1. All Articles

    25-48 of 19990 « 1 2 3 4 5 ... 831 832 833 »
    1. Culprit plaque morphology in STEMI – an optical coherence tomography study: insights from the TOTAL-OCT substudy

      Culprit plaque morphology in STEMI – an optical coherence tomography study: insights from the TOTAL-OCT substudy

      Aims: Our aim was to compare stenosis severity and plaque content between STEMI culprit lesions with intact fibrous cap (IFC) and those with plaque rupture (PR) in a prospective study. Methods and results: We evaluated 93 patients undergoing OCT and thrombectomy as part of a prospective substudy of the TOTAL (ThrOmbecTomy versus PCI ALone) trial. Culprit lesion morphology was assessable by OCT in 70/93 (75.3%). IFC was found in 31 (44.3%), PR in 34 (48.6%) and calcified nodule in five (7.1%) patients. Following thrombectomy, OCT demonstrated similar lumen area stenosis in IFC (79.3%) and ...

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    2. Optical coherence tomography visualisation of burst balloon catheter trapped by coronary stent

      Optical coherence tomography visualisation of burst balloon catheter trapped by coronary stent

      A 69-year-old man with prior anterior myocardial infarction underwent percutaneous coronary intervention for significant stenosis of the left anterior descending (LAD) artery. High-pressure inflation by non-compliant balloon was required because of severe calcification in the culprit lesion. The balloon ruptured during inflation and an angiographic filling defect appeared in the LAD. The balloon catheter was pulled out of the body and the tip and membranous part of the catheter was lost ( Panel A , black arrowhead). Although we attempted to retrieve…

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    3. Optical coherence tomographic predictor of retinal non-perfused areas in eyes with macular oedema associated with retinal vein occlusion

      Optical coherence tomographic predictor of retinal non-perfused areas in eyes with macular oedema associated with retinal vein occlusion

      Aim To determine whether the low reflective spaces in the retinal nerve fibre layer (RNFL) in the optical coherence tomographic (OCT) images are related to the presence of the retinal non-perfused areas in eyes with macular oedema associated with a retinal vein occlusion (RVO). Methods We reviewed the medical records of 97 eyes with macular oedema associated with RVO. At the initial visit, eyes with macular oedema were classified into those with and those without low reflective spaces in the RNFL in the OCT images. In the fluorescein angiographic (FA) images, the eyes with more than one disc diameter of ...

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    4. A signal separation technique for sub-cellular imaging using dynamic optical coherence tomography

      A signal separation technique for sub-cellular imaging using dynamic optical coherence tomography

      This paper aims at imaging the dynamics of metabolic activity of cells. Using dynamic optical coherence tomography, we introduce a new multiparticle dynamical model to simulate the movements of the collagen and the cell metabolic activity and develop an efficient signal separation technique for sub-cellular imaging. We perform a singular-value decomposition of the dynamic optical images to isolate the intensity of the metabolic activity. We prove that the largest eigenvalue of the associated Casorati matrix corresponds to the collagen. We present several numerical simulations to illustrate and validate our approach.

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    5. Association between Intraocular Pressure and Rates of Retinal Nerve Fiber Layer Loss Measured by Optical Coherence Tomography

      Association between Intraocular Pressure and Rates of Retinal Nerve Fiber Layer Loss Measured by Optical Coherence Tomography

      Purpose To evaluate the relationship between intraocular pressure (IOP) and rates of retinal nerve fiber layer (RNFL) thickness change over time measured by spectral-domain (SD) optical coherence tomography (OCT). Design Observational cohort study. Participants The study involved 547 eyes of 339 patients followed up for an average of 3.9±0.9 years. Three hundred eight (56.3%) had a diagnosis of glaucoma and 239 (43.7%) were considered glaucoma suspects. Methods All eyes underwent imaging using the Spectralis SD OCT (Heidelberg Engineering GmbH, Heidelberg, Germany), along with IOP measurements and standard automated perimetry (SAP). Glaucoma progression was defined as ...

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    6. Clinical Utility of Optical Coherence Tomography in Glaucoma

      Clinical Utility of Optical Coherence Tomography in Glaucoma

      Optical coherence tomography (OCT) has established itself as the dominant imaging modality in the management of glaucoma and retinal diseases, providing high-resolution visualization of ocular microstructures and objective quantification of tissue thickness and change. This article reviews the history of OCT imaging with a specific focus on glaucoma. We examine the clinical utility of OCT with respect to diagnosis and progression monitoring, with additional emphasis on advances in OCT technology that continue to facilitate glaucoma research and inform clinical management strategies.

