1. Articles from Shuo Tang

    1-15 of 15
    1. Detecting human articular cartilage degeneration in its early stage with polarization-sensitive optical coherence tomography

      Detecting human articular cartilage degeneration in its early stage with polarization-sensitive optical coherence tomography

      Detecting articular cartilage (AC) degeneration in its early stage plays a critical role in the diagnosis and treatment of osteoarthritis (OA). Polarization-sensitive optical coherence tomography (PS-OCT) is sensitive to the alteration and disruption of collagen organization that happens during OA progression. This study proposes an effective OA evaluating method based on PS-OCT imaging. A slope-based analysis is applied on the phase retardation images to segment articular cartilage into three zones along the depth direction. The boundaries and birefringence coefficients (BRCs) of each zone are quantified. Two parameters, namely phase homogeneity index (PHI) and zonal distinguishability ( D z), are further developed ...

      Read Full Article
    2. Slope-based segmentation of articular cartilage using polarization-sensitive optical coherence tomography phase retardation image

      Slope-based segmentation of articular cartilage using polarization-sensitive optical coherence tomography phase retardation image

      A segmentation method based on phase retardation measurements from polarization-sensitive optical coherence tomography (PS-OCT) is developed to differentiate the structural zones of articular cartilage. The organization of collagen matrix in articular cartilage varies over the different structural zones, generating different tissue birefringence. Analyzing the slope of the accumulated phase retardation at different depths can detect the variation in tissue birefringence and be used to segment the structural zones. The method is validated on phantoms composed of layers of different materials. Articular cartilage samples from adult swine are segmented with the method. The characteristics in each segmented zone are also examined ...

      Read Full Article
    3. Correlation between polarization sensitive optical coherence tomography and SHG microscopy in articular cartilage

      Correlation between polarization sensitive optical coherence tomography and SHG microscopy in articular cartilage

      Polarization-sensitive optical coherence tomography (PS-OCT) and second harmonic generation (SHG) microscopy are two imaging modalities with different resolutions, field-of-views (FOV), and contrasts, while they both have the capability of imaging collagen fibers in biological tissues. PS-OCT can measure the tissue birefringence which is induced by highly organized fibers while SHG can image the collagen fiber organization with high resolution. Articular cartilage, with abundant structural collagen fibers, is a suitable sample to study the correlation between PS-OCT and SHG microscopy. Qualitative conjecture has been made that the phase retardation measured by PS-OCT is affected by the relationship between the collagen fiber ...

      Read Full Article
    4. Usage of polarization-sensitive optical coherence tomography for investigation of collagen cross-linking

      Usage of polarization-sensitive optical coherence tomography for investigation of collagen cross-linking

      To investigate morphological alternation in corneal stroma induced by collagen cross-linking (CXL) treatment, polarization-sensitive optical coherence tomography (PS-OCT) capable of providing scattering, phase retardation, and degree of polarization uniformity (DOPU) images were employed on fresh bovine cornea. Significant corneal thickness reduction was observed after the CXL procedure, and its variation was quantitatively analyzed. From the scattering contrast, a hyperscattering region was observed in the anterior of the cornea immediately after the CXL procedure and its range increased with time. Within the scattering region, a slow increase was observed in the phase retardation image, and a discriminable characteristic was found in ...

      Read Full Article
    5. Cornea characterization using a combined multiphoton microscopy and optical coherence tomography system

      Cornea characterization using a combined multiphoton microscopy and optical coherence tomography system

      We present a multimodal imaging system which combines multiphoton microscopy and optical coherence tomography to visualize the morphological structures, and to quantify the refractive index (RI) and thickness of cornea. The morphological similarities and differences at different corneal layers across various species are identified. In the piscine and human corneas, the stromata exhibit thin fibers that indicate an overall collagen direction. Human corneas display collagen micro-folds which cause increased light attenuation. In the murine, porcine and bovine corneas, the stromata show interwoven collagen patterns. The Bowman’s layer and the Descemet’s membrane are also distinguished in some species. The ...

