1. Featured Articles

    25-48 of 54 « 1 2 3 »
    1. Validation of Airway Wall Measurements by Optical Coherence Tomography in Porcine Airways

      Validation of Airway Wall Measurements by Optical Coherence Tomography in Porcine Airways

      Examining and quantifying changes in airway morphology is critical for studying longitudinal pathogenesis and interventions in diseases such as chronic obstructive pulmonary disease and asthma. Here we present fiber-optic optical coherence tomography (OCT) as a nondestructive technique to precisely and accurately measure the 2-dimensional cross-sectional areas of airway wall substructure divided into the mucosa (WA muc ), submucosa (WA sub ), cartilage (WA cart ), and the airway total wall area (WAt). Porcine lung airway specimens were dissected from freshly resected lung lobes (N = 10). Three-dimensional OCT imaging using a fiber-optic rotary-pullback probe was performed immediately on airways greater than 0.9 mm ...

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    2. Perspectives of mid-infrared optical coherence tomography for inspection and micrometrology of industrial ceramics

      Perspectives of mid-infrared optical coherence tomography for inspection and micrometrology of industrial ceramics

      Optical coherence tomography (OCT) is a promising tool for detecting micro channels, metal prints, defects and delaminations embedded in alumina and zirconia ceramic layers at hundreds of micrometers beneath surfaces. The effect of surface roughness and scattering of probing radiation within sample on OCT inspection is analyzed from the experimental and simulated OCT images of the ceramic samples with varying surface roughnesses and operating wavelengths. By Monte Carlo simulations of the OCT images in the mid-IR the optimal operating wavelength is found to be 4 µm for the alumina samples and 2 µm for the zirconia samples for achieving sufficient ...

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    3. Reproducibility of the Carpet View system: a novel technical solution for display and off line analysis of OCT images

      Reproducibility of the Carpet View system: a novel technical solution for display and off line analysis of OCT images

      The optical coherence tomography (OCT) evaluation of the stent anatomy requires the inspection of sequential cross section (CS). However stent coils cannot be appreciated in the conventional format as the OCT CS simply display stent struts, that are poorly representative of the stent architecture. The aim of the present study was to validate a new software ( Carpet View ), which unfolds the stented segment, reconstructing it as an open structure and displaying the stent meshwork. 21 patients were studied with frequency domain OCT after the deployment of different stents: seven bio-absorbable scaffolds (Dream), seven bare metal stent (Vision/Multilink8), seven drug ...

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      Mentions: Francesco Prati
    4. Coherence revival multiplexed, buffered swept source optical coherence tomography: 400  kHz imaging with a 100  kHz source

      Coherence revival multiplexed, buffered swept source optical coherence tomography: 400  kHz imaging with a 100  kHz source

      The effective speed of a swept source optical coherence tomography (SSOCT) imaging system was quadrupled using efficient sweep buffering along with coherence revival and spatial multiplexing. A polarizing beam splitter and fold mirror assembly were used to create a dual spot sample arm with a common objective designed for near-diffraction-limited retinal imaging. Using coherence revival, a variable optical delay line allowed for separate locations within a sample to be simultaneously imaged and frequency encoded by carefully controlling the optical path length of each sample path. This method can be used to efficiently quadruple the imaging speed of any SSOCT system ...

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    5. NinePoint Medical Receives 2014 MDEA Silver Medal for NvisionVLE Imaging System

      NinePoint Medical Receives 2014 MDEA Silver Medal for NvisionVLE Imaging System

      NinePoint Medical, Inc., an emerging leader in the development of medical devices for advanced optical imaging, today announced the company was honored with a silver medal at the 2014 Medical Design Excellence Awards (MDEA) for the company’s volumetric optical coherence tomography device, the NvisionVLE Imaging System™. NinePoint and NvisionVLE were among 54 cutting-edge products and companies across 11 medical technology product categories selected as finalists. “Our team has worked diligently over the past four years to bring the NvisionVLE Imaging System to clinicians and patients, and we are pleased that our efforts were recognized by the MDEA with this ...

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    6. Fiber-optic polarization diversity detection for rotary probe optical coherence tomography

      Fiber-optic polarization diversity detection for rotary probe optical coherence tomography

      We report a polarization diversity detection scheme for optical coherence tomography with a new, custom, miniaturized fiber coupler with single mode (SM) fiber inputs and polarization maintaining (PM) fiber outputs. The SM fiber inputs obviate matching the optical lengths of the X and Y OCT polarization channels prior to interference and the PM fiber outputs ensure defined X and Y axes after interference. Advantages for this scheme include easier alignment, lower cost, and easier miniaturization compared to designs with free-space bulk optical components. We demonstrate the utility of the detection system to mitigate the effects of rapidly changing polarization states ...

