Optical Coherence Tomography Angiography Features Research Articles

Microsecond Pulsing Laser for Choroidal Neovascularization Associated with Central Serous Chorioretinopathy

Purpose To analyze the efficacy and safety of microsecond pulsing laser therapy (MLT) in the management of central serous chorioretinopathy (CSCR) complicated by choroidal neovascularization (CNV). Methods Patients with CSCR complicated by CNV defined as the presence of characteristic OCT angiography features were randomly assigned to either study or control group. All patients of the study group underwent MLT targeting CNV area using navigated laser system followed by at least 6-month follow-up. Sham treatment was performed in the control group. No other treatment or anti-VEGF therapy was used during the follow-up. Main outcome measure was complete resolution of subretinal fluid at the end of follow-up. Results Twenty-three eyes (13 males and 10 females, mean age 58.2 ± 8.0 years) with a mean CNV area 0.62 ± 0.77 mm2 were included in the study group. Fourteen (60.9%) patients achieved complete resolution of SRF, five (21.7%) patients demonstrated some reduction of SRF, and four (17.4%) patients demonstrated no improvement after MLT in the study group. Twelve eyes (8 males and 4 females, mean age 59.8 ± 4.6 years) were included in the control group where none of them demonstrated resolution of SRF at the end of the follow-up (p = 0.0018 compared to the study group). No adverse effects, such as changes of CNV size, deterioration of exudation, or decline in visual acuity were observed in the study group. Conclusion Microsecond pulsing laser is an effective and safe option for the treatment of CSCR complicated by relatively small CNV and achieves complete resolution of SRF in 61% of cases.

Subtyping stage 3 epiretinal membrane: a comprehensive study of ectopic inner foveal layers architecture and its clinical implications

AimsTo evaluate the visual function and foveal architecture in patients with stage 3 idiopathic epiretinal membrane (iERM).MethodsA cross-sectional observational study included 56 eyes of 52 patients with stage 3 iERM....

OCTA-ReVA: an open-source toolbox for comprehensive retinal vessel feature analysis in optical coherence tomography angiography.

Optical coherence tomography angiography (OCTA) has significantly advanced the study and diagnosis of eye diseases. However, current clinical OCTA systems and software tools lack comprehensive quantitative analysis capabilities, limiting their full clinical utility. This paper introduces the OCTA Retinal Vessel Analyzer (OCTA-ReVA), a versatile open-source platform featuring a user-friendly graphical interface designed for the automated extraction and quantitative analysis of OCTA features. OCTA-ReVA includes traditional established OCTA features based on binary vascular image processing, such as blood vessel density (BVD), foveal avascular zone area (FAZ-A), blood vessel tortuosity (BVT), and blood vessel caliber (BVC). Additionally, it introduces new features based on blood perfusion intensity processing, such as perfusion intensity density (PID), vessel area flux (VAF), and normalized blood flow index (NBFI), which provide deeper insights into retinal perfusion conditions. These additional capabilities are crucial for the early detection and monitoring of retinal diseases. OCTA-ReVA demystifies the intricate task of retinal vasculature quantification, offering a robust tool for researchers and clinicians to objectively evaluate eye diseases and enhance the precision of retinal health assessments.

Linking disease activity with optical coherence tomography angiography in neovascular age related macular degeneration using artificial intelligence

