All Articles from Anthony M. D. Lee -Optical Coherence Tomography News

Articles from Anthony M. D. Lee

1-22 of 22
1. Depth-multiplexed optical coherence tomography dual-beam manually-actuated distortion-corrected imaging (DMDI) with a micromotor catheter
  
  Explore OSA | OSA Publishing Oct 27 2018
  
  We present a new micromotor catheter implementation of dual-beam manually-actuated distortion-corrected imaging (DMDI). The new catheter called a depth-multiplexed dual-beam micromotor catheter, or mDBMC, maintains the primary advantage of unlimited field-of-view distortion-corrected imaging along the catheter axis. The mDBMC uses a polarization beam splitter and cube mirror to create two beams that scan circularly with approximately constant separation at the catheter surface. This arrangement also multiplexes both imaging channels into a single optical coherence tomography channel by offsetting them in depth, requiring half the data bandwidth compared to previous DMDI demonstrations that used two parallel image acquisition systems. Furthermore, the ...
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  Mentions: British Columbia Cancer Agency Pierre M. Lane
2. Dual-beam manually actuated distortion-corrected imaging (DMDI): two dimensional scanning with a single-axis galvanometer
  
  Explore OSA | OSA Publishing Jul 10 2018 Probes
  
  We recently demonstrated a new two-dimensional imaging paradigm called dual-beam manually actuated distortion-corrected imaging (DMDI). This technique uses a single mechanical scanner and two spatially separated beams to determine relative sample velocity and simultaneously corrects image distortions due to manual actuation. DMDI was first demonstrated using a rotating dual-beam micromotor catheter. Here, we present a new implementation of DMDI using a single axis galvanometer to scan a pair of beams in approximately parallel lines onto a sample. Furthermore, we present a method for automated distortion correction based on frame co-registration between images acquired by the two beams. Distortion correction is ...
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  Mentions: British Columbia Cancer Agency Pierre M. Lane
3. Correction of motion artifacts in endoscopic optical coherence tomography and autofluorescence images based on azimuthal en face image registration
  
  Explore SPIE Digital Library Jan 9 2018 Cardiology
  
  We present a method for the correction of motion artifacts present in two- and three-dimensional in vivoendoscopic images produced by rotary-pullback catheters. This method can correct for cardiac/breathing-based motion artifacts and catheter-based motion artifacts such as nonuniform rotational distortion (NURD). This method assumes that en face tissue imaging contains slowly varying structures that are roughly parallel to the pullback axis. The method reduces motion artifacts using a dynamic time warping solution through a cost matrix that measures similarities between adjacent frames in en face images. We optimize and demonstrate the suitability of this method using a real and ...
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  Mentions: British Columbia Cancer Agency Stephen Lam Pierre M. Lane
4. Dual-beam manually-actuated distortion-corrected imaging (DMDI) with micromotor catheters
  
  Explore OSA | OSA Publishing Sep 11 2017
  
  e present a new paradigm for performing two-dimensional scanning called dual-beam manually-actuated distortion-corrected imaging (DMDI). DMDI operates by imaging the same object with two spatially-separated beams that are being mechanically scanned rapidly in one dimension with slower manual actuation along a second dimension. Registration of common features between the two imaging channels allows remapping of the images to correct for distortions due to manual actuation. We demonstrate DMDI using a 4.7 mm OD rotationally scanning dual-beam micromotor catheter (DBMC). The DBMC requires a simple, one-time calibration of the beam paths by imaging a patterned phantom. DMDI allows for distortion ...
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  Mentions: British Columbia Cancer Agency Pierre M. Lane
5. Reproducibility of optical coherence tomography airway imaging
  
  Explore OSA | OSA Publishing Oct 14 2015 Pulmonology
  
  Optical coherence tomography (OCT) is a promising imaging technique to evaluate small airway remodeling. However, the short-term insertion-reinsertion reproducibility of OCT for evaluating the same bronchial pathway has yet to be established. We evaluated 74 OCT data sets from 38 current or former smokers twice within a single imaging session. Although the overall insertion-reinsertion airway wall thickness (WT) measurement coefficient of variation (CV) was moderate at 12%, much of the variability between repeat imaging was attributed to the observer; CV for repeated measurements of the same airway (intra-observer CV) was 9%. Therefore, reproducibility may be improved by introduction of automated ...
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  Mentions: University of British Columbia Stephen Lam Harvey O. Coxson
6. Endoscopic Doppler optical coherence tomography and autofluorescence imaging of peripheral pulmonary nodules and vasculature
  
