Toward quantitative and reproducible clinical use of OCT-Angiography.
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ABSTRACT:
SUBMITTER: Douma I
PROVIDER: S-EPMC6034792 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:PurposeTo compare the quality of four OCT-angiography(OCT-A) modules.MethodThe retina of nineteen healthy volunteers were scanned with four OCT-devices (Topcon DRI-OCT Triton Swept-source OCT, Optovue RTVue-XR, a prototype Spectralis OCT2, Heidelberg-Engineering and Zeiss Cirrus 5000-HD-OCT). The device-software generated en-face OCT-A images of the superficial (SCP) and deep capillary plexuses (DCP) were evaluated and scored by 3 independent retinal imaging experts. The SCP vessel density was assessed using Angiotool-software. After the inter-grader reliability assessment, a consensus grading was performed and the modules were ranked based on their scoring.ResultsThere was no significant difference in the vessel density among the modules (Zeiss 48.7±4%, Optovue 47.9±3%, Topcon 48.3±2%, Heidelberg 46.5±4%, p = 0.2). The numbers of discernible vessel-bifurcations differed significantly on each module (Zeiss 2±0.9 bifurcations, Optovue 2.5±1.2, Topcon 1.3±0.7 and Heidelberg 0.5±0.6, p≤0.001). The ranking of each module differed depending on the evaluated parameter. In the overall ranking, the Zeiss module was superior and in 90% better than the median (Bonferroni corrected p-value = 0.04). Optovue was better than the median in 60%, Topcon in 40% and Heidelberg module in 10%, however these differences were not statistically significant.ConclusionEach of the four evaluated OCT-A modules had particular strengths, which differentiated it from their competitors.
| S-EPMC5425250 | biostudies-literature
Project description:PurposeTo analyze the effect of induced astigmatism on en-face spectral-domain optical coherence tomography angiography quantitative metrics.DesignProspective crossover study.MethodsNormal eyes without astigmatism and with 0.75, 1.75, and 2.75 diopters (D) of with-the-rule (WTR) astigmatism were imaged using a 3 × 3-mm scan pattern SD-OCTA CIRRUS 5000 HD-OCT with AngioPlex (Carl Zeiss Meditec, Dublin, CA, USA). Quantitative parameters, including foveal avascular zone metrics, parafoveal vessel length density (VD), and perfusion density (PD) were corrected for magnification secondary to axial length and analyzed. Univariate linear regressions were performed within each eye to correlate quantitative metrics to the level of an induced astigmatic cylinder.ResultsFifteen eyes from 15 patients were imaged. Every 1-D increase in induced WTR astigmatism was associated with a statistically significant decrease in VD and PD within all Early Treatment Diabetic Retinopathy Study inner ring quadrants; however, especially more so nasally (VD: 0.63; P < .001; PD: 0.0089; P = .001). For every 1-D increase in induced astigmatism, the resulting decrease in the inner ring superior quadrant was 12% greater for VD and 16% greater for PD versus that in the inferior quadrant. The resulting decrease in the inner ring nasal quadrant was 40% greater for VD and 48% greater for PD versus that in the temporal quadrant.ConclusionsIncreasing levels of induced WTR astigmatism correlated with globally diminishing VD and PD, was more symmetrical for vertical than horizontal quadrants, and was most pronounced nasally. This may be due to a high prevalence of horizontally oriented vessels nasally and the horizontal optical defocus induced by WTR astigmatism.