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    7. Quantitative and Qualitative Characteristics of Retinal Vasculature Shadowing on Enface Swept Source OCT, in Healthy Subjects and Diabetic Macular Edema

      Quantitative and Qualitative Characteristics of Retinal Vasculature Shadowing on Enface Swept Source OCT, in Healthy Subjects and Diabetic Macular Edema

      Background: To evaluate the characteristics of retinal vascular shadowing, viewed through en face swept source optical coherence tomography (SS-OCT) imaging in normality and diabetic macular edema (DME). Design: Prospective case series conducted at Shaare Zedek Medical Center. Participants or Samples: 34 eyes of 17 healthy subjects and 30 eyes of 16 diabetic patients. Methods: Collected data included demographics, Snellen chart measured visual acuity, current HBA1C levels, previous laser treatments and swept source OCT measured central retinal subfield thickness. SS-OCT en face images were generated and flattened at three planes: ganglion cell layer (GCL), inner plexiform layer (IPL), retinal pigment epithelium ...

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    8. Optical coherence tomography imaging after successful percutaneous coronary intervention treatment of coronary perforation following bioabsorbable vascular scaffold implantation: Consecutive ping-pong and child-in-mother techniques

      Optical coherence tomography imaging after successful percutaneous coronary intervention treatment of coronary perforation following bioabsorbable vascular scaffold implantation: Consecutive ping-pong and child-in-mother techniques

      A 68-year-old male, former smoker, with dyslipidemia, and 7-year history of stable angina was admitted to our center due to symptom progression and positive treadmill test under optimal medical treatment with aspirin, beta-blockers, and highdose statins. Transradial coronary angiography evidenced a chronic total occlusion (CTO) of the proximal left anterior descending artery (LAD), severe stenosis of the proximal left circumflex artery (LCx), and a dominant right coronary artery with collateral flow to the mid and distal bed of the LAD (Rentrop 3, CC 2). Left ventricular (LV)-angiography evidenced LV normal size and function. LCx stenosis was successfully treated with ...

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    9. Investigation of the Etiology of Central Serous Chorioretinopathy Using En-Face Optical Coherence Tomography and Indocyanine Green Angiography

      Investigation of the Etiology of Central Serous Chorioretinopathy Using En-Face Optical Coherence Tomography and Indocyanine Green Angiography

      Purpose: To identify locations of hypofluorescent lesions on late-phase indocyanine green angiography (ICGA) in patients with central serous chorioretinopathy (CSC) using en-face optical coherence tomography (OCT). Procedures: We retrospectively studied 25 consecutive untreated CSC patients, using swept-source OCT and ICGA. En-face swept-source OCT images were automatically segmented and flattened with Bruch's membrane (BrM). We compared the sizes of hyperreflective areas in the 25 CSC and 25 contralateral eyes on en-face images and hypofluorescent areas on ICGA after 30 min. Results: All 25 CSC eyes and 13 contralateral eyes showed abnormal hypofluorescent areas on late-phase ICGA and hyperreflective areas on ...

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    10. Optical coherence tomography for blood glucose monitoring in vitro through spatial and temporal approaches

      Optical coherence tomography for blood glucose monitoring in vitro through spatial and temporal approaches

      As diabetes causes millions of deaths worldwide every year, new methods for blood glucose monitoring are in demand. Noninvasive approaches may increase patient adherence to treatment while reducing costs, and optical coherence tomography (OCT) may be a feasible alternative to current invasive diagnostics. This study presents two methods for blood sugar monitoring with OCT in vitro . The first, based on spatial statistics, exploits changes in the light total attenuation coefficient caused by different concentrations of glucose in the sample using a 930-nm commercial OCT system. The second, based on temporal analysis, calculates differences in the decorrelation time of the speckle ...

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    11. Familial Incomplete Punctal Canalization: Clinical and Fourier Domain Optical Coherence Tomography Features

      Familial Incomplete Punctal Canalization: Clinical and Fourier Domain Optical Coherence Tomography Features

      Incomplete punctal canalization is a form of punctal dysgenesis with membranous noncanalization and can be confused with punctal agenesis. The clinical and diagnostic features are known; however, familial incomplete punctal canalization has not been reported earlier. A family with 3 affected members is presented in this series with similar incomplete punctal canalization and nasolacrimal duct obstructions. After membranotomy and endoscopic dacryocystorhinostomy with bicanalicular intubation, all of them are free of epiphora at last visit.

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    12. Angiographic, optical coherence tomography and histology findings from combination of a drug-coated balloon with an everolimus-eluting stent in a porcine mode

      Angiographic, optical coherence tomography and histology findings from combination of a drug-coated balloon with an everolimus-eluting stent in a porcine mode

      Background We designed a porcine model to compare the angiographic, optical coherence tomography (OCT) and histological findings of implanting an everolimus-eluting stent (EES) in the same segment of the coronary artery pre-treated with a drug-coating balloon (DCB; paccocath as carrier) with EES alone and DCB plus a bare metal stent (BMS). Methods Seven female swine averaging 46.0±2.4 kg were treated by random assignment as follows: DCB followed by EES; DCB followed by BMS; and EES alone. Quantitative coronary angiography (QCA) and OCT were carried out post-implantation and repeated after 28±1 days. Results All arteries remained patent ...

