Comparison of vascular parameters between normal cynomolgus macaques and healthy humans by optical coherence tomography angiography.
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ABSTRACT:
SUBMITTER: Peng J
PROVIDER: S-EPMC6788001 | biostudies-literature | 2019 Oct
REPOSITORIES: biostudies-literature
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Project description:PurposeWe evaluated the repeatability of wide-field en face swept-source optical coherence tomography angiography (SS-OCTA) in healthy subjects.MethodsHealthy subjects underwent two imaging sessions, on average 8 days apart, with a 100 kHz SS-OCTA instrument. The imaging protocol included a central 3 × 3 and 12 × 12 mm scans of the four quadrants resulting in more than a 70° wide-field OCTA of the posterior pole. Quantitative analysis was performed using the inbuilt Macular Density Algorithm Version v0.6.1 and AngioTool software. Consistency for the foveal avascular zone (FAZ), vessel density, and perfusion density of the superficial and deep capillary plexus slabs and the wide-field OCTA superficial slab, and the number of artefacts on the wide-field images were assessed.ResultsA total of 21 healthy volunteers (seven men and 14 women; mean age 32 years; range, 18-61; standard deviation, 10.28 years) were included in this analysis. Internal consistency was highest for FAZ area with an intraclass correlation (ICC) = 0.998 (95% confidence interval [CI], 0.997-0.999), a FAZ perimeter with an ICC = 0.995 (95% CI, 0.990-0.997), a FAZ circularity with an ICC= 0.976 (95% CI, 0.956-0.987), followed by the vessel density of the inner ring in the superficial slab with an ICC = 0.834 (95% CI, 0.691-0.911), and a vessel density of the inner ring in the deep slab with an ICC = 0.523 (95% CI, 0.113-0.744).The reproducibility of the average vessels length of the wide-field OCTA cropped images was strong (ICC = 0.801; 95% CI, 0.624-0.895), followed by the reproducibility of total number of junctions (ICC = 0.795; 95% CI, 0.613-0.892) and the vessels percentage area (ICC = 0.662; 95% CI, 0.361-0.821).ConclusionsThe level of reproducibility for assessing the microvascular anatomy in wide-field OCTA is strong and can be used to quantify microvascular changes over time. Refinements in analysis strategies and a consensus of which parameters are most useful for quantitative assessment of wide-field OCTA images would be useful in the future.Translational relevanceThese findings bridge the gap between basic imaging research and clinical use for quantitative wide-field OCTA.
| S-EPMC6502067 | biostudies-literature
Project description:BackgroundMany studies suggest the existence of an alteration of the retinal hemoperfusion in primary open-angle glaucoma. The OCT-A is a novel technique that allows to provide information on retinal microcirculation in a non-invasive way, thus it represents a possible imaging target for the early diagnosis and follow-up of glaucoma. The aim of our work is to evaluate the contribution of vascular parameters provided by OCT-A and their diagnostic abilities in the different stages of primary open-angle glaucoma.MethodThis is a prospective cross-sectional study involving 200 eyes of control subjects and 250 eyes of glaucomatous subjects divided into early glaucoma, moderate glaucoma and advanced glaucoma subgroups. They were assessed for MD, LV by visual field, RNFL and GCC thickness by SS-OCT papillary and macular vascular densities by SS-OCT A.ResultsOCT-A vessel densities determined in the optic nerve head, in the peripapillary and in the macular regions were significantly lower in glaucomatous eyes. Among the vascular parameters studied the whole image vascular density showed the best diagnostic ability in the discrimination between glaucomatous eyes and healthy eyes with an AUC of 0.949. Nevertheless, the diagnostic ability of vascular parameters remains lower than of the structural parameters RNFL (AUC: 0.981). A significant correlation was found between structural, functional and vascular parameters with r < 0.05. The quadratic non-linear model defines better the relationship between structural, vascular and functional damage in glaucoma.ConclusionThe OCT-A plays an important role in the early diagnosis and follow-up of PAOG. It also contributes to the understanding of some aspects of the vascular role in glaucoma.