To investigate quantitative associations between AI-assessed disease activity and optical coherence tomography angiography (OCTA)-derived parameters in patients with neovascular age-related macular degeneration (nAMD) undergoing anti-VEGF therapy. OCTA and SD-OCT images obtained from multicenter, randomized study data were evaluated. A deep learning algorithm (RetInSight) was used to detect and quantify macular fluid on SD-OCT. Mixed effects models were applied to evaluate correlations between fluid volumes, macular neovascularization (MNV)-type and OCTA-derived MNV parameters; lesion size (LS) and vessel area (NVA). 230 patients were included. A significant positive correlation was observed between SRF and NVA (estimate = 199.8 nl/mm2, p = 0.023), while a non-significant but negative correlation was found between SRF and LS (estimate = − 71.3 nl/mm2, p = 0.126). The presence of Type I and Type II MNV was associated with significantly less intraretinal fluid (IRF) compared to Type III MNV (estimate type I:− 52.1 nl, p = 0.019; estimate type II:− 51.7 nl, p = 0.021). A significant correlation was observed between pigment epithelial detachment (PED) and the interaction between NVA and LS (estimate:28.97 nl/mm2; p = 0.012). Residual IRF at week 12 significantly correlated to baseline NVA (estimate:38.1 nl/mm2; p = 0.015) and LS (estimate:− 22.6 nl/mm2; p = 0.012). Fluid in different compartments demonstrated disparate associations with MNV OCTA features. While IRF at baseline was most pronounced in type III MNV, residual IRF was driven by neovascular MNV characteristics. Greater NVA in proportion to LS was associated with higher amounts of SRF and PED. The correlation between these parameters may represent MNV maturation and can be used as a biomarker for resolution of disease activity. AI-based OCT analysis allows for a deeper understanding of neovascular disease in AMD and the potential to adjust therapeutic strategies to optimize outcomes through precision medicine.

Optical coherence tomography angiography features in Waldenström macroglobulinemia patients without Hyperviscosity syndrome: A pilot prospective study

PurposeTo evaluate the retinal vessel density (VD) with optical coherence tomography angiography (OCTA) in asymptomatic patients affected by Waldenström macroglobulinemia (WM) without hyperviscosity syndrome (HVS) and to highlight the presence of microvascular damage in theese clinically asymptomatic WD patients. DesignProspective study. MethodsA total of 43 eyes from 43 WM patients (24 females, 19 males, mean age 55.1 ± 13.6 years) were enrolled from January 2023 to December 2023 in the Eye Clinic of the University of Naples Federico II. Along with WM patients, 40 healthy subjects (HS) (20 females, 20 males, mean age 52.3 ± 15.6 years) with a normal ophthalmic examination and no history of intraocular surgery or retinal pathologic features were included as control group All patients and controls underwent OCTA ResultsThe two groups were not significantly different for age and sex Visual acuity examination showed no statistically significant difference in BCVA between controls and patients Compared to HS, WD patients showed lower VD values in the SCP in the whole image (47.95 ± 5.17% vs. 52.99 ± 2.52 %; p < 0.001), as well as in the parafovea (53.01 ± 6.69% vs. 55.30 ± 2.61 %; p = 0.002), and fovea (21.38 ± 9.01% vs. 30.31 ± 5.84 %; p < 0.0001). On the other hand, in the DCP VD values were significantly higher in patients compared to controls in the whole image (55.82 ± 8.07% vs. 50.83 ± 5.46 %; p = 0.005), as well as in the parafovea (56.76 ± 6.26% vs. 52.59 ± 5.46 %; p = 0.0001), and fovea (38.75 ± 8.59% vs. 33.43 ± 8.68 %; p < 0.0001). ConclusionThe finding that OCTA confirmed the presence of widespread microvascular damage in WD patients clinically silent. Thus, OCTA is a safe rapid imaging technique that could represent a valid biomarker of systemic vascular dysfunction.

Optical coherence tomography angiography features of retinal artery occlusion: A case series

Optical coherence tomography angiography features of retinal artery occlusion: A case series

OCTA characteristics in non-arteritic central retinal artery occlusion and correlation with visual acuity.