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    13. Microarchitecture of the Vitreous Body: A High-Resolution Optical Coherence Tomography Study

      I read with great interest the article by Uji and Yoshimura1 on new and original observations of microarchitecture of the vitreous body. The authors wrote: “these findings are consistent with the theory proposed by Zinn in 1780, which states that the vitreous is arranged in a concentric, lamellar configuration, similar to that observed in a cut onion.” This statement has been made previously.2,3 Johann Gottfried Zinn (1727–1759) published his treatise “Descriptio anatomica oculi humani,” considered to be the first complete description of the eye's anatomy, in 1755, with a second edition in 1780.

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    14. Choroidal neovascularisation on optical coherence tomography angiography in punctate inner choroidopathy and multifocal choroiditis

      Choroidal neovascularisation on optical coherence tomography angiography in punctate inner choroidopathy and multifocal choroiditis

      Purpose To describe the findings seen on optical coherence tomography angiography (OCTA) in patients with punctate inner choroidopathy (PIC) and multifocal choroiditis and panuveitis (MCP) complicated by choroidal neovascular membranes. Methods This was an Institutional Review Board-approved prospective, descriptive case series. 12 patients with PIC and MCP complicated by choroidal neovascularisation (CNV) were included. Each patient underwent slit-lamp examination by a uveitis specialist followed by conventional spectral domain OCT imaging of the macula. OCTA images of the macula were then obtained. Results 12 patients were enrolled in the study, out of which 9 patients were followed longitudinally. CNV was identified ...

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    15. Measurement of biofilm growth and local hydrodynamics using optical coherence tomography

      Measurement of biofilm growth and local hydrodynamics using optical coherence tomography

      We report on localized and simultaneous measurement of biofilm growth and local hydrodynamics in a microfluidic channel using optical coherence tomography. We measure independently with high spatio-temporal resolution the longitudinal flow velocity component parallel to the imaging beam and the transverse flow velocity component perpendicular to the imaging beam. Based on the measured velocities we calculate the shear-rates in the flow channel. We show the relation between the measured biofilm structure and flow velocities as biofilm growth progresses over the course of 48 hours.

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    16. Optical Coherence Tomography for Lesion Assessment

      Optical Coherence Tomography for Lesion Assessment

      Optical coherence tomography (OCT) is an intravascular imaging technology that employs an optical source for image acquisition, allowing high-resolution (10–20 μm) analysis of the coronary vasculature. The development of this imaging tool over the last decade, along with European CE Mark approval in March 2009 and US Food and Drug Administration approval in April 2010, has led to a dramatic increase in the number of operators and institutions using this technology. In many ways, early experience with this technology mimics the early experience with intravascular ultrasound (IVUS) 2 decades earlier, and as a still-emerging innovative imaging modality, much of ...

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      Mentions: St. Jude Medical
    17. Investigating Elastic Anisotropy of the Porcine Cornea as a Function of Intraocular Pressure With Optical Coherence Elastography

      Investigating Elastic Anisotropy of the Porcine Cornea as a Function of Intraocular Pressure With Optical Coherence Elastography

      PURPOSE: To evaluate the elastic anisotropy of porcine corneas at different intraocular pressures (IOPs) using a noncontact optical coherence elastography (OCE) technique. METHODS: A focused air-pulse induced low amplitude (≤ 10 µ m) elastic waves in fresh porcine corneas (n = 7) in situ in the whole eye globe configuration. A home-built phase-stabilized swept source optical coherence elastography (PhS-SSOCE) system imaged the elastic wave propagation at different stepped radial directions. A closed-loop feedback system was used to artificially control the IOP and the OCE measurements were repeated as the IOP was incrementally increased from 15 to 30 mm Hg in 5-mm Hg increments ...

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    18. Optical Coherence Tomography: Clinical Applications in Gastrointestinal Endoscopy (Book Chapter)

      Optical Coherence Tomography: Clinical Applications in Gastrointestinal Endoscopy (Book Chapter)

      Optical coherence tomography (OCT) is a high-resolution imaging modality that uses principles of light interferometry. It has achieved clinical application in several other specialties such as ophthalmology and cardiology where its high resolution and deeper penetration into the surface permits much more detailed examination of the mucosa. In the field of gastroenterology, the technology has evolved through several iterations beginning with a focal magnifying imaging technique and evolving into currently a widefield imaging modality that can scan a relatively large area of mucosa with high resolution. OCT has been used to detect dysplasia in Barrett’s esophagus, differentiate between inflammatory ...