| S-EPMC7606665 | biostudies-literature
Project description:ObjectiveTo study peripapillary retinal capillary circulation in eyes treated with I-125 plaque brachytherapy for uveal melanoma using optical coherence tomography angiography (OCTA).DesignCross-sectional study of 10 subjects imaged with OCTA prior to uveal melanoma treatment and 15 subjects imaged after development of radiation retinopathy and/or optic neuropathy.ParticipantsFollowing IRB approval, subjects were enrolled from an academic ocular oncology clinical practice. All subjects had uveal melanoma in one eye and treatment with I-125 plaque brachytherapy was planned or had previously taken place. Patients with low vision at baseline and uncontrolled hypertension were excluded. In the post-treatment group, seven subjects were male and eight were female; age range 38 to 81 years. Visual acuities in the irradiated eyes ranged from 20/20 to counting fingers. Visual acuities in the untreated fellow eyes were 20/25 or better.MethodsPeripapillary retinal capillary circulation was measured by OCTA (Optovue, Inc). 4.5×4.5 mm optic disc scans were obtained. 10 subjects were imaged prior to brachytherapy treatment and 15 subjects were imaged after development of clinically apparent radiation retinopathy and/or radiation optic neuropathy post-brachytherapy.Main outcome measuresThe relationship of the peripapillary retinal capillary density (PPCD) as measured by OCTA to the calculated dose to the optic nerve (D50, the dose to 50% of the disc) and the LogMAR vision was evaluated.ResultsNo significant difference was seen in the PPCD as measured by OCTA when comparing the eye with melanoma to the fellow eye prior to brachytherapy; however the PPCD was significantly lower in treated eyes (52.9% +/- 22.4%) than in fellow eyes that did not receive radiation (73.3% +/- 13.7%, p = 0.004). There was an inverse linear correlation between D50 and the PPCD (Pearson's; r= -0.528, P=0.043) and between visual acuity and the PPCD (Pearson's; r= -0.564, P=0.028).ConclusionsAmong patients with clinically apparent radiation retinopathy and/or radiation optic neuropathy, PPCD was lower in the treated eye and correlated with the radiation dose to the optic nerve and the visual acuity. OCTA provides a measure of capillary changes following radiation, and may serve as a quantitative endpoint to address visual prognosis.
| S-EPMC5932624 | biostudies-literature
Project description:IntroductionTo quantify optical coherence tomography angiography (OCTA) signal changes at the level of the choriocapillaris (CC) in patients with different stages of central serous chorioretinopathy (CSC) and to explore any correlation between subretinal fluid (SRF) and retinal pigment epithelium (RPE) alterations and the OCTA CC signal.MethodsOne hundred one CSC eyes and 42 healthy control eyes were included in this retrospective study. CSC patients were allocated into four groups: acute, non-resolving, chronic atrophic and inactive CSC. CC OCTA images (AngioPlex®, Zeiss) were automatically quantified using an image-processing algorithm. Spatial correlation analysis of OCTA signals was performed by overlapping macular edema heatmaps and fundus autofluorescence images with corresponding OCTA images.ResultsActive CSC subgroups demonstrated significantly more increased and decreased flow pixels in the CC compared with controls (p < 0.0001). No significant OCTA changes were seen within the active CSC groups or between the inactive and healthy subgroup. Spatial correlation analysis revealed a decreased OCTA signal in the SRF area and an increased signal outside the SRF area in acute CSC. Areas of RPE atrophy co-localized with areas of increased choriocapillaris OCTA signal, while areas with RPE alterations exhibited a normal signal compared with unaffected RPE.ConclusionThe decreased OCTA signal in the area of SRF in acute CSC could be evidence of localized CC hypoperfusion or due to shadowing artifacts. The missing CC OCTA changes in altered RPE adjacent to atrophy argues against CC injury. Studies with higher resolution and optimized image acquisition are warranted to further validate our findings.
| S-EPMC6393260 | biostudies-literature
Project description:In recent years, advances in optical coherence tomography (OCT) techniques have increased our understanding of diabetic retinopathy, an important microvascular complication of diabetes. OCT angiography is a non-invasive method that visualizes the retinal vasculature by detecting motion contrast from flowing blood. Visible-light OCT shows promise as a novel technique for quantifying retinal hypoxia by measuring the retinal oxygen delivery and metabolic rates. In this article, we discuss recent insights provided by these techniques into the vascular pathophysiology of diabetic retinopathy. The next milestones for these modalities are large multicenter studies to establish consensus on the most reliable and consistent outcome parameters to study diabetic retinopathy.
