1. 1-24 of 339 1 2 3 4 ... 13 14 15 »
    1. Diabetic macular oedema quantified with spectral-domain optical coherence tomography – evaluation of boundary line artefacts and the effect on retinal thickness

      Diabetic macular oedema quantified with spectral-domain optical coherence tomography – evaluation of boundary line artefacts and the effect on retinal thickness

      Purpose To characterize frequency, morphological cause and time-dependent change of boundary line artefacts in optical coherence tomography (OCT) examinations of centre-involved diabetic macular oedema (ciDME) patients who underwent ranibizumab treatment with 1-year follow-up and to evaluate the impact of artefacts on retinal thickness. Methods One hundred and fourteen patients were examined with radial scan protocol by Topcon 3D OCT at baseline, 3 and 12 months. All B scans from all visits were examined for boundary line artefacts (artefacts) and were stratified by morphological element causing artefacts including hard exudates (HE), epiretinal membranes (ERM), optical opacities and serous detachments. Boundary line ...

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    2. Grader learning effect and reproducibility of Doppler Spectral‐Domain Optical Coherence Tomography derived retinal blood flow measurements

      Grader learning effect and reproducibility of Doppler Spectral‐Domain Optical Coherence Tomography derived retinal blood flow measurements

      Purpose To investigate grader learning effect and to quantify intergrader reproducibility of Doppler Spectral-Domain Optical Coherence Tomography (SD-OCT) derived retinal blood flow measurements. Methods Fifteen healthy young subjects (mean age 28.44; SD 3 years) underwent Doppler SD-OCT scans of one eye using the circumpapillary double circular scan protocol of the Optovue RTVue by one of two experienced operators. One trained (i.e. having undergone certification) and one novice (i.e. preliminary training comprising five standard practice data sets) individual then graded a standardized set of scans, consisting of 15 data sets (session 1) using custom Doppler Optical Coherence Tomography ...

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    3. Evaluation of the chorioretinal thickness changes in Alzheimer's disease using spectral-domain optical coherence tomography

      Evaluation of the chorioretinal thickness changes in Alzheimer's disease using spectral-domain optical coherence tomography

      Background To assess the chorioretinal thickness changes using spectral-domain optical coherence tomography (SD-OCT) and to evaluate the association between these structural changes and cognitive impairment in Alzheimer's disease (AD). Design Prospective, cross-sectional study Participants 31 eyes of 31 consecutive patients with AD and 30 eyes of 30 cognitively healthy age-matched control subjects were recruited Methods SD-OCT (RTVue-100) was used to measure the macular ganglion cell complex thickness (mGCC), outer retinal thickness (ORL), and the choroidal thickness (CT). Cognitive function was evaluated by Mini-Mental State examination (MMSE) on the same day of the optical examination. Main Outcome Measures chorioretinal thickness ...

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    4. Achromatopsia: case presentation and literature review emphasising the value of spectral domain optical coherence tomography

      Achromatopsia: case presentation and literature review emphasising the value of spectral domain optical coherence tomography

      A literature review and case presentation are used to discuss the diagnostic value of spectral domain optical coherence tomography (SD-OCT) in the assessment and management of congenital achromatopsia. A 24-year-old Hispanic man presented to the clinic with a longstanding history of decreased vision and associated possible recent progression. A comprehensive eye examination and a battery of tests including SD-OCT, fundus photography, electroretinogram (ERG) and Farnsworth D-15 were completed. SD-OCT and photopic ERG confirmed the clinical diagnosis of congenital achromatopsia. There was the classic subfoveal flattened hyporeflective ‘punched out’ zone, resulting from an absence of inner segment/outer segment junction. SD-OCT ...

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    5. Morphometric grading of osteoarthritis by optical coherence tomography - An ex vivo study

      Morphometric grading of osteoarthritis by optical coherence tomography - An ex vivo study

      Optical Coherence Tomography (OCT) yields microscopic cross-sectional images of cartilage in real time and at high resolution. As yet, comprehensive grading of degenerative cartilage changes based on OCT has rarely been performed. This study investigated the potential of quantitative OCT using algorithm-based image parameters such as irregularity (OII – Optical Irregularity Index), homogeneity (OHI – Optical Homogeneity Index) and attenuation (OAI – Optical Attenuation Index) in the objective grading of cartilage degeneration. Therefore, OCT was used to image and assess 113 human osteochondral samples obtained from total knee replacements. Processing included the analysis of OII (by calculation of the standard deviation with regards ...

