Optical coherence tomography angiography (OCTA) is a noninvasive, depth-resolved imaging tool for the appraisement of retinal vascular changes. Since its introduction, the understanding of diabetic ...retinopathy, age-related macular degeneration, central serous retinopathy, and other diseases has been enriched on many fronts. Its dyeless imaging property maps retinal as well as deeper choroidal vasculature in quick succession with good reproducibility. Hence, it can play an important role in the diagnosis and management of optic nerve–related diseases as well. A detailed literature review for its role in nonarteritic anterior ischemic optic neuropathy, papilledema, optic disc drusen, papillitis, hereditary optic neuropathies, central nervous system diseases, and others highlights its role. The whole spectrum of neuro-ophthalmological diseases shows consistent peripapillary and macular capillary changes with structural and functional correlation. The superficial and deeper retinal and choroidal vasculatures are affected depending on the nature of the disease process. Hence, OCTA positions itself as a useful, noninvasive tool in the armamentarium of a neuro-ophthalmologist in future; however, there are several limitations of the OCTA with respect to its technical abilities in challenging neuro-ophthalmic cases. Therefore, future research should be directed to enhance the technical capabilities of OCTA and to determine the more precise role of it in the prognosis of neuro-ophthalmic diseases.
The purpose of this study was to compare imaging of choroidal neovascularization (CNV) using swept-source (SS) and spectral-domain (SD) optical coherence tomography angiography (OCTA).
Optical ...coherence tomography angiography was performed using a 100-kHz SS-OCT instrument and a 68-kHz SD-OCTA instrument (Carl Zeiss Meditec, Inc.). Both 3 × 3- and 6 × 6-mm2 scans were obtained on both instruments. The 3 × 3-mm2 SS-OCTA scans consisted of 300 A-scans per B-scan at 300 B-scan positions, and the SD-OCTA scans consisted of 245 A-scans at 245 B-scan positions. The 6 × 6-mm2 SS-OCTA scans consisted of 420 A-scans per B-scan at 420 B-scan positions, and the SD-OCTA scans consisted of 350 A-scans and 350 B-scan positions. B-scans were repeated four times at each position in the 3 × 3-mm2 scans and twice in the 6 × 6-mm2 scans. Choroidal neovascularization was excluded if not fully contained within the 3 × 3-mm2 scans. The same algorithm was used to detect CNV on both instruments. Two graders outlined the CNV, and the lesion areas were compared between instruments.
Twenty-seven consecutive eyes from 23 patients were analyzed. For the 3 × 3-mm2 scans, the mean lesion areas for the SS-OCTA and SD-OCTA instruments were 1.17 and 1.01 mm2, respectively (P = 0.047). For the 6 × 6-mm2 scans, the mean lesion areas for the SS-OCTA and SD-OCTA instruments were 1.24 and 0.74 mm2 (P = 0.003).
The areas of CNV tended to be larger when imaged with SS-OCTA than with SD-OCTA, and this difference was greater for the 6 × 6-mm2 scans.
To assess the efficacy of customized slab segmentation in eliminating projection artifacts in swept-source optical coherence tomography angiography (SS-OCTA) images of Best vitelliform macular ...dystrophy (BVMD).
Prospective case series including different stages of BVMD. We analyzed SS-OCTA images for flow signals in the outer retina and coregistered B-scan images for distortion of the segmentation slabs defining the outer retina. We applied a customized method for slab realignment whenever BVMD lesions produced distortion of the slabs. Afterward, we checked the images to determine whether the previously noted flow signal had persisted or disappeared, described as "true flow" or "pseudoflow", respectively. Categorical variables were analyzed with X
or Fisher's exact tests, while quantitative variables were analyzed with independent
-test at
<0.05.
The study included 39 eyes of 22 patients. We detected BVMD patterns I (dome-shaped hyperreflective lesion without neurosensory retinal detachment), II (knob-like hyperreflective lesion with localized neurosensory retinal detachment), and III (heterogeneous scattered hyperreflective material) in 49%, 23%, and 28% of eyes, respectively. Pseudoflow was evident mostly in eyes with pattern II lesions, presence of flow signal within BVMD lesions, and lesions whose height represented >80% of the retinal thickness (
<0.001).
Customized slab segmentation is effective in eliminating projection artifact in SS-OCTA images of BVMD.
Projection artifact is a significant confounding factor in emerging SS-OCTA technology through production of pseudoflow signals that can lead to misinterpretation of images of BVMD lesions. The present study proposes a customized method for correction of segmentation errors to eliminate projection artifacts in SS-OCTA images of BVMD patients.
To achieve reproducible imaging of the choriocapillaris and associated flow voids using swept-source OCT angiography (SS-OCTA).