  Explore OSA | OSA Publishing Sep 30 2015 Oncology , Pulmonology
  
  We present the first endoscopic Doppler optical coherence tomography and co-registered autofluorescence imaging (DOCT-AFI) of peripheral pulmonary nodules and vascular networks in vivo using a small 0.9 mm diameter catheter. Using exemplary images from volumetric data sets collected from 31 patients during flexible bronchoscopy, we demonstrate how DOCT and AFI offer complementary information that may increase the ability to locate and characterize pulmonary nodules. AFI offers a sensitive visual presentation for the rapid identification of suspicious airway sites, while co-registered OCT provides detailed structural information to assess the airway morphology. We demonstrate the ability of AFI to visualize vascular ...
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  Mentions: British Columbia Cancer Agency Stephen Lam Pierre M. Lane
7. Wide-field in vivo oral OCT imaging
  
  Explore OSA | OSA Publishing Jul 26 2015
  
  We have built a polarization-sensitive swept source Optical Coherence Tomography (OCT) instrument capable of wide-field in vivo imaging in the oral cavity. This instrument uses a hand-held side-looking fiber-optic rotary pullback catheter that can cover two dimensional tissue imaging fields approximately 2.5 mm wide by up to 90 mm length in a single image acquisition. The catheter spins at 100 Hz with pullback speeds up to 15 mm/s allowing imaging of areas up to 225 mm 2 field-of-view in seconds. A catheter sheath and two optional catheter sheath holders have been designed to allow imaging at all locations ...
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  Mentions: University of British Columbia Lucas Cahill
8. Bronchial thermoplasty in asthma: 2-year follow-up using optical coherence tomography
  
  Explore European Respiratory Journal May 30 2015 Pulmonology
  
  Bronchial thermoplasty (BT) is a novel, nonpharmacological procedure for treatment of severe asthma. Recently, the Asthma Intervention Research 2 clinical trial demonstrated asthmatics had fewer hospitalisations following BT, which persisted 5 years after therapy [1]. However, it is well recognised that asthma is a heterogeneous disease with distinct asthma phenotypes and, not surprisingly, not all asthmatics in that trial benefited from BT [2].
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  Mentions: University of British Columbia Stephen Lam Peking University
9. Passive endoscopic polarization sensitive optical coherence tomography with completely fiber based optical components
  
  Explore Conference Proceedings Mar 8 2015 Gastroenterology
  
  Polarization Sensitive Optical Coherence Tomography (PSOCT) is a functional extension of Optical Coherence Tomography (OCT) that is sensitive to well-structured, birefringent tissue such as scars, smooth muscle and cartilage. In this work, we present a novel completely fiber based swept source PSOCT system using a fiber-optic rotary pullback catheter. This PSOCT implementation uses only passive optical components and requires no calibration while adding minimal additional cost to a standard structural OCT imaging system. Due to its complete fiber construction, the system can be made compact and robust, while the fiber-optic catheter allows access to most endoscopic imaging sites. The 1 ...
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  Mentions: University of British Columbia British Columbia Cancer Agency Stephen Lam
10. Doppler optical coherence tomography and co-registered autofluorescence imaging of peripheral lung cancer
  
  Explore Conference Proceedings Mar 8 2015 Oncology , Pulmonology
  
  Diagnosis of peripheral lung nodules is challenging because they are rarely visualized endobronchially. Imaging techniques such as endobronchial ultrasound (EBUS) are employed to improve tumor localization. The current EBUS probe provides limited nodule characterization and has an outer diameter of 1.4 mm that restricts access to small peripheral airways. We report a novel co-registered autofluoresence Doppler optical coherence tomography (AF/DOCT) system with a 0.9 mm diameter probe to characterize peripheral lung nodules prior to biopsy in vivo. Method: Patients referred for evaluation of peripheral lung nodules underwent bronchoscopy with examination of standard EBUS and the novel AF ...
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  Mentions: British Columbia Cancer Agency Stephen Lam Matthew Brenner
11. Optical coherence tomography and autofluorescence imaging of human tonsil
  