To observe the retinal and choroidal circulations in patients with non-arteritic permanent central retinal artery occlusion (NA-CRAO) via optical coherence tomography angiography (OCTA) and analyze their correlation with visual acuity. Sixty-two eyes with clinically confirmed acute NA-CRAO were included in the study and divided into: A type (mild n=29), B type (moderate n=27) and C type (severe n=6) based on the degree of visual loss, retinal edema, and arterial blood flow delay in fundus fluorescence angiography (FFA). Contralateral healthy eyes were used as the control group. Best-corrected visual acuity (BCVA), slit lamp microscopy, indirect ophthalmoscopy, fundus color photography, OCTA, and FFA were performed. Spearman's correlation analysis was used to determine the correlations between retinal and choroidal vessels and visual acuity. There were no statistically significant differences in age, gender, and intraocular pressure among the three types and the control group (P>0.05). Vessel density in deep capillary plexus (VD-DCP) significantly decreased (P<0.05) in all three types of NA-CRAO patients compared to the control group. Vessel density in superficial vascular plexus (VD-SVP) significantly decreased (P<0.05) in type A patients and choriocapillaris flow area significantly decreased (P<0.05) in type B and type C patients compared to the control group; while outer retinal flow areas significantly increased in the type A (P<0.05) and decreased in type C patients (P<0.05). The retinal thickness significantly increased in type C group (P<0.05). The VD-SVP at fovea in the type A was significantly lower than both of type B and C. The VD-SVP at nasal parafovea in type A and B was significantly lower than type C (P<0.05). The logMAR BCVA of type A was significantly better than that of type B and C groups (P<0.05). Spearman's correlation analysis showed that the logMAR BCVA was positively correlated with VD-SVP at fovea (r=0.679, P=0.031) and nasal parafovea (r=0.826, P=0.013). OCTA is valuable for assessing retinal ischemia, and evaluating visual impairment. Deep retinal vasculature is commonly affected in all NA-CRAO types. VD-SVPs at fovea and nasal parafovea can serve as reliable markers of visual impairment in NA-CRAO.

Features of optical coherence tomography angiography in age-related macular degeneration with residual fluid after three loading doses of aflibercept

BackgroundTo identify the macular neovascularization (MNV) features in exudative age-related macular degeneration (AMD) patients who exhibited residual fluid after receiving three loading doses of aflibercept.MethodsPatients were classified into two groups: Group 1, which did not exhibit intraretinal fluid (IRF) and subretinal fluid (SRF), and Group 2, which did exhibit IRF and/or SRF. Optical coherence tomography angiography (OCTA) features were assessed and compared between the groups.ResultsA total of 101 eyes were enrolled; 65 for Group 1 and 36 for Group 2. No significant differences were found in baseline MNV size (2.94 ± 2.51 µm2 vs. 2.22 ± 2.26 µm2, P = 0.178) or vessel density (47.1 ± 15.4 % vs. 41.3 ± 10.5%, P = 0.052) between Groups 1 and 2. There were significant differences in the presence of loops (52.3% vs. 75%, P = 0.026) and peripheral arcades (29.2% vs. 55.6%, P < 0.001) at baseline between the two groups. In Group 1, there was a significant reduction in the presence of branching (P < 0.001) and loops (P = 0.016) after treatment. In Group 2, only the presence of branching decreased significantly (P < 0.001) after treatment. Multivariable analysis revealed that the presence of a peripheral arcade (B = 4.77, P = 0.001) was significantly associated with residual fluid.ConclusionsAlthough responding to treatment, the presence of loops and peripheral arcades in exudative AMD patients may contribute to residual fluid following the three loading doses of aflibercept. The peripheral arcade, in particular, may play a more significant role in the presence of residual fluid.

Longitudinal changes in optical coherence tomography angiography characteristics in normal-tension glaucoma with or without high myopia.

