1. Articles in category: Pulmonology

    193-216 of 243 « 1 2 ... 6 7 8 9 10 11 »
    1. Airway Narrowing Assessed by Anatomical Optical Coherence Tomography In Vitro: Dynamic Airway Wall Morphology and Function

      Airway Narrowing Assessed by Anatomical Optical Coherence Tomography In Vitro: Dynamic Airway Wall Morphology and Function

      Regulation of airway caliber by lung volume or bronchoconstrictor stimulation is dependent on physiological, structural and mechanical events within the airway wall, including airway smooth muscle (ASM) contraction, deformation of the mucosa and cartilage, and tensioning of elastic matrices linking wall components. Despite close association between events in the airway wall and the resulting airway caliber these have typically been studied separately: the former primarily using histological approaches, the latter with a range of imaging modalities. We describe a new optical technique, anatomical optical coherence tomography (aOCT), which allows changes at the luminal surface (airway caliber) to be temporally related ...

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    2. Simultaneous three-dimensional optical coherence tomography and intravital microscopy for imaging subpleural pulmonary alveoli in isolated rabbit lungs

      There is a growing interest in analyzing lung mechanics at the level of the alveoli in order to understand stress-related pathogenesis and possibly avoid ventilator associated lung injury. Emerging quantitative models to simulate fluid mechanics and the associated stresses and strains on delicate alveolar walls require realistic quantitative input on alveolar geometry and its dynamics during ventilation. Here, three-dimensional optical coherence tomography (OCT) and conventional intravital microscopy are joined in one setup to investigate the geometric changes of subpleural alveoli during stepwise pressure increase and release in an isolated and perfused rabbit lung model. We describe good qualitative agreement and ...
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    3. Comparison of two in vivo microscopy techniques to visualize alveolar mechanics

      Objective In conventional in vivo microscopy, a three dimensional illustration of tissue is lacking. Concerning the microscopic analysis of the pulmonary alveolar network, surgical preparation of the thorax and fixation of the lung is required to place the microscope’s objective. These effects may have influence on the mechanical behaviour of alveoli. Relatively new methods exist for in vivo microscopy being less invasive and enabling an observation without fixation of the lung. The aim of this study was to compare a fibered confocal laser scanning microscopy (FCLSM) with optical coherence tomography (OCT) in a mouse and a rabbit model. Moreover ...
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    4. Developmental Aspects of the Upper Airway

      The upper airway serves three important functions: respiration, swallowing, and speech. During development it undergoes significant structural and functional changes that affect its size, shape, and mechanical properties. Abnormalities of the upper airway require prompt attention, because these often alter ventilatory patterns and gas exchange, particularly during sleep when upper airway motor tone and ventilatory drive are diminished. Recognizing the relationship of early life events to lung health and disease, the National Heart, Lung, and Blood Institute (NHLBI), with cofunding from the Office of Rare Diseases (ORD), convened a workshop of extramural experts, from many disciplines. The objective of the ...
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    5. Detection and monitoring of early airway injury effects of half-mustard (2-chloroethylethylsulfide) exposure using high-resolution optical coherence tomography

      Optical coherence tomography (OCT) is a noninvasive, high-resolution imaging technology capable of delivering real-time, near-histologic images of tissues. Mustard gas is a vesicant-blistering agent that can cause severe and lethal damage to airway and lungs. The ability to detect and assess airway injury in the clinical setting of mustard exposure is currently limited. The purpose of this study is to assess the ability to detect and monitor progression of half-mustard [2-chloroethylethylsulfide (CEES)] airway injuries with OCT techniques. A ventilated rabbit mustard exposure airway injury model is developed. A flexible fiber optic OCT probe is introduced into the distal trachea to ...
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    6. Proceedings of the American Thoracic Society: Chair's Summary

      Proceedings of the American Thoracic Society: Chair's Summary
      Many imaging modalities can be used for visualization of target molecular signatures in the lungs, yet no single modality offers a winning combination of maximal spatial resolution, specificity, selectivity, sensitivity, signal penetration (see articles by Kauczor and colleagues, Emami and colleagues, Divgi, and Coxson and Lam, pages 439–443, this issue). Selection of the best modality is further complicated by practical issues of affordability, safety, and availability (e.g., generator versus cyclotron-produced radioisotopes). For example, the excellent structural resolution afforded by MRI (22) is inferior in its sensitivity to other modalities, like PET and SPECT for molecular imaging. The difficulties ...
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    7. Quantitative Assessment of the Airway Wall Using Computed Tomography and Optical Coherence Tomography