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    19. Imaging hemodynamic response after ischemic stroke in mouse cortex using visible-light optical coherence tomography

      Imaging hemodynamic response after ischemic stroke in mouse cortex using visible-light optical coherence tomography

      Visible-light optical coherence tomography (Vis-OCT) is an emerging technology that can image hemodynamic response in microvasculature. Vis-OCT can retrieve blood oxygen saturation (sO 2 ) mapping using intrinsic optical absorption contrast while providing high-resolution anatomical vascular structures at the same time. To improve the accuracy of Vis-OCT oximetry on vessels embedded in highly scattering medium, i.e., brain cortex, we developed and formulated a novel dual-depth sampling and normalization strategy that allowed us to minimize the detrimental effect of ubiquitous tissue scattering. We applied our newly developed approach to monitor the hemodynamic response in mouse cortex after focal photothrombosis. We observed ...

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    20. Measuring Airway Remodeling in Patients with Different COPD Staging Using Endobronchial Optical Coherence Tomography

      Measuring Airway Remodeling in Patients with Different COPD Staging Using Endobronchial Optical Coherence Tomography

      Background Although forced expiratory volume in one second (FEV 1 ) remains the gold standard for staging COPD, the association between airway remodeling and airflow limitation remains unclear. Objective Endobronchial optical coherence tomography (EB-OCT) was performed to assess the association between disorders of large- and medium-to-small-sized airways and COPD staging. We also evaluated small-airway architecture in heavy-smokers with normal FEV 1 (S NL ) and healthy never-smokers. Methods We recruited 48 COPD patients (stage Ⅰ, n=14; stage Ⅱ, n=15; stage Ⅲ-Ⅳ, n=19), 21 S NL , and 17 healthy never-smokers. Smoking history inquiry, spirometry, chest computed tomography, bronchoscopy and EB-OCT ...

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      Mentions: Wei Wang
    21. Volumetric rendering and metrology of spherical gradient refractive index lens imaged by angular scan optical coherence tomography system

      Volumetric rendering and metrology of spherical gradient refractive index lens imaged by angular scan optical coherence tomography system

      In this paper, we develop the methodology, including the refraction correction, geometrical thickness correction, coordinate transformation, and layer segmentation algorithms, for 3D rendering and metrology of a layered spherical gradient refractive index (S-GRIN) lens based on the imaging data collected by an angular scan optical coherence tomography (OCT) system. The 3D mapping and rendering enables direct 3D visualization and internal defect inspection of the lens. The metrology provides assessment of the surface geometry, the lens thickness, the radii of curvature of the internal layer interfaces, and the misalignment of the internal S-GRIN distribution with respect to the lens surface. The ...

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    22. EN FACE OPTICAL COHERENCE TOMOGRAPHY (OCT) AND OCT ANGIOGRAPHY FINDINGS IN RETINAL ASTROCYTIC HAMARTOMAS

      EN FACE OPTICAL COHERENCE TOMOGRAPHY (OCT) AND OCT ANGIOGRAPHY FINDINGS IN RETINAL ASTROCYTIC HAMARTOMAS

      Purpose: To report spectral-domain optical coherence tomography, en face optical coherence tomography (OCT), and optical coherence tomography angiography findings in retinal astrocytic hamartomas. Methods: Four cases of retinal astrocytic hamartomas, with small white or yellowish typical retinal mass, were imaged with fundus photography, intravenous fluorescein angiography, fundus autofluorescence, spectral-domain OCT, en face OCT, and OCT angiography. Results: The tumor was solitary in all cases and involved the posterior pole. It was idiopathic in three cases and was related to tuberous sclerosis complex in one case. The OCT findings included intralesional lucencies in two cases with no exudation. The tumor was ...

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    23. Multi-modality Optical Imaging of Rat Kidney Dysfunction: In Vivo Response to Various Ischemia Times

      Multi-modality Optical Imaging of Rat Kidney Dysfunction: In Vivo Response to Various Ischemia Times

      We observed in vivo kidney dysfunction with various ischemia times at 30, 75, 90, and 120 min using multi-modality optical imaging: optical coherence tomography (OCT), Doppler OCT (DOCT), and two-photon microscopy (TPM). We imaged the renal tubule lumens and glomerulus at several areas of each kidney before, during, and after ischemia of 5-month-old female Munich-Wistar rats. For animals with 30 and 75 min ischemia times, we observed that all areas were recovered after ischemia, that tubule lumens were re-opened and the blood flow of the glomerulus was re-established. For animals with 90 and 120 min ischemia times, we observed unrecovered ...

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