      Read Full Article
    6. Three-dimensional volumetric human meibomian gland investigation using polarization-sensitive optical coherence tomography

      Three-dimensional volumetric human meibomian gland investigation using polarization-sensitive optical coherence tomography

      In this study, polarization-sensitive optical coherence tomography (PS-OCT) capable of providing polarization contrasts such as phase retardation and degree of polarization uniformity (DOPU) was used for visualizing human meibomian glands (MGs) and investigating morphological characteristics of them. Especially, with the help of the DOPU contrast, MGs were exclusively extracted from the volumetric OCT image. In vivo PS-OCT measurements were performed on the upper eyelids of different age groups. From these measurements, different age-dependent aspects of the MG structure were also observed. Based on these observations, it can be inferred that the PS-OCT system has the potential for clinical diagnosis and ...

      Read Full Article
    7. Advanced multi-contrast Jones matrix optical coherence tomography for Doppler and polarization sensitive imaging

      Advanced multi-contrast Jones matrix optical coherence tomography for Doppler and polarization sensitive imaging

      An advanced version of Jones matrix optical coherence tomography (JMT) is demonstrated for Doppler and polarization sensitive imaging of the posterior eye. JMT is capable of providing localized flow tomography by Doppler detection and investigating the birefringence property of tissue through a three-dimensional (3-D) Jones matrix measurement. Owing to an incident polarization multiplexing scheme based on passive optical components, this system is stable, safe in a clinical environment, and cost effective. Since the properties of this version of JMT provide intrinsic compensation for system imperfection, the system is easy to calibrate. Compared with the previous version of JMT, this advanced ...

      Read Full Article
    8. Tri-modal microscopy with multiphoton and optical coherence microscopy/tomography for multi-scale and multi-contrast imaging

      Tri-modal microscopy with multiphoton and optical coherence microscopy/tomography for multi-scale and multi-contrast imaging

      Multi-scale multimodal microscopy is a very useful technique by providing multiple imaging contrasts with adjustable field of views and spatial resolutions. Here, we present a tri-modal microscope combining multiphoton microscopy (MPM), optical coherence microscopy (OCM) and optical coherence tomography (OCT) for subsurface visualization of biological tissues. The advantages of the tri-modal system are demonstrated on various biological samples. It enables the visualization of multiple intrinsic contrasts including scattering, two-photon excitation fluorescence (TPEF), and second harmonic generation (SHG). It also enables a rapid scanning over a large tissue area and a high resolution zoom-in for cellular-level structures on regions of interest ...

      Read Full Article
    9. Corneal imaging and refractive index measurement using a combined multiphoton microscopy and optical coherence tomography system

      Corneal imaging and refractive index measurement using a combined multiphoton microscopy and optical coherence tomography system

      Refractive index (RI) is the optical property of a medium that describes its ability to bend incident light. The corneal refractive index is an especially important measurement in corneal and intraocular refractive surgery where its precise estimation is necessary to obtain accurate surgical outcomes. In this study, we calculated the corneal RI using a combined multiphoton microscopy (MPM) and optical coherence tomography (OCT) system. MPM excites and detects nonlinear signals including two photon excitation fluorescence (TPEF) and second harmonic generation (SHG). TPEF signals are observed from NADH in the cytoplasm, allowing MPM to image the cellular structures in the corneal ...

      Read Full Article
    10. Characterizing refractive index and thickness of biological tissues using combined multiphoton microscopy and optical coherence tomography

      Characterizing refractive index and thickness of biological tissues using combined multiphoton microscopy and optical coherence tomography

      We present a noninvasive method for characterizing the refractive index (RI) and thickness distribution in biological tissues using a combined multiphoton microscopy (MPM) and optical coherence tomography (OCT) system. Tissue layers are distinguished by the MPM and OCT images, and the RI and thickness of each layer are determined by analyzing the co-registered MPM and OCT images. The precision of this method is evaluated on four standard samples which are water, air, immersion oil and cover glass. Precision of within ~1% error compared to reference values is obtained. Biological tissue measurement is demonstrated on fish cornea. Three layers are detected ...