      Ever since the site and nature of airflow obstruction in chronic obstructive pulmonary disease was described by Hogg, Thurlbeck, and Macklem, investigators have been looking for methods to noninvasively measure the airway wall dimensions. Recent advances in computed tomography technology and new computer algorithms have made it possible to visualize and measure the airway wall and lumen without the need for tissue. However, while there is great hope for computed tomographic assessment of airways, it is well known that the spatial resolution does not allow small airways to be visualized and there are still concerns about the sensitivity of these ...

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    8. Alveolar dynamics in acute lung injury: Heterogeneous distension rather than cyclic opening and collapse *

      Objectives: To analyze alveolar dynamics in healthy and acid-injured lungs of ventilated mice. Protective ventilation is potentially lifesaving in patients with acute lung injury. However, optimization of ventilation strategies is hampered by an incomplete understanding of the effects of mechanical ventilation at the alveolar level. Design: In anesthetized and ventilated Balb/c mice, subpleural alveoli were visualized by darkfield intravital microscopy and optical coherence tomography. Setting: Animal research laboratory. Subjects: Male Balb/c mice. Interventions: Lung injury was induced by intratracheal instillation of hydrochloric acid. In control animals and mice with lung injury, ventilation pressures were varied between 0 and ...
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    9. Three-dimensional measurement of alveolar airspace volumes in normal and emphysematous lungs using micro-CT

      In pulmonary emphysema, the alveolar structure progressively breaks down via a three-dimensional (3D) process that leads to airspace enlargement. The characterization of such structural changes has, however, been based on measurements from two-dimensional (2D) tissue sections or estimates of 3D structure from 2D measurements. In this study, we developed a novel silver staining method for visualizing tissue structure in 3D using micro-computed tomographic (CT) imaging, which showed that at 30 cmH20 fixing pressure, the mean alveolar airspace volume increased from 0.12 nl in normal mice to 0.44 nl and 2.14 nl in emphysematous mice, respectively, at 7 ...
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    10. New and Current Clinical Imaging Techniques To Study Chronic Obstructive Pulmonary Disease

      Chronic obstructive pulmonary disease (COPD) is a heterogeneous disease, characterized by both small airway and parenchymal abnormalities. There is increasing evidence to suggest that these two morphologic phenotypes, while related, may have different clinical presentations, prognosis and therapeutic responses to medications. With the advent of novel imaging modalities, it is now possible to evaluate these two morphologic phenotypes in large clinical studies using non or minially invasive methods such as computed tomography (CT), magentic resonance imaging (MRI) and optical coherence tomography (OCT). In this paper, we provide a pictorial overview of these modalities in the context of COPD and discuss ...

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    11. Endoscopic low coherence interferometry in upper airways

      We introduce Endoscopic Low Coherence Interferometry to obtain topology of upper airways through commonly used rigid endoscopes. Quantitative dimensioning of upper airways pathologies is crucial to provide maximum health recovery chances, for example in order to choose the correct stent to treat endoluminal obstructing pathologies. Our device is fully compatible with procedures used in day-to-day examinations and can potentially be brought to bedside. Besides this, the approach described here can be almost straightforwardly adapted to other endoscopy-related field of interest, such as gastroscopy and arthroscopy. The principle of the method is first exposed, then filtering procedure used to extract the ...
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    12. 4D in vivo imaging of subpleural lung parenchyma by swept source optical coherence tomography

      4D in vivo imaging of subpleural lung parenchyma by swept source optical coherence tomography
      In this feasibility study we present a method for 4D imaging of healthy and injured subpleural lung tissue in a mouse model. We used triggered swept source optical coherence tomography with an A-scan frequency of 20 kHz to image murine subpleural alveoli during the ventilation cycle. The data acquisition was gated to the pulmonary airway pressure to take one B-scan in each ventilation cycle for different pressure levels. The acquired B-scans were combined offline to one C-scan for each pressure level. Due to the high acquisition rate of the used optical coherence tomography system, we are also able to perform ...
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    13. Quantifying tracheobronchial tree dimensions: methods, limitations and emerging techniques

