Optical coherence tomographic angiography study of perfusion recovery after surgical lowering of intraocular pressure.
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ABSTRACT:
SUBMITTER: Liu L
PROVIDER: S-EPMC8390670 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:Shadowgraphic projection artifacts from superficial vasculature interfere with the visualization of deeper vascular networks in optical coherence tomography angiography (OCT-A). We developed a novel algorithm to remove this artifact by resolving the ambiguity between in situ and projected flow signals. The algorithm identifies voxels with in situ flow as those where intensity-normalized decorrelation values are higher than all shallower voxels in the same axial scan line. This "projection-resolved" (PR) algorithm effectively suppressed the projection artifact on both en face and cross-sectional angiograms and enhanced depth resolution of vascular networks. In the human macula, the enhanced angiograms show three distinct vascular plexuses in the inner retina and no vessels in the outer retina. We demonstrate that PR OCT-A cleanly removes flow projection from the normally avascular outer retinal slab while preserving the density and continuity of the intermediate and deep retinal capillary plexuses.
| S-EPMC4866458 | biostudies-literature
Project description:ImportanceBiomarker testing for asymptomatic, preclinical Alzheimer disease (AD) is invasive and expensive. Optical coherence tomographic angiography (OCTA) is a noninvasive technique that allows analysis of retinal and microvascular anatomy, which is altered in early-stage AD.ObjectiveTo determine whether OCTA can detect early retinal alterations in cognitively normal study participants with preclinical AD diagnosed by criterion standard biomarker testing.Design, setting, and participantsThis case-control study included 32 participants recruited from the Charles F. and Joanne Knight Alzheimer Disease Research Center, Washington University in St Louis, St Louis, Missouri. Results of extensive neuropsychometric testing determined that all participants were cognitively normal. Participants underwent positron emission tomography and/or cerebral spinal fluid testing to determine biomarker status. Individuals with prior ophthalmic disease, media opacity, diabetes, or uncontrolled hypertension were excluded. Data were collected from July 1, 2016, through September 30, 2017, and analyzed from July 30, 2016, through December 31, 2017.Main outcomes and measuresAutomated measurements of retinal nerve fiber layer thickness, ganglion cell layer thickness, inner and outer foveal thickness, vascular density, macular volume, and foveal avascular zone were collected using an OCTA system from both eyes of all participants. Separate model III analyses of covariance were used to analyze individual data outcome.ResultsFifty-eight eyes from 30 participants (53% female; mean [SD] age, 74.5 [5.6] years; age range, 62-92 years) were included in the analysis. One participant was African American and 29 were white. Fourteen participants had biomarkers positive for AD and thus a diagnosis of preclinical AD (mean [SD] age, 73.5 [4.7] years); 16 without biomarkers served as a control group (mean [SD] age, 75.4 [6.6] years). The foveal avascular zone was increased in the biomarker-positive group compared with controls (mean [SD], 0.364 [0.095] vs 0.275 [0.060] mm2; P = .002). Mean (SD) inner foveal thickness was decreased in the biomarker-positive group (66.0 [9.9] vs 75.4 [10.6] μm; P = .03).Conclusions and relevanceThis study suggests that cognitively healthy individuals with preclinical AD have retinal microvascular abnormalities in addition to architectural alterations and that these changes occur at earlier stages of AD than has previously been demonstrated. Longitudinal studies in larger cohorts are needed to determine whether this finding has value in identifying preclinical AD.
| S-EPMC6248182 | biostudies-literature
Project description:PurposeTo investigate responses of macular capillary vessel area density (VAD) of superficial and deep retinal vascular plexuses to elevations in intraocular pressure (IOP) in cynomolgus macaque monkeys using optical coherence tomography angiography (OCTA).MethodsIn five general anesthetized male cynomolgus monkeys, the IOP was increased incrementally by 10 mmHg from baseline (10 mmHg) to 70 mmHg and then decreased back to 10 mmHg (recovery state). Structural OCT (30° × 30°) and OCTA (20° × 15°) centered on the macula were obtained at each IOP and 3, 15, and 30 minutes after recovery. En face images of the superficial vascular complex (SVC) and deep vascular complex (DVC) were extracted, and VAD (%) compared with that at baseline was calculated.ResultsThe VADs in the SVC and DVC at baseline and at 30 mmHg IOP were 34.96%, 34.15%, 35.38%, and 30.12%, respectively. The VAD plateaued until 30 mmHg; however, the VAD was affected more in the DVC than in the SVC (P = 0.008) at 30 mmHg. It showed a significant reduction at 40 mmHg (16.52% SVC, P = 0.006; 18.59% DVC, P = 0.012). In the recovery state, the SVC showed full retention of baseline VAD, but the DVC maintained VAD approximately 70% of that at baseline. Structural OCT showed hyperreflectivity in the nuclear layer, retinal swelling, and an undifferentiated ellipsoid zone from 50 mmHg.ConclusionsDespite physiological autoregulation, perifoveal microcirculation was affected at high IOP ≥ 40 mmHg, especially in the DVC, which explains the pathological mechanism of macular vulnerability in ischemic diseases.
| S-EPMC8709935 | biostudies-literature
Project description:PurposeTo use projection-resolved optical coherence tomographic angiography (PR-OCTA) to characterize the microvascular changes in 3 distinct retinal plexuses in retinitis pigmentosa (RP) patients.DesignProspective cross-sectional study.MethodsA commercial 70-kHz spectral-domain optical coherence tomography (OCT) system was used to acquire 6-mm macular scans from RP patients and age-matched healthy participants at a tertiary academic center. Blood flow was detected using a commercial version of split-spectrum amplitude-decorrelation angiography (SSADA) algorithm. The PR-OCTA algorithm was used to suppress projection artifacts and resolve microvasculature in 3 plexuses around the macula. Vessel density was calculated from en face OCTA of the parafoveal and perifoveal regions in each of the 3 plexuses, as well as the all-plexus inner retinal slab. Inner and outer retinal thicknesses were measured form structural OCT scans. Generalized estimating equations and Spearman's rank correlation statistical methods were used.ResultsForty-four eyes from 26 RP patients and 34 eyes from 26 healthy subjects were included. Significant reduction in vessel density was detected in the perifovea but not the parafovea of inner retinal slab of RP patients (P = .001 and P = .56, respectively) compared to controls. We also found deeper retinal plexuses (intermediate and deep capillary plexuses, ICP and DCP) were primarily damaged by RP, compared to superficial vascular complex (SVC). Significant thickening of the inner retina and thinning of the outer retina were also observed. Strong correlation was found between the vessel density in the perifoveal ICP and DCP and outer retinal thickness in RP patients with no history of cystoid macular edema.ConclusionsPR-OCTA enables the detection of microvascular changes in the perifoveal regions of the ICP and DCP in RP, with relative sparing of the SVC. OCT and OCTA parameters might be able to provide better understanding of the pathophysiology of the disease, as well as monitoring disease progression and the response to experimental treatments.
| S-EPMC7001722 | biostudies-literature
Project description:ImportanceQuantitative measurements based on optical coherence tomographic angiography (OCTA) may have value in managing diabetic retinopathy (DR), but there is limited information on the ability of OCTA to distinguish eyes with DR.ObjectiveTo evaluate the ability of measurements of retinal microvasculature using OCTA to distinguish healthy eyes from eyes with DR.Design, setting, and participantsIn this prospective cross-sectional study, OCTA was used to examine the eyes of participants with type 2 diabetes with or without DR and the eyes of participants without diabetes from September 17, 2015, to April 6, 2016. Density maps based on superficial retinal layer (SRL) and deeper retinal layer (DRL) images were generated after a method to remove decorrelation tails was applied to the DRL images.ExposuresBoth eyes of each participant were examined by means of a 3-mm OCTA scan and 7-field fundus photography using the Diabetic Retinopathy Severity Scale.Main outcomes and measuresTwo measures were examined: perfusion density, based on the area of vessels, and vessel density, based on a map with vessels of 1-pixel width. The size of the foveal avascular zone was also calculated automatically, and so was the area under the receiver operating characteristic curve.ResultsA total of 50 eyes from 26 participants with diabetes (10 women and 16 men; mean [SD] age, 64.9 [7.5] years) and 50 healthy eyes from 25 participants without diabetes (14 women and 11 men; mean [SD] age, 64.0 [7.1] years) were imaged. All participants were white. Vessel density measured in the SRL had the highest area under the receiver operating characteristic curve (0.893 [95% CI, 0.827-0.959]), compared with perfusion density in the SRL (0.794 [95% CI, 0.707-0.881]), foveal avascular zone area (0.472 [95% CI, 0.356-0.588]), and vessel density in the DRL (0.703 [95% CI, 0.601-0.805]). Vessel density in the SRL negatively correlated with best-corrected visual acuity (r = -0.28; P = .05) and severity of DR (r = -0.46; P = .001). Density metrics correlated with age. No correlation was detected between vascular density or foveal avascular zone metrics and hemoglobin A1C or duration of diabetes.Conclusions and relevanceVessel density measured by OCTA provides a quantitative metric of capillary closure that correlates with severity of DR and may allow staging, diagnosis, and monitoring that do not require subjective evaluation of fundus images.
| S-EPMC5470403 | biostudies-literature
Project description:We evaluated the agreements in foveal avascular zone (FAZ) area and vessel density (VD) parameters (within the superficial capillary plexus region), between two widely used optical coherence tomography angiography machines. Participants who attended the Singapore Malay Eye Study III between 29th March and 6th August 2018, were enrolled in this study. Participants underwent fovea-centered 6×6-mm macular cube scan, using both AngioVue and Cirrus HDOCT machines. Scans were analyzed automatically using built-in review software of each machine. 177 eyes (95 participants) without retinal diseases were included for final analysis. Mean FAZ area was 0.38?±?0.11 mm2 and 0.30?±?0.10 mm2, based on AngioVue and Cirrus HDOCT, respectively. Mean parafoveal VD was 0.50?±?0.04 in Angiovue, and 0.43?±?0.04 in Cirrus HDOCT. Cirrus HDOCT measurements were consistently lower than those by AngioVue, with a mean difference of -0.08 (95% limits of agreement [LOA], -0.30-0.13) mm2 for FAZ area, and -0.07 (95% LOA, -0.17-0.03) for parafoveal VD. Intraclass correlation coefficients for FAZ area and parafoveal VD were 0.33 and 0.07, respectively. Our data suggest that agreements between AngioVue and Cirrus HDOCT machines were poor to fair, thus alternating use between these two machines may not be recommended especially for follow up evaluations.
| S-EPMC7239842 | biostudies-literature
Project description:The ability to quantify and visualize submicrometer-scale oscillatory motions of objects in three dimensions has a wide range of application in acoustics, materials sciences, and medical imaging. Here we demonstrate that volumetric snapshots of rapid periodic motion can be captured using optical coherence tomography (OCT) with subnanometer-scale motion sensitivity and microsecond-scale temporal resolution. This technique, termed OCT vibrography, was applied to generate time-resolved volumetric vibrographs of a miniature drum driven acoustically at several kilohertz.
| S-EPMC3740196 | biostudies-literature
Project description:PurposeTo investigate changes in peripapillary and macular vessel density (VD) in vascular paralytic strabismus using optical coherence tomography angiography (OCTA).MethodsMedical records of patients who recovered from monocular vascular paralytic strabismus were retrospectively analyzed. Age, sex, presence of underlying diseases, strabismus type and severity, time to recovery, and visual acuity at diagnosis were evaluated. VD in the optic disc area and macular capillary plexus density were estimated using OCTA. The effect of paralytic strabismus on intraocular VD was investigated by comparing VD between the paralysis and contralateral eyes. To analyze hemodynamic changes, VD changes in the paralysis eye during the attack and recovery were compared.ResultsThirty-one patients (mean age, 64.1±13.0 years; 21 males, 10 females) were included and mean recovery time was 3.0±1.6 months. The most common paralysis was sixth nerve palsy (54.8%). When comparing OCTA results between the paralysis and contralateral non-paralysis eyes, foveal VD in the superficial capillary plexus (SCP) was significantly lower in the paralysis eye (P = 0.034); however, VD in the optic disc area was not different. In the paralysis eye, foveal VD in the SCP significantly increased after paralysis recovery (P = 0.04). During attack, the maximal deviation angle and severity of duction limitation were significantly related to foveal VD in SCP. The greater the deviation angle and the more severe the eye movement restriction, the lower the foveal VD in SCP.ConclusionsTransient retinal ischemia of the paralysis eye was observed in a patient with paralytic strabismus, which corresponded to the degree of deviation angle and ocular motor restriction. Ischemic factors, which are the etiology of vascular paralytic strabismus, affect intraocular blood flow.
| S-EPMC9469969 | biostudies-literature
Project description:ObjectiveTo report the morphologic characteristics of tumor-related vasculatures and their association with secondary choroidal neovascularization (CNV), subretinal fluid (SRF), choroidal thickness, retinal pigment epithelium (RPE) alterations, subretinal hemorrhage, and tumor decalcification in eyes with choroidal osteoma (CO), using swept-source optical coherence tomographic angiography (SS-OCTA).DesignCross-sectional observational study.ParticipantsWe included 26 patients recruited from Beijing Tongren Hospital with a diagnosis of CO, based on the presence of yellow-orange mass deep to the RPE under indirect ophthalmoscopy and occupying the choroid with well-defined margins and bone density on ultrasonography or computed tomography and focal hyperfluorescent spots with no homogeneous pattern on fluorescein angiography/indocyanine green angiography (FA/ICGA). Data were collected from April 1, 2020, to April 1, 2021, and analyzed from April 30 through May 30, 2021.MethodsApplying SS-OCTA systems operating at 1,050-nm wavelengths, eyes with CO were imaged.Main outcome and measuresTumor-related vasculature in eyes with CO was characterized using multimodal imaging that included fundus photography, FA/ICGA, SS-OCT, and SS-OCTA, and the images were anatomically aligned. CO thickness was manually measured as the distance between the upper boundary of the tumor and the underlying sclerochoroidal interface on the SS-OCT images. Subfoveal choroidal thickness was manually measured as the distance between the Bruch membrane and the sclerochoroidal interface on the SS-OCT images.ResultsOf the 26 Asian patients, 16 (62%) were women and 10 (38%) were men. The mean age was 26.8 years (median, 23; range, 8-45 years), and the mean best corrected visual acuity (BCVA) was 20/40. Thirty-three eyes underwent imaging and were diagnosed with CO. Indocyanine green angiography identified inhomogeneous hyperfluorescence due to tumor-related vasculature, and all corresponded to the structures that appeared as sea-fan vascular networks (SFVNs) combined with clusters of tangled vessels on SS-OCTA images. SFVNs were detected on SS-OCTA imaging in all eyes (100%), terminal tangled vascular structures in 32 of 33 eyes (97%), but not identified on ICGA. Of the 33 tangled vascular structures, 32 (97%) were located at the edge of or inside the tumor, and only 1 (3%) was associated with type 2 neovascularization. In addition, SS-OCT revealed SRF in 33 eyes (100%), 33 (100%) were located at the edge of CO, and only 1 was underlying macular. SRF with retinal edema was seen in 30 of 32 eyes (94%).ConclusionsIn eyes with CO undergoing SS-OCTA imaging, tumor-related vasculature appears as SFVNs combined with tangled vascular structures or few type 2 neovascularization. The identification of actual tumor vasculature in patients with CO as SFVNs with inner or terminal vascular tangles rather than previously described CNV may help facilitate understanding of their pathogenesis, tumor control, and response to treatment.
| S-EPMC8591199 | biostudies-literature
Project description:PurposeTo simulate 24-2 visual field (VF) using optical coherence tomographic angiography (OCTA) for glaucoma evaluation.DesignCross-sectional study.MethodsOne eye each of 39 glaucoma and 31 age-matched normal participants was scanned using 4.5-mm OCTA scans centered on the disc. The peripapillary retinal nerve fiber layer plexus capillary density (NFLP-CD, %area) was measured. The NFLP-CD and 24-2 VF maps were divided into 8 corresponding sectors using an extension of Garway-Heath scheme.ResultsSector NFLP-CD was transformed to a logarithmic dB scale and converted to sector simulated VF deviation maps. Comparing simulated and actual 24-2 VF maps, the worst sector was in the same or adjacent location in the same hemisphere 97% of the time. VF mean deviation (VF-MD) was simulated by NFLP mean deviation (NFLP-MD). The differences between NFLP-MD and VF-MD in early, moderate, and severe glaucoma stages were -0.9 ± 2.0, 0.9 ± 2.9, and 5.8 ± 3.2 dB. NFLP-MD had better (P = .015) between-visit reproducibility (0.63 dB pooled standard deviation) than VF-MD (1.03 dB). NFLP-MD had a significantly higher sensitivity than VF-MD (P < .001) and overall NFL thickness (P = .031).ConclusionsOCTA-based simulated VF agreed well with actual 24-2 VF in terms of both the location and severity of glaucoma damage, with the exception of severe glaucoma in which the simulation tended to underestimate severity. The NFLP-MD had better reproducibility than actual VF-MD and holds promise for improving glaucoma monitoring. The NFLP-MD had better diagnostic accuracy than both VF-MD and overall NFL thickness and may be useful for early glaucoma diagnosis.
| S-EPMC7113124 | biostudies-literature