1. 1-24 of 501 1 2 3 4 ... 19 20 21 »
    1. Automatic Identification of Intraretinal Cystoid Regions in Optical Coherence Tomography

      Automatic Identification of Intraretinal Cystoid Regions in Optical Coherence Tomography

      Optical Coherence Tomography (OCT) is, nowadays, one of the most referred ophthalmological imaging techniques. OCT imaging offers a window to the eye fundus in a non-invasive way, permitting the inspection of the retinal layers in a cross sectional visualization. For that reason, OCT images are frequently used in the analysis of relevant diseases such as hypertension or diabetes. Among other pathological structures, a correct identification of cystoid regions is a crucial task to achieve an adequate clinical analysis and characterization, as in the case of the analysis of the exudative macular disease. This paper proposes a new methodology for the ...

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    2. Optical coherence tomography angiography in pre-perimetric open-angle glaucoma

      Optical coherence tomography angiography in pre-perimetric open-angle glaucoma

      Purpose To evaluate the diagnostic efficacy of optical coherence tomography (OCT) angiography, in patients with pre-perimetric open-angle glaucoma. Methods Thirty-eight consecutive eyes of 26 patients with pre-perimetric open-angle glaucoma and 48 normal eyes of 32 controls were included in this prospective study. We evaluated OCT angiography, spectral-domain OCT and visual fields parameters. Differences between controls and patients and between OCT angiography parameters and traditional glaucoma measurements were evaluated. Receiver operating characteristic curves for OCT angiography parameters were assessed. Results The flow index ( p = 0.021) and vessel density ( p = 0.001) were significantly lower in pre-perimetric glaucoma eyes versus normal ...

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    3. Microvascular changes after vitrectomy with internal limiting membrane peeling: an optical coherence tomography angiography study

      Microvascular changes after vitrectomy with internal limiting membrane peeling: an optical coherence tomography angiography study

      Purpose To evaluate superficial capillary plexus (SCP) changes occurring after internal limiting membrane (ILM) peeling for the treatment of idiopathic epiretinal membrane (ERM). Methods A total of 15 eyes of 15 patients affected by idiopathic ERM (eight males and seven females; mean age 59.8 ± 9.6 years) were enrolled in the study. Patients were treated with pars plana vitrectomy followed by ERM and ILM peeling. Subjects were evaluated at baseline and at the week-1 and month-1 follow-up visits. At each visit, patients were evaluated with a complete ophthalmologic evaluation, which included imaging with optical coherence tomography angiography. Results Overall ...

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    4. Spectral Domain Optical Coherence Tomography in Macular Disease (Textbook)

      Spectral Domain Optical Coherence Tomography in Macular Disease (Textbook)

      . This book aims to build concepts and create a solid foundation in the field of optical coherence tomography (OCT) for the general ophthalmologists as well as for the resident trainees and fellows. The chapters are written by leading international authorities in a style comprehensible to a broad audience. Numerous clinical pictures and SD-OCT scans help elucidate various clinical entities.OCT is the optical analog of ultrasound imaging and has emerged as a powerful imaging technique that enables non-invasive, in-vivo, high-resolution, cross-sectional imaging in retinal tissue. A new generation spectral domain optical coherence tomography (SD-OCT) technology has now been developed, representing ...

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    5. Automatic Detection of Epiretinal Membrane in OCT Images by Means of Local Luminosity Patterns

      Automatic Detection of Epiretinal Membrane in OCT Images by Means of Local Luminosity Patterns

      This work presents a novel approach for automatic detection of the epiretinal membrane in Optical Coherence Tomography (OCT) images. A tool able to detect this pathology is very valued since it can prevent further ocular damage by doing an early detection. This approach is based in the location of the inner limiting membrane (ILM) layers of the retina. Then, the detected locations are classified using a local-feature based vector in order to determine presence of the membrane. Different tests are run and compared to establish the appropriateness of the approach as well as its practical validity.

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    6. Recent Advances in the Field of Optical Coherence Tomography

      Recent Advances in the Field of Optical Coherence Tomography

      Purpose of Review The scope of this text is to critically review the most important recent advances in the field of optical coherence tomography, both from a clinical, scientific, and technical point of view. Recent Findings In recent years, important steps forward have been put in the field of optimization of PCI (with a focus on optimal sizing of stents and optimization of stent expansion after implantation) and the differentiation and its possible applications of various underlying morphologic characteristics of acute coronary syndrome lesions. Several efforts have been made to elucidate underlying mechanical causes of stent thrombosis, based on optical ...

