1. All Articles

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    1. Feature Of The Week 10.16.2017: Optical coherence tomography detects necrotic regions and volumetrically quantifies multicellular tumor spheroids

      Feature Of The Week 10.16.2017: Optical coherence tomography detects necrotic regions and volumetrically quantifies multicellular tumor spheroids

      Three-dimensional (3D) tumor spheroid models have gained increased recognition as important tools in cancer research and anti-cancer drug development. However, currently available imaging approaches employed in high-throughput screening drug discovery platforms e.g. bright field, phase contrast, and fluorescence microscopies, are unable to resolve 3D structures deep inside (>50 μm) tumor spheroids. In this study, we established a label-free, non-invasive optical coherence tomography (OCT) imaging platform to characterize 3D morphological and physiological information of multicellular tumor spheroids (MCTS) growing from ~250 μm up to ~600 μm in height over 21 days. In particular, tumor spheroids of two cell lines glioblastoma ...

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    2. Canine central corneal thickness measurements via Pentacam-HR®, optical coherence tomography (Optovue iVue®), and high-resolution ultrasound biomicroscopy

      Canine central corneal thickness measurements via Pentacam-HR®, optical coherence tomography (Optovue iVue®), and high-resolution ultrasound biomicroscopy

      Objective To compare central corneal thickness (CCT) values in canine eyes using Pentacam-HR ® Scheimpflug imaging (Pentacam), Optovue ® iVue spectral-domain optical coherence tomography (SD-OCT), and high-resolution ultrasound biomicroscopy (UBM) and generate normative canine Pentacam CCT values. Animals studied Twenty-four client-owned dogs (37 eyes) with nondiseased cornea(s) presenting to the Colorado State University Veterinary Teaching Hospital. Procedures Corneal images were acquired via Pentacam, SD-OCT, and UBM in the listed order. Machine-calculated values of CCT from Pentacam and SD-OCT were compared to operator-measured values from UBM. Bland–Altman analysis was performed to evaluate agreement between instruments. Results Mean CCT ± SD measured by ...

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      Mentions: Optovue
    3. Comparison between the Correlations of Retinal Nerve Fiber Layer Thickness Measured by Spectral Domain Optical Coherence Tomography and Visual Field Defects in Standard Automated White-on-White Perimetry versus Pulsar Perimetry

      Comparison between the Correlations of Retinal Nerve Fiber Layer Thickness Measured by Spectral Domain Optical Coherence Tomography and Visual Field Defects in Standard Automated White-on-White Perimetry versus Pulsar Perimetry

      Purpose. To compare the structure-function relationships between retinal nerve fiber layer thickness (RNFLT) and visual field defects measured either by standard automated perimetry (SAP) or by Pulsar perimetry (PP). Materials and Methods. 263 eyes of 143 patients were prospectively included. Depending on the RNFLT, patients were assigned to the glaucoma group (group A: RNFL score 3–6) or the control group (group B: RNFL score 0–2). Structure-function relationships between RNFLT and mean sensitivity (MS) measured by SAP and PP were analyzed. Results. Throughout the entire group, the MS assessed by PP and SAP correlated significantly with RNFLT in all ...

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    4. Changes in Retinal and Choroidal Vascular Blood Flow after Oral Sildenafil: An Optical Coherence Tomography Angiography Study

      Changes in Retinal and Choroidal Vascular Blood Flow after Oral Sildenafil: An Optical Coherence Tomography Angiography Study

      Purpose . To describe changes in the retina and choroidal flow by optical coherence tomography angiography (OCT-A) after a single dose of oral sildenafil. Method . A case-control study. Patients in the study group received 50 mg of oral sildenafil. Patients in the control group received a sham pill. Retinal and choroidal images were obtained at baseline (before pill ingestion) and 1 hour after ingestion. Central macular and choroidal thickness, choroidal and outer retina flow, and the retinal and choroidal vascular density were compared using a Mann-Whitney U test. Results . Twenty eyes were enrolled into the study group and 10 eyes in ...

