1,720,980 research outputs found
Depth-Resolved Imaging of Papillary Vitreoretinal Neovascularization: OCT-Angiography Assessment in Ocular Ischemic Syndrome
No full textFractal analysis of polypoidal choroidal neovascularisation in age-related macular degeneration
Full text linkAim To describe optical coherence tomography angiography (OCTA) features of polypoidal choroidal neovascularisation (PCNV) secondary to age-related macular degeneration.
Methods A retrospective consecutive series of 51 patients with a diagnosis of PCNV, based on clinical and multimodal imaging, was analysed. All patients with PCNV underwent a comprehensive ophthalmological examination, including fluorescein and indocyanine green angiography, structural optical coherence tomography (OCT) and OCTA. Two blinded retinal specialists carefully reviewed OCTA slabs in order to assess the morphological patterns of PCNV lesions. Furthermore, fractal analysis of PCNV en face images on OCTA, including vascular perfusion density (VPD), fractal dimension (FD) and lacunarity (LAC), was performed.
Results Fifty-one PCNV eyes were included in the study. In all, the branching vascular network appeared hyper-reflective. Polyps showed two different patterns: in 34/51 (67%) eyes, they corresponded to hypo-reflective structures, whereas in the remaining 17 (33%) eyes, they appeared as hyper-reflective lesions. In all PCNV eyes, mean VPD, FD and LAC were 0.76±0.17%, 1.46±0.12 and 2.4±0.87, respectively. No significant difference was found between PCNVs showing a different OCTA pattern, in terms of quantitative OCTA parameters.
Conclusion Fractal analysis provides quantitative parameters demonstrating that PCNVs with different OCTA patterns share the same neovascular architecture and branching complexity. These new findings improve our ability to interpret OCTA slabs, opening new areas of discussion about this type of neovascular lesion
Optical Coherence Tomography Angiography in Healthy Subjects and Diabetic Patients
No full textFluorescein angiography and indocyanine green angiography provide information about the normal retinal and choroidal vascular perfusion. They allow the evaluation of different diseases and increase the capability to define and diagnose several pathological conditions. Fluorescein angio graphy is the “gold standard” in imaging the retinal vascular bed and its changes, although not all the different layers of the capillary network can be visualized in a bidimensional examination. Optical coherence tomography angiography allows a depth-resolved visualization of the retinal and choroidal microvasculature, by calculating the difference (decorrelation) between static and nonstatic tissue. Given that the main moving elements in the eye fundus are contained in vessels, determining a vascular decorrelation signal permits a three-dimensional visualization of the retinal and choroidal vascular network without the administration of an intravenous dye. Moreover, a complete morphofunctional assessment may help in defining both the origin and the clinical activity of different vascular diseases such as diabetic retinopathy.</jats:p
POLYPOIDAL CHOROIDAL NEOVASCULARIZATION VERSUS TYPE 1 CHOROIDAL NEOVASCULARIZATION IN AGE-RELATED MACULAR DEGENERATION
No full textTo compare quantitative optical coherence tomography angiography parameters between polypoidal choroidal neovascularizations (PCNVs) and Type 1 choroidal neovascularizations (CNVs) in patients with age-related macular degeneration. METHODS: PCNV and Type 1 CNV lesions were retrospectively recruited in a cohort of patients with age-related macular degeneration. All the patients underwent a comprehensive ophthalmic evaluation, including best-corrected visual acuity, fluorescein and indocyanine green angiography, structural optical coherence tomography (OCT), and optical coherence tomography angiography. Vascular perfusion density, fractal dimension, and lacunarity were computed by means of fractal analysis of neovascular en face optical coherence tomography angiography slabs. RESULTS: Sixty-eight eyes were included in the analysis. Of them, 35 of 68 eyes (51.5%) had PCNV and 33 of 68 (48.5%) had Type 1 CNV. Patients with PCNV were significantly younger (P = 0.0003) and had a higher best-corrected visual acuity (P < 0.0001). The mean vascular perfusion density was 0.83 ± 0.11% in PCNVs and 0.46 ± 0.10% in Type 1 CNVs (P < 0.0001). The mean fractal dimension was 1.44 ± 0.1 in PCNVs and 1.45 ± 0.09 in Type 1 CNVs (P = 0.86) while the mean lacunarity was 2.46 ± 1.03 in PCNVs and 1.86 ± 0.52 in Type 1 CNVs (P = 0.006). CONCLUSION: PCNVs resulted to be more heterogeneous and characterized by higher vascular perfusion density and lacunarity values than Type 1 CNVs. These interesting findings seem to support the idea that PCNVs and Type 1 CNVs are two separate clinical entities. However, future studies based on optical coherence tomography angiography fractal analysis, but also involving other relevant parameters such as demographics, presentation, morphology on multimodal imaging, and response to treatment, are necessary before drawing any definitive conclusions on whether PCNV is a specific clinical entity or a neovascular age-related macular degeneration variant
Automated Quantitative Analysis of Retinal Microvasculature in Normal Eyes on Optical Coherence Tomography Angiography
No full textPurpose To describe a new automated quantitative technique for displaying and analyzing macular vascular perfusion using optical coherence tomography angiography (OCT-A) and to determine a normative data set, which might be used as reference in identifying progressive changes due to different retinal vascular diseases. Design Reliability study. Methods A retrospective review of 47 eyes of 47 consecutive healthy subjects imaged with a spectral-domain OCT-A device was performed in a single institution. Full-spectrum amplitude-decorrelation angiography generated OCT angiograms of the retinal superficial and deep capillary plexuses. A fully automated custom-built software was used to provide quantitative data on the foveal avascular zone (FAZ) features and the total vascular and avascular surfaces. A comparative analysis between central macular thickness (and volume) and FAZ metrics was performed. Repeatability and reproducibility were also assessed in order to establish the feasibility and reliability of the method. Results The comparative analysis between the superficial capillary plexus and the deep capillary plexus revealed a statistically significant difference (P < .05) in terms of FAZ perimeter, surface, and major axis and a not statistically significant difference (P > .05) when considering total vascular and avascular surfaces. A linear correlation was demonstrated between central macular thickness (and volume) and the FAZ surface. Coefficients of repeatability and reproducibility were less than 0.4, thus demonstrating high intraobserver repeatability and interobserver reproducibility for all the examined data. Conclusions A quantitative approach on retinal vascular perfusion, which is visible on Spectralis OCT angiography, may offer an objective and reliable method for monitoring disease progression in several retinal vascular diseases
'False-friend' images on optical coherence tomography angiography: early choroidal neovascularization or artefact?