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    7. Short cavity active mode locking fiber laser for optical sensing and imaging

      Short cavity active mode locking fiber laser for optical sensing and imaging

      We demonstrate a highly linear wavenumber- swept active mode locking (AML) fiber laser for optical sensing and imaging without any wavenumber-space resampling process. In this all-electric AML wavenumber-swept mechanism, a conventional wavelength selection filter is eliminated and, instead, the suitable programmed electric modulation signal is directly applied to the gain medium. Various types of wavenumber (or wavelength) tunings can be implemented because of the filter-less cavity configuration. Therefore, we successfully demonstrate a linearly wavenumber-swept AML fiber laser with 26.5 mW of output power to obtain an in-vivo OCT image at the 100 kHz swept rate.

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    8. OCT in Zero Gravity

      OCT in Zero Gravity

      Heidelberg Engineering’s annual 2014 Xtreme Research Award was presented to the NASA Ocular Health Study during the recent award ceremony in Orlando, Florida. Over 200 scientists who were in the city for the annual meeting of the Association for Research in Vision and Ophthalmology (ARVO) gathered for the event. Dr. Nimesh Patel, Assistant Professor at the University of Houston, College of Optometry and a consultant to NASA accepted the award and presented the award lecture. In the presentation, entitled “OCT in Zero G,” Dr. Patel provided details about the use of SPECTRALIS ® Optical Coherence Tomography (OCT) on board the ...

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    9. Feasibility of Intracoronary Frequency Domain Optical Coherence Tomography Derived Fractional Flow Reserve for the Assessment of Coronary Artery Stenosis

      Feasibility of Intracoronary Frequency Domain Optical Coherence Tomography Derived Fractional Flow Reserve for the Assessment of Coronary Artery Stenosis

      Frequency domain optical coherence tomography (FD-OCT) provides cross-sectional images of coronary arteries and deployed stents with micron resolution and measures lumen dimensions with excellent reproducibility. FD-OCT combined with a blood flow resistances model can overcome many limitations of conventional measures of stenosis severity based on quantitative coronary angiography (QCA) and intravascular ultrasound (IVUS). The aim of this feasibility study was to investigate the relationship between pressure derived fractional flow reserve (FFR) and FD-OCT derived FFR, a new method for quantitative measure of stenosis severity that estimates the blood flow resistance and microvascular resistance of the vessel segments imaged by FD-OCT ...

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    10. Choroidal Haller's and Sattler's Layer Thickness Measurement Using 3-Dimensional 1060-nm Optical Coherence Tomography

      Choroidal Haller's and Sattler's Layer Thickness Measurement Using 3-Dimensional 1060-nm Optical Coherence Tomography

      Objectives To examine the feasibility of automatically segmented choroidal vessels in three-dimensional (3D) 1060-nmOCT by testing repeatability in healthy and AMD eyes and by mapping Haller's and Sattler's layer thickness in healthy eyes Methods Fifty-five eyes (from 45 healthy subjects and 10 with non-neovascular age-related macular degeneration (AMD) subjects) were imaged by 3D-1060-nmOCT over a 36°x36° field of view. Haller's and Sattler's layer were automatically segmented, mapped and averaged across the Early Treatment Diabetic Retinopathy Study grid. For ten AMD eyes and ten healthy eyes, imaging was repeated within the same session and on another ...

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    11. Variations in optical coherence tomography resolution and uniformity: a multi-system performance comparison

      Variations in optical coherence tomography resolution and uniformity: a multi-system performance comparison

      Point spread function (PSF) phantoms based on unstructured distributions of sub-resolution particles in a transparent matrix have been demonstrated as a useful tool for evaluating resolution and its spatial variation across image volumes in optical coherence tomography (OCT) systems. Measurements based on PSF phantoms have the potential to become a standard test method for consistent, objective and quantitative inter-comparison of OCT system performance. Towards this end, we have evaluated three PSF phantoms and investigated their ability to compare the performance of four OCT systems. The phantoms are based on 260-nm-diameter gold nanoshells, 400-nm-diameter iron oxide particles and 1.5-micron-diameter silica ...