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    5. Optical coherence tomography angiography as an imaging modality for evaluation of diabetic macular edema

      Optical coherence tomography angiography as an imaging modality for evaluation of diabetic macular edema

      iabetic retinopathy remains a leading cause of blindness worldwide in patients aged 20–64 years. [1] Diabetic macular edema (DME) threating or involving the fovea is a common etiology for vision loss. Traditionally, treatment methods have been guided by contact and non-contact slit lamp biomicroscopy, fluorescein angiography and fundus stereo photography. [1] Fluorescein angiography (FA) is a dynamic, invasive imaging technique first described in 1961 and more thoroughly invested and popularized by Gass in 1967. [2] In principle, this technique uses a series of exciting and barrier filters to visualize fluorescein dye excursion through retinal arterial, capillary, and venous structures ...

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    6. Temporal and spatial flap variability in laser in-situ keratomileusis by optical coherence tomography

      Temporal and spatial flap variability in laser in-situ keratomileusis by optical coherence tomography

      Purpose: To study changes in flap thickness made with two different microkeratome heads across different corneal locations using anterior segment optical coherence tomography (OCT). Methods: In this prospective, non-randomized, consecutive case series, subjects who had their laser in-situ keratomileusis (LASIK) flaps made using 90 μm (MSU90) or 130 μm (MSU130) disposable M2 microkeratome heads were examined using OCT. The measurements were performed at three locations (central and 2.5 mm to either side) at 1 day, 1 week, and 1 month postoperatively. Results: The central flap thickness was 123 ± 15, 130 ± 14, and 127 ± 13 μm, respectively, at 1 day ...

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    7. Tunable Optical Coherence Tomography in the Infrared Range Using Visible Photons

      Tunable Optical Coherence Tomography in the Infrared Range Using Visible Photons

      We report a proof-of-concept demonstration of a tunable infrared (IR) optical coherence tomography (OCT) technique with detection of only visible range photons. Our method is based on the nonclassical interference of frequency correlated photon pairs. The nonlinear crystal, introduced in the Michelson-type interferometer, generates photon pairs with one photon in the visible and another in the IR range. The intensity of detected visible photons depends on the phase and loss of IR photons, which interact with the sample under study. This enables us to perform imaging and characterize sample properties in the IR range by detecting visible photons. The technique ...

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    8. Advances in intraoperative optical coherence tomography for surgical guidance

      Advances in intraoperative optical coherence tomography for surgical guidance

      Translation of optical coherence tomography (OCT) technologies for intraoperative visualization enables in vivo micron-resolution imaging of subsurface tissue structures and image-guided clinical decision-making. Over the last decade, intraoperative OCT has evolved from two-dimensional imaging using handheld probes to include biopsy-needles for minimally invasive deep-tissue imaging, surgical instrumentation using optical feedback for tremor dampening and stabilization, and stereomicroscope integrated systems that provide real-time three- and four-dimensional visualization of surgical maneuvers. In addition, several preliminary studies have demonstrated the feasibility and utility of combining intraoperative OCT imaging with novel image-processing and display methods to implement augmented/virtual reality and robotic surgical guidance ...

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    9. CHOROIDAL STRUCTURAL CHANGES AND VASCULARITY INDEX IN STARGARDT DISEASE ON SWEPT SOURCE OPTICAL COHERENCE TOMOGRAPHY

      CHOROIDAL STRUCTURAL CHANGES AND VASCULARITY INDEX IN STARGARDT DISEASE ON SWEPT SOURCE OPTICAL COHERENCE TOMOGRAPHY

      Purpose: To evaluate structural changes in the choroid of patients with Stargardt disease using swept source optical coherence tomography scans. Methods: A retrospective comparison cohort study was conducted on 39 patients with Stargardt disease, and on 25 age and gender matched-healthy controls. Subfoveal choroidal thickness (SFCT) was computed from the swept source optical coherence tomography machine, and the scans were binarized into luminal area and stromal areas, which were then used to derive choroidal vascularity index (CVI). Choroidal vascularity index and SFCT were analyzed independently using linear mixed effects model. Results: There was no significant difference in SFCT between the ...