| S-EPMC5723235 | biostudies-literature
Project description:BACKGROUND:Varying degrees of macular ischemia generally occur in diabetic retinopathy (DR). This study aims to evaluate the effect of conbercept with 3+ pro re nata (PRN) on macular perfusion status in patients with diabetic macular edema (DME) and quantitatively assess changes in foveal avascular zone (FAZ) areas and capillary density in macular regions by applying optical coherence tomography angiography (OCTA). METHODS:Fifty patients were divided into ischemic (n =?31) and non-ischemic (n =?19) groups according to the presence of ischemia on OCTA at baseline. All patients received intravitreal injections of 0.5?mg of conbercept with 3+ PRN principle. The FAZ areas and macular vessel density measured using OCTA were evaluated at baseline, 3?months, and 6?months after treatment in both groups. RESULTS:At months 3 and 6, the FAZ area in the ischemic group changed from 0.510?±?0.171?mm2 to 0.441?±?0.158?mm2 then to 0.427?±?0.153?mm2 (p =?0.003, p =?0.296); in the non-ischemic group, it remained stable (p =?0.269, p =?0.926). The superficial vessel density changed from 41.1?±?4.1 to 42.5%?±?4.7% then to 42.6%?±?4.6% (p =?0.043, p =?0.812), and the deep vessel density changed from 40.7?±?4.4 to 42.3%?±?3.6% then to 42.3%?±?4.7% (p =?0.072, p =?0.961) in the ischemic group. In the non-ischemic group, the superficial vessel density changed from 44.8?±?3.2 to 46.0%?±?3.5% then to 45.7%?±?3.3% (p =?0.108, p =?0.666), whereas the deep vessel density changed from 43.6?±?3.6 to 43.8%?±?3.2% then to 43.5%?±?4.5% (p =?0.882, p =?0.736). Reperfusion in macular nonperfusion areas was observed. CONCLUSION:Anti-vascular endothelial growth factor treatment may have a positive effect on macular perfusion status. Furthermore, OCTA had advantages in quantifying and calculating blood flow index in the study of macular perfusion status.
| S-EPMC7519504 | biostudies-literature
Project description:PurposeTo determine if OCT angiography (OCTA)-derived vessel density measurements can extend the available dynamic range for detecting glaucoma compared with spectral-domain (SD) OCT-derived thickness measurements.DesignObservational, cross-sectional study.ParticipantsA total of 509 eyes from 38 healthy participants, 63 glaucoma suspects, and 193 glaucoma patients enrolled in the Diagnostic Innovations in Glaucoma Study.MethodsRelative vessel density and tissue thickness measurement floors of perifoveal vessel density (pfVD), circumpapillary capillary density (cpCD), circumpapillary retinal nerve fiber (cpRNFL) thickness, ganglion cell complex (GCC) thickness, and visual field (VF) mean deviation (MD) were investigated and compared with a previously reported linear change point model (CPM) and locally weighted scatterplot smoothing curves.Main outcome measuresEstimated vessel density and tissue thickness measurement floors and corresponding dynamic ranges.ResultsVisual field MD ranged from -30.1 to 2.8 decibels (dB). No measurement floor was found for pfVD, which continued to decrease constantly until very advanced disease. A true floor (i.e., slope of approximately 0 after observed CPM change point) was detected for cpRNFL thickness only. The post-CPM estimated floors were 49.5±2.6 μm for cpRNFL thickness, 70.7±1.0 μm for GCC thickness, and 31.2±1.1% for cpCD. Perifoveal vessel density reached the post-CPM estimated floor later in the disease (VF MD, -25.8±3.8 dB) than cpCD (VF MD, -19.3±2.4 dB), cpRNFL thickness (VF MD, -17.5±3.3 dB), and GCC thickness (VF MD, -13.9±1.8 dB; P < 0.001). The number of available measurement steps from normal values to the CPM estimated floor was greatest for cpRNFL thickness (8.9), followed by GCC thickness (7.4), cpCD (4.5), and pfVD (3.8).ConclusionsIn late-stage glaucoma, particularly when VF MD is worse than -14 dB, OCTA-measured pfVD is a promising tool for monitoring progression because it does not have a detectable measurement floor. However, the number of steps within the dynamic range of a parameter also needs to be considered. Although thickness parameters reached the floor earlier than OCTA-measured pfVD, there are more such steps with thickness than OCTA parameters.