To evaluate the structural, microvascular, and functional progression of normal tension glaucoma (NTG) with or without high myopia by examining longitudinal changes in optical coherence tomography angiography (OCTA) and visual field (VF) parameters. We evaluated 61 NTG eyes and classified 25 of the eyes with axial lengths (ALs) of ≥26 mm as highly myopic. We assessed the rate of change in OCTA parameters, namely radial peripapillary capillary (RPC) vessel density (VD), parafovea VD, deep parafovea VD, retinal nerve fibre layer (RNFL) thickness, and ganglion cell complex thickness. We evaluated the correlation of the rate of change in OCTA parameters with VF loss and AL. Among the 61 NTG eyes, rates of loss of RPC VD, parafovea VD, deep parafovea VD, and RNFL thickness were significantly different from zero despite the nonsignificant rate of change in VF mean deviation (MD). Changes in these OCTA parameters did not differ significantly in highly myopic NTG eyes. The rate of change in VF MD was significantly correlated with the rate of change in parafovea VD in highly myopic and non-highly myopic NTG eyes. In highly myopic NTG eyes, AL was negatively correlated with the rates of loss of RNFL thickness, VF MD, and VF PSD. NTG eyes with a relatively stable VF exhibited loss of VD and RNFL thickness. VF progression in NTG was correlated with decreasing parafovea VD, indicating a structure-function correlation. Greater AL may indicate faster VF loss and RNFL thinning in highly myopic NTG eyes.

Comparison of Widefield OCT Angiography Features Between Severe Non-Proliferative and Proliferative Diabetic Retinopathy.

There is a high and ever-increasing global prevalence of diabetic retinopathy (DR) and invasive imaging techniques are often required to confirm the presence of proliferative disease. The aim of this study was to explore the images of a rapid and non-invasive technique, widefield optical coherence tomography angiography (OCT-A), to study differences between patients with severe non-proliferative and proliferative DR (PDR). We conducted an observational longitudinal study from November 2022 to March 2023. We recruited 75 patients who were classified into a proliferative group (28 patients) and severe non-proliferative group (47 patients). Classification was done by specialist clinicians who had full access to any multimodal imaging they required to be confident of their diagnosis, including fluorescein angiography. For all patients, we performed single-shot 4 × 4 and 10 × 10mm (widefield) OCT-A imaging and when possible, the multiple images required for mosaic 17.5 × 17.5mm (ultra widefield) OCT-A imaging. We assessed the frequency with which proliferative disease was identifiable solely from these OCT-A images and used custom-built MATLAB software to analyze the images and determine computerized metrics such as density and intensity of vessels, foveal avascular zone, and ischemic areas. On clinically assessing the OCT-A 10 × 10 fields, we were only able to detect new vessels in 25% of known proliferative images. Using ultra-widefield mosaic images, however, we were able to detect new vessels in 100% of PDR patients. The image analysis metrics of 4 × 4 and 10 × 10mm images did not show any significant differences between the two clinical groups. For mosaics, however, there were significant differences in the capillary density in patients with PDR compared to severe non-PDR (9.1% ± 1.9 in the PDR group versus 11.0% ± 1.9 for severe group). We also found with mosaics a significant difference in the metrics of ischemic areas; average area of ischemic zones (253,930.1 ± 108,636 for the proliferative group versus 149,104.2 ± 55,101.8 for the severe group. Our study showed a high sensitivity for detecting PDR using only ultra-widefield mosaic OCT-A imaging, compared to multimodal including fluorescein angiography imaging. It also suggests that image analysis of aspects such as ischemia levels may be useful in identifying higher risk groups as a warning sign for future conversion to neovascularization.

Quantitative characterization of retinal features in translated OCTA.