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    10. Flexible needle with integrated optical coherence tomography probe for imaging during transbronchial tissue aspiration

      Flexible needle with integrated optical coherence tomography probe for imaging during transbronchial tissue aspiration

      Transbronchial needle aspiration (TBNA) of small lesions or lymph nodes in the lung may result in nondiagnostic tissue samples. We demonstrate the integration of an optical coherence tomography (OCT) probe into a 19-gauge flexible needle for lung tissue aspiration. This probe allows simultaneous visualization and aspiration of the tissue. By eliminating the need for insertion and withdrawal of a separate imaging probe, this integrated design minimizes the risk of dislodging the needle from the lesion prior to aspiration and may facilitate more accurate placement of the needle. Results from in situ imaging in a sheep lung show clear distinction between ...

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    11. Optical Coherence Tomography and Its Correlations With VEP in Multiple Sclerosis Patients

      Optical Coherence Tomography and Its Correlations With VEP in Multiple Sclerosis Patients

      Results and conclusion: The performed ОСТ examinations demonstrated substantial thinning of RNFL (83.38 μm) and GCC (79.18 μm) in the eyes with ON in the past. The changes found in this group are more severe in comparison to the findings in patients with acute ON (mean thickness of 87.16 μm for RNFL and 86.08 μm for GCC). Most probably the reason for this fact is the time needed for the development of the reported atrophic changes.

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      Mentions: Optovue
    12. NinePoint Medical is featuring the NvisionVLE® Imaging System with Real-time Targeting™ at ACG 2017; Eight Scientific Abstracts to be Presented

      NinePoint Medical is featuring the NvisionVLE® Imaging System with Real-time Targeting™ at ACG 2017; Eight Scientific Abstracts to be Presented

      Visit us at ACG 2017! Booth #825 NinePoint Medical is featuring the NvisionVLE ® Imaging System with Real-time Targeting™ at ACG 2017; Eight Scientific Abstracts to be Presented NinePoint Medical, Inc., a transformative medical device company pioneering the use of an advanced imaging platform for gastrointestinal applications, today announced that new clinical data relating to its proprietary NvisionVLE ® Imaging System with Real-time Targeting™ will be presented at two upcoming major conferences. Seven clinical abstracts will be featured at the World Congress of Gastroenterology @ the ACG 2017 conference taking place October 13-18 in Orlando, FL, and one poster session will be presented ...

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    13. Postdoctoral Fellow Positions at Case Western Reserve University

      Postdoctoral Fellow Positions at Case Western Reserve University

      Location: Case Western Reserve University, Cleveland, OH, 44106-7080 Application Deadline: Open until filled, available immediately Job description: Post-doctoral research training positions available immediately to join a team of biomedical engineers, neurobiologists, and electrophysiologists to assess the mechanisms by which infrared light (infrared neuromodulation - IRN) can modulate axons and neurons in ganglia as a therapeutic alternative to systemic drug delivery, as well as creating novel tools for visualizing and manipulating neurons and axons using infrared light. Successful applicants will be expected to work in an interdisciplinary team, including coordination with research and clinical collaborators and providing leadership to junior researchers. Outstanding ...

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    14. Presenter: Always image both eyes with OCT

      Presenter: Always image both eyes with OCT

      Eye care providers may have the opportunity to identify neurodegenerative diseases earlier through the use of high-resolution optical coherence tomography, according to Robert Sergott, MD, of Wills Eye Hospital. Sergott participated in the American Academy of Optometry’s plenary session, which was co-sponsored by Primary Care Optometry News. “In Alzheimer’s disease, 99% of clinical trials fail because there’s nothing left to treat. It’s diagnosed too late,” Sergott said. “This is the case for high-resolution OCT in your practice. It gives you objective vs. subjective data.” Sergott presented a number of case reports to illustrate his “rules” for ...

