1. 1-7 of 7
    1. Optical coherence tomography in the assessment of acute changes in cutaneous vascular diameter induced by heat stress

      Optical coherence tomography in the assessment of acute changes in cutaneous vascular diameter induced by heat stress

      There are limited imaging technologies available that can accurately assess or provide surrogate markers of the in vivo cutaneous microvessel network in humans. In this study, we establish the use of optical coherence tomography (OCT) as a novel imaging technique to assess acute changes in cutaneous microvessel area density and diameter in humans. OCT speckle decorrelation images of the skin on the ventral side of the forearm up to a depth of 500 μm were obtained prior to and following 20-25 mins of lower limb heating in eight healthy males (30.3±7.6 yrs). Skin red blood cell flux ...

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    2. Does smooth muscle in an intact airway undergo length adaptation during a sustained change in transmural pressure?

      Does smooth muscle in an intact airway undergo length adaptation during a sustained change in transmural pressure?

      In isolated airway smooth muscle (ASM) strips, an increase or decrease in ASM length away from its current optimum length causes an immediate reduction in force production followed by a gradual time-dependent recovery in force, a phenomenon termed length adaptation. In situ, length adaptation may be initiated by a change in transmural pressure (Ptm), which is a primary physiological determinant of ASM length. The present study sought to determine the effect of sustained changes in Ptm and therefore, ASM perimeter, on airway function. We measured contractile responses in whole porcine bronchial segments in vitro before and after a ...

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    3. Quantitative assessment of muscle damage in the mdx mouse model of Duchenne muscular dystrophy using polarization-sensitive optical coherence tomography

      Quantitative assessment of muscle damage in the mdx mouse model of Duchenne muscular dystrophy using polarization-sensitive optical coherence tomography

      Minimally invasive, high-resolution imaging of muscle necrosis has the potential to aid in the assessment of diseases such as Duchenne muscular dystrophy. Undamaged muscle tissue possesses high levels of optical birefringence due to its anisotropic ultrastructure, and this birefringence decreases when the tissue undergoes necrosis. In this study, we present a novel technique to image muscle necrosis using polarization-sensitive optical coherence tomography (PS-OCT). From PS-OCT scans, our technique is able to quantify the birefringence in muscle tissue, generating an image indicative of the tissue ultrastructure, with areas of abnormally low birefringence indicating necrosis. The technique is demonstrated on excised skeletal ...

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    4. Static and dynamic imaging of alveoli using optical coherence tomography needle probes

      Static and dynamic imaging of alveoli using optical coherence tomography needle probes

      Imaging of alveoli in situ has for the most part been infeasible due to the high resolution required to discern individual alveoli and limited access to alveoli beneath the lung surface. In this study, we present a novel technique to image alveoli using optical coherence tomography (OCT). We propose the use of OCT needle probes, where the distal imaging probe has been miniaturized and encased within a hypodermic needle (as small as 30-gauge, outer diameter 310 μm), allowing insertion deep within the lung tissue with minimal tissue distortion. Such probes enable imaging at a resolution of ~12 μm within a ...

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    5. 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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    6. 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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    7. 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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    1-7 of 7
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