This study explores the feasibility of quantitative Optical Coherence Tomography Angiography (OCTA) features translated from OCT using generative machine learning (ML) for characterizing vascular changes in retina. A generative adversarial network framework was employed alongside a 2D vascular segmentation and a 2D OCTA image translation model, trained on the OCT-500 public dataset and validated with data from the University of Illinois at Chicago (UIC) retina clinic. Datasets are categorized by scanning range (Field of view) and disease status. Validation involved quality and quantitative metrics, comparing translated OCTA (TR-OCTA) with ground truth OCTAs (GT-OCTA) to assess the feasibility for objective disease diagnosis. In our study, TR-OCTAs showed high image quality in both 3 and 6mm datasets (high-resolution and contrast quality, moderate structural similarity compared to GT-OCTAs). Vascular features like tortuosity and vessel perimeter index exhibits more consistent trends compared to density features which are affected by local vascular distortions. For the validation dataset (UIC), the metrics show similar trend with a slightly decreased performance since the model training was blind on UIC data, to evaluate inference performance. Overall, this study presents a promising solution to the limitations of OCTA adoption in clinical practice by using vascular features from TR-OCTA for disease detection. By making detailed vascular imaging more widely accessible and reducing reliance on expensive OCTA equipment, this research has the potential to significantly enhance the diagnostic process for retinal diseases.

Optical coherence tomography angiography features of the chorioretinal complex and choriocapillaris perfusion before and after vitrectomy with conventional versus fovea-sparing internal limiting membrane peeling for idiopathic macular hole

Purpose: To assess optical coherence tomography angiography (OCTA)-measured changes in the chorioretinal complex and choriocapillaris perfusion density in the macula before and after vitrectomy with fovea-sparing versus conventional internal limiting membrane (ILM) peeling for idiopathic macular hole (IMH). Material and Methods: Eyes with stage-2 to stage-4 holes as per the classification by Gass received 25-G vitrectomy with conventional or fovea-sparing ILM peeling and gas tamponade with 20% SF6 or 15% С3F8. IMH diameter, foveal avascular zone (FAZ) area in the deep retinal plexus and choriocapillaris perfusion density (CPD) were assessed before and 1 month after surgery. Results: Totally, 70 patients had an IMH surgery in 71 eyes. The mean age ± standard deviation (SD) was 65.7 ± 6.8 years, median IMH duration (interquartile range or IQR), 3.0 (1.0-6.0) months, median best-corrected visual acuity or BCVA (IQR), 0.19 (0.1-0.25), and median maximum IMH diameter (IQR), 673.5 (549.5–1010.5) µm. In eyes with IMH and fellow eyes, the median FAZ area (IQR) was 0.51 (0.15–0.53) mm2, and 0.46 (0.10–0.74) mm2, respectively (р = 0.49), and mean CPD ± SD, 0.11 ± 0.06, and 0.29 ± 0.13 (р = 0.0001), respectively. Thirty-four eyes received conventional ILM peeling and 37 eyes, fovea-sparing ILM peeling, and there was no significant intergroup difference in baseline characteristics. One month after surgery, IMH closure was achieved in 63/71 eyes (i.e., the closure rate was 88.7% for total operated eyes, and 88.2% and 89.2%, respectively, for eyes in conventional ILM peeling and fovea-sparing ILM peeling groups), and median BCVA (IQR) improved to 0.60 (0.4–0.8) (р = 0.00001). After IMH closure, in operated eyes, median FAZ area (IQR) decreased to 0.30 (0.12–0.6) mm2, but the difference was not significant, whereas mean CPD ± SD increased significantly from 0.11 ± 0.06 to 0.25 ± 0.10 (р = 0.0001). No significant difference in OCTA-based retinal microcirculation and choriocappillaris characteristics was observed between the conventional ILM peeling and fovea-sparing ILM peeling groups. Conclusion: The presence of macular hole is accompanied by abnormal perfusion in the choriocapillaris, but the CPD recovers after IMH closure. Postoperative CPD recovery is not influenced by the type (conventional or fovea-sparing) of ILM peeling.