      The ability to measure airway dimensions is important for clinicians, interventional bronchoscopists and researchers in order to accurately quantify structural abnormalities and track their changes over time or in response to treatment. Most quantitative airway measurements are based on X-ray computed tomography and, more recently, on multidetector computed tomography. Quantitative bronchoscopic techniques have also been developed, although these are less widely employed. Emerging techniques, including magnetic resonance imaging, endoscopic optical coherence tomography, endobronchial ultrasound and confocal endomicroscopy, provide new research tools with potential clinical applications. An understanding of issues related to the acquisition, processing and analysis of images, and how ...
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    14. Multimodality bonchoscopic imaging of tracheopathica osteochondroplastica

      Results of a commercial optical coherence tomography system used as part of a multimodality diagnostic bronchoscopy platform are presented for a 61-year-old patient with central airway obstruction from tracheopathica osteochondroplastica. Comparison to results of white-light bronchoscopy, histology, ... [J. Biomed. Opt. 14, 034035 (2009)] published Thu Jun 25, 2009.
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    15. A Method Of Providing Quantitative Information About The Lower Airways Of A Lung (Wo 2009/059368)

      A Method Of Providing Quantitative Information About The Lower Airways Of A Lung (Wo 2009/059368)
      The present disclosure provides a method of providing quantitative information about a property of the lower airways of a lung using optical coherence tomography. The method comprises inserting a probe head of an anatomical optical coherence tomography device into the lower airways. Further, the method comprises directing light to, and receiving reflected light from, an internal wall portion of the lower airways. The light is suitable for optical coherence tomography. An electronic signal indicative of a phase difference between reference light and the received light is then generated. In addition the method comprises determining a quantity associated with a property ...
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    16. Respiratory gating of anatomical optical coherence tomography images of the human airway

      Respiratory gating of anatomical optical coherence tomography images of the human airway
      Anatomical optical coherence tomography (aOCT) is a longrange endoscopic imaging modality capable of quantifying size and shape of the human airway. A challenge to its in vivo application is motion artifact due to respiratory-related movement of the airway walls. This paper represents the first demonstration of respiratory gating of aOCT airway data, and introduces a novel error measure to guide appropriate parameter selection. Results indicate that at least four gates per respiratory cycle should be used, with only minor improvements as the number of gates is further increased. It is shown that respiratory gating can substantially improve the quality of ...
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    17. Gender Differences in Airway Wall Measurements with Optical Coherence Tomography (OCT).

      Purpose: To examine the difference in the relationship between airway wall dimensions and lung function in male and female smokers. Methods: 35 male and 18 female subjects from the BC Lung Health Cohort, who underwent OCT imaging and spirometry, were studied. OCT images, acquired at the time of bronchoscopy, were converted to digital images at 0.5s intervals using frame capture software. Airways were measured using ImageJ (NIH) image analysis software on 5 consecutive frames when the airway attained the diameter of the OCT probe (1.5mm) Lung function, represented by FEV1% predicted, was plotted against the wall area percent ...

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    18. Inter- and Intra-Observer Variability in Measurements of Airways Using Optical Coherence Tomography (OCT).

      Purpose: To devise a protocol for the measurement of airways using optical coherence tomography (OCT) with acceptable inter− and intra−observer variability. Methods: 59 subjects from the British Columbia Lung Health Cohort who underwent OCT imaging were studied. OCT images, acquired at the time of bronchoscopy were converted to digital images at 0.5s intervals using frame capture software. Airways were measured using ImageJ (NIH) image analysis software on 5 consecutive frames when the probe was located in an airway with the same diameter as the probe (1.5mm). The airway lumen and wall areas were measured using the circular ...

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    19. Feature Of The Week 3/1/09: Optical Coherence Tomography to Improve Diagnostic and Therapeutic Bronchoscopy

      Feature Of The Week 3/1/09: Optical Coherence Tomography to Improve Diagnostic and Therapeutic Bronchoscopy
      Feature Of The Week 3/1/09: Ophthalmic and Cardiovascular applications are two of the leading commercialized areas of OCT. There are an ever increasing number of applications poised to make the successful transition to commercialization thanks to progress by researchers around the world. One such area is Bronchoscopy where, for example, researchers at University of Western Australia and Sir Charles Gairdner Hospital have been very active. A recent publication by Jonathan P. Williamson et al presents new work on anatomical optical coherence tomography to accurately measure diameter and lumen area of the central airways during bronchoscopy. This study describes ...
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