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    12. Application of Optical Coherence Tomography to Identify Pulp Exposure During Access Cavity Preparation Using an Er:YAG Laser

      Application of Optical Coherence Tomography to Identify Pulp Exposure During Access Cavity Preparation Using an Er:YAG Laser

      Objective : The study aimed to evaluate the ability of optical coherence tomography (OCT) to guide and identify pulp exposure using an erbium: yttrium–aluminum–garnet (Er:YAG) laser. Background data: The Er:YAG laser has been proven to be effective in ablating dental hard tissue and offers advantages, as there is none of the vibration and noise you get with conventional methods, but it has limitations in relation to the tactile feedback that would aid in identification of entry into the pulp chamber. Based on depth-resolved optical reflectivity, OCT technology has been developed to provide high-resolution, cross-sectional images of the ...

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    13. Research and Clinical Applications of Optical Coherence Tomography in Invasive Cardiology: A Review

      Research and Clinical Applications of Optical Coherence Tomography in Invasive Cardiology: A Review

      In cardiology, optical coherence tomography (OCT) is an invasive imaging technique based on the principle of light coherence. This system was developed to obtain three-dimensional high resolution images to examine coronary artery normal and/or pathological structure. This technique replaces the ultrasound used by its main alternative procedure, intravascular ultrasound, by a near-infrared light source. Acute coronary syndromes due to atherosclerotic vascular disease are the leading cause of mortality in developed and developing countries. As a consequence, intravascular imaging systems became an important area of research and 1991 marks the first use of OCT in coronary artery observations. Since its ...

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    14. Speckle statistics in OCT images: Monte Carlo simulations and experimental studies

      Speckle statistics in OCT images: Monte Carlo simulations and experimental studies

      The speckle pattern of an optical coherence tomography (OCT) image carries potentially useful sample information that may assist in tissue characterization. Recent biomedical results in vivo indicate that the distribution of signal intensities within an OCT tissue image is well described by a log-normal-like (Gamma) function. To fully understand and exploit this finding, an OCT Monte Carlo model that accounts for speckle effects was developed. The resultant Monte Carlo speckle statistics predictions agree well with experimental OCT results from a series of control phantoms with variable scattering properties; the Gamma distribution provides a good fit to the theoretical and experimental ...

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    15. Methods, systems and computer program products for collapsing volume data to lower dimensional representations thereof using histogram projection

      Methods, systems and computer program products for collapsing volume data to lower dimensional representations thereof using histogram projection

      Methods of collapsing volume data to a lower dimensional representation of the volume data are provided. The methods include collapsing volume data to a lower dimensional representation of the volume data using histogram projection. Related systems and computer program products are also provided.

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    16. Haag-Streit Surgical Intraoperative OCT "iOCT" Product Brochure

      Haag-Streit Surgical Intraoperative OCT "iOCT" Product Brochure

      HAAG-STREIT SURGICAL is pleased to introduce the world‘s first intraoperative OCT system, developed by OPMedT. An OCT camera is integrated into the high class operating microscope HS Hi-R NEO 900A NIR and its mounting system. OCT scans of the eye’s anterior and posterior segments are performed live during surgery, thus increasing the patient’s safety and improving quality control mechanisms for the surgeon. Discover more details than with a standard surgical microscope and enhance your performance! To see product brochure click HERE.

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      Mentions: Haag-Streit OPMedT
    17. Probabilistic intra-retinal layer segmentation in 3-D OCT images using global shape regularization

      Probabilistic intra-retinal layer segmentation in 3-D OCT images using global shape regularization

      With the introduction of spectral-domain optical coherence tomography (OCT), resulting in a significant increase in acquisition speed, the fast and accurate segmentation of 3-D OCT scans has become evermore important. This paper presents a novel probabilistic approach, that models the appearance of retinal layers as well as the global shape variations of layer boundaries. Given an OCT scan, the full posterior distribution over segmentations is approximately inferred using a variational method enabling efficient probabilistic inference in terms of computationally tractable model components: Segmenting a full 3-D volume takes around a minute. Accurate segmentations demonstrate the benefit of using global shape ...

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    18. OCT Findings from the European Multi-centre Prestige Stent Thrombosis Study

      OCT Findings from the European Multi-centre Prestige Stent Thrombosis Study

      Background Coronary stent thrombosis (ST) remains the ‘Achilles Heel’ of percutaneous coronary intervention (PCI). Although relatively rare, it is associated with a high rate of acute myocardial infarction and death.A specific point of concern is the ongoing risk of very late ST, occurring more than one year after stent implantation, and the fact that this seems to occur steadily at an annual rate of 0.5% with a high risk of recurrence. The exact mechanisms are multi-factorial and poorly understood and previous studies have been hampered by small sample sizes, incomplete patient characterisation, and a lack of intracoronary imaging ...

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      Mentions: St. Jude Medical
    19. En-face full-field optical coherence tomography for fast and efficient fingerprints acquisition

      En-face full-field optical coherence tomography for fast and efficient fingerprints acquisition

      Optical coherence tomography (OCT) has been recently proposed by a number of laboratories as a promising tool for fingerprints acquisitions and for fakes discrimination. Indeed OCT being a non-contact, non-destructive optical method that virtually sections the volume of biological tissues that strongly scatter light it appears obvious to use it for fingerprints. Nevertheless most of the OCT setups have to go through the long acquisition of a full 3D image to isolate an “en-face” image suitable for fingerprint analysis. A few “en-face” OCT approaches have been proposed that use either a complex 2D scanning setup and image processing, or a ...

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    20. A proposed model membrane and test method for microneedle insertion studies

      A proposed model membrane and test method for microneedle insertion studies

      A commercial polymeric film (Parafilm M ® , a blend of a hydrocarbon wax and a polyolefin) was evaluated as a model membrane for microneedle (MN) insertion studies. Polymeric MN arrays were inserted into Parafilm M ® (PF) and also into excised neonatal porcine skin. Parafilm M ® was folded before the insertions to closely approximate thickness of the excised skin. Insertion depths were evaluated using optical coherence tomography (OCT) using either a force applied by a Texture Analyser or by a group of human volunteers. The obtained insertion depths were, in general, slightly lower, especially for higher forces, for PF than for skin ...

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    21. Region segmentation in 3-D optical coherence tomography images

      Region segmentation in 3-D optical coherence tomography images

      This paper describes a novel region segmentation method created to enhance spatial relationships in 3-D optical coherence tomography (OCT) images. To reduce the noise and distortion problems in low-resolution OCT images, previous work used the mean value and an enhanced-fuzzy-c-mean algorithm to cluster pixels in 2-D OCT images and find the edge between different clustered regions. To utilize more spatial relationships and to reduce computation time, the proposed method uses the mean value and a 3-D filter-based-fuzzy-c-mean algorithm to cluster pixels in 3-D OCT images and find the edge between different clustered regions. The OCT images of an artificial object ...

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    22. Feasibility of Optical Coherence Tomography in Children with Kawasaki Disease and Pediatric Heart Transplant Recipients

      Feasibility of Optical Coherence Tomography in Children with Kawasaki Disease and Pediatric Heart Transplant Recipients

      Background —Optical Coherence Tomography (OCT) is a high-resolution intravascular imaging technique used in adults. We tested the hypothesis that OCT could identify coronary abnormalities not seen by angiography in children with a history of Kawasaki Disease (KD) and pediatric heart transplant (TX) recipients. Methods and Results —KD patients and TX recipients were evaluated between December 2012 and October 2013 with angiography and OCT (Ilumien System, LightLabs, St Jude Medical, Westford, MA). Modifications were made to the adult OCT protocol to adapt this technique for children. Serial cross sectional area (CSA) measurements of the lumen, intima and media were made. Entire ...

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    23. Full field optical coherence tomography (FFOCT) of prostate biopsies: A step towards pre-histological diagnosis?

      Full field optical coherence tomography (FFOCT) of prostate biopsies: A step towards pre-histological diagnosis?

      Full-field optical coherence tomography (FFOCT) may be a potential additional tool in the strategy of prostate cancer detection. If the technique can be performed safely during transrectal ultrasound (TRUS) biopsy, and without adding significant time to the procedure, the information provided by FFOCT imaging during biopsy would increase the performance level of cancer detection. FFOCT imaging would allow immediate additional sampling in an area suspicious of cancer involvement, thus optimizing its characterization. In cases where there’s an absence of suspicious FFOCT image results in other areas, sampling could be limited to one core, thus decreasing the total number of ...

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    24. Precision-Guided Epidurals and Better Blood Monitors

      Precision-Guided Epidurals and Better Blood Monitors

      The march of modern medicine is often driven by revolutions in medical imaging. When technology advances, doctors are better able to peer deeply into human tissues, and thus able to detect, diagnose and treat human diseases more effectively. Now, researchers have taken an established imaging technology called “optical coherence tomography,” or OCT, and integrated it with other instruments to bring about the next revolution in imaging by helping doctors provide safer, less painful and more effective care for women in labor and people with diabetic retinopathy and glaucoma. Their research will be presented at CLEO: 2014 being held June 8-13 ...

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