No full textOptical Coherence Tomography Angiography during Follow-Up: Qualitative and Quantitative Analysis of Mixed Type I and II Choroidal Neovascularization after Vascular Endothelial Growth Factor Trap Therapy
No full textPurpose: To report the optical coherence tomography angiography (OCT-A) findings in an exudative age-related macular degeneration (AMD) patient presenting mixed type I and II choroidal neovascularization (CNV) during follow-up after intravitreal vascular endothelial growth factor (VEGF) trap treatment. Methods: The clinical assessment included both traditional multimodal imaging, based on fluorescein angiography (FA), indocyanine green angiography (ICGA) and B-scan OCT, and OCT-A at baseline and follow-up. OCT-A images were obtained using a Spectralis OCT-A prototype able to acquire 70,000 A-scans per second, with a resolution of 7 μm axially and 14 μm laterally. An amplitude decorrelation algorithm developed by Heidelberg Engineering was applied to a volume scan, on a 15 × 5° area, which was composed of 131 B-scans (35 frames per scan) at a distance of 11 μm each. The borders of type I and type II CNV were manually outlined and then the areas were analyzed using the provided automated software before and after treatment. Results: The qualitative approach revealed a substantial decrease in the visibility of tiny branching vessels and anastomoses both in type I and type II components of the neovascular complex, associated with persistence of a clear hyperintense signal coming from the larger trunks, which remained well-perfused. Quantitative analysis confirmed a reduction of the lesion area after VEGF trap treatment: the type II component decreased from 0.25 to 0.19 mm2, while the type I component decreased from 2.03 to 1.80 mm2. Conclusions: Our study qualitatively and quantitatively demonstrated the response of a mixed type I-II CNV to intravitreal VEGF trap therapy. Although FA remains the gold standard for determining the presence of leakage and OCT easily shows fluid accumulation and its variations, OCT-A offers noninvasive monitoring of the retinal and choriocapillaris microvasculature in patients with CNV, aiding in diagnosis and treatment decisions during follow-up
Optical Coherence Tomography Angiography of a Choroidal Neovascularization in Adult Onset Foveomacular Vitelliform Dystrophy: Pearls and Pitfalls
No full textPURPOSE. The purpose of this study was to determine the sensitivity and specificity of optical coherence tomography angiography (OCT-A) in detecting choroidal neovascularization (CNV)-complicating adult onset foveomacular vitelliform dystrophy (AOFVD) and to highlight the possible pitfalls related to the heterogeneous spectrum of acquired vitelliform maculopathies. METHODS. Twenty-five eyes of 22 consecutive AOFVD patients with suspected CNV were enrolled. Conventional multimodal imaging findings, based on fluorescein angiography (FA), indocyanine green angiography (ICGA) and B-Scan OCT, were used as a basis and were compared with those obtained from OCT-A to define its sensitivity and specificity for detecting CNV in the case of AOFVD. A qualitative and quantitative analysis of the CNV appearance and of the associated OCT-A findings were also performed with the aim of defining features and elucidating possible diagnostic pitfalls. RESULTS. Conventional multimodal imaging allowed diagnosis of a CNV in 5 of 25 eyes (20%), whereas a CNV lesion was clearly observed on OCT-A in 4 of 25 cases (16%). The sensitivity and specificity of CNV detection by OCT-A in cases of AOFVD was 4 of 5 cases (80%) and 20 of 20 cases (100%), respectively. Optical coherence tomography angiography in 10 cases (40%) showed a focal hyperintense signal, without vascular aspects, at the level of the outer nuclear layer or immediately above the subretinal material accumulation. CONCLUSIONS. Our study demonstrates the capability of OCT-A to allow diagnosis of the presence of a CNV in AOFVD patients. Although FA remains the gold standard for determining the presence of a neovascular network, OCT-A offers noninvasive monitoring of the retinal and choroidal microvasculature, aiding in diagnosis and treatment decisions during follow-up
Optical Coherence Tomography Angiography in Macular Edema
No full textOCT angiography is a promising new method to visualize the retinal vasculature and choroidal vascular layers in the macular area and provides depth resolved functional information of the blood flow in the vessels. Given that the main moving elements in the eye fundus are contained in vessels, determining a vascular decorrelation signal enables visualization of 3-dimensional retinal and choroidal vascular network without the administration of intravenous dye and thus reducing the risk of potential adverse events
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