| S-EPMC6589389 | biostudies-literature
Project description:PurposeTo examine and quantify choriocapillaris lesions in active and quiescent serpiginous choroiditis (SC) using swept-source optical coherence tomography angiography (SS-OCTA) and en-face image analysis.DesignProspective observational case series.ParticipantsPatients with a clinical diagnosis of SC.MethodsA SS-OCTA prototype was used to image active and quiescent serpiginous lesions longitudinally before and after anti-inflammatory treatment. En-face slabs of choriocapillaris flow (CC-slab) or outer nuclear layer structure (ONL-slab) were generated from OCTA and OCT data, respectively.Main outcome measuresQualitative and quantitative analyses on lesion boundary and area using a semi-automated MATLAB algorithm. Lesions were also compared to traditional multimodal imaging.ResultsSix eyes of three patients were imaged. Choroidal lesions were identified and analyzed in four of six eyes. Lesions with well-defined boundaries were identified in the CC-slab in areas of both active and inactive choroiditis. CC-slab lesion size and shape showed good correlation with lesions identified on indocyanine green angiography. CC-slab lesion area increased with disease activity and decreased with corticosteroid treatment. During active disease, the CC-slab lesion area was larger than both the ONL-slab and fundus autofluorescence lesion areas. Active CC-slab lesions not associated with corresponding abnormal autofluorescence resolved without clinical scarring after treatment. In inactive scars, the areas of retinal and choriocapillaris lesions were similar and did not change over time.ConclusionsEn-face analysis of SS-OCTA choriocapillaris flow voids provide a non-invasive method for the detection of lesions in patients with SC. The presence of lesions in the choriocapillaris in the absence of retinal pigment epithelium and outer retinal abnormalities supports the hypothesis that choriocapillaris is the primary site of pathology in SC, and may be a sensitive early sign of disease activity. We propose a simple grading system of SC lesions based on SS-OCTA and fundus autofluorescence findings. SS-OCTA is a promising non-invasive method for monitoring patients with SC.
| S-EPMC6103638 | biostudies-literature
Project description:PurposeTo provide guidance on how to appropriately quantitate various choriocapillaris (CC) parameters with optical coherence tomography angiography (OCTA).DesignEvidence-based perspective.MethodsReview of literature and experience of authors.ResultsAccurate and reliable quantification of CC using OCTA requires that CC can be visualized and that the measurements of various CC parameters are validated. For accurate visualization, the selected CC slab must be physiologically sound, must produce images consistent with histology, and must yield qualitatively similar images when viewing repeats of the same scan or scans of different sizes. For accurate quantification, the measured intercapillary distances (ICDs) should be consistent with known measurements using histology and adaptive optics and/or OCTA, the selected CC parameters must be physiologically and physically meaningful based on the resolution of the instrument and the density of the scans, the selected algorithm for CC binarization must be appropriate and generate meaningful results, and the CC measurements calculated from multiple scans of the same and different sizes should be quantitatively similar. If the Phansalkar local thresholding method is used, then its parameters must be optimized for CC based on the OCTA instrument and scan patterns used. It is recommended that the window radius used in the Phansalkar method should be related to the expected average ICD in normal eyes.ConclusionsQuantitative analysis of CC using commercially available OCTA instruments is complicated, and researchers need to tailor their strategies based on the instrument, scan patterns, anatomy, and thresholding strategies to achieve accurate and reliable measurements.
| S-EPMC7930158 | biostudies-literature
Project description: Not available
| S-EPMC7576063 | biostudies-literature