1. Articles in category: Pulmonology

    121-144 of 234 « 1 2 3 4 5 6 7 8 9 10 »
    1. Modeling the effect of refraction on OCT imaging of lung tissue: a ray-tracing approach

      Modeling the effect of refraction on OCT imaging of lung tissue: a ray-tracing approach

      Determining the structure of lung tissue is difficult in ex-vivo samples. Optical coherence tomography (OCT) can image alveoli but ignores optical effects that distort the images. For example, light refracts and changes speed at the alveolar air-tissue surface. We employ ray-tracing to model OCT imaging with directional and speed changes included, using spherical shapes in 2D. Results show apparent thickening of inter-aveolar walls and distortion of shape and depth. Our approach suggests a correction algorithm by combining the model with image analysis. Distortion correction will allow inference of tissue mechanical properties and deeper imaging.

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    2. Multimodal imaging of lung tissue using optical coherence tomography and two photon microscopy

      Multimodal imaging of lung tissue using optical coherence tomography and two photon microscopy

      In the context of protective artificial ventilation strategies for patients with severe lung diseases, the contribution of ventilator settings to tissue changes on the alveolar level of the lung is still a question under debate. To understand the impact of respiratory settings as well as the dynamic process of respiration, high-resolution monitoring and visualization of the dynamics of lung alveoli are essential. An instrument allowing 3D imaging of lung tissue as well as imaging of functional constituents, such as elastin fibers, in in situ experimental conditions is presented in this study using a combination of Fourier domain optical coherence tomography ...

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    3. Quantitative investigation of alveolar structures with OCT using total liquid ventilation during mechanical ventilation

      Quantitative investigation of alveolar structures with OCT using total liquid ventilation during mechanical ventilation

      To develop new treatment possibilities for patients with severe lung diseases it is crucial to understand the lung function on an alveolar level. Optical coherence tomography (OCT) in combination with intravital microscopy (IVM) are used for imaging subpleural alveoli in animal models to gain information about dynamic and morphological changes of lung tissue during mechanical ventilation. The image content suitable for further analysis is influenced by image artifacts caused by scattering, refraction, reflection, and absorbance. Because the refractive index varies with each air-tissue interface in lung tissue, these effects decrease OCT image quality exceedingly. The quality of OCT images can ...

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    4. Ultrahigh resolution optical coherence tomography imaging of diseased rat lung using Gaussian shaped super continuum sources

      Ultrahigh resolution optical coherence tomography imaging of diseased rat lung using Gaussian shaped super continuum sources

      We have been investigating ultrahigh resolution optical coherence tomography (UHR-OCT) imaging of lung tissues using fiber super continuum sources. The high power, low-noise, Gaussian shaped supercontinuum generated with ultrashort pulses and optical fibers at several wavelengths were used as the broadband light sources for UHR-OCT. For the 800 nm wavelength region, the axial resolution was 3.0 um in air and 2.0 um in tissue. Since the lung consists of tiny alveoli which are separated by thin wall, the UHR-OCT is supposed to be effective for lung imaging. The clear images of alveoli of rat were observed with and ...

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    5. Lung vasculature imaging using speckle variance optical coherence tomography

      Lung vasculature imaging using speckle variance optical coherence tomography

      Architectural changes in and remodeling of the bronchial and pulmonary vasculature are important pathways in diseases such as asthma, chronic obstructive pulmonary disease (COPD), and lung cancer. However, there is a lack of methods that can find and examine small bronchial vasculature in vivo. Structural lung airway imaging using optical coherence tomography (OCT) has previously been shown to be of great utility in examining bronchial lesions during lung cancer screening under the guidance of autofluorescence bronchoscopy. Using a fiber optic endoscopic OCT probe, we acquire OCT images from in vivo human subjects. The side-looking, circumferentially-scanning probe is inserted down the ...

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    6. Quantification of Glucose Diffusion in Human Lung Tissues by Using Fourier Domain Optical Coherence Tomography

      Quantification of Glucose Diffusion in Human Lung Tissues by Using Fourier Domain Optical Coherence Tomography

      In this study, we report permeability coefficients of 30% glucose diffusion by the optical coherence tomography signal slope (OCTSS) method in four kind of human lung tissue in vitro: normal lung tissue, benign granulomatosis lung tissue, squamous cell carcinoma, and adenocarcinoma tumor. To quantify the permeability coefficient of the agent, the monitored region was the 80 um thickness at a tissue depth of approximately 230 um from the surface. The permeability coefficients of 30% glucose from 10 independent experiments were averaged and found to be (1.35 ± 0.13)×10 −5 cm/s from the normal lung tissue, (1.78 ...

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    7. Frontiers in Bronchoscopic Imaging

      Frontiers in Bronchoscopic Imaging
      Bronchoscopy is a minimally-invasive method for diagnosis of diseases of the airways and the lung parenchyma. Standard bronchoscopy uses the reflectance/scattering properties of white light from tissue to examine the macroscopic appearance of airways. It does not exploit the full spectrum of the optical properties of bronchial tissues. Advances in optical imaging such as optical coherence tomography (OCT), confocal endomicroscopy, autofluorescence imaging and laser Raman spectroscopy are at the forefront to allow in-vivo high resolution probing of the microscopic structure, biochemical compositions and even molecular alterations in disease states. OCT can visualize cellular and extracellular structures at and below ...
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    8. Early detection and treatment of squamous cell lung cancer

      Early detection and treatment of squamous cell lung cancer
      In this review, we discuss the detection, staging, and treatment of early-stage squamous cell lung cancer, with a focus on bronchoscopic techniques, including electrocauterization, argon plasma coagulation, cryotherapy, neodymium:yttriumaluminum- garnet laser therapy, photodynamic therapy, and intraluminal brachytherapy. The cure rate achieved with bronchoscopic techniques is 43-97%. Most bronchoscopic strategies are less morbid and less toxic than is non-bronchoscopic radiation therapy. Success depends on the application of stringent selection criteria for appropriate tumors, smaller tumors responding better. In some cases, electrocauterization, argon plasma coagulation, and cryotherapy can be conducted safely in an outpatient setting. There is sufficient technology available for ...
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    9. Investigating in vivo airway wall mechanics during tidal breathing with optical coherence tomography

      Investigating in vivo airway wall mechanics during tidal breathing with optical coherence tomography
      Optical coherence tomography (OCT) is a nondestructive imaging technique offering high temporal and spatial resolution, which makes it a natural choice for assessing tissue mechanical properties. We have developed methods to mechanically analyze the compliance of the rabbit trachea in vivo using tissue deformations induced by tidal breathing, offering a unique tool to assess the behavior of the airways during their normal function. Four-hundred images were acquired during tidal breathing with a custom-built endoscopic OCT system. The surface of the tissue was extracted from a set of these images via image processing algorithms, filtered with a bandpass filter set at ...
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    10. Recent advances in optical coherence tomography for the diagnoses of lung disorders

      Recent advances in optical coherence tomography for the diagnoses of lung disorders
      There have been many advances in the field of diagnostic and therapeutic pulmonary medicine in the past several years, with major progress in the field of imaging. Optical coherence tomography (OCT) is a high-resolution (micron level) imaging modality currently being advanced with the potential to image airway wall structures in real time and at higher resolution than previously possible. OCT has the potential to increase the sensitivity and specificity of biopsies, create 3D images of the airway to guide diagnostics, and may have a future role in diverse areas such as the evaluation and treatment of patients with obstructive sleep ...
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    11. Ultrathin side-viewing needle probe for optical coherence tomography

      Ultrathin side-viewing needle probe for optical coherence tomography

      We present the smallest reported side-viewing needle probe for optical coherence tomography (OCT). Design, fabrication, optical characterization, and initial application of a 30-gauge (outer diameter 0.31 mm) needle probe are demonstrated. Extreme miniaturization is achieved by using a simple all-fiber probe design incorporating an angle-polished and reflection-coated fiber-tip beam deflector. When inserted into biological tissue, aqueous interstitial fluids reduce the probe’s inherent astigmatism ratio to 1.8, resulting in a working distance of 300 μm and a depth-of-field of 550 μm with beam diameters below 30 μm. The needle probe was interfaced with an 840 nm spectral-domain OCT ...

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    12. Early Cystic Fibrosis Lung Disease Studies in Humans, NHLBI (R01)

      Early Cystic Fibrosis Lung Disease Studies in Humans, NHLBI (R01)
      This FOA, issued by the National Heart, Lung, and Blood Institute (NHLBI), National Institutes of Health, invites Research Project Grant (R01) applications that propose to investigate the early origins of cystic fibrosis (CF) lung disease and the mechanisms involved in development and progression of pulmonary abnormalities in young children with this condition. Studies may explore novel strategies for detecting early lung disease in infants and young children with CF, including minimally invasive biomarkers and/or imaging approaches, and utilize these methods to elucidate the molecular and cellular mechanisms of early lung disease onset and progression. The ultimate goal is development ...
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    13. B.C. Cancer Research Center Receives CIHR Grant To Investigate High-Resolution OCT Imaging of Bronchial Epithelium

      B.C. Cancer Research Center Receives CIHR Grant To Investigate High-Resolution OCT Imaging of Bronchial Epithelium
      B.C. Cancer Research Center received an operating grant from the Canadian Institutes of Health Research for $84,255 (Canadian Dollars) to investigate high-resolution OCT Imaging of Bronchial Epithelium. The principal investigator is Pierre Lane. Below is a summary of that work. Lung cancer is the most common cause of cancer death world-wide. More than 1.3 million people die annually and the 5-year survival rates have improved only marginally in the last three decades. We propose to combine autofluorescence bronchoscopy and optical coherence tomography (OCT) to manage this disease through earlier detection and treatment. Autofluorescence bronchoscopy is a technique ...
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    14. UC Irvine Wins NIH Grant for Linking Biological, Optical, and Mechanical Properties in the Airway Mucosa.

      UC Irvine Wins NIH Grant for Linking Biological, Optical, and Mechanical Properties in the Airway Mucosa.
      The University of California at Irvine received a $396,400 NIH grant for linking biological, optical, and mechanical properties in the airway mucosa.  The principal investigator is Steven George.  Below is a summary of that work. Airway epithelial injury occurs following inhalation of toxic agents, infection, intubation, and in a chronic repetitive disease such as asthma which impacts approximately 10% of the population in the United States. The wound repair response of the epithelium can induce changes in the structure and mechanical properties of the underlying connective tissue that can alter normal lung function. In bronchial asthma, alterations in the ...
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    15. UC Irvine Receives NIH Grant for Work on High Resolution OCT for Early Airway Cancer Detection

      UC Irvine Receives NIH Grant for Work on High Resolution OCT for Early Airway Cancer Detection
      The University of California at Irvine received a $252,952 NIH grant for work on high resolution optical coherence tomography for early airway cancer detection.  The Principal investigator is Matthew Brenner.  Below is a summary of that work.  Background: Lung cancer is the leading cause of cancer death in the US. Development of novel high resolution endoscopy is essential for more accurate diagnosis, staging, and treatment of endobronchial malignancy. Recent advances in rapid acquisition high-resolution flexible fiberoptic and rigid probe optical coherence tomography (OCT) offer the potential for endoscopic real-time near histologic level optical maging to substantially advance detection, diagnostics ...
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    16. Pilot Study to Evaluate Optical Frequency Domain Imaging for Diagnosis of Central Airway Disease

      Pilot Study to Evaluate Optical Frequency Domain Imaging for Diagnosis of Central Airway Disease
      This study will evaluate a new imaging technology, termed optical frequency domain imaging (OFDI) for detecting and diagnosing pulmonary malignancy in the central airways. The prevalence and high mortality rate associated with lung squamous cell carcinoma and the lack of any widely accepted screening and surveillance tools, highlights the need for new imaging paradigms that will ultimately lead to a reduction in patient mortality. Bronchial carcinoma-in-situ will progress to invasive cancer in over 40% of individuals, and although the progression occurs over a long period of time, the majority of carcinomas are detected in the later stages of disease development ...
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    17. Cutting Edge Technologies in Respiratory Research: lung function testing

      Cutting Edge Technologies in Respiratory Research: lung function testing
      Pulmonary function testing is part of routine clinical practice in respiratory medicine. It is based around spirometry, which will remain the central measurement of lung function given its prognostic significance and its integral role in defining severity of airways disease. However, there is an increasing body of evidence from studies using new methods of lung function measurement which are providing new insights into pathophysiology of disease. This body of data is forming a basis for their future clinical role, once the economics of producing the relevant devices becomes attractive. The forced oscillation technique and multiple breath nitrogen washout are currently ...
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    18. Mechanical and Optical Dynamic Model of Lung

      Mechanical and Optical Dynamic Model of Lung
      A multiscale, multiphysics model generates synthetic images of alveolar compression under spherical indentation at the visceral pleura of inflated lung. A mechanical model connects the millimeter scale of an indenter tip to the behavior of alveoli, walls, and membrane at the micrometer scale. A finite difference model of optical coherence tomography (OCT) generates the resulting images. Results show good agreement with experiments performed using a unique indenterOCT system. The images depict the physical result with the addition of refractive artifacts and speckle. Compression of the alveoli alters the refractive effects which introduce systematic errors in the computation of alveolar volume ...
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    19. Microfluidic characterization of cilia-driven fluid flow using optical coherence tomography-based particle tracking velocimetry

      Microfluidic characterization of cilia-driven fluid flow using optical coherence tomography-based particle tracking velocimetry
      Motile cilia are cellular organelles that generate directional fluid flow across various epithelial surfaces including the embryonic node and respiratory mucosa. The proper functioning of cilia is necessary for normal embryo development and, for the respiratory system, the clearance of mucus and potentially harmful particulate matter. Here we show that optical coherence tomography (OCT) is well-suited for quantitatively characterizing the microfluidic-scale flow generated by motile cilia. Our imaging focuses on the ciliated epithelium of Xenopus tropicalis embryos, a genetically manipulable and experimentally tractable animal model of human disease. We show qualitative flow profile characterization using OCT-based particle pathline imaging. We ...
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    20. Investigation of alveolar tissue deformations using OCT combined with fluorescence microscopy

      Investigation of alveolar tissue deformations using OCT combined with fluorescence microscopy

      In critical care medicine, artificial ventilation is a life saving tool providing sufficient blood oxygenation to patients suffering from respiratory failure. Essential for their survival is the use of protective ventilation strategies to prevent further lung damage due to ventilator induced lung injury (VILI). Since there is only little known about implications of lung tissue overdistension on the alveolar level, especially in the case of diseased lungs, this research deals with the investigation of lung tissue deformation on a microscale. A combined setup utilizing optical coherence tomography (OCT) and confocal fluorescence microscopy, is used to study the elastic behavior of ...

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    21. Improved OCT imaging of lung tissue using a prototype for total liquid ventilation

      Improved OCT imaging of lung tissue using a prototype for total liquid ventilation
      Optical coherence tomography (OCT) is used for imaging subpleural alveoli in animal models to gain information about dynamic and morphological changes of lung tissue during mechanical ventilation. The quality of OCT images can be increased if the refraction index inside the alveoli is matched to the one of tissue via liquid-filling. Thereby, scattering loss can be decreased and higher penetration depth and tissue contrast can be achieved. Until now, images of liquid-filled lungs were acquired in isolated and fixated lungs only, so that an in vivo measurement situation is not present. To use the advantages of liquid-filling for in vivo ...
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    22. Optical coherence tomography for imaging of subpleural alveolar structure using a Fourier domain mode locked laser

      Optical coherence tomography for imaging of subpleural alveolar structure using a Fourier domain mode locked laser

      Optical coherence tomography (OCT) is a noninvasive imaging modality generating cross sectional and volumetric images of translucent samples. In Fourier domain OCT (FD OCT), the depth profile is calculated by a fast Fourier transformation of the interference spectrum, providing speed and SNR advantage and thus making FD OCT well suitable in biomedical applications. The interference spectrum can be acquired spectrally resolved in spectral domain OCT or time-resolved in optical frequency domain imaging (OFDI). Since OCT images still suffer from motion artifacts, especially under in vivo conditions, increased depth scan rates are required. Therefor, the principle of Fourier domain mode locking ...

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    23. Postdoctoral Fellow Position in Biomedical Optics At Massachusetts General Hospital within the Pulmonary and Critical Care Unit and the Wellman Center for Photomedicine

      Postdoctoral Fellow Position in Biomedical Optics At Massachusetts General Hospital within the Pulmonary and Critical Care Unit and the Wellman Center for Photomedicine
      A Postdoctoral research opportunity in biomedical optics is available at the Massachusetts General Hospital within the Pulmonary and Critical Care Unit and the Wellman Center for Photomedicine. Harvard Medical School appointment will be at the postdoctoral rank. The successful candidate will work within a highly collaborative research environment focused on the development and use of optical diagnostics for studying lung pathology, structure and function both in preclinical animal studies and in first-in-patient pilot clinical studies. The position will involve the design and fabrication of novel optical imaging systems including polarization-sensitive optical coherence tomography, and confocal microscopy systems, and the design ...
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    24. Tomophase Announces First Sale of Its OCT Imaging System (OCTIS™) for Research Use to the University of Texas

      Tomophase Announces First Sale of Its OCT Imaging System (OCTIS™) for Research Use to the University of Texas
      Tomophase Press Release - Tomophase Corporation, a leading developer of minimally invasive optical coherence tomography (OCT) tissue imaging devices, announced today that it has installed the first of its OCT Imaging Systems (OCTIS™) at the University of Texas Medical Branch (UTMB) in Galveston, Texas. This first system sale will be for research use in the laboratory of Dr. Massoud Motamedi, Director, Center for Biomedical Engineering at UTMB. Dr. Motamedi will be conducting research on application of OCT in intraluminal imaging. Dr Motamedi said, "There is a great need for the development of a high resolution image-based technique for non-invasive assessment of ...
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    121-144 of 234 « 1 2 3 4 5 6 7 8 9 10 »
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