1. Stephen Lam

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    1. Mentioned In 14 Articles

    2. In vivo lung microvasculature visualized in three dimensions using fiber-optic color Doppler optical coherence tomography

      In vivo lung microvasculature visualized in three dimensions using fiber-optic color Doppler optical coherence tomography

      For the first time, the use of fiber-optic color Doppler optical coherence tomography (CDOCT) to map in vivo the three-dimensional (3-D) vascular network of airway segments in human lungs is demonstrated. Visualizing the 3-D vascular network in the lungs may provide new opportunities for detecting and monitoring lung diseases such as asthma, chronic obstructive pulmonary disease, and lung cancer. Our CDOCT instrument employs a rotary fiber-optic probe that provides simultaneous two-dimensional (2-D) real-time structural optical coherence tomography (OCT) and CDOCT imaging at frame rates up to 12.5 frames per second. Controlled pullback of the probe allows 3-D vascular mapping ...

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    3. Interventions in Pulmonary Medicine (Book)

      Interventions in Pulmonary Medicine (Book)

      Optical coherence tomography (OCT) is a promising technique for clinical diagnosis of various types of tissue, because high-resolution tomography is easily obtained by its compact imaging optics. The fundamental principles of OCT evolved from optical one-dimensional low-coherence reflectometry, which uses a Michelson interferometer and a broadband light source. Due to the additional transverse scanning (B-scan), two-dimensional imaging was obtained, and this technique was named OCT by Fujimoto and rapidly expanded to numerous biomedical and clinical applications

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    4. 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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    5. 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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    6. 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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    7. 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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    8. 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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    9. In vivo Optical Coherence Tomography Imaging of Preinvasive Bronchial Lesions

      ...d Surgery, International University of Health and Welfare, Mita Hospital, Tokyo, Japan Requests for reprints: Stephen Lam, Cancer Imaging Department, British Columbia Cancer Agency, 675 West 10 Avenue, Vancouver, British...
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    10. Airway Wall Thickness Assessed Using Computed Tomography and Optical Coherence Tomography

      Airway Wall Thickness Assessed Using Computed Tomography and Optical Coherence Tomography

      Rationale: Computed tomography (CT) has been shown to reliably measure the airway wall dimensions of medium to large airways. Optical coherence tomography (OCT) is a promising new micron-scale resolution imaging technique that can image small airways 2 mm in diameter or less. Objectives: To correlate OCT measurements of airway dimensions with measurements assessed using CT scans and lung function. Methods: Forty-four current and former smokers received spirometry, CT scans, and OCT imaging at the time of bronchoscopy. Specific bronchial segments were identified and measured using the OCT images and three-dimensional reconstructions of the bronchial tree using CT. Measurements and Main ...

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    11. Apparatus for in vivo imaging of the respiratory tract and other internal organs

      Apparatus for acquiring in vivo images of a site of interest within the internal organs of a body. The apparatus includes an elongate, flexible catheter. The catheter is introducible into the body and has a first end that remains external to the body and a second and positionable adjacent the site of interest. A movable scanning unit having at least one sensor for acquiring images is housed adjacent the second end of the catheter. There is a drive mechanism to control movement of the movable scanning unit from the first external end of the catheter to acquire multiple images of ...
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    12. 1-14 of 14
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  2. About Stephen Lam

    Stephen Lam

    Stephen Lam is with the Cancer Imaging Department at the  British Columbia Cancer Agency in Canada.