Topographic comparison of the retinal microvascular changes between patients with compressive and glaucomatous optic neuropathies

We investigated the difference in optical coherence tomography angiography characteristics between the patients with compressive optic neuropathy (CON, n = 26) and glaucomatous optic neuropathy (GON, n = 26), who were matched for the severity of visual field defect. The peripapillary retinal nerve fiber layer (pRNFL) thickness in the nasal and temporal sectors was thinner in the CON group, whereas the inferior pRNFL thickness was thinner in the GON group. Accordingly, the CON group had lower peripapillary vessel density (pVD) in the nasal and temporal sectors, and the GON group in the inferior sector. In the macular area, the CON group had a thinner macular ganglion cell-inner plexiform layer in the superior and nasal sectors, whereas the GON group in the inferior sector. However, the CON group did not have a lower macular VD than the GON group in any sector, whereas the GON group exhibited lower superficial capillary plexus VD in the superior, inferior, and temporal sectors. Comparison of the structure–vasculature correlation revealed a significant difference in the nasal and temporal peripapillary areas and superior and nasal macular sectors; a decrease in VD was greater in the GON group than in the CON group when the comparable structural change occurred.

Local ocular factors associated with the development of diabetic macular edema: an inter-eye study

To investigate local ocular factors associated with the development of diabetic macular edema (DME), we classified each eye of patients with unilateral DME as the DME eyes or the fellow eyes (without DME). We compared the clinical characteristics, optical coherence tomography (OCT), and OCT angiography (OCTA), ultra-wide field fundus photography, and angiography features of each eye. As a result, fifty-five patients with unilateral DME were enrolled. Although the diabetic retinopathy stage was not different between each group of eyes, DME eyes showed a higher prevalence of venous beading and a larger area of nonperfusion region than did fellow eyes (all P < 0.05). OCTA features of DME eyes also showed a larger foveal avascular zone in the deep capillary plexus and a lower vascular density in both the superficial and deep capillary plexuses (all P < 0.05). This study highlighted ocular features reflecting retinal ischemia, such as venous beading, area of nonperfusion region, and vascular density in the central retinal area, are associated with the development of DME. OCTA and ultra-wide field fluorescein angiography may be useful for evaluating the parameters of retinal ischemia and the risk of DME development.

Macular Imaging Characteristics in Children with Myelinated Retinal Nerve Fiber and High Myopia Syndrome.

To investigate the macular imaging features in patients with unilateral myelinated retinal nerve fiber (MRNF) and high myopia syndrome. Six patients with unilateral MRNF and high myopia syndrome and 13 myopic controls were enrolled in this study. Spectral domain (SD) optical coherence tomography (OCT), SD enhanced depth imaging OCT, and OCT angiography (OCTA) imaging results of MRNF-affected eyes were compared with the fellow eyes and myopic controls. All patients had abnormal foveal reflex and/or ectopia. No significant difference in retinal thickness parameters were noted between the groups. In OCT scans, posterior vitreous detachment (PVD) was observed in 4 out of the 6 MRNF-affected eyes. Regarding OCTA parameters, only a significant increase in acircularity index was noted in myelinated eyes (p=0.01). All patients demonstrated normal foveal contours, macular structure, and OCTA features except for a higher acircularity index. The incidence of PVD was notably increased in the myelinated eyes.

Optical coherence tomography angiography characteristics of retinochoroidal and optic nerve head microcirculation in cryptogenic organizing pneumonia