Subjects were enrolled and SS-OCTA was performed using the 3 × 3 mm ...scan pattern. Blood flow was identified using the complex optical microangiography (OMAG) algorithm. The choriocapillaris was defined as a slab from the outer boundary of Bruch's membrane (BM) to approximately 20 μm below BM. Compensation for the shadowing effect caused by the RPE and BM complex on the choriocapillaris angiogram was achieved by using the structural information from the same slab. A thresholding method to calculate the percentage of flow voids from a region was developed based on a normal database.
Twenty normal subjects and 12 subjects with drusen were enrolled. SS-OCTA identified the choriocapillaris in normal subjects as a lobular plexus of capillaries in the central macula and the lobular arrangement became more evident toward the periphery. In all eyes, signal compensation resulted in fewer choriocapillaris flow voids with improved repeatability of measurements. The best repeatability for the measurement was achieved by using 1 standard deviation (SD) for the thresholding strategy.
SS-OCTA can image the choriocapillaris in vivo, and the repeatability of flow void measurements is high in the presence of drusen. The ability to image the choriocapillaris and associated flow voids should prove useful in understanding disease onset, progression, and response to therapies.
To assess the ability of optical coherence tomography (OCT) alone and in combination with OCT angiography (OCTA) to differentiate polypoidal choroidal vasculopathy (PCV) from neovascular age-related ...macular degeneration, as compared to fluorescein angiography and indocyanine green angiography.
This is a cross-sectional study. All participants had a standardized history, clinical examination including measurement of best-corrected visual acuity, slit-lamp biomicroscopy, and indirect fundus examination, and underwent standardized imaging (color photography, fluorescein and indocyanine green angiography, OCT, and OCTA) after predefined protocols. We used a 2-step approach (Step 1: spectral domain OCT; Step 2: addition of OCTA) combining structural OCT and OCTA to differentiate 50 treatment-naive eyes with PCV, choroidal neovascularization, and retinal angiomatous proliferation and compared with the diagnosis based on fluorescein angiography and indocyanine green angiography. Spectral domain OCT signs used to diagnose PCV included presence of two out of three of any retinal pigment epithelium detachment (pigment epithelial detachment/double-layer sign), notched or narrow-peaked pigment epithelial detachment, or round subretinal pigment epithelium structure. Optical coherence tomography angiography signs used to diagnose PCV included presence of a localized subretinal pigment epithelium hyperflow signal in the cross-sectional OCTA and/or presence of a focal hyperflow sign in en face OCTA based on outer retina slab.
Based on fluorescein angiography and indocyanine green angiography, the diagnosis was choroidal neovascularization in 24 eyes, PCV in 23 eyes, and retinal angiomatous proliferation in 3 eyes. Based on spectral domain OCT signs, PCV was diagnosed in 19/23 (82.6%) eyes; however, specificity of OCT was only 51.9%. Cross-sectional OCTA showed a diffuse hyperflow signal in all 24 (100.0%) eyes with choroidal neovascularization, whereas a localized subretinal pigment epithelium hyperflow signal was detected in 19/23 (82.6%) eyes with PCV. En face OCTA only detected a nodular hyperflow signal in 10/23 eyes (43.5%) with PCV. Combination of OCT and OCTA achieved 82.6% sensitivity and 100.0% specificity for differentiating PCV from choroidal neovascularization/retinal angiomatous proliferation.
Cross-sectional OCTA is more sensitive than en face OCTA in detecting flow signal in polyps. Combination of structural OCT and OCTA can be used to screen for PCV with a high level of sensitivity and specificity.
Background: Diabetic macular edema DME is a major factor contributing to the visual deterioration in most developed nations. OCTA helps visualization of diabetic microvascular changes such as ...microaneurysms, FAZ enlargement, and capillary non-perfusion areas.Aim of the work: This study aims to assess the changes in the macular perfusion of diabetic patients before and after intravitreal triamcinolone acetonide injection compared to intravitreal ranibizumab injection by OCTA. Patients and methods: This comparative study included 40 eyes having DME scheduled at Al-Azhar university hospital, Damietta. Twenty eyes underwent intravitreal ranibizumab injection Group I and Twenty eyes underwent intravitreal triamcinolone acetonide injection Group II.Results: This study demonstrated that BCVA and CMT significantly improved in 1st week up to 3 months in both groups. There was no statistically significant difference between the 2 groups as regards BCVA and CMT improvement P value > 0.05. As regards SCP superficial capillary plexus, and DCP Deep capillary plexus, there was some improvement in the macular perfusion of DCP in the ranibizumab group with no difference in macular perfusion of SCP in both groups and mild worsening of DCP in the triamcinolone group. The difference between the 2 groups was not significant statistically all over follow-up periods P value > 0.05. Also, the difference between the baseline macular perfusion and postoperative one in each group was not significant statistically P value > 0.05.Conclusion: Our study showed no significant changes in macular perfusion SCP or DCP following ranibizumab or triamcinolone injection in DME. In both groups.