| S-EPMC8361292 | biostudies-literature
Project description:BackgroundRetinitis Pigmentosa (RP) represents a retinal dystrophy with an extremely complex pathogenesis further worsened by the impairment of the retinal vascular supply. The main goal of this study was to identify different vascular patterns in RP, by means of optical coherence tomography angiography (OCTA).MethodsA total of 32 RP patients (16 males, 50%; mean age 45.93 ± 11.4) and 32 healthy age-matched controls (16 males, 50%; age 42.8 ± 11.2). High resolution OCT and OCTA images were obtained from all participants. Several quantitative parameters were extracted both from structural OCT and OCTA images. A post-hoc analysis assessed the relationship between the quantitative OCTA parameters adopted and the following measures: best corrected visual acuity (BCVA), central macular thickness (CMT) and retinal nerve fiber layer (RNFL).ResultsMean LogMAR BCVA was 0.24 ± 0.32 for RP patients and 0.0 ± 0.0 for controls (p < 0.01). CMT, choroidal thickness and RNFL were statistically different between RP and controls (p < 0.01). OCTA parameters showed strong alterations of the retinal vascular network in RP (all p < 0.01). Several statistically significant correlations were also found. Furthermore, a vessel tortuosity cut-off of 4.80 and a vessel rarefaction cut-off of 0.62 enabled the RP cohort to be divided into two significantly different sub-groups in terms of BCVA, RNFL and CMT.ConclusionsQuantitative OCTA parameters help identify vascular abnormalities in RP, separating two different vascular patterns.
| S-EPMC6780333 | biostudies-literature
Project description:In this prospective study, we analysed the changes in retinal vessel density (VD) using optical coherence tomography angiography (OCTA) in patients with commotio retinae up to 6 months after blunt ocular trauma. We analysed the VD in the superficial capillary plexus (SCP), deep capillary plexus (DCP), radial peripapillary capillary (RPC) and the foveal avascular zone (FAZ) area at 48 h, and 1, 3 and 6 months after the trauma and compared results with those of healthy fellow eyes. We also evaluated the best-corrected visual acuity (BCVA) and the structural, spectral domain (SD)-OCT parameters: ganglion cell complex (GCC) and retinal nerve fibre layer (RNFL). A total of 18 eyes of 18 patients (8 males, 10 females, mean age 49.61 ± 9.2 years) and 18 healthy control eyes were evaluated. GCC and RNFL thicknesses showed a significant trend towards progressively lower values from 1 month and 3 months after the trauma, respectively, compared to healthy eyes (p < 0.005). The reduction in SD-OCT parameters reached a plateau at 6 months. Similar behaviour was found in the VD of the SCP and RPC that significantly decreased, starting from 1 and 3 months after the trauma, respectively (p < 0.001). At 6 months, the VD values were stable. The DCP presented an initial decrease of VD (p < 0.001), and after 1 month, the values statistically increased until the sixth month, reaching values similar to those of the control group. The FAZ area and BCVA did not show statistically significant changes during the follow-up. OCTA provided a detailed and quantitative analysis of early retinal vascular perfusion alterations after commotio retinae, demonstrating that the impairment of the retinal microvasculature and its progressive changes over time occurred even in the absence of compromised visual acuity.
| S-EPMC7602990 | biostudies-literature
Project description:PurposeTo compare the retinal vessel density and glaucomatous parameters in primary angle closure glaucoma (PACG), to evaluate the diagnostic and monitoring abilities of the peripapillary and macular vessel density in the progression of glaucoma.MethodsThis was a observational, prospective and cross-sectional study. According to Glaucoma Staging System, 218 eyes (116 participants) were divided into 5 groups: no glaucoma, early glaucoma, moderate glaucoma, advance glaucoma, severe glaucoma. All participants underwent a comprehensive ocular examination, which included corrected distance visual acuity measurement, slit-lamp biomicroscopy, intra ocular pressure (IOP), gonioscopy, fundus examination, stereoscopic optic disc photography, Humphrey visual field test(VF), peripapillary and macular optical coherence tomography angiography(OCTA) scan. SPSS software was used to calculate and compare retinal vessel density (peripapillary vessel density, PVD and macular vessel density, MVD) and glaucomatous parameters (mean deviation (MD),pattern standard deviation(PSD), retinal nerve fiber layer (RNFL), ganglion cell-inner plexiform layer(GCIPL),rim area, average cup/disc(C/D) ratio).ResultsThe GCIPL thickness, RNFL thickness, PVD and MVD are significantly reduced in PACG. There were significant differences in all measurements among the groups (P<0.01).Reduced peripapillary and macular vessel density in glaucoma were detected and a statistically significant correlation with glaucoma stages (P<0.01). In addition, the results of retinal vessel density, reduced RNFL thickness and GCIPL thickness were also statistically related to the stage of glaucoma. As expected, the rim area was significantly smaller with higher C/D area ratios in glaucomatous eyes corresponding to the severity of disease.ConclusionsThe changes of PVD and MVD had strongly positive correlation with GCIPL thickness and RNFL thickness, had negative correlation with the severity of glaucoma, which meant the more severe the glaucoma was, the lower PVD and MVD were. Compared to traditional glaucoma staging system judged by VF, the changes of PVD and MVD obtained by OCTA might be a new method to grade the stage of glaucoma. These findings theorize that the changes of PVD and MVD may be better facilitated for the observation and monitoring of glaucoma progression.
| S-EPMC7316331 | biostudies-literature
Project description:Optical coherence tomography (OCT) is the gold standard for quantitative ophthalmic imaging. The majority of commercial and research systems require patients to fixate and be imaged in a seated upright position, which limits the ability to perform ophthalmic imaging in bedridden or pediatric patients. Handheld OCT devices overcome this limitation, but image quality often suffers due to a lack of real-time aiming and patient eye and photographer motion. We describe a handheld spectrally encoded coherence tomography and reflectometry (SECTR) system that enables simultaneous en face reflectance and cross-sectional OCT imaging. The handheld probe utilizes a custom double-pass scan lens for fully telecentric OCT scanning with a compact optomechanical design and a rapid-prototyped enclosure to reduce the overall system size and weight. We also introduce a variable velocity scan waveform that allows for simultaneous acquisition of densely sampled OCT angiography (OCTA) volumes and widefield reflectance images, which enables high-resolution vascular imaging with precision motion-tracking for volumetric motion correction and multivolumetric mosaicking. Finally, we demonstrate in vivo human retinal OCT and OCT angiography (OCTA) imaging using handheld SECTR on a healthy volunteer. Clinical translation of handheld SECTR will allow for high-speed, motion-corrected widefield OCT and OCTA imaging in bedridden and pediatric patients who may benefit ophthalmic disease diagnosis and monitoring.
| S-EPMC6991137 | biostudies-literature
Project description:Background To evaluate choroidal vascular changes, including choriocapillaris (CC) and middle/large choroidal vessels, in retinitis pigmentosa (RP) patients using wide-angle optical coherence tomography angiography (OCTA) and to determine whether changes in the choroidal vascularity have a relationship with visual function and retinal structural changes. Methods 34 patients with a confirmed diagnosis of RP and 48 controls were recruited. All patients underwent detailed ophthalmologic and imaging examinations, including two types of OCTA (Optovue, 3?×?3?mm, 6?×?6?mm; VG-200, 12?×?12?mm). CC defects were defined according to the choroidal vascular structure in five degrees. To evaluate middle and large choroidal vascular changes, the choroidal vascularity index (CVI), which was the luminance volume to the total choroidal volume, was used. Results Defects of choroidal vascularity of RP eyes were detected in comparison to control eyes. The defects were observed in the CC layer with a concentric or lobular pattern at different degrees. CVI, which was used to reflect middle/large choroidal vascularity, decreased in the perifoveal, pararetinal and periretinal regions in the RP eyes. CC defects degree were correlated with the BCVA (p?=?0.001, r?=???0.556), the Humphrey indexes (mean deviation, MD, p?<?0.001, r?=???0.673; PVF, p?=?0.003, r?=???0.639; 10° mean sensitivity, 10° MS, p?=?0.002, r?=???0.651) and microperimetry index (mean sensitivity, MS, p?<?0.001, r?=???0.807). The preserved CC area (mean value: 28.65?±?12.50?mm2) was negatively correlated with MS measured by microperimetry (p?=?0.005, r?=???0.449). Ordinary regression analysis revealed that the CC defect degree was associated with the CVI of perifovea (p?=?0.002, 95% CI: ??102.14 to ??24.01), the EZ length (p?=?0.006, 95% CI: ??0.006 to ??0.001) and the VAD (vascular area density) of the DCP (deep capillary plexus) in the fovea (p?=?0.022, 95% CI: 0.038–0.478). No correlations were detected between BCVA and CVI in any retinal regions. No correlations were found between the CVI and the VAD in any retinal regions. Conclusion The choroidal vascularity was widely defected in RP. Choriocapillaris and middle/large choroidal vascularity defects were correlated with each other. Visual function and retinal structural changes were found to be associated with choriocapillaris defects but not with middle/large choroidal vascular defects.
| S-EPMC7523071 | biostudies-literature
Project description:PurposeTo assess the connection among arterioles, venules, and capillaries in three retinal capillary plexuses using optical coherence tomography angiography (OCTA).MethodsThis was a prospective, cross-sectional, observational study including 20 eyes of 10 healthy subjects. En face and cross-sectional OCTA images were segmented to study the superficial (SCP), middle (MCP), and deep capillary plexuses (DCP). Using thin slabs and manual segmentation within the three plexuses, we examined the connections between the large-caliber superficial vessels within a 3 × 3 mm2 OCTA scan (arterioles and venules) and the smaller capillaries in each plexus.ResultsTwenty eyes of 10 healthy subjects (5 females; average age of 30.8 ± 6.3 years) were included in the analysis. We identified vascular interconnections linking the superficial arterioles and venules with capillaries in each plexus (SCP, MCP, and DCP). We found capillaries in the DCP crossed the horizontal raphe.ConclusionsOur findings show that each of the three capillary plexuses in the parafovea has its own feeding arteriolar supply and draining venules, supporting a physiologic model in which each plexus controls its own oxygenated blood supply to match the metabolic needs of each distinct retinal neurovascular unit.
| S-EPMC6071478 | biostudies-literature
Project description:Importance:Whether optical coherence tomography angiography (OCT-A) outperforms OCT to detect glaucoma remains inconclusive. Objective:To compare (1) the diagnostic performance for detection of glaucoma and (2) the structure-function association between inner macular vessel density and inner macular thickness. Design, Setting, and Participants:This cross-sectional study included 115 patients with glaucoma and 35 healthy individuals for measurements of retinal thickness and retinal vessel density, segmented between the anterior boundary of internal limiting membrane and the posterior boundary of the inner plexiform layer, over the 3 × 3-mm2 macula using swept-source OCT. All participants were Chinese. Visual sensitivity corresponding to the 3 × 3-mm2 macular region was expressed in unlogged 1/lambert for investigation of the structure-function associations. Diagnostic performance was evaluated with area under the receiver operating characteristic curves (AUCs). The study was conducted between January 12, 2016, and December 12, 2016. Main Outcomes and Measures:Area under the receiver operating characteristic curve and R2 analysis. Results:Of the 115 patients with glaucoma, 42 (36.5%) were women (mean [SD] age, 53.5 [13.4] years); of the 35 individuals with healthy eyes, 25 (71.4%) were women (age, 60.6 [5.9] years). Inner macular vessel density and thickness were 4.3% (95% CI, 2.4%-6.1%) and 21.1 μm (95% CI, 17.4-24.9 μm) smaller, respectively, in eyes with glaucoma compared with healthy eyes. The AUC of mean inner macular thickness for glaucoma detection was greater than that of mean inner macular vessel density (difference, 0.17; 95% CI, 0.01-0.31; P = .03). At 90% specificity, the sensitivity of mean inner macular thicknesses for detection of glaucoma was greater than that of mean inner macular vessel densities (difference, 29.2%; 95% CI, 11.5%-64.6%; P = .02). The strength of the structure-function association was stronger for mean inner macular thickness than mean inner macular vessel density in the linear (difference in R2 = 0.38; 95% CI, 0.22-0.54; P < .001) and nonlinear (difference in R2 = 0.36; 95% CI, 0.21-0.51; P < .001) regression models. Conclusions and Relevance:In this study, OCT measurement of inner macular thickness shows a higher diagnostic performance to detect glaucoma and a stronger structure-function association than the currently used OCT-A measurement of inner macular vessel density. These findings may suggest that OCT-A of the macula has a limited role in the diagnostic evaluation of glaucoma.
| S-EPMC6142951 | biostudies-literature
Project description:To compare visualization of choroidal neovascularization (CNV) secondary to age-related macular degeneration (AMD) using an ultrahigh-speed swept-source (SS) optical coherence tomography angiography (OCTA) prototype vs a spectral-domain (SD) OCTA device.Comparative analysis of diagnostic instruments.Patients were prospectively recruited to be imaged on SD OCT and SS OCT devices on the same day. The SD OCT device employed is the RTVue Avanti (Optovue, Inc, Fremont, California, USA), which operates at ?840 nm wavelength and 70 000 A-scans/second. The SS OCT device used is an ultrahigh-speed long-wavelength prototype that operates at ?1050 nm wavelength and 400 000 A-scans/second. Two observers independently measured the CNV area on OCTA en face images from the 2 devices. The nonparametric Wilcoxon signed rank test was used to compare area measurements and P values of <.05 were considered statistically significant.Fourteen eyes from 13 patients were enrolled. The CNV in 11 eyes (78.6%) were classified as type 1, 2 eyes (14.3%) as type 2, and 1 eye (7.1%) as mixed type. Total CNV area measured using SS OCT and SD OCT 3 mm × 3 mm OCTA were 0.949 ± 1.168 mm(2) and 0.340 ± 0.301 mm(2), respectively (P = .001). For the 6 mm × 6 mm OCTA the total CNV area using SS OCT and SD OCT were 1.218 ± 1.284 mm(2) and 0.604 ± 0.597 mm(2), respectively (P = .0019). The field of view did not significantly affect the measured CNV area (P = .19 and P = .18 for SS OCT and SD OCT, respectively).SS OCTA yielded significantly larger CNV areas than SD OCTA. It is possible that SS OCTA is better able to demarcate the full extent of CNV vasculature.
| S-EPMC4811690 | biostudies-literature