race-matched healthy controls were included. One randomly selected eye per study participant was analysed. FAZ perimeter and acircularity index were significantly greater in SCR eyes when compared with the controls. While parafoveal capillary density was significantly lower, per cent area deviated from normal distribution was significantly higher in SCR eyes than that of the control. However, no statistically significant difference between the two SCR stages was observed. In quadrant-based analysis, the temporal quadrant showed greater parafoveal capillary dropout due to SCR, with the most profound effect in patients with proliferative SCR. Conclusions Abnormal FAZ morphology and altered parafoveal capillary perfusion were found in patients with SCR. Our customised OCT-A image analysis method uniquely highlights significant quantitative alterations in perfusion density mapping in a qualitative display, with minimal obscuration of OCT-A image detail.
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utility of ultra widefield retinal imaging for the staging and management of Sickle Cell Retinopathy
Retina-the Journal of Retinal and Vitreous Diseases, 2019Co-Authors: Ian C. Han, Marguerite O. Linz, Alice Yang Zhang, Tin Yan Alvin Liu, Adrienne W. ScottAbstract:Purpose To determine whether ultra-widefield (UWF) retinal imaging changes the staging or management of Sickle Cell Retinopathy compared with clinical examination. Methods Prospective, observational study including patients with Sickle Cell disease. All patients underwent dilated fundus examination by a fellowship-trained retina specialist, as well as UWF fundus photography (FF) and fluorescein angiography (FA). Sickle Retinopathy stage and treatment recommendation per eye were determined after clinical examination, UWF-FF, and UWF-FA, respectively, and differences in Retinopathy stage and treatment recommendation were compared. Results A total of 70 eyes from 35 patients (17 women, 48.6%), mean age 30.4 years, were included. Sickle genotypes included 26 patients with Sickle SS (74.3%), 7 SC (20.0%), and 2 β(+)thalassemia (5.7%). Based on examination, most eyes (42/70; 60.0%) had no visible Retinopathy. Based on UWF-FF, about half of the eyes were found to be Goldberg Stage 2 or above (36/70; 51.4%). Based on UWF-FA, nearly all eyes were Goldberg Stage 2 or above (63/70; 90%). However, clinical examination reliably detected neovascularization, and in no case did the addition of UWF imaging change management relative to examination alone. Conclusion Ultra-widefield imaging detects a higher stage of Sickle Cell Retinopathy compared with clinical examination alone, but these differences may not be clinically significant.
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clinical and ophthalmic factors associated with the severity of Sickle Cell Retinopathy
American Journal of Ophthalmology, 2019Co-Authors: Xiangyun J Duan, Marguerite O. Linz, Sophie Lanzkron, Caroline Ewing, Jiangxia Wang, Adrienne W. ScottAbstract:Purpose To identify associations between severity of Sickle Cell Retinopathy (SCR) and other clinical, laboratory, or treatment factors relevant to Sickle Cell disease (SCD). Design Retrospective cohort study. Methods We investigated clinical, laboratory, and demographic associations with the severity of SCR in 296 patients seen at both our SCD specialty clinic and our retina clinic. Multivariate multinomial logistic regression was used to estimate the association between each clinical variable and severity of SCR. Results Multivariate analysis showed that in patients with Sickle Cell anemia (SCA) genotypes, older age (95% confidence interval [CI], 1.04-1.15; P Conclusions These findings may inform clinicians of the symptoms, systemic findings, and disease-modifying therapies most frequently associated with SCR in SCD patients. Visual symptoms such as blurred vision or floaters were associated with progression of SCR and may be criteria for referral for retinal examination. Chronic transfusion therapy may be protective against the need for retinal laser photocoagulation or vitrectomy. Prospective studies are necessary to further explore risk factors for SCR and to identify which individuals with SCD are at risk for incident or progression of Retinopathy.