To compare the lesion sizes of choroidal neovascularization (CNV) imaged with spectral-domain (SD) and swept-source (SS) optical coherence tomography angiography (OCTA) and measured using an ...automated detection algorithm.
Patients diagnosed with CNV were imaged by SD-OCTA and SS-OCTA systems using 3 × 3-mm and 6 × 6-mm scans. The complex optical microangiography (OMAGC) algorithm was used to generate the OCTA images. Optical coherence tomography A datasets for imaging CNV were derived by segmenting from the outer retina to 8 μm below Bruch's membrane. An artifact removal algorithm was used to generate angiograms free of retinal vessel projection artifacts. An automated detection algorithm was developed to quantify the size of the CNV. Automated measurements were compared with manual measurements. Measurements from SD-OCTA and SS-OCTA instruments were compared as well.
Twenty-seven eyes from 23 subjects diagnosed with CNV were analyzed. No significant differences were detected between manual and automatic measurements: SD-OCTA 3 × 3-mm (P = 0.61, paired t-test) and 6 × 6-mm (P = 0.09, paired t-test) scans and the SS-OCTA 3 × 3-mm (P = 0.41, paired t-test) and 6 × 6-mm (P = 0.16, paired t-test) scans. Bland-Altman analyses were performed to confirm the agreement between automatic and manual measurements. Mean lesion sizes were significantly larger for the SS-OCTA images compared with the SD-OCTA images: 3 × 3-mm scans (P = 0.011, paired sample t-test) and the 6 × 6-mm scans (P = 0.021, paired t-test).
The automated algorithm measurements of CNV were in agreement with the hand-drawn measurements. On average, automated SS-OCTA measurements were larger than SD-OCTA measurements and consistent with the results from using hand-drawn measurements.
Fibromyalgia (FM) is a widespread musculoskeletal pain disorder. Although the pathogenesis of fibromyalgia is unknown, central neurotransmitter systems and autonomic nervous system abnormalities may ...play a critical role. Today, the diagnosis is made by clinical findings, and there is no objective, confirmatory tests. Studies examining ophthalmic structures in patients with fibromyalgia using optic coherence tomography (OCT) and optic coherence tomography angiography (OCTA) sought objective evidence of both the neurodegenerative and vascular processes of the disease. In the results of these few studies, some findings of retinal and vascular density changes were found.
In this cross-sectional study, retinal superficial and deep vascular plexus density (SVP and DVP), choroid thickness, and choriocapillaris density were investigated in 42 patients with fibromyalgia and 42 healthy controls using OCTA.
42 fibromyalgia patients, including 42 age- and gender-matched healthy controls, were enrolled in this study. Central macular thickness (CMT) was found to be significantly thinner in fibromyalgia patients than in healthy groups. Retinal SVP and DVP were evaluated. No significant differences were observed between FM patients and control subjects as regards DVP density in the macular area. However, SVP density significantly decreased in the superior and inferior quadrants of fibromyalgia patients compared to the healthy controls. There was no significant difference in choriocapillaris density and choroid thickness between the patients with fibromyalgia and the healthy group in all quadrants.
We evaluated detailed ophthalmic vascular structures of patients with fibromyalgia using OCTA in our study. We found changes only superior and inferior quadrants of retinal superficial structures. There was no significant difference in other superficial vascular quadrants of the retina, deep vascular structures, and choriocapillaris density. On the other hand, the central macular thickness was thinner in FM patients. Therefore, these data show that the role of vascular processes in the pathogenesis of fibromyalgia is small, but thinner central macular thickness in FM may be significant as an objective finding of the disease
To combine advances in high-speed, wide-field optical coherence tomography angiography (OCTA) with image processing methods for semiautomatic quantitative analysis of capillary nonperfusion in ...patients with diabetic retinopathy (DR).
Sixty-eight diabetic patients (73 eyes), either without retinopathy or with different degrees of retinopathy, were prospectively recruited for volumetric swept-source OCTA imaging using 12 mm × 12 mm fields centered at the fovea. A custom, semiautomatic software algorithm was used to quantify areas of capillary nonperfusion.
The mean percentage of nonperfused area was 0.1% (95% confidence interval: 0.0-0.4) in the eyes without DR; 2.1% (95% confidence interval: 1.2-3.7) in the nonproliferative DR eyes (mild, moderate, and severe), and 8.5% (95% confidence interval: 5.0-14.3) in the proliferative DR eyes. The percentage of nonperfused area increased in a statistically significant manner from eyes without DR, to eyes with nonproliferative DR, to eyes with proliferative DR.
Capillary nonperfusion area in the posterior retina increases with increasing DR severity as measured by swept-source OCTA. Quantitative analysis of retinal nonperfusion on wide-field OCTA may be useful for early detection and monitoring of disease in patients with diabetes and DR.
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