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    15. An optical coherence tomography study of neointimal morphology and strut coverage at different time intervals from implantation of biodegradable polymer-coated sirolimus-eluting stents

      An optical coherence tomography study of neointimal morphology and strut coverage at different time intervals from implantation of biodegradable polymer-coated sirolimus-eluting stents

      Objectives The aim of the study was to capture the evolution of neointima after implantation of a biodegradable polymer–coated, sirolimus–eluting, cobalt–chromium coronary stent system (BP-DES). Background Optical coherence tomography (OCT) suggests that in-stent neointimal morphology influences clinical outcomes after DES implantation. Methods Sixty patients treated with single BP-DES implantation were examined by quantitative coronary angiography (QCA) and OCT at 3, 6, and 12-month follow-up. Results Median late lumen loss by QCA (mm) was 0.04 (IQR 0, 0.08), 0.17 (IQR 0, 0.32), and 0.14 (IQR 0.07, 0.31) at 3, 6, and ...

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    16. The association between photoreceptor layer thickness measured by optical coherence tomography and visual sensitivity in glaucomatous eyes

      The association between photoreceptor layer thickness measured by optical coherence tomography and visual sensitivity in glaucomatous eyes

      Purpose To assess the thickness of the photoreceptor layer in the macular region in glaucomatous eyes. Method Humphrey 10–2 visual field (VF) testing was carried out and mean threshold (mTH) was calculated in 118 eyes from 118 patients with open angle glaucoma. Macular optical coherence tomography (OCT) measurements (RS 3000, Nidek Co.ltd., Aichi, Japan) were also carried out in all eyes. Thickness measurements were recorded in the outer segment and retinal pigment epithelium (OS+RPE), the nerve fiber layer (NFL), the ganglion cell layer and inner plexiform layer (GCL+IPL), the inner nuclear layer and outer plexiform layer ...

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    17. Variability of choroidal and retinal thicknesses in healthy eyes using swept-source optical coherence tomography – implications for designing clinical trials

      Variability of choroidal and retinal thicknesses in healthy eyes using swept-source optical coherence tomography – implications for designing clinical trials

      Aim: The aim was to study the variability of choroidal scleral interface (CSI) thickness in healthy subjects and its relevance for designing future studies. Methods: A total of 123 volunteers were imaged using swept-source optical coherence tomography. Early treatment diabetic retinopathy grid was used. Results: Mean central retinal thickness was 285.85±14.53 µm and 287.18±12.93 µm, and mean central CSI thickness was 273.94±77.77 µm and 271.19±78.85 µm for the right and left eyes, respectively. Mean retinal and CSI thicknesses correlated negatively with age ( p =0.023, r =–0.208 ...

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    18. Cellular Characterization of Optical Coherence Tomography and Outer Retinal Bands Using Specific Immunohistochemistry Markers and Clinical Implications

      Cellular Characterization of Optical Coherence Tomography and Outer Retinal Bands Using Specific Immunohistochemistry Markers and Clinical Implications

      Purpose Optical coherence tomography has been a technological breakthrough in the diagnosis, treatment, and follow-up of many ocular diseases, especially retinal and neuro-ophthalmologic pathologic conditions. Until now, several controversies have arisen over the specific cell types that the bands observed in the OCT represent, especially over the 4 outer retinal bands. Design To correlate the 4 outer hyperreflective bands observed in the OCT with the histologic structures using human retinal sections and immunocytochemistry at the fovea level. Participants Eyes from human donors. Methods Vertical cryosections of human retinas were immunostained with antibodies specific for cones photoreceptors, bipolar cells, mitochondria, M ...

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    19. Special Feature Development and Application of Optical Coherence Tomography (OCT)

      Special Feature Development and Application of Optical Coherence Tomography (OCT)

      To celebrate the 25th anniversary of the introduction of OCT, the special feature issue entitled “Development and Application of Optical Coherence Tomography (OCT)” had been initiated. OCT originated from low coherence interferometry [1] and was adapted for tomographic imaging in 1991 [2]. In OCT, broad bandwidth light is used in order to produce cross-sectional images of turbid and translucent samples with high axial resolution (in the order of a few µm). Thereby, the imaging speed of OCT can be as high as several millions of depth scans (A-scans) per second, which allows for volumetric investigations of dynamic processes [3]. Nowadays ...