BackgroundTo assess retinochoroidal and optic nerve head microcirculation alterations in cryptogenic organizing pneumonia. MethodsThirty cryptogenic organizing pneumonia patients in the resolution phase (group 1, 30 right eyes) and 33 healthy subjects (group 2, 33 right eyes) were compared. Patients had 40 mg/day corticosteroids for 8–10 days, and a pulmonary function test, which revealed only minimally restrictive ventilation features. After gathering demographic data, a comprehensive ophthalmological exam and optical coherence tomography angiography were performed three months following maximum disease resolution with corticosteroid therapy ResultsGroups 1 and 2 had mean ages of 54.37±14.87 and 49.61±12.36 years, respectively (P = 0.171). Despite the lack of statistical significance, superficial and deep capillary plexus vessel densities in all macular regions were lower in group 1, as were foveal avascular zone parameters (P>0.05). However, the outer retinal and choriocapillaris flows increased significantly in group 1, especially in select areas (P<0.001, for both). There were no significant differences in whole image (P = 0.346), inside disk (P = 0.438), or peripapillary (P = 0.185) optic nerve head vessel densities between the two groups; however, nasal (P<0.001) and inferior quadrant (P = 0.006) vessel densities differed significantly. Global retinal nerve fiber layer thickness did not differ significantly between groups 1 and 2 (112.83±14.71 versus 111.45±12.74 µm, respectively; P = 0.692). Group 1, however, had significantly higher superior, nasal, and inferior quadrant, and significantly lower temporal quadrant retinal nerve fiber layer thickness (P<0.001, for all). ConclusionsConcerning the impact of probable cryptogenic organizing pneumonia-induced hypoxia on ocular tissues, optical coherence tomography angiography assessments of retinochoroidal and optic nerve head microcirculation could be employed as a biomarker for cerebral microcirculation.

Evaluation of Peripapillary and Macular Optical Coherence Tomography Angiography Characteristics in Different Stages of Papilledema.

Prospective evaluation of optical coherence tomography (OCT) and OCT angiography (OCT-A) characteristics in different stages of papilledema in idiopathic intracranial hypertension (IIH). In this prospective, observational study patients of IIH with papilledema were recruited and divided into 3 groups-early/established (Group 1), chronic (Group 2), and atrophic papilledema (Group 3). Peripapillary retinal nerve fiber layer (RNFL) and macular ganglion cell inner plexiform layer (GC-IPL) were recorded on OCT. Peripapillary and macular perfusion was documented at superficial retinal, deep retinal, and choriocapillary level using OCT-A. The investigations were repeated at 3 months. RNFL showed significant thinning in all groups on follow-up with the atrophic group showing maximum thinning ( P = 0.01-Group 3). GC-IPL was significantly reduced in all stages of papilledema at baseline compared with the controls. Thinnest GC-IPL was noted in the atrophic group (52.75 ± 7.44 μm; P = 0.00 in Group 3 vs controls) that showed further deterioration on follow-up. On Image J analysis, significant decrease was noted at various levels in the peripapillary and macular perfusion at baseline especially in the atrophic group which showed further deterioration noted on follow-up. The final visual acuity showed a statistically significant weak negative correlation with baseline RNFL (r = -0.306) and GC-IPL (r = -0.384) and moderately negative correlation with baseline superficial peripapillary retinal perfusion (r = -0.553). A significant negative correlation was seen between increasing grade of papilledema and superficial peripapillary retinal perfusion with both Image J and automated indices (r = -0.46; r = -0.61), respectively. GC-IPL may help identify early damage in papilledema even in the presence of thicker RNFL. Significant vascular changes can be observed on OCT-A that may help predict the final visual outcome in papilledema due to IIH.

COMPARATIVE ANALYSIS OF OCT AND OCT ANGIOGRAPHY CHARACTERISTICS IN EARLY DIABETIC RETINOPATHY.

To assess the quantitative characteristics of optical coherence tomography (OCT) and OCT angiography (OCTA) for the objective detection of early diabetic retinopathy (DR). This was a retrospective and cross-sectional study, which was carried out at a tertiary academic practice with a subspecialty. Twenty control participants, 15 people with diabetics without retinopathy (NoDR), and 22 people with mild nonproliferative diabetic retinopathy (NPDR) were included in this study. Quantitative OCT characteristics were derived from the photoreceptor hyperreflective bands, i.e., inner segment ellipsoid (ISe) and retinal pigment epithelium (RPE). OCTA characteristics, including vessel diameter index (VDI), vessel perimeter index (VPI), and vessel skeleton density (VSD), were evaluated. Quantitative OCT analysis indicated that the ISe intensity was significantly trending downward with DR advancement. Comparative OCTA revealed VDI, VPI, and VSD as the most sensitive characteristics of DR. Correlation analysis of OCT and OCTA characteristics revealed weak variable correlation between the two imaging modalities. Quantitative OCT and OCTA analyses revealed photoreceptor and vascular distortions in early DR. Comparative analysis revealed that the OCT intensity ratio, ISe/RPE, has the best sensitivity for early DR detection. Weak variable correlation of the OCT and OCTA characteristics suggests that OCT and OCTA are providing supplementary information for DR detection and classification.