      Read Full Article
    11. Multimodal optical imaging with multiphoton microscopy and optical coherence tomography

      Multimodal optical imaging with multiphoton microscopy and optical coherence tomography

      Two types of combined multiphoton microscopy and optical coherence tomography (MPM/OCT) are compared for multimodal optical imaging. Single-scale multiphoton microscopy and optical coherence microscopy (MPM/OCM) is shown to acquire multiple contrasts from MPM and OCT simultaneously. Multi-scale MPM/OCT is shown to provide multiple field-of-views (FOVs), where OCT provides tissue level imaging and MPM provides cellular level imaging. In both types, the MPM includes two channels which are two-photon excited fluorescence (TPEF) and second harmonic generation (SHG). Representative images using each system are demonstrated on biological specimens. A detailed comparison of the two types of MPM/OCT shows ...

      Read Full Article
    12. Selection of convolution kernel in non-uniform fast Fourier transform for Fourier domain optical coherence tomography

      Selection of convolution kernel in non-uniform fast Fourier transform for Fourier domain optical coherence tomography
      Gridding based non-uniform fast Fourier transform (NUFFT) has recently been shown as an efficient method of processing non-linearly sampled data from Fourier-domain optical coherence tomography (FD-OCT). This method requires selecting design parameters, such as kernel function type, oversampling ratio and kernel width, to balance between computational complexity and accuracy. The Kaiser-Bessel (KB) and Gaussian kernels have been used independently on the NUFFT algorithm for FD-OCT. This paper compares the reconstruction error and speed for the optimization of these design parameters and justifies particular kernel choice for FD-OCT applications. It is found that for on-the-fly computation of the kernel function, the ...
      Read Full Article
    13. Multiscale multimodal imaging with multiphoton microscopy and optical coherence tomography

      Multiscale multimodal imaging with multiphoton microscopy and optical coherence tomography
      A multiscale multiphoton microscopy (MPM) and optical coherence tomography (OCT) system has been developed using a sub-10 fs Ti:sapphire laser. The system performs cross-sectional OCT imaging over millimeter field-of-view and en-face high-resolution MPM imaging with submicrometer resolution from the same sample location. With fish cornea, we have demonstrated cross-sectional imaging of cornea tissue layers using OCT, and the zoom-in imaging of cells and collagen fibers in each layer using MPM. The multiscale MPM/OCT system shows the potential of a rapid coarse scan to search for abnormal regions and the subsequent fine zoom-in imaging for diagnosis.
      Read Full Article
    14. High-speed spectral domain 
optical coherence tomography using 
non-uniform fast Fourier transform

      High-speed spectral domain 
optical coherence tomography using 
non-uniform fast Fourier transform
      The useful imaging range in spectral domain optical coherence tomography (SD-OCT) is often limited by the depth dependent sensitivity fall-off. Processing SD-OCT data with the non-uniform fast Fourier transform (NFFT) can improve the sensitivity fall-off at maximum depth by greater than 5dB concurrently with a 30 fold decrease in processing time compared to the fast Fourier transform with cubic spline interpolation method. NFFT can also improve local signal to noise ratio (SNR) and reduce image artifacts introduced in post-processing. Combined with parallel processing, NFFT is shown to have the ability to process up to 90k A-lines per second. High-speed SD-OCT ...
      Read Full Article
    15. Optical approach to the salivary pellicle

      The salivary pellicle plays an important role in oral physiology, yet noninvasive in situ characterization and mapping of this layer remains elusive. The goal of this study is to develop an optical approach for the real-time, noninvasive mapping and characterization of salivary pellicles using optical coherence tomography (OCT) and optical coherence microscopy (OCM). The long-term goals are to improve diagnostic capabilities in the oral cavity, gain a better understanding of physiological and pathological processes related to the oral hard tissues, and monitor treatment responses. A salivary pellicle is incubated on small enamel cubes using human whole saliva. OCT and OCM ...
      Read Full Article
    1-15 of 15
  1. Categories

    1. Applications:

      Art, Cardiology, Dentistry, Dermatology, Developmental Biology, Gastroenterology, Gynecology, Microscopy, NDE/NDT, Neurology, Oncology, Ophthalmology, Other Non-Medical, Otolaryngology, Pulