1. Articles in category: Pulmonology

    97-120 of 227 « 1 2 3 4 5 6 7 8 9 10 »
    1. Four-dimensional optical coherence tomography imaging of subpleural alveoli in mice

      Four-dimensional optical coherence tomography imaging of subpleural alveoli in mice

      The development of protective ventilation strategies for patients suffering from life-threatening lung diseases and the promotion of numerical simulation of lung tissue mechanics requires detailed knowledge about the three-dimensional alveolar micro-structure, their dynamics and elastic properties. Subpleural lung tissue can be observed in animal models utilizing optical coherence tomography (OCT) with a high spatial resolution. We present four-dimensional high-speed OCT imaging of single alveoli as a suitable technique for the visualization of the temporal changes of the three-dimensional structure during the ventilation with a temporal resolution of 17 stacks per ventilation cycle. The acquired four-dimensional information allows a quantitative evaluation ...

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    2. University of North Carolina at Chapel Hill Receives a 2012 NIH Grant for Development of a Method for In Situ Nanorehology of Human Airway Mucus

      University of North Carolina at Chapel Hill Receives a 2012 NIH Grant for Development of a Method for In Situ Nanorehology of Human Airway Mucus

      University of North Carolina at Chapel Hill Receives a 2012 NIH Grant for $223,507 Development of a Method for In Situ Nanorehology of Human Airway Mucus. The program is a multi-year program and started in 2012 and ends in 2014. The principle investigator is Amy Oldenburg. A brief description of the project is given below. We propose to develop a novel nanorheology platform to simultaneously map mucus viscoelasticity and mucus flow in situ. Increase in airway mucus complex viscoelastic shear modulus (G*) hinders mucus clearance and is associated with respiratory diseases including chronic obstructive pulmonary disease (COPD) and cystic ...

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    3. University of California Irvine receives a 2012 NIH Grant for Linking Biological, Optical, and Mechanical Properties in the Airway Mucosa

      University of California Irvine receives a 2012 NIH Grant for Linking Biological, Optical, and Mechanical Properties in the Airway Mucosa

      University of California Irvine receives a 2012 NIH Grant for $443,776 for Linking Biological, Optical, and Mechanical Properties in the Airway Mucosa. The program is a multi-year program and started in 2001 and ends in 2013. The principle investigator is Steven George. A brief description of the project is given below. 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 ...

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    4. Flexible transbronchial optical frequency domain imaging smart needle for biopsy guidance

      Flexible transbronchial optical frequency domain imaging smart needle for biopsy guidance

      Transbronchial needle aspiration (TBNA) is a procedure routinely performed to diagnose peripheral pulmonary lesions. However, TBNA is associated with a low diagnostic yield due to inappropriate needle placement. We have developed a flexible transbronchial optical frequency domain imaging (TB-OFDI) catheter that functions as a “smart needle” to confirm the needle placement within the target lesion prior to biopsy. The TB-OFDI smart needle consists of a flexible and removable OFDI catheter (430 µm dia.) that operates within a standard 21-gauge TBNA needle. The OFDI imaging core is based on an angle polished ball lens design with a working distance of 160 ...

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    5. Monitoring airway mucus flow and ciliary activity with optical coherence tomography

      Monitoring airway mucus flow and ciliary activity with optical coherence tomography

      Muco-ciliary transport in the human airway is a crucial defense mechanism for removing inhaled pathogens. Optical coherence tomography (OCT) is well-suited to monitor functional dynamics of cilia and mucus on the airway epithelium. Here we demonstrate several OCT-based methods upon an actively transporting in vitro bronchial epithelial model and ex vivo mouse trachea. We show quantitative flow imaging of optically turbid mucus, semi-quantitative analysis of the ciliary beat frequency, and functional imaging of the periciliary layer. These may translate to clinical methods for endoscopic monitoring of muco-ciliary transport in diseases such as cystic fibrosis and chronic obstructive pulmonary disease (COPD).

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    6. The Role and Potential of Imaging in COPD

      The Role and Potential of Imaging in COPD

      Chronic obstructive pulmonary disease is a heterogeneous condition of the lungs and body. Techniques in chest imaging and quantitative image analysis provide novel in vivo insight into the disease and potentially examine divergent responses to therapy. This article reviews the strengths and limitations of the leading imaging techniques: computed tomography, magnetic resonance imaging, positron emission tomography, and optical coherence tomography. Following an explanation of the technique, each section details some of the useful information obtained with these examinations. Future clinical care and investigation will likely include some combination of these imaging modalities and more standard assessments of disease severity.

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    7. Feature Of The Week 7/15/12: 3D Simultaneous Optical Coherence Tomography and Confocal Fluorescence Microscopy for Investigation of Lung Tissue

      Feature Of The Week 7/15/12: 3D Simultaneous Optical Coherence Tomography and Confocal Fluorescence Microscopy for Investigation of Lung Tissue

      The acute respiratory distress syndrome (ARDS) is a life-threatening condition of the lung leading to a state of decreased lung compliance and blood oxygenation efficiency. The treatment of patients utilizes artificial ventilation, which has a tremendous impact on the lung’s sensitive microenvironment and can even lead to further damage in the form of ventilator induced lung injury (VILI). As a basis for the understanding of physiological processes occurring on the microscale of lung tissue, the alveolar tissue, contact free imaging can elucidate dynamic changes during artificial ventilation. The main interest focuses here on the rearrangement of alveolar geometry and ...

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    8. Corrections and improvements of lung imaging under Optical Coherence Tomography (OCT) (Thesis)

      Corrections and improvements of lung imaging under Optical Coherence Tomography (OCT)  (Thesis)

      Visualization and correct assessment of alveolar volume via intact lung imaging is important to study and assess respiratory mechanics. Optical Coherence Tomography (OCT), a real time imaging technique based on near-infrared interferometry, can image several layers of distal alveoli in intact, ex-vivo lung tissue. However optical effects associated with heterogeneity of lung tissue, including the refraction caused by air-tissue interfaces along alveoli and duct walls, and changes in speed of light as it travels through the tissue, result in inaccurate measurement of alveolar volume. Experimentally such errors have been difficult to analyze because of lack of ''ground truth,'' as the ...

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    9. Interventional Pulmonology: Focus on Pulmonary Diagnostics

      Interventional Pulmonology: Focus on Pulmonary Diagnostics

      Interventional pulmonology (IP) allows comprehensive assessment of patients with benign and malignant airway, lung parenchymal and pleural disease. This relatively new branch of pulmonary medicine utilises advanced diagnostic and therapeutic techniques to treat patients with pulmonary diseases. Endobronchial ultrasound revolutionized assessment of pulmonary nodules, mediastinal lymphadenopathy and lung cancer staging allowing minimally-invasive, highly accurate assessment of lung parenchymal and mediastinal disease, with both macro- and microscopic tissue characterization including molecular signature analysis. High spatial resolution, new endobronchial imaging techniques including Autofluorescence Bronchoscopy (ABI), Narrow Band Imaging (NBI), Optical Coherence Tomography and confocal microscopy enable detailed evaluation of airways with increasing ...

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    10. New Techniques for Optical and Molecular Visualization of Lung Cancer

      New Techniques for Optical and Molecular Visualization of Lung Cancer

      Current imaging techniques do not allow visualization of the histology of pulmonary lesions prior to biopsy and, thus, sampling errors may lead to incorrect diagnoses, optimal areas of a tumor may not be sampled for diagnosis and heterogeneous patterns within a single cancer having an impact on treatment may not be sampled. Several imaging modalities are under investigation to provide real-time in vivo histologic images with subcellular resolution, equivalent to traditional histologic sections, and potential identification of molecular targets in vivo, greatly enhancing biopsy procurement and possibly replacing traditional biopsy with “optical biopsy” in the future. Potential benefits of these ...

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    11. Three-dimensional simultaneous optical coherence tomography and confocal fluorescence microscopy for investigation of lung tissue

      Three-dimensional simultaneous optical coherence tomography and confocal fluorescence microscopy for investigation of lung tissue

      Although several strategies exist for a minimal-invasive treatment of patients with lung failure, the mortality rate of acute respiratory distress syndrome still reaches 30% at minimum. This striking number indicates the necessity of understanding lung dynamics on an alveolar level. To investigate the dynamical behavior on a microscale, we used three-dimensional geometrical and functional imaging to observe tissue parameters including alveolar size and length of embedded elastic fibers during ventilation. We established a combined optical coherence tomography (OCT) and confocal fluorescence microscopy system that is able to monitor the distension of alveolar tissue and elastin fibers simultaneously within three dimensions ...

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    12. Evaluation of optical reflectance techniques for imaging of alveolar structure

      Evaluation of optical reflectance techniques for imaging of alveolar structure

      Three-dimensional (3-D) visualization of the fine structures within the lung parenchyma could advance our understanding of alveolar physiology and pathophysiology. Current knowledge has been primarily based on histology, but it is a destructive two-dimensional (2-D) technique that is limited by tissue processing artifacts. Micro-CT provides high-resolution three-dimensional (3-D) imaging within a limited sample size, but is not applicable to intact lungs from larger animals or humans. Optical reflectance techniques offer the promise to visualize alveolar regions of the large animal or human lung with sub-cellular resolution in three dimensions. Here, we present the capabilities of three optical reflectance techniques, namely ...

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    13. Feature Of The Week 5/20/12: Dresden University of Technology Investigates Precision Lung Dynamics Using Four-Dimensional OCT

      Feature Of The Week 5/20/12: Dresden University of Technology Investigates Precision Lung Dynamics Using Four-Dimensional OCT

      The treatment of urgent lung diseases, such as the acute respiratory distress syndrome and the acute lung injury, requires the development of protective ventilation strategies with the help of numerical simulations. For this purpose, information about the structure of lung tissue and its dynamics is required on an alveolar level. Optical coherence tomography (OCT) can obtain high resolution cross-sectional and volumetric data of lung tissue using rodent models. Access to the lung tissue is obtained by preparing a transparent thorax window. In previous studies, OCT imaging was limited by the depth scan rate and three-dimensional information has been obtained by ...

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    14. Airway Imaging in Disease; Gimmick or Useful Tool?

      Airway Imaging in Disease; Gimmick or Useful Tool?

      Airway remodeling is an important pathophysiological mechanism in a variety of chronic airway diseases. Historically investigators have had to use invasive techniques such as histological examination of excised tissue to study airway wall structure. The last several years has seen a proliferation of relatively non-invasive techniques to assess the airway branching pattern, wall thickness and, more recently, airway wall tissue components. These methods include computed tomography, magnetic resonance imaging and optical coherence tomography. These new imaging technologies have become popular because in order to understand the physiology of lung disease it is important we understand the underlying anatomy. However, these ...

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    15. Optical coherence tomography in conjunction with bronchoscopy

      Optical coherence tomography in conjunction with bronchoscopy

      Objective: To evaluate the diagnostic accuracy of bronchoscopy in patients with clinical or radiological suspicion of tuberculosis who were unable to produce sputum or with negative sputum smear microscopy results. Methods: A prospective cross-sectional study involving 286 patients under clinical or radiological suspicion of having pulmonary tuberculosis and submitted to bronchoscopy-BAL and transbronchial biopsy (TBB). The BAL specimens were submitted to direct testing and culture for AFB and fungi, whereas the TBB specimens were submitted to histopathological examination. Results: Of the 286 patients studied, 225 (79%) were diagnosed on the basis of bronchoscopic findings, as follows: pulmonary tuberculosis, in 127 ...

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    16. Refractive errors and corrections for OCT images in an inflated lung phantom

      Refractive errors and corrections for OCT images in an inflated lung phantom

      Visualization and correct assessment of alveolar volume via intact lung imaging is important to study and assess respiratory mechanics. Optical Coherence Tomography (OCT), a real-time imaging technique based on near-infrared interferometry, can image several layers of distal alveoli in intact, ex vivo lung tissue. However optical effects associated with heterogeneity of lung tissue, including the refraction caused by air-tissue interfaces along alveoli and duct walls, and changes in speed of light as it travels through the tissue, result in inaccurate measurement of alveolar volume. Experimentally such errors have been difficult to analyze because of lack of ’ground truth,’ as the ...

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    17. Four-dimensional imaging of murine subpleural alveoli using high-speed optical coherence tomography

      Four-dimensional imaging of murine subpleural alveoli using high-speed optical coherence tomography

      The investigation of lung dynamics on alveolar scale is crucial for the understanding and treatment of lung diseases, such as acute lung injury and ventilator induced lung injury, and to promote the development of protective ventilation strategies. One approach to this is the establishment of numerical simulations of lung tissue mechanics where detailed knowledge about three-dimensional alveolar structure changes during the ventilation cycle is required. We suggest four-dimensional optical coherence tomography (OCT) imaging as a promising modality for visualizing the structural dynamics of single alveoli in subpleural lung tissue with high temporal resolution using a mouse model. A high-speed OCT ...

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    18. 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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    19. 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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    20. 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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    21. 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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    22. 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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    23. 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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    24. 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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    97-120 of 227 « 1 2 3 4 5 6 7 8 9 10 »
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