Quantitative Evaluation of the Retinal Vascular Parameters With OCTA in Patients With Behçet Disease Without Ocular Involvement

Optical coherence tomography angiography analysis methods: a systematic review and meta-analysis

Optical coherence tomography angiography (OCTA) is widely used for non-invasive retinal vascular imaging, but the OCTA methods used to assess retinal perfusion vary. We evaluated the different methods used to assess retinal perfusion between OCTA studies. MEDLINE and Embase were searched from 2014 to August 2021. We included prospective studies including ≥ 50 participants using OCTA to assess retinal perfusion in either global retinal or systemic disorders. Risk of bias was assessed using the National Institute of Health quality assessment tool for observational cohort and cross-sectional studies. Heterogeneity of data was assessed by Q statistics, Chi-square test, and I2 index. Of the 5974 studies identified, 191 studies were included in this evaluation. The selected studies employed seven OCTA devices, six macula volume dimensions, four macula subregions, nine perfusion analyses, and five vessel layer definitions, totalling 197 distinct methods of assessing macula perfusion and over 7000 possible combinations. Meta-analysis was performed on 88 studies reporting vessel density and foveal avascular zone area, showing lower retinal perfusion in patients with diabetes mellitus than in healthy controls, but with high heterogeneity. Heterogeneity was lowest and reported vascular effects strongest in superficial capillary plexus assessments. Systematic review of OCTA studies revealed massive heterogeneity in the methods employed to assess retinal perfusion, supporting calls for standardisation of methodology.

Experts Opinion: OCTA vs. FFA/ICG in Uveitis - Which Will Survive?

Will optical coherence tomography angiography (OCTA) replace invasive imaging techniques like fundus fluorescein angiography (FFA) and indocyanine green (ICG) angiography entirely? While OCTA is being increasingly applied in the field of medical retina, will we see this change in the subspeciality of uveitis? In this article, five uveitis specialists with renowned imaging expertise answer to 10 specific questions to address this issue. The final verdict based on the comments of the experts suggests that FFA and ICG cannot be replaced by OCTA in uveitis, at least for now. While OCTA can offer new insights into the pathogenesis of certain inflammatory conditions and help in the diagnosis of complications like inflammatory choroidal neovascularisation, multimodal imaging is still the preferred approach in the assessment of patients with uveitis.

Retinal and choroidal microvascular alterations in Behcet’s disease without ocular manifestations: A systematic review and meta-analysis

Purpose

We performed a systematic review and meta-analysis to examine the microvascular alterations in non-ocular Behcet’s disease (BD) using optical coherence tomography angiography (OCTA).

Methods

A comprehensive search was performed in Pubmed, Embase and Cochrane databases for eligible studies from inception to February 2022. Detailed clinical demographics were extracted from each study by two independent reviewers. The weighted mean difference (WMD) and 95% confidence intervals (CI) were used to compare the OCTA parameters between non-ocular BD and healthy controls. Stata 12.0 was adopted to conduct statistical analyses.

Results

Ten cross-sectional studies involving 386 eyes in non-ocular BD and 418 eyes in healthy volunteers were ultimately included in the present analysis. When considering superficial capillary plexus (SCP) and deep capillary plexus (DCP), no significant differences of vessel densities in the whole enface image, fovea and perifovea were evaluated between two groups. Significantly reduced parafoveal vessel density of SCP was observed in non-ocular BD in comparison with healthy group (WMD = −1.33, 95%CI: −1.78, −0.89; I2 = 0.6%), while slightly decreased parafoveal vessel density was assessed in DCP (WMD = −1.47, 95%CI: −3.30, 0.35; I2 = 89.3%). Significantly increasing foveal avascular zone (FAZ) area was observed in non-ocular BD when compared to healthy controls (WMD = 0.11, 95%CI: 0.03, 0.19; I2 = 95.3%). There was no significant difference in flow area of choriocapillaris between non-ocular BD and control group (WMD = 0.06, 95%CI: −0.19, 0.32; I2 = 0%).

Conclusion

Based on current analysis, our results demonstrated significantly lower parafoveal vessel density of SCP and lager FAZ area in full vasculature in non-ocular BD. The retinal microvascular alterations appear before the emergence of ocular manifestations.