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    6. Evaluation of the macular choroidal thickness using spectral optical coherence tomography in patients with obstructive sleep apnea syndrome

      Evaluation of the macular choroidal thickness using spectral optical coherence tomography in patients with obstructive sleep apnea syndrome

      Background To assess the choroidal thickness (CT) in patients with obstructive sleep apnea syndrome (OSAS) and healthy controls. Design Prospective, cross-sectional study Participants 92 eyes of 92 patients with OSAS and 32 eyes of 32 age- and body mass index-matched healthy subjects were enrolled. Methods OSAS patients were further divided into mild, moderate and severe OSAS groups according to their apnea hypopnea index (AHI) values. The macular CT and peripapillary retinal nerve fiber layer (RNFL) thickness measurements of the subjects were obtained using spectral domain optical coherence tomography (RTVue-100, Optovue). The CT and RNFL thickness measurements of the groups were ...

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    7. Optical coherence tomography for the evaluation of asymmetric cardiac allograft vasculopathy in a child

      Optical coherence tomography for the evaluation of asymmetric cardiac allograft vasculopathy in a child

      We present an unusual case of CAV in a child with isolated disease in the LAD coronary artery. Initial progression of the disease appeared to have been halted by the use of sirolimus, but the assessment of disease in other vessels (particularly the RCA) was of particular importance in deciding whether or not to relist this patient for transplantation. Due to the known limitations of coronary angiography, we used OCT to assess for angiographically silent CAV. The normal intravascular appearance of the RCA by OCT was reassuring, and the child was not relisted for transplantation. OCT offers multiple advantages for ...

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    8. Mechanism of luminal patency of the self-expanding sideguard sidebranch stent: Evaluation by intravascular ultrasound and optical coherence tomography

      Mechanism of luminal patency of the self-expanding sideguard sidebranch stent: Evaluation by intravascular ultrasound and optical coherence tomography

      Background : The Cappella Sideguard (CS) sidebranch stent is a self-expanding, thin-strut, nitinol device with anatomic flaring at the sidebranch ostium designed to treat bifurcation lesions. Objective : To evaluate the mechanism of long-term lumen patency of the novel, self-expanding CS sidebranch stent compared to a balloon-expandable stent in the main vessel. Methods : We performed intravascular ultrasound (IVUS) post-intervention and at follow-up in 24 CS stents and in 28 balloon-expandable drug-eluting stents deployed in the corresponding main vessel. Thirteen patients also had optical coherence tomography (OCT) at follow-up to evaluate neointimal hyperplasia and strut coverage. Results : CS stent area at the sidebranch ...

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    9. Multimodality imaging of the effects of a novel dentifrice on oral biofilm

      Multimodality imaging of the effects of a novel dentifrice on oral biofilm

      Objective Oral biofilm formation and progression on the surface of the tooth can lead to advanced oral disease such as gingivitis. The purpose of this randomized, controlled, double-blinded study was to evaluate the effects of a novel dental gel on oral plaque biofilm using multimodal imaging techniques. Materials and Methods Twenty-five subjects with moderate gingival inflammation (Löe and Silness Gingival Index ≥2) and pocket depths <4 were randomly assigned to brush twice daily for 21 days with the test or the control dental gel. In vivo multimodality in situ imaging was performed over a 3-week period using in vivo ...

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    10. Optical coherence tomography as a tool for characterization of complex biological surfaces

      Optical coherence tomography as a tool for characterization of complex biological surfaces

      The advent of scanning electron microscopy has facilitated our understanding of the biology in relation to surface microstructure of many invertebrates. In recent years, interest in biomimetics and bio-inspired materials has further propelled the search for novel microstructures from natural surfaces. As this search widens in diversity to nurture deeper understanding of form and function, the need often arises to examine rare specimens. Unfortunately, most methods for characterization of the microtopography of natural surfaces are sacrificial, and as such, place limiting constraints on research progress in situations where only a few rare specimens are known, such as the rich resources ...

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    11. Sun protection and hydration of stratum corneum: a study by 2D differential method

      Sun protection and hydration of stratum corneum: a study by 2D differential method

      The stratum corneum (written SC in the following) is the outermost layer of the epidermis and serves as a barrier against environmental aggression, such as infection, dehydration or sun damages. Within the SC, death cells called corneocytes, linked by an intercellular bridge called desmosomes, form layers. Depending on the body part and environmental factors, the number of layers and the thickness of each one can vary.