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    20. Macular fluid reduces reproducibility of choroidal thickness measurements on enhanced depth optical coherence tomography

      Macular fluid reduces reproducibility of choroidal thickness measurements on enhanced depth optical coherence tomography

      Purpose To determine if different types of retinal fluid in the central macula affect the reproducibility of choroidal thickness (CT) measurements on enhanced depth imaging optical coherence tomography (EDI-OCT) Design retrospective, reliability analysis Methods EDI-OCT images were obtained and the choroidal-scleral junction was analyzed through semi-automated segmentation. CT was measured at the fovea and averaged across the central 3 mm horizontal segment. Demographic data, central macular thickness and type of fluid present were recorded. Intragrader and intergrader repeatability were assessed using the intraclass correlation coefficient (ICC) and coefficient of repeatability (CR). Results Of 124 eyes analyzed, 60 (48.4%) had ...

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    21. Correlations between local peripapillary choroidal thickness and axial length, optic disc tilt, and papillo-macular position in young healthy eyes

      Correlations between local peripapillary choroidal thickness and axial length, optic disc tilt, and papillo-macular position in young healthy eyes

      Optical coherence tomography (OCT) has made it possible for clinicians to measure the peripapillary choroidal thickness (ppCT) noninvasively in various ocular diseases. However, the ocular factors associated with the ppCT have not been conclusively determined. The purpose of this study was to determine the relationship between the local ppCT and the axial length, optic disc tilt, and the angle of the papillo-macular position (PMP) in healthy eyes. This was a prospective, observational cross-sectional study of 119 right eyes of 119 healthy Japanese volunteers. The ppCT was manually measured at eight sectors around the optic disc using the B-scan images of ...

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    22. Retinal pulse wave velocity measurement using spectral-domain optical coherence tomography

      Retinal pulse wave velocity measurement using spectral-domain optical coherence tomography

      The human eyes provide a natural window for noninvasive measurement of the pulse wave velocity (PWV) of small arteries. By measuring the retinal PWV, the stiffness of small arteries can be assessed, which may better detect early vascular diseases. Therefore, retinal PWV measurement has attracted increasing attention. In this study, a jump-scanning method was proposed for non-invasive measurement of retinal PWV using spectral-domain OCT. The jump-scanning method uses the phase-resolved Doppler OCT to obtain the pulse shapes. To realize PWV measurement, the jump-scanning method extracts the transit time of the pulse wave from an original OCT scanning site to another ...

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    23. Sickle cell disease and the eye

      Sickle cell disease and the eye

      Purpose of review To review recent literature pertaining to sickle cell retinopathy (SCR) and, in particular, sickle cell maculopathy. Recent findings Several recent studies suggest that macular perfusion abnormalities seen in patients with sickle cell disease of various genotypes may affect both the superficial and deep capillary plexi, with a predilection for the deep capillary plexus. Further, these changes may be associated with areas of macular thinning, as well as with peripheral retinal ischemia, even in individuals without visual symptoms, contrary to what has previously been described in both diabetic retinopathy and retinal vein occlusion. Several cases also suggest that ...

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    24. Atlas of Coronary Intravascular Optical Coherence Tomography (Textbook)

      Atlas of Coronary Intravascular Optical Coherence Tomography (Textbook)

      This atlas is a practical and fully illustrated guide to the use of intravascular OCT in diagnosis and treatment of coronary artery disease. It consists of two parts. The first part of the book provides a systematic introduction to coronary imaging with OCT. It describes how to interpret images and describes abnormal findings seen in atherosclerosis, complications after intervention, and stent assessment. The second part of the book presents real-life case studies that show how OCT is used in clinical practice in Mount Sinai to assess the disease, select appropriate treatment, and evaluate complications and results. Each case includes a ...

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