Optical Coherence Tomography Angiography Images Research Articles

Optical coherence tomography angiography changes in patients with hemoglobinopathy

Aim: The aim of this study is to evaluate retinal vascular changes in patients with sickle cell disease (SCD) and beta-thalassemia with optical coherence tomography angiography (OCT-A). Methods: For this purpose, 98 patients with SCD, 75 patients with beta-thalassemia, and 100 healthy controls in Mersin University Hospital between January 1, 2020, and November 1, 2021, were included in this study. OCT-A imaging was performed with ZEISS AngioPlex OCT angiography (Carl Zeiss Meditec, Dublin, CA, USA). Results: All OCT-A parameters (FAZ area, perimeter, circularity, vessel, and perfusion density) were found to be statistically significantly different in both patients with thalassemia and patients with sickle cell disease when compared to the controls. Conclusions: In conclusion, retinopathy related to both hemoglobinopathy subgroups can be diagnosed and followed up with OCT-A. It was also found that OCT-A parameters are affected before the development of clinically detectable retinopathy.

Parafoveal capillary density as a potential biomarker in the assessment of diabetic retinopathy progression

AbstractPurposeThe aim of this study was to assess longitudinal changes in retinal vessel density in diabetic patients using optical coherence tomography angiography (OCTA) to identify the most sensitive parameter for detecting retinopathy progression.MethodsPatients with diabetes mellitus were enrolled in this study. Each study subject underwent two imaging sessions, during which three OCTA images of the macular area and three images of the optic nerve head were obtained. The two sessions took place one year apart. The OCTA imaging was performed using an AngioVue device. Superficial vessel density was evaluated in the central 3 mm and parafoveal area, and the nonflow area was measured using the built-in automated AngioAnalytics software of the Optovue system.ResultsThis study included 78 eyes of 39 diabetic patients (age: 55.16 ± 13.73 years) with a mean of 7.70 ± 1.07 mmol L−1 HgA1c level at baseline. At the one-year visit, the eyes of the diabetic subjects had significantly lower superficial vessel density in the parafoveal macula compared to corresponding values at baseline (p < 0.05). There was no statistically significant difference between the baseline and one-year results for the other vascular density parameters and the foveal avascular zone (p > 0.05).ConclusionAt the one-year follow-up, we found that vessel density had decreased in the parafoveal ring in these patients, while there was no significant change in other vascular parameters. This result suggests that superficial parafoveal capillary density is the most sensitive OCTA parameter that can be used as a biomarker for diabetic retinopathy progression. None of the other vascular density parameters nor the foveal avascular zone were able to indicate the subtle changes in retinal microcirculation due to the progression of diabetic microvasculopathy.

Analysis of Choriocapillaris Reperfusion Topography following Faricimab Treatment for Neovascular Age-Related Macular Degeneration in Non-Treatment-Naïve Patients.

To assess changes in choriocapillaris (CC) vascular density surrounding macular neovascularization (MNV) in age-related macular degeneration (AMD) when transitioning from various anti-VEGF treatments to faricimab, using optical coherence tomography angiography (OCTA). 25 eyes of 22 individuals who underwent intravitreal faricimab injections for neovascular AMD with type 1 MNV were included. OCTA images were obtained prior to (T0), after one (T1), and after three faricimab injections (T2); Noteworthy changes occurred in the first ring at T2 in comparison to T0. The percentage of CC flow deficit (FD%), FD average area (FDa), and FD number (FDn) in 5 rings (R1-R5) surrounding the dark halo around the MNV were calculated. A reduction in FD% at T2 compared to T0 (50.5 ± 10.2% at T0, 46.4 ± 10.6% at T2; p = 0.020) was seen, indicating CC reperfusion. Additionally, we observed a reduction in the average FDa (140.2 ± 172.1% at T0, 93.7 ± 101.8% at T2; p = 0.029). Our study highlights an FD% after three consecutive faricimab injections. The most pronounced effect was observed in the first ring, directly adjacent to the dark halo, suggesting a partial CC reperfusion surrounding the MNV, potentially indicating disease regression.

Aflibercept combined with triamcinolone acetonide in the treatment of diabetic macular edema: optical coherence tomography and optical coherence tomography angiography.

To analyze the relationship between optical coherence tomography (OCT) and OCT angiography (OCTA) imaging in patients with diabetic macular edema (DME) who are treated with a combination of aflibercept and triamcinolone acetonide (TA). A total of 76 eyes newly diagnosed DME were included in this study. They were randomly assigned to receive either aflibercept or a combination of aflibercept and TA. Injections once a month for a total of three injections. Central macular thickness (CMT), number of hyperreflective foci (HRF), height of subretinal fluid (SRF), and area of foveal avascular zone (FAZ) were evaluated using OCT and OCTA at baseline and after each monthly treatment. Both groups showed improvement in best corrected visual acuity (BCVA) and reduction in macular edema after treatment, and the difference in BCVA between the two groups was statistically significant after each treatment (P<0.05). The difference in CMT between the two groups was statistically significant after the first two injections (P<0.01), but not after the third injection (P=0.875). The number of HRF (1mo: 7.41±8.25 vs 10.86±7.22, P=0.027; 2mo: 5.33±6.13 vs 9.12±8.61, P=0.034; 3mo: 3.58±3.00 vs 6.37±5.97, P=0.007) and height of SRF (1mo: 82.39±39.12 vs 105.77±42.26 µm, P=0.011; 2mo: 36.84±10.02 vs 83.59±37.78 µm, P<0.01; 3mo: 11.57±3.29 vs 45.43±12.60 µm, P<0.01) in combined group were statistically significant less than aflibercept group after each injection, while the area of FAZ showed no significant change before and after treatment in both groups. The combination therapy of aflibercept and TA shows more significant effects on DME eyes with decreased HRF and SRF. However, both aflibercept and combination therapy show no significant change in the area of FAZ.

Computational Retinal Microvascular Biomarkers from an OCTA Image in Clinical Investigation.

Retinal structural and functional changes in humans can be manifestations of different physiological or pathological conditions. Retinal imaging is the only way to directly inspect blood vessels and their pathological changes throughout the whole body non-invasively. Various quantitative analysis metrics have been used to measure the abnormalities of retinal microvasculature in the context of different retinal, cerebral and systemic disorders. Recently developed optical coherence tomography angiography (OCTA) is a non-invasive imaging tool that allows high-resolution three-dimensional mapping of the retinal microvasculature. The identification of retinal biomarkers from OCTA images could facilitate clinical investigation in various scenarios. We provide a framework for extracting computational retinal microvasculature biomarkers (CRMBs) from OCTA images through a knowledge-driven computerized automatic analytical system. Our method allows for improved identification of the foveal avascular zone (FAZ) and introduces a novel definition of vessel dispersion in the macular region. Furthermore, retinal large vessels and capillaries of the superficial and deep plexus can be differentiated, correlating with retinal pathology. The diagnostic value of OCTA CRMBs was demonstrated by a cross-sectional study with 30 healthy subjects and 43 retinal vein occlusion (RVO) patients, which identified strong correlations between OCTA CRMBs and retinal function in RVO patients. These OCTA CRMBs generated through this "all-in-one" pipeline may provide clinicians with insights about disease severity, treatment response and prognosis, aiding in the management and early detection of various disorders.

Quantitative evaluation of OCT angiography images in healthy and glaucomatous subjects through a novel approach: exploring inter-image variability

PurposeThis study aims to investigate inter-image intra-observer variability of macular, and optic disc (ONH) microvasculature measurements of glaucomatous and normal subjects using Swept-Source Optical Coherence Tomography Angiography (OCT-A) (OCT Topcon ImageNet 6; DRI OCT Triton, Topcon Corporation, JAPAN) - based imaging data analysis and processing with a newly made quantitative approach.MethodsA total of 20 glaucomatous and 20 healthy eyes underwent three OCT-A scanning of the ONH and macula. Macular and papillary and peripapillary vascular networks were calculated. For each eye, eighteen scans were analyzed using a novel approach: custom MATLAB 2021b scripts were employed for imaging analyses. Grayscale distribution was performed using the histcounts MATLAB function with 51 bins. For all layers, the vascular layer coefficient of variation (vl CoV) of the three measures were performed. The vl CoV difference between the two groups was analyzed by Student t-test.ResultsIn glaucomatous eyes, the vl CoV ranged from 4.49% to 8.54%, while in the control group from 3.58% to 8.32%. Both groups exhibited higher CoVs when assessing the optic disc. The papillary and macular microvasculature reproducibility was comparable between groups.ConclusionsUtilizing Swept-Source OCT-A images our study has identified an easy and reproducible method that appears to be fast and can assist physicians in assessing macular and ONH perfusion with less inter-image variability, particularly in the 70 μm superficial area of the optic disc. The high reliability obtained suggested that this method could be useful as early clinical biomarker.

Multimodal deep transfer learning to predict retinal vein occlusion macular edema recurrence after anti-VEGF therapy

PurposeTo develop a multimodal deep transfer learning (DTL) fusion model using optical coherence tomography angiography (OCTA) images to predict the recurrence of retinal vein occlusion (RVO) and macular edema (ME) after three consecutive anti-VEGF therapies. MethodsThis retrospective cross-sectional study consisted of 2800 B-scan OCTA macular images collected from 140 patients with RVO-ME. The central macular thickness (CMT) > 250 μm was used as a criterion for recurrence in the three-month follow-up after three injections of anti-VEGF therapy. The qualified OCTA image preprocessing and the lesion area segmentation were performed by senior ophthalmologists. We developed and validated the clinical, DTL, and multimodal fusion models based on clinical and extracted OCTA imaging features. The performance of the models and experts predictions were evaluated using several performance metrics, including the area under the receiver operating characteristic curve (AUC), accuracy, sensitivity, and specificity. ResultsThe DTL models exhibited higher prediction efficacy than the clinical models and experts’ predictions. Among the DTL models, the Vgg19 performed better than that of the other models, with an AUC of 0.968 (95 % CI, 0.943–0.994), accuracy of 0.913, sensitivity of 0.922, and specificity of 0.902 in the validation cohort. Moreover, the fusion Vgg19 model showed the highest prediction efficacy among all the models, with an AUC of 0.972 (95 % CI, 0.946–0.997), accuracy of 0.935, sensitivity of 0.935, and specificity of 0.934 in the validation cohort. ConclusionsMultimodal fusion DTL models showed robust performance in predicting RVO-ME recurrence and may be applied to assist clinicians in determining patients’ follow-up time after anti-VEGF therapy.

The impact of serum BNP on retinal perfusion assessed by an AI-based denoising optical coherence tomography angiography in CHD patients

BackgroundTo investigate the correlation between retinal vessel density (VD) parameters with serum B-type natriuretic peptide (BNP) in patients with coronary heart disease (CHD) using novel optical coherence tomography angiography (OCTA) denoising images based on artificial intelligence (AI). MethodsOCTA images of the optic nerve and macular area were obtained using a Canon-HS100 OCT device in 176 patients with CHD. Baseline information and blood test results were recorded. ResultsRetinal VD parameters of the macular and optic nerves on OCTA were significantly decreased in patients with CHD after denoising. Retinal VD of the superficial capillary plexus (SCP), deep capillary plexus (DCP) and radial peripapillary capillary (RPC) was strongly correlated with serum BNP levels in patients with CHD. Significant differences were noted in retinal thickness and retinal VD (SCP, DCP and RPC) between the increased BNP and normal BNP groups in patients with CHD. ConclusionDeep learning denoising can remove background noise and smooth rough vessel surfaces. SCP,DCP and RPC may be potential clinical markers of cardiac function in patients with CHD. Denoising shows great potential for improving the sensitivity of OCTA images as a biomarker for CHD progression.

Imaging of human corneoscleral junction (Limbus) vasculature with 100 KHz A-scan rate swept-source optical coherence tomography/angiography (OCT/A) system

The study demonstrates in-vivo three-dimensional depth-resolved Optical Coherence Tomography Angiography (OCTA) and Doppler OCT imaging performed on the anterior segment of the human eye. A high-speed swept-source OCT system was developed utilizing a swept-source laser having a 100 kHz A-scan sweep rate and centre wavelength at 1060 nm. The proposed system has an axial resolution of 4.5 µm and a transverse imaging resolution of 14 µm. The Doppler OCT provides information regarding the direction of blood flow in corneoscleral junction vessels, which employs the Joint Spectral and Time domain OCT (STdOCT) method. Parameters influencing the imaging of various vessels, like scanning density, A-scan rate, B-scan averaging, and number of BM scanning repeats, were also studied. Slit lamp images and OCT angiography en-face projections produced from PVOCTA (Phase-variance OCTA) and STdOCTA from the same regular patients were compared in order to demonstrate the additional potential of the system. The vascular systems at the Limbus consisting of circulatory, lymphatic, and aqueous outflow systems were imaged and presented. The output clinical parameters of the system will contribute to understanding the blood circulation with directionality at the limbus location, which can be further utilized to identify glaucoma. In the author's opinion, this article represents the first attempt to provide Doppler OCTA data for the anterior chamber of the human eye.

The longitudinal follow-up of a newly proposed OCTA imaging finding (SSPiM) and the importance of it as a new biomarker for treatment response in diabetic macular edema

PurposeThis study aimed to evaluate the frequency of SSPiM (suspended scattering particles in motion), systemic risk factors, ocular findings, progression characteristics, and treatment response in diabetic retinopathy (DR) patients.MethodsIn this prospective study, a total of 109 eyes of 109 patients with diabetic macular edema (DME) were included. Demographic characteristics and systemic data of the patients were recorded. In addition to a detailed ophthalmological examination, optical coherence tomography (OCT) and OCT angiography (OCTA) imaging were performed. According to the OCTA images, the patients were divided into two categories: SSPiM detected (SSPiM +) and undetected (SSPiM −). The patients were followed up at 0, 3, and 6 months. Treatment responses at 6 months in treatment-administered patients with and without SSPiM were examined.ResultsThe frequency of SSPiM in DME cases was found to be 34.9%. No significant correlation was found between SSPiM and demographic characteristics, systemic, and biochemical parameters (p > 0.05). It was observed that SSPIM was most frequently localized in the outer nuclear layer adjacent to the outer plexiform (81.6%). SSPiM appearance disappeared in 7 (19.4%) of 36 patients with SSPiM who had regular follow-up for 6 months. In 4 (11.1%) of these seven patients, hard exudate plaques developed in the areas where SSPiM disappeared. Regarding treatment response at 6 months, the decrease in CMT was statistically significantly lower in the SSPiM group compared to cases without SSPiM.ConclusionSSPiM is a finding seen in approximately one-third of DME patients and may adversely affect the response to the treatment.

Choriocapillaris flow features in children with myopic anisometropia

AimsTo examine differences between the eyes in choriocapillaris perfusion and choroidal thickness in children with myopic anisometropia.MethodsIn this observational and prospective study, 46 children with myopic anisometropia were enrolled. Choriocapillaris...

Retinal vasculature of different diameters and plexuses exhibit distinct vulnerability in varying severity of diabetic retinopathy.

To study the changes in vessel densities (VD) stratified by vessel diameter in the retinal superficial and deep vascular complexes (SVC/DVC) using optical coherence tomography angiography (OCTA) images obtained from people with diabetes and age-matched healthy controls. We quantified the VD based on vessel diameter categorized as <10, 10-20 and >20 μm in the SVC/DVC obtained on 3 × 3 mm2 OCTA scans using a deep learning-based segmentation and vascular graph extraction tool in people with diabetes and age-matched healthy controls. OCTA images obtained from 854 eyes of 854 subjects were divided into 5 groups: healthy controls (n = 555); people with diabetes with no diabetic retinopathy (DR, n = 90), mild and moderate non-proliferative DR (NPDR) (n = 96), severe NPDR (n = 42) and proliferative DR (PDR) (n = 71). Both SVC and DVC showed significant decrease in VD with increasing DR severity (p < 0.001). The largest difference was observed in the <10 μm vessels of the SVC between healthy controls and no DR (13.9% lower in no DR, p < 0.001). Progressive decrease in <10 μm vessels of the SVC and DVC was seen with increasing DR severity (p < 0.001). However, 10-20 μm vessels only showed decline in the DVC, but not the SVC (p < 0.001) and there was no change observed in the >20 μm vessels in either plexus. Our findings suggest that OCTA is able to demonstrate a distinct vulnerability of the smallest retinal vessels in both plexuses that worsens with increasing severity of DR.

DEEP LEARNING FOR AUTOMATIC PREDICTION OF EARLY ACTIVATION OF TREATMENT-NAIVE NONEXUDATIVE MACULAR NEOVASCULARIZATIONS IN AGE-RELATED MACULAR DEGENERATION.

Around 30% of nonexudative macular neovascularizations exudate within 2 years from diagnosis in patients with age-related macular degeneration. The aim of this study is to develop a deep learning classifier based on optical coherence tomography (OCT) and OCT angiography (OCTA) to identify nonexudative macular neovascularizations at risk of exudation. Patients with age-related macular degeneration showing OCTA and fluorescein angiography-documented nonexudative macular neovascularization with a 2-year minimum imaging follow-up were retrospectively selected. Patients showing OCT B-scan-documented macular neovascularization exudation within the first 2 years formed the EX GROUP while the others formed the QU GROUP. ResNet-101, Inception-ResNet-v2, and DenseNet-201 were independently trained on OCTA and OCT B-scan images. Combinations of the six models were evaluated with major and soft voting techniques. Eighty-nine eyes of 89 patients with a follow-up of 5.7 ± 1.5 years were recruited (35 EX GROUP and 54 QU GROUP). Inception-ResNet-v2 was the best performing among the three single convolutional neural networks. The major voting model resulting from the association of the three different convolutional neural networks resulted in an improvement of performance both for OCTA and OCT B-scan (both significantly higher than human graders' performance). The soft voting model resulting from the combination of OCTA and OCT B-scan-based major voting models showed a testing accuracy of 94.4%. Peripheral arcades and large vessels on OCTA en face imaging were more prevalent in the QU GROUP. Artificial intelligence shows high performances in identifications of nonexudative macular neovascularizations at risk for exudation within the first 2 years of follow-up, allowing better customization of follow-up timing and avoiding treatment delay. Better results are obtained with the combination of OCTA and OCT B-scan image analysis.

Glycemic Control and Retinal Microvascular Changes in Type 2 Diabetes Mellitus Patients without Clinical Retinopathy.

To investigate the association of glycemic control and retinal microvascular changes in patients with type 2 diabetes mellitus (T2DM) without diabetic retinopathy (DR). This retrospective, observational, cohort study included patients with T2DM without DR. The patients were categorized into intensive control (IC; mean glycosylated hemoglobin [HbA1c] ≤7.0%) and moderate control (MC; mean HbA1c >7.0%) groups. Optical coherence tomography (OCT) and swept-source OCT angiography (OCTA) image parameters were compared between three groups, including healthy controls. In total, 259 eyes of 259 participants (88 IC, 81 MC, and 90 controls) were included. The foveal avascular zone area was significantly larger in the MC group than IC and control groups (all P<0.05). The IC group had lower vessel density in the superficial retinal layer and deep retinal layer than the controls (all P<0.05). The choriocapillaris (CC) flow deficit (FD) was significantly greater in the MC group than in the IC and control groups (18.2%, 16.7%, and 14.2%, respectively; all P<0.01). In multivariate regression analysis, CC-FD was associated with the mean HbA1c level (P=0.008). There were no significant differences in OCT parameters among the groups. OCTA revealed that early CC impairment is associated with HbA1c levels; the CC changes precede clinically apparent DR. The OCTA parameters differed among the groups according to the degree of glycemic control. Our results suggest that microvascular changes precede DR and are closely related to glycemic control.

Towards standardising retinal OCT angiography image analysis with open-source toolbox OCTAVA

Quantitative assessment of retinal microvasculature in optical coherence tomography angiography (OCTA) images is important for studying, diagnosing, monitoring, and guiding the treatment of ocular and systemic diseases. However, the OCTA user community lacks universal and transparent image analysis tools that can be applied to images from a range of OCTA instruments and provide reliable and consistent microvascular metrics from diverse datasets. We present a retinal extension to the OCTA Vascular Analyser (OCTAVA) that addresses the challenges of providing robust, easy-to-use, and transparent analysis of retinal OCTA images. OCTAVA is a user-friendly, open-source toolbox that can analyse retinal OCTA images from various instruments. The toolbox delivers seven microvascular metrics for the whole image or subregions and six metrics characterising the foveal avascular zone. We validate OCTAVA using images collected by four commercial OCTA instruments demonstrating robust performance across datasets from different instruments acquired at different sites from different study cohorts. We show that OCTAVA delivers values for retinal microvascular metrics comparable to the literature and reduces their variation between studies compared to their commercial equivalents. By making OCTAVA publicly available, we aim to expand standardised research and thereby improve the reproducibility of quantitative analysis of retinal microvascular imaging. Such improvements will help to better identify more reliable and sensitive biomarkers of ocular and systemic diseases.

Qualitative and quantitative comparisons of type 1 macular neovascularizations between pachychoroid neovasculopathy and neovascular age-related macular degeneration using optical coherence tomography angiography

ObjectivesTo compare qualitative and quantitative features of type 1 macular neovascularizations (MNV) in pachychoroid neovasculopathy (PNV) and neovascular age-related macular degeneration (nAMD).MethodsForty-three treatment-naive eyes of 41 PNV patients and 40 treatment-naive eyes of 38 patients with nAMD were included. The patients were classified as PNV or nAMD according to the presence of pachychoroid features and soft/reticular drusen. Presence of central trunk and maturity of the MNV were evaluated on optical coherence tomography angiography (OCTA) images. MNV area, vessel density (VD), total vessel length (VL), number of intersection points (IPs), fractal dimension (FD), and lacunarity (LAC) were calculated using ImageJ software and FracLac plugin.ResultsThe mean age was 56.8 ± 8.7 years in PNV and 70.4 ± 8.8 years in neovascular AMD groups (p < 0.001). Compared to nAMD, the presence of central trunk was less frequent in PNV (48.8% vs 77.5%, p = 0.007). Immature MNV pattern was observed more frequently in PNV eyes than nAMD (41.9% vs 20.0%, p = 0.009). PNV cases had significantly lower median MNV area [0.913(1.115) vs 2.542(3.273) mm²], total VL [14.84 (20.46) vs 36.34 (44.68) mm], number of IPs [104(140) vs 335(417.3)], and FD [1.56(0.10) vs 1.59(0.11)] comparing to nAMD cases (p < 0.001, p = 0.001, p < 0.001, p = 0.043 respectively). However, the mean VD (42.4 ± 6.8 vs 42.9 ± 9.0%) and the median LAC values [0.42 (0.09) vs 0.42 (0.09)] did not differ significantly between groups (p = 0.776, p = 0.526, respectively).ConclusionMorphological and quantitative differences exist in type 1 neovascular lesions. Type 1 MNVs in the PNV group are characterized by a smaller and less complex structure.

Evaluation of agreement in macular vascular density measured by different protocols: 4.5 mm × 4.5 mm and 6 mm × 6 mm.

To evaluate the agreement in the macular vascular density (MVD) measured by two protocols: 4.5 mm × 4.5 mm and 6 mm × 6 mm. Cross-sectional observational study. Healthy volunteers between the age group of 19 and 39 years were recruited. Topcon DRI OCT Triton plus (Topcon Corporation, Tokyo, Japan) was used to acquire the fovea-centered optical coherence tomography angiography (OCTA) image using two protocols: 4.5 mm × 4.5 mm and 6 mm × 6 mm. MVD was measured by the manufacturer software in the superficial capillary plexus slab in five regions: central, superior, nasal, inferior, and temporal subfields of early treatment diabetic retinopathy study grid in each protocol. The study included 79 eyes of 40 healthy volunteers. The difference in the mean MVD between two protocols was 3.84% in right eye and 4.2% in left eye in central subfield, 0.93% in right eye and 1.13% in left eye in superior subfield, 0.06% in right eye and 1.45% in left eye in nasal subfield, 1.65% in right eye and 0.7% in left eye in inferior subfield, 0.4% in right eye and 0.54% in left eye in temporal subfield. The measurements were significantly higher in 6 mm × 6 mm in central subfield in both the eyes and in nasal field in the left eye. Whereas, the measurements were significantly higher in 4.5 mm × 4.5 mm in superior and inferior subfield in both the eyes and in temporal subfield in the left eye. The protocols should not be used interchangeably and it is necessary to include recommendation of the field of view to measure MVD while standardizing OCTA reporting.

Edible oil based optical clearing for optical coherence tomography angiography imaging

In optical imaging, optical clearing agents are commonly used to enhance the structural details of a sample. The current study investigates how to use it to improve the data obtained by an optical coherence tomography angiography system. A natural edible oil with no chemical base has been used for optical clearing. In-vivo testing on mice and humans yielded excellent optical clearing. Using computational techniques, the improvement in angiography signal caused by the optical clearing agent is investigated qualitatively and quantitatively. Compared to the control group, applying the edible oil-based optical clearing agent demonstrated improved vessel percentage and refined vascular signal intensity along depth.

Clinical Features Related to OCT Angiography Artifacts in Patients with Diabetic Macular Edema

To investigate the frequency and type of artifacts on OCT angiography (OCTA) images and the relationship with clinical features in eyes with diabetic macular edema (DME). Retrospective, cross-sectional comparative study. One hundred ninety-two eyes of 140 patients with DME were included. Medical records, OCT and OCTA images (Spectralis), and ultrawidefield color fundus photographs (Optos plc) were evaluated. The frequency of artifact types (segmentation, motion, projection artifact, and low signal) was determined. The relationships between artifact types and clinical features such as best-corrected visual acuity (BCVA), mean central retinal thickness (CRT), foveal avascular zone (FAZ) area, perimeter, circularity index, perfusion density (PD), vessel density (VD), fractal dimension (FD) in the superficial capillary plexus, intermediate capillary plexus (ICP), and deep capillary plexus (DCP), flow voids (FVs) in the choriocapillaris, presence of hard exudate (HE), and cataract were determined. The mean age was 71.6 ± 11.4 years, and 86 (61.4%) out of 140 were men. Artifacts were present in 63 (32.8%) of 192 eyes. Twenty-nine (15.1%) eyes had segmentation artifacts, 12 (6.3%) had motion artifacts, 11 (5.7%) had projection artifacts, and 18 (9.4%) had low signal. Best-corrected visual acuity, PD, VD, and FD in ICP and DCP were significantly lower; and CRT, FAZ area and perimeter in ICP and DCP, and presence of cystoid macular edema, HE, and cataract were higher in eyes with artifacts versus eyes without artifacts (P < 0.05 for each). Multivariate linear regression analysis showed a significant association between segmentation artifacts and decreased BCVA (odds ratio [OR],5.277; P= 0.02), increased CRT (OR, 1.015; P < 0.001), increased area of FAZ in DCP (OR, 6.625; P= 0.02), and increased perimeter of FAZ in DCP (OR, 1.775; P < 0.04); there was also a significant association between projection artifacts and presence of HE (OR, 2.017; P= 0.02) and between motion artifacts and presence of cataract (OR, 4.102; P= 0.01). OCT angiography artifacts were present in one third of DME eyes, with segmentation artifacts being the most frequent type. Determining OCTA artifacts is crucial to ensure accurate clinical evaluation. These data could help in developing more standardized clinical protocols for image acquisition and interpretation used in clinical practice and research. Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Retinal vascular density as a potential biomarker of diabetic cerebral small vessel disease.

The retina and brain share similar anatomical and physiological features. Thus, retinal imaging by optical coherence tomography angiography (OCTA) might be a potential tool for the early diagnosis of diabetic cerebral small vessel disease (CSVD). In this study, we aimed to evaluate retinal vascular density (VD) in diabetic CSVD by OCTA imaging and explore the associations between retinal VD and cerebral magnetic resonance imaging (MRI) markers and cognitive function. In total, 131 patients were enrolled, including CSVD (n = 43) and non-CSVD groups (n = 88). The VD and foveal avascular zone of the retinal capillary plexus were measured with OCTA. A brain MRI was performed. MRI imaging showed that in the diabetic CSVD group, white matter hyperintensities (WMHs), particularly deep WMHs (58.82%), are the most common MRI marker, followed by cerebral microbleeds in the subtentorial and cortical areas (34.78%). The CSVD group showed increases in the prevalence of cognitive dysfunction (p = .034) and depression (p = .033) and decreases in visuospatial/executive ability and delayed recall ability. In the CSVD group, VDs of the macular superficial vascular plexus (32.93 ± 7.15% vs. 36.97 ± 6.59%, p = .002), intermediate capillary plexus (20.87 ± 4.30% vs. 23.08 ± 4.30%, p = .005) and deep capillary plexus (23.54 ± 5.00% vs. 26.05 ± 4.20%, p = .003) were lower than those of the non-CSVD group. Multiple linear regression analysis showed that VD of the macular superficial vascular plexus was independently associated with cerebral microbleeds. Meanwhile, VD of the macular intermediate capillary plexus was associated with white matter lacunar infarcts after adjustment. Diabetic CSVDs are characterized by MRI markers, including deep WMHs and cerebral microbleeds, and showed impaired cognition with decreased visuospatial/executive ability and delayed recall ability. OCTA imaging revealed a significant decrease in retinal microvascular perfusion in diabetic CSVD, which was related to MRI markers and cognitive function. OCTA might be a valuable potential measurement for the early diagnosis of CSVD.