An open-source deep learning network AVA-Net for arterial-venous area segmentation in optical coherence tomography angiography

BackgroundDifferential artery-vein (AV) analysis in optical coherence tomography angiography (OCTA) holds promise for the early detection of eye diseases. However, currently available methods for AV analysis are limited for binary processing of retinal vasculature in OCTA, without quantitative information of vascular perfusion intensity. This study is to develop and validate a method for quantitative AV analysis of vascular perfusion intensity.MethodA deep learning network AVA-Net has been developed for automated AV area (AVA) segmentation in OCTA. Seven new OCTA features, including arterial area (AA), venous area (VA), AVA ratio (AVAR), total perfusion intensity density (T-PID), arterial PID (A-PID), venous PID (V-PID), and arterial-venous PID ratio (AV-PIDR), were extracted and tested for early detection of diabetic retinopathy (DR). Each of these seven features was evaluated for quantitative evaluation of OCTA images from healthy controls, diabetic patients without DR (NoDR), and mild DR.ResultsIt was observed that the area features, i.e., AA, VA and AVAR, can reveal significant differences between the control and mild DR. Vascular perfusion parameters, including T-PID and A-PID, can differentiate mild DR from control group. AV-PIDR can disclose significant differences among all three groups, i.e., control, NoDR, and mild DR. According to Bonferroni correction, the combination of A-PID and AV-PIDR can reveal significant differences in all three groups.ConclusionsAVA-Net, which is available on GitHub for open access, enables quantitative AV analysis of AV area and vascular perfusion intensity. Comparative analysis revealed AV-PIDR as the most sensitive feature for OCTA detection of early DR. Ensemble AV feature analysis, e.g., the combination of A-PID and AV-PIDR, can further improve the performance for early DR assessment.

Normalized Blood Flow Index in Optical Coherence Tomography Angiography Provides a Sensitive Biomarker of Early Diabetic Retinopathy.

To evaluate the sensitivity of normalized blood flow index (NBFI) for detecting early diabetic retinopathy (DR). Optical coherence tomography angiography (OCTA) images of healthy controls, diabetic patients without DR (NoDR), and patients with mild nonproliferative DR (NPDR) were analyzed in this study. The OCTA images were centered on the fovea and covered a 6 mm × 6 mm area. Enface projections of the superficial vascular plexus (SVP) and the deep capillary plexus (DCP) were obtained for the quantitative OCTA feature analysis. Three quantitative OCTA features were examined: blood vessel density (BVD), blood flow flux (BFF), and NBFI. Each feature was calculated from both the SVP and DCP and their sensitivities to distinguish the three cohorts of the study were evaluated. The only quantitative feature capable of distinguishing all three cohorts was NBFI in the DCP image. Comparative study revealed that both BVD and BFF were able to distinguish the controls and NoDR from mild NPDR. However, neither BVD nor BFF was sensitive enough to separate NoDR from the healthy controls. The NBFI has been demonstrated as a sensitive biomarker of early DR, revealing retinal blood flow abnormality better than traditional BVD and BFF. The NBFI in the DCP was verified as the most sensitive biomarker, supporting that diabetes affects the DCP earlier than SVP in DR. NBFI provides a robust biomarker for quantitative analysis of DR-caused blood flow abnormalities, promising early detection and objective classification of DR.