Systematic Trial Registration

[https://www.crd.york.ac.uk/PROSPERO/], identifier [CRD42021244856].

Consensus-based recommendations for optical coherence tomography angiography reporting in uveitis

BACKGROUND/AIMS

To establish a consensus in the nomenclature for reporting optical coherence tomography angiography (OCTA findings in uveitis.

METHODS

The modified Delphi process consisted of two rounds of electronic questionnaires, followed by a face-to-face meeting conducted virtually. Twenty-one items were included for discussion. The three main areas of discussion were: wide field OCTA (WF-OCTA), nomenclature of OCTA findings and OCTA signal attenuation assessment and measurement. Seventeen specialists in uveitis and retinal imaging were selected by the executive committee to constitute the OCTA nomenclature in Uveitis Delphi Study Group. The study endpoint was defined by the degree of consensus for each question: 'strong consensus' was defined as >90% agreement, 'consensus' as 85%-90% and 'near consensus' as >80% but <85%.

RESULTS

There was a strong consensus to apply the term 'wide field' to OCTA images measuring over 70° of field of view, to use the terms 'flow void' and 'non-detectable flow signal' to describe abnormal OCTA flow signal secondary to vessels displacement and slow flow respectively, to use the terms 'loose' and 'dense' to describe the appearance of inflammatory choroidal neovascularisation, and to use the percentage of flow signal decrease to measure OCTA ischaemia with a threshold greater than or equal to 30% as a 'large area'.

CONCLUSIONS

This study sets up consensus recommendations for reporting OCTA findings in uveitis by an expert panel, which may prove suitable for use in routine clinical care and clinical trials.

Quantitative changes in peripapillary, macular, and choriocapillaris microvasculatures of patients with non-ocular Behçet's disease and relationship with systemic vascular involvement, an optical coherence tomography angiography study

BACKGROUND

To evaluate the changes in the peripapillary, macular and choriocapillaris microvasculatures in the eyes of patients with Behçet's disease (BD) without ocular involvement by optical coherence tomography angiography (OCT-A) and to investigate the relationship with systemic vascular involvement (SVI).

METHODS

The study included 56 eyes of 33 patients with non-ocular BD and 61 eyes of 33 healthy subjects. The macular microvascular (MMV) vessel densities (VDs), FAZ parameters, Choriocapillaris flow area (CCFA), radial peripapillary capillary (RPC) VDs and optic nerve head (ONH) analyses were performed with OCT-A. MMV, RPC, ONH, and CCFA measurements were compared between the non-ocular BD patients and healthy controls. Then, the patient group was divided into two subgroups according to the presence of SVI. MMV, RPC, and CCFA measurements of these subgroups were compared with the healthy controls.

RESULTS

While deep capillary plexus VD and foveal density decreased in MMV analysis in the BD group compared to the control group, CCFA was not different. In the RPC and ONH analysis, the VDs of the inside-disc small vessels and the VDs of the inside-disc all vessels were decreased while the cup/disk area ratio and cup volume were increased in the BD group compared to the healthy controls. Furthermore, the VDs of the inside-disc vessels were reduced in patients without SVI compared to those with SVI and healthy controls.

CONCLUSIONS

The RPC network, ONH and MMV architecture analysis by OCT-A revealed changes in the MMV, RPC, and ONH structures in non-ocular BD patients. Moreover, the decrease in RPC VDs and MMV VDs in patients without SVI suggested that the patients with BD without SVI had subclinical ocular involvement even in the absence of clinical ocular findings.

Optical coherence tomography angiography of subclinical ocular features in pediatric Behçet disease

PURPOSE

To investigate macular and optic nerve head (ONH) vascular density (VD), foveal avascular zone (FAZ) area, choroidal thickness, outer retina and choriocapillaris flow, and morphological changes of foveal microvasculature in pediatric Behçet disease (BD) without ocular involvement using optical coherence tomography angiography (OCTA).

METHODS

We analyzed 22 eyes of 22 pediatric patients diagnosed with BD without ocular involvement and 24 age- and sex-matched healthy controls in this prospective, cross-sectional study. The superficial capillary plexus (SCP) and the deep capillary plexus (DCP), FAZ parameters, the flow area of the outer retina, and choriocapillaris were evaluated using OCTA.