  Explore PLoS ONE Dec 30 2014 Otolaryngology
  
  For the first time, we present co-registered autofluorescence imaging and optical coherence tomography (AF/OCT) of excised human palatine tonsils to evaluate the capabilities of OCT to visualize tonsil tissue components. Despite limited penetration depth, OCT can provide detailed structural information about tonsil tissue with much higher resolution than that of computed tomography, magnetic resonance imaging, and Ultrasound. Different tonsil tissue components such as epithelium, dense connective tissue, lymphoid nodules, and crypts can be visualized by OCT. The co-registered AF imaging can provide matching biochemical information. AF/OCT scans may provide a non-invasive tool for detecting tonsillar cancers and for ...
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  Mentions: University of British Columbia British Columbia Cancer Agency Pierre M. Lane
12. Fiber-Based Polarization Diversity Detection for Polarization-Sensitive Optical Coherence Tomography
  
  Explore MDPI Open Access Journals Platform Oct 5 2014
  
  We present a new fiber-based polarization diversity detection (PDD) scheme for polarization sensitive optical coherence tomography (PSOCT). This implementation uses a new custom miniaturized polarization-maintaining fiber coupler with single mode (SM) fiber inputs and polarization maintaining (PM) fiber outputs. The SM fiber inputs obviate matching the optical lengths of the two orthogonal OCT polarization channels prior to interference while the PM fiber outputs ensure defined orthogonal axes after interference. Advantages of this detection scheme over those with bulk optics PDD include lower cost, easier miniaturization, and more relaxed alignment and handling issues. We incorporate this PDD scheme into a galvanometer-scanned ...
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  Mentions: British Columbia Cancer Agency Stephen Lam Pierre M. Lane
13. A high-efficiency fiber-based imaging system for co-registered autofluorescence and optical coherence tomography
  
  Explore opticsinfobase.org Aug 6 2014 Pulmonology
  
  We present a power-efficient fiber-based imaging system capable of co-registered autofluorescence imaging and optical coherence tomography (AF/OCT). The system employs a custom fiber optic rotary joint (FORJ) with an embedded dichroic mirror to efficiently combine the OCT and AF pathways. This three-port wavelength multiplexing FORJ setup has a throughput of more than 83% for collected AF emission, significantly more efficient compared to previously reported fiber-based methods. A custom 900 µm diameter catheter ‒ consisting of a rotating lens assembly, double-clad fiber (DCF), and torque cable in a stationary plastic tube ‒ was fabricated to allow AF/OCT imaging of small airways ...
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  Mentions: Victor X. D. Yang British Columbia Cancer Agency Stephen Lam
14. Validation of Airway Wall Measurements by Optical Coherence Tomography in Porcine Airways
  
  Explore PLoS ONE Jun 20 2014 Pulmonology
  
  Examining and quantifying changes in airway morphology is critical for studying longitudinal pathogenesis and interventions in diseases such as chronic obstructive pulmonary disease and asthma. Here we present fiber-optic optical coherence tomography (OCT) as a nondestructive technique to precisely and accurately measure the 2-dimensional cross-sectional areas of airway wall substructure divided into the mucosa (WA muc ), submucosa (WA sub ), cartilage (WA cart ), and the airway total wall area (WAt). Porcine lung airway specimens were dissected from freshly resected lung lobes (N = 10). Three-dimensional OCT imaging using a fiber-optic rotary-pullback probe was performed immediately on airways greater than 0.9 mm ...
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  Mentions: British Columbia Cancer Agency Stephen Lam Lightlab C7 XR OCT Imaging System
15. Fiber-optic polarization diversity detection for rotary probe optical coherence tomography
  
  Explore opticsinfobase.org Jun 11 2014 Probes
  
  We report a polarization diversity detection scheme for optical coherence tomography with a new, custom, miniaturized fiber coupler with single mode (SM) fiber inputs and polarization maintaining (PM) fiber outputs. The SM fiber inputs obviate matching the optical lengths of the X and Y OCT polarization channels prior to interference and the PM fiber outputs ensure defined X and Y axes after interference. Advantages for this scheme include easier alignment, lower cost, and easier miniaturization compared to designs with free-space bulk optical components. We demonstrate the utility of the detection system to mitigate the effects of rapidly changing polarization states ...
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  Mentions: Victor X. D. Yang British Columbia Cancer Agency Stephen Lam
16. Coregistered autofluorescence-optical coherence tomography imaging of human lung sections
  
  Explore SPIE | Journal Apr 2 2014 Pulmonology
  
  Autofluorescence (AF) imaging can provide valuable information about the structural and metabolic state of tissue that can be useful for elucidating physiological and pathological processes. Optical coherence tomography (OCT) provides high resolution detailed information about tissue morphology. We present coregistered AF-OCT imaging of human lung sections. Adjacent hematoxylin and eosin stained histological sections are used to identify tissue structures observed in the OCT images. Segmentation of these structures in the OCT images allowed determination of relative AF intensities of human lung components. Since the AF imaging was performed on tissue sections perpendicular to the airway axis, the results show the ...
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  Mentions: British Columbia Cancer Agency Stephen Lam Pierre M. Lane
17. High speed, wide velocity dynamic range Doppler optical coherence tomography (Part IV): split spectrum processing in rotary catheter probes
  
  Explore opticsinfobase.org Apr 1 2014 Probes
  
  We report a technique for blood flow detection using split spectrum Doppler optical coherence tomography (ssDOCT) that shows improved sensitivity over existing Doppler OCT methods. In ssDOCT, the Doppler signal is averaged over multiple sub-bands of the interferogram, increasing the SNR of the Doppler signal. We explore the parameterization of this technique in terms of number of sub-band windows, width and overlap of the windows, and their effect on the Doppler signal to noise in a flow phantom. Compared to conventional DOCT, ssDOCT processing has increased flow sensitivity. We demonstrate the effectiveness of ssDOCT in-vivo for intravascular flow detection within ...
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  Mentions: University of Toronto Sunnybrook Health Sciences Centre Victor X. D. Yang
18. Automated segmentation of porcine airway wall layers using optical coherence tomography: comparison with manual segmentation and histology
  
  Explore Conference Proceedings Mar 8 2014 Pulmonology
  
  The objective was to develop an automated optical coherence tomography (OCT) segmentation method. We evaluated three ex-vivo porcine airway specimens; six non-sequential OCT images were selected from each airway specimen. Histology was also performed for each airway and histology images were co-registered to OCT images for comparison. Manual segmentation of the airway luminal area, mucosa area, submucosa area and the outer airway wall area were performed for histology and OCT images. Automated segmentation of OCT images employed a despecking filter for pre-processing, a hessian-based filter for lumen and outer airway wall area segmentation, and K-means clustering for mucosa and submucosa ...
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  Mentions: University of British Columbia British Columbia Cancer Agency Stephen Lam
19. Multimodal tissue imaging: using coregistered optical tomography data to estimate tissue autofluorescence intensity change due to scattering and absorption by neoplastic epithelial cells
  
  Explore SPIE | Journal Oct 12 2013 Oncology
  
  Autofluorescence (AF) imaging provides valuable information about the structural and chemical states of tissue that can be used for early cancer detection. Optical scattering and absorption of excitation and emission light by the epithelium can significantly affect observed tissue AF intensity. Determining the effect of epithelial attenuation on the AF intensity could lead to a more accurate interpretation of AF intensity. We propose to use optical coherence tomography coregistered with AF imaging to characterize the AF attenuation due to the epithelium. We present imaging results from three vital tissue models, each consisting of a three-dimensional tissue culture grown from one ...
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  Mentions: British Columbia Cancer Agency Stephen Lam Pierre M. Lane
20. In vivo lung microvasculature visualized in three dimensions using fiber-optic color Doppler optical coherence tomography
  
  Explore SPIE | Journal Apr 30 2013 Pulmonology
  
  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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  Mentions: Victor X. D. Yang British Columbia Cancer Agency Stephen Lam
21. Lung vasculature imaging using speckle variance optical coherence tomography
  
  Explore SPIE Digital Library Feb 9 2012 Oncology , Pulmonology
  
  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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  Mentions: Victor X. D. Yang British Columbia Cancer Agency Stephen Lam
22. Frontiers in Bronchoscopic Imaging
  
  Explore Wiley Online Library Dec 1 2011 Pulmonology
  
  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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  Mentions: University of British Columbia British Columbia Cancer Agency Stephen Lam
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