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    12. Optical Coherence Tomography for the Study of Polymer and Polymer Matrix Composites

      Optical Coherence Tomography for the Study of Polymer and Polymer Matrix Composites

      Based on low-coherence interferometry, a hybrid optical coherence tomography (OCT) system has been built. It coupled time-domain OCT (TD-OCT) and Fourier-domain OCT (FD-OCT) into one system. TD-OCT can take the advantage of a large axial scan range while FD-OCT has superior performance in fast imaging as no axial scan is needed. The two imaging modalities shared a broad bandwidth light source with a centre wavelength of 1550 nm, which is less scattering and can give better penetration depth in the polymer-based material than the shorter wavelength used for biomedical applications. 2D translation stages were incorporated in the system to make ...

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    13. High frequency ultrasonography but not 930nm-optical coherence tomography reliably evaluates melanoma thickness in vivo: a prospective validation study.

      High frequency ultrasonography but not 930nm-optical coherence tomography reliably evaluates melanoma thickness in vivo: a prospective validation study.

      Background Early diagnosis and rapid surgical excision are essential for improving the prognosis of melanoma patients. Reflectance confocal microscopy has been validated as a feasible procedure for in vivo diagnosis of melanoma but cannot be used to measure tumour thickness. However, ultrasonography and optical coherence tomography may allow melanoma thickness to be measured in vivo . Objectives Primary: To validate the accuracy and reliability of high-frequency ultrasonography and optical coherence tomography for assessing melanoma thickness in vivo . Methods We conducted a prospective study on 131 patients with at least one equivocal melanocytic lesion. Each lesion underwent optical coherence tomography and high-frequency ...

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    14. Anterior segment morphology and morphometry in selected reptile species using optical coherence tomography

      Anterior segment morphology and morphometry in selected reptile species using optical coherence tomography

      Objective To provide new and original images of the anterior segment (AS) of the eye of selected Ophidian, Chelonian, and Saurian species and to compare the AS architecture among and within these three groups. Animals studied 17 Saurians, 14 Ophidians, and 11 Chelonians with no concurrent systemic or eye disease were included in the study. Procedure Age, weight, nose-cloaca distance (NCD), and pupil shape were collected for each animal. The AS was examined by optical coherence tomography (OCT). After gross description of the appearance of the AS, the central and peripheral corneal thickness (CCT, PCT) and anterior chamber depth (ACD ...

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    15. Spectral-domain optical coherence tomography evaluation of the cornea, retina, and optic nerve in normal horses

      Spectral-domain optical coherence tomography evaluation of the cornea, retina, and optic nerve in normal horses

      Purpose To determine the feasibility of using a handheld spectral-domain optical coherence tomography (SD-OCT) instrument to characterize normal corneal, retinal, and optic nerve head anatomy in vivo in standing horses. Methods Clinically normal horses under sedation, palpebral nerve blockage, and pharmacologically induced mydriasis were imaged with a SD-OCT instrument (Envisu SD-OCT, Bioptigen, Inc., Morrisville, NC). Radial volumes from the cornea (axial, superior, inferior, nasal, and temporal), and rectangular volumes from the retina (dorsal, ventral, nasal, and temporal) and optic nerve head were acquired. Manual measurements of the corneal layers within the five regions, retinal and nerve fiber layer thickness in ...

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    16. Spectral domain optical coherence tomography imaging of spectacular ecdysis in the royal python (Python regius)

      Spectral domain optical coherence tomography imaging of spectacular ecdysis in the royal python (Python regius)

      Objective To describe using spectral domain optical coherence tomography (SD-OCT), digital slit-lamp biomicroscopy, and external photography, changes in the ophidian cuticle, spectacle, and cornea during ecdysis. Animals Studied Four normal royal pythons ( Python regius) . Procedures Snakes were assessed once daily throughout a complete shed cycle using nasal, axial, and temporal SD-OCT images, digital slit-lamp biomicroscopy, and external photography. Results Spectral domain optical coherence tomography (SD-OCT) images reliably showed the spectacular cuticle and stroma, subcuticular space (SCS), cornea, anterior chamber, iris, and Schlemm's canal. When visible, the subspectacular space (SSS) was more distended peripherally than axially. Ocular surface changes throughout ...

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      Mentions: UC Davis
    17. Scanning laser ophthalmoscopy and optical coherence tomography imaging of spectacular ecdysis in the corn snake (Pantherophis guttatus) and the California king snake (Lampropeltis getulus californiae) - Cazalot - 2014 - Veterinary Ophthalmology

      Scanning laser ophthalmoscopy and optical coherence tomography imaging of spectacular ecdysis in the corn snake (Pantherophis guttatus) and the California king snake (Lampropeltis getulus californiae) - Cazalot - 2014 - Veterinary Ophthalmology

      Purpose One of the singularities of the eyes of snakes is the presence of the spectacle, a transparent and vascularized integument covering the cornea. The spectacle is completely renewed during ecdysis. Combined scanning laser ophthalmoscopy (SLO), optical coherence tomography (OCT), and conventional macrophotography were used to image this phenomenon. Material and Methods A spectral OCT/SLO examination and macrophotography were performed in four healthy adult corn snakes ( Pantherophis guttatus ) and one healthy adult California king snake ( Lampropeltis getulus californiae ) the day before the start of ecdysis and then daily during ecdysis. Results In all animals, ecdysis lasted 5 days. The ...