RESULTS

Vessel density of the whole image, fovea, parafovea, and perifovea in DCP were significantly lower in the nonocular pediatric BD group (P = 0.008, P = 0.038, P = 0.046, and P = 0.008, resp.). There was no significant difference between the groups in VD parameters of both SCP and ONH, as well as FAZ parameters (P > 0.05 for all). Although outer retina and choriocapillaris flow area at 1 mm, 2 mm, and 3 mm radius were lower in the nonocular pediatric BD group than in the control group, the difference was statistically significant only in the outer retina flow area at 3 mm radius (P = 0.011).

CONCLUSIONS

In this cohort of pediatric nonocular BD patients, there was decreased vessel density in the DCP and decreased outer retinal flow. Hence, OCTA can reveal microvascular changes in patients without detectable ocular involvement.

Normative Data of Superficial Retinal Vascular Plexus and the Relationship to Retinal Layers

Objectives:

The aim of this study was to evaluate the relationship between optical coherence tomography (OCT) and optical coherence tomography angiography (OCTA) parameters in a healthy population and to detect any changes that occur with age.

Methods:

A total of 100 healthy participants were included in this prospective, observational, and comparative study. The participants were categorized in 4 groups according to age: Group 1: 21-30 years, Group 2: 31-40 years, Group 3: 41-50 years, Group 4: 51-60 years of age. Mean macular thickness, retinal nerve fiber layer (RNFL), ganglion cell inner plexiform layer (GC-IPL), and the choroidal thickness (ChT), vessel density (VD), perfusion density (PD), foveal avascular zone (FAZ), and parapapillary perfusion density parameters were recorded and analyzed.

Results:

In comparisons between groups, no significant difference in OCTA parameters was observed. There were inverse correlations between the outer VD, PD, and intraocular pressure (IOP) (r= -0.307, p=0.006 and r= -0.284, p=0.011, respectively). The correlation between parapapillary perfusion density and IOP was close to being significant (r= -0.213, p=0.059). There were significant relationships between OCTA parameters and macular, RNFL, and GC-IPL thickness. No significant relationship between ChT and OCTA parameters was seen.

Conclusion:

The size and characteristics of superficial VD, PD, parapapillary perfusion density, and FAZ were determined in a population with standardized demographic and ocular clinical features, and the relationship between these parameters and retinal layers was established.

Preclinical ocular features in patients with Behçet's disease detected by optical coherence tomography angiography

OBJECTIVE

The aim of this study was to evaluate the perifoveal and peripapillary microvascular structure in patients with Behçet's disease (BD) without clinically ocular involvement.

METHODS

Fifty-six eyes of 28 patients with Behçet's disease without clinically ocular involvement and 50 age-matched healthy eyes were included in this prospective study. Vessel densities (VD) of macula and optic nerve head, foveal avascular zone (FAZ), choroid capillary plexus (CCP) flow area, perifoveal capillary nonperfusion, capillary dilatation and/or telangiectasia and perifoveal capillary arcade disruption were analyzed with optical coherence tomography angiography (OCTA). The relationship between duration of disease and vessel densities was also evaluated.

RESULTS

The FAZ was significantly higher in the BD group (p < 0.001). VD of the foveal and parafoveal region in deep capillary plexus (DCP) were significantly lower in the BD group than in the control group (p < 0.001, p < 0.001). Total disc, peripapillary and inside-disc VD were significantly lower in BD group (p = 0.001, p = 0.002, p = 0.004). Perifoveal morphological changes in DCP were significantly higher in nonocular BD (p < 0.001, p < 0.001, p < 0.001). There was a mild negative correlation between disease duration and whole VD in DCP, total disc VD, peripapillary VD was determined (For whole VD in DCP, r = -0.400, p = 0.035; for total disc VD r = -0.396, p = 0.037; for peripapillary VD r = -0.442, p = 0.018).

DISCUSSION

Perifoveal and peripapillary microvascular changes that can be detected by OCTA may occur in Behçet's patients without clinically ocular involvement.