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    7. Ganglion cell loss in early glaucoma, as assessed by photopic negative response, pattern electroretinogram, and spectral-domain optical coherence tomography

      Ganglion cell loss in early glaucoma, as assessed by photopic negative response, pattern electroretinogram, and spectral-domain optical coherence tomography

      Purpose To evaluate discrimination ability of pattern electroretinography (PERG) and photopic negative response (PhNR) between early glaucoma and healthy controls, and their relationship with structural measurements using spectral-domain optical coherence tomography (SD-OCT). Methods Cross-sectional study with 34 patients with ocular hypertension ( n = 7), suspect glaucoma ( n = 17), and early glaucoma ( n = 10), plus 24 age-matched controls. The following parameters were analyzed: P50 and N95 amplitude of the PERG, PhNR amplitude and PhNR/b-wave ratio, peripapillary retinal and macular nerve fiber layer (NFL) thicknesses, and ganglion cell complex (GCC) thickness. Data from only one eye per individual were included in the ...

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    8. Wire bias in coronary measurement using optical coherence tomography

      Wire bias in coronary measurement using optical coherence tomography

      OCT is widely used for accurate coronary stent sizing; however, the impact of coronary tortuosity or guide wire weight on the accuracy of OCT in assessing coronary dimensions is not known. This study sought to determine whether guide wire properties impact on coronary diameter and length estimation by optical coherence tomography (OCT) in tortuous segments of coronary artery. OCT coronary diameters were determined in selected patients with tortuous arteries before and after removal of a supportive guide wire to obtain unobscured images. In addition, a coronary model was created with lumen diameters of 1.7–4.8 mm. This was ...

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    9. Classification of Fingerprints Captured Using Optical Coherence Tomography

      Classification of Fingerprints Captured Using Optical Coherence Tomography

      We propose a technique for analysis of fingerprints scanned free-air (not pressed against a glass) with Optical Coherence Tomography (OCT). Fingerprints from the surface and subdermal parts of the finger are extracted from a 2 GB volumetric scan in cca. 2 s using our specialized technique and GPU acceleration on GeForce GTX 980. The technique provides fingerprints that perform with promising error rates that demonstrate the potential of the OCT for improved fingerprint identification, as well as its potential for prevention of biometric spoofing (PAD).

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    10. Proposal of a simple optical coherence tomography-based scoring system for progression of age-related macular degeneration

      Proposal of a simple optical coherence tomography-based scoring system for progression of age-related macular degeneration

      Purpose To develop a simple, clinically practical, optical coherence tomography (OCT)-based scoring system for early age-related macular degeneration (AMD) to prognosticate risk for progression to late AMD. Methods We retrospectively reviewed OCT images (512 × 128 macular cube, Cirrus) from 138 patients diagnosed of early AMD in at least one eye and follow-up of at least 12 months. For patients with early AMD in both eyes, only the right eye was chosen as the study eye for longitudinal assessment. Scans were graded on four SD-OCT criteria associated with disease progression in previous studies: drusen volume within a central 3-mm circle ...

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    11. Optical coherence tomography angiography wide-field montage in branch retinal vein occlusion before and after anti-vascular endothelial-derived growth factor injection

      Optical coherence tomography angiography wide-field montage in branch retinal vein occlusion before and after anti-vascular endothelial-derived growth factor injection

      The wide-field montage technique of optical coherence tomography angiography provides good delineation of the improvement in microvascular disturbance associated with branch retinal vein occlusion after treatment with anti-vascular endothelial-derived growth factor injection. It may be further evaluated for the assessment of treatment progress in patients with retinal vein occlusion.

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    12. Optical coherence tomography as a marker of neurodegeneration in patients with Wilson’s disease

      Optical coherence tomography as a marker of neurodegeneration in patients with Wilson’s disease

      Wilson’s disease (WD) is an inherited autosomal recessive disorder that leads to pathological copper accumulation in different organs. Optical coherence tomography (OCT) is proposed as a marker of neurodegeneration in many neurological diseases. Thinning of the total retinal nerve fiber layer (RNFL) and macular thickness (Mth) examined by OCT was detected in patients with WD, especially those with brain magnetic resonance imaging changes. The aim of this study was to evaluate the relationship between OCT parameters and the progression of neurological signs measured by the Unified Wilson’s Disease Rating Scale (UWDRS) in patients with WD. Consecutive patients with ...

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    13. Supercontinuum Generation in a Silicon Nanowire Embedded Photonic Crystal Fiber for Optical Coherence Tomography Applications (Book Chapter)

      Supercontinuum Generation in a Silicon Nanowire Embedded Photonic Crystal Fiber for Optical Coherence Tomography Applications (Book Chapter)

      In this paper, we design a silicon nanowire embedded photonic crystal fiber (SN-PCF) using fully vectorial finite element method. Further, we analyze the various optical properties, namely, waveguide dispersion and nonlinearity by varying the core diameter from 400 to 500 nm for a wide range of wavelengths from 0.8 to 1.7 μm. The proposed structure exhibits a low second (−0.4909 ps 2 /m) and third order (0.6595 10 −3 ps 3 /m) dispersions with very high nonlinearity (1358 W −1 m −1 ) for 480 nm core diameter at 0.8 μm wavelength. Besides, we investigate the ...

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    14. Relationship between laser speckle flowgraphy and optical coherence tomography angiography measurements of ocular microcirculation

      Relationship between laser speckle flowgraphy and optical coherence tomography angiography measurements of ocular microcirculation

      Purpose The purpose of this study was to investigate the relationship between laser speckle flowgraphy (LSFG) and optical coherence tomography angiography (OCTA) measurements of ocular microcirculation in normal and open-angle glaucoma (OAG) subjects. Methods This study included 18 eyes of 18 OAG patients and ten eyes of ten age-matched healthy controls. LSFG was used to measure mean blur rate (MBR) in the optic nerve head (ONH) vessel area (MV) and tissue area (MT). OCTA was used to measure a new parameter, peripapillary relative intensity (PRI), in the superficial retina, superficial choroid, and deep choroid. Statistical associations were then determined. Results ...

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    15. Comparison of in-stent neoatherosclerosis and tissue characteristics between early and late in-stent restenosis in second-generation drug-eluting stents: an optical coherence tomography study

      Comparison of in-stent neoatherosclerosis and tissue characteristics between early and late in-stent restenosis in second-generation drug-eluting stents: an optical coherence tomography study

      Optical frequency domain imaging (OFDI) was utilized to compare the prevalence of neoatherosclerosis (NA) and morphological characteristics of the neointimal tissue in second generation drug eluting stent (G2-DES)-treated lesions between early (<1 year, E-ISR) and late (>1 year, L-ISR) in-stent restenotic phases. Data comparing NA and in vivo tissue characteristics between early and late in-stent restenosis (ISR) after implantation of G2-DES is limited. An OFDI analysis was performed in 50 G2-DESs {35 everolimus-eluting stent [22 cobalt-chromium (CoCr), 13 platinum-chromium (PtCr)], and 15 biolimus-eluting stent [BES]} ISR lesions (46 consecutive patients) undergoing target lesion revascularization, classified as E-ISR (n = 22 ...

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      Mentions: Kazushige Kadota
    16. Optical coherence tomography angiography vessel density mapping at various retinal layers in healthy and normal tension glaucoma eyes

      Optical coherence tomography angiography vessel density mapping at various retinal layers in healthy and normal tension glaucoma eyes

      Purpose To investigate peripapillary vessel density at various spatial locations and layers in healthy and normal tension glaucoma eyes using optical coherence tomography angiography (OCTA). Methods A commercial OCTA device (AngioPlex; Carl Zeiss Meditec) was used to image microvasculature in a 6 × 6-mm optic disc region. Vessel densities of superficial and deep retinal layers were calculated using an automatic thresholding algorithm. Vessel density maps were plotted by averaging individual angiogram images. The spatial characteristics of vessel densities were analyzed at clock-hour sectors and in five 0.7-mm-thick concentric circles from a diameter of 2.0 to 5.5 mm. Areas ...

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    17. Bioresorbable vascular scaffolds in coronary chronic total occlusions revascularization: safety assessment related to struts coverage and apposition in 6-month OCT follow-up

      Bioresorbable vascular scaffolds in coronary chronic total occlusions revascularization: safety assessment related to struts coverage and apposition in 6-month OCT follow-up

      Beneficial properties of bioresorbable vascular scaffolds (BVS) regarding to vasomotility restoration and no caging of the vessel make them attractive devices in chronic total occlusions (CTO) revascularization. However, more evidence is needed attending to their use in this specific setting. We aim to determine feasibility and safety of BVS use in CTO revascularization attending to struts coverage and apposition, as well as re-stenosis and stent thrombosis (ST) rates. 29 BVS were deployed in 9 CTO lesions revascularization (mean J-CTO score ≥3) with an acute procedural success rate of 100%. Clinical and angiographic follow-up was performed 6 months later, including intracoronary ...

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    18. Post-dilatation after implantation of bioresorbable everolimus- and novolimus-eluting scaffolds: an observational optical coherence tomography study of acute mechanical effects

      Post-dilatation after implantation of bioresorbable everolimus- and novolimus-eluting scaffolds: an observational optical coherence tomography study of acute mechanical effects

      bjectives The objective was to investigate the acute mechanical effects of post-dilatation on bioresorbable scaffolds (BRS) as determined by optical coherence tomography (OCT). Background Post-dilatation with high-pressure balloons is regarded as a key component of BRS implantation for treatment of coronary artery stenoses. However, the impact of post-dilatation on BRS in vivo has not been thoroughly investigated. Methods OCT was performed after the implantation procedure of 51 everolimus-eluting or novolimus-eluting polylactic acid-based BRS with ( n = 27) or without non-compliant balloon post-dilatation ( n = 24). The number of malapposed struts, strut fractures, edge dissections, residual in-scaffold area stenosis, and incomplete scaffold apposition ...

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    19. Optical Coherence Tomography and Wide-Field Fluorescein Angiography in Retinopathy of Prematurity (Book Chapter)

      Optical Coherence Tomography and Wide-Field Fluorescein Angiography in Retinopathy of Prematurity (Book Chapter)

      The advent and adaptation of many imaging modalities promise to revolutionize our understanding of retinopathy of prematurity (ROP) by improving the detection, diagnosis, and monitoring of response to treatment of this disease. Diagnosis and classification of ROP traditionally relies on an eye exam by an ophthalmologist expert in this area who characterizes extent and character of retinal vascularization via indirect ophthalmoscopy. Many tools now exist that allow for data acquisition by nurses, technicians, and other trained staff with the images analyzed in a more centralized location. We will focus on two rapidly evolving technologies, optical coherence tomography (OCT), and wide ...

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    20. A Comparative Optical Coherence Tomography Study of Spinocerebellar Ataxia Types 3 and 10

      A Comparative Optical Coherence Tomography Study of Spinocerebellar Ataxia Types 3 and 10

      SCA3 presents with a CAG expansion at 14q24.3-q32 while SCA10 shows an ATTCT expansion at 22q13-qter. SCA10 seems to be less aggressive than SCA3. For an in vivo, noninvasive approach of the correlation between central nervous system and clinical evolution, we can use optic coherence tomography (OCT) to measure retinal nerve fiber (RNFL) and ganglion cell layer (GCL) thickness. To describe OCT findings in SCA10, correlate it with expansion size and disease severity and compare with those of SCA3. We analyzed ten individuals with SCA3 and nine with SCA10 recruited from the neurology service of Hospital de Clínicas ...

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    21. Monitoring the Course of MS With Optical Coherence Tomography

      Monitoring the Course of MS With Optical Coherence Tomography

      Retinae of patients with multiple sclerosis (MS), as part of the central nervous system (CNS), display inflammatory and neurodegenerative changes. There is increasing evidence suggesting that retinal changes, and in particular neurodegeneration, mirror global CNS alterations in MS. Spectral domain optical coherence tomography (SD-OCT) is an inexpensive, rapid, non-invasive, and reproducible imaging technique that generates high-resolution images of tissues such as the retina. An advantage of SD-OCT over magnetic resonance imaging techniques in the assessment of neurodegeneration may be its sensitivity to capture changes at the individual patient level. Several studies demonstrate that changes within the inner retina (primarily as ...

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    22. Assessment of choroidal osteoma complicating choroidal neovascularization by optical coherence tomography angiography

      Assessment of choroidal osteoma complicating choroidal neovascularization by optical coherence tomography angiography

      Purpose Choroidal osteoma (CO) frequently leads to progressive visual loss due to complications of secondary choroidal neovascularization (CNV).We report herein the function of optical coherence tomography angiography (OCTA) in observation of CO complicating CNV. Methods A 25-year-old female presented to our hospital with chief complaint of sudden unilateral visual acuity decrease for one week, with metamorphopsia in the left eye. Her best corrected visual acuity was 0.12 in the left eye. Then complete ophthalmological examinations including fundus photography, B-scan ultrasound, fundus fluorescent angiography, and spectral-domain optical coherence tomography (SD-OCT) were performed. She was diagnosed as CO on the ...

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