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    18. Assessment of early occlusal caries pre- and post- sealant application—An imaging approach

      Assessment of early occlusal caries pre- and post- sealant application—An imaging approach

      Background and Objective Clinicians have difficulty assessing and monitoring early occlusal caries. Traditional clinical exam and radiographs are unable to detect the subtle alterations in enamel indicative of de- or re-mineralization, particularly under dental sealants. Although clinicians have used laser fluorescence (LF) to address this gap, this modality has demonstrated weak correlation with histology. The International Caries Detection and Assessment System (ICDAS-II) has demonstrated high sensitivity and specificity for caries detection, but since it is based on visual assessment, it is of no use in areas beneath the most commonly used dental sealants which are opaque. Optical coherence tomography (OCT ...

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    19. Optic nerve head assesment: comparison of Cirrus optic coherence tomography and Heidelberg Retinal Tomograph 3

      Optic nerve head assesment: comparison of Cirrus optic coherence tomography and Heidelberg Retinal Tomograph 3

      Background The purpose of this study was to analyze the relationship between Optic Nerve Head (ONH) parameters measured by spectral domain optical coherence tomography and confocal scanning laser ophthalmoscope. Design Prospective, cross-sectional study. Hospital setting. Participants One hundred seventy-three subjects (85 glaucoma and 88 normal subjects). Methods One eye from each individual was selected randomly for ONH imaging by the spectral domain Cirrus OCT and Heidelberg Retinal Tomograph 3 (HRT3). Main Outcome Measures Four ONH parameters that are measured by both technologies (average cup to disc ratio (CDR), rim area, disc area and cup volume) were analyzed and compared for ...

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    20. Optical Coherence Tomography-Guided Retinal Prosthesis Design: Model of Degenerated Retinal Curvature and Thickness for Patient-Specific Devices

      Optical Coherence Tomography-Guided Retinal Prosthesis Design: Model of Degenerated Retinal Curvature and Thickness for Patient-Specific Devices

      Retinitis pigmentosa affects over 1.5 million people worldwide and is a leading cause of vision loss and blindness. While retinal prostheses have shown some success in restoring basic levels of vision, only generic, “one-size-fits-all” devices are currently being implanted. In this study, we used optical coherence tomography scans of the degenerated retina from 88 patients with retinitis pigmentosa to generate models of retinal thickness and curvature for the design of customized implants. We found the average retinal thickness at the fovea to be 152.9 ± 61.3 μm, increasing to a maximum retinal thickness of 250.9 ± 57.5 ...

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    21. Miniature forward-imaging B-scan optical coherence tomography probe to guide real-time laser ablation

      Miniature forward-imaging B-scan optical coherence tomography probe to guide real-time laser ablation

      Background and Objective Investigations have shown that pulsed lasers tuned to 6.1 µm in wavelength are capable of ablating ocular and neural tissue with minimal collateral damage. This study investigated whether a miniature B-scan forward-imaging optical coherence tomography (OCT) probe can be combined with the laser to provide real-time visual feedback during laser incisions. Study Design/Methods and Materials A miniature 25-gauge B-scan forward-imaging OCT probe was developed and combined with a 250 µm hollow-glass waveguide to permit delivery of 6.1 µm laser energy. A gelatin mixture and both porcine corneal and retinal tissues were simultaneously imaged and ...

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    22. Spectroscopic study on appearances of make-up skins using a visible RGB-LED OCT

      Spectroscopic study on appearances of make-up skins using a visible RGB-LED OCT

      Background/purpose Facial foundation is very effective to correct color irregularities of the skin surface and to protect the skin from harmful light. This depends strongly on both the optical properties and the coating condition of foundation on the skin surface. Methods We constructed the full-field optical coherence tomography (OCT) (FF-OCT) microscope with visible light sources of RGB LEDs. The commercially available skin replicas were used as the model of skin in the experiment, which were composed of two layers, a thin polyurethane film transcribed from cheek surface of a female and a beige-colored silicone substrate. The foundations were applied ...

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    1-24 of 339 1 2 3 4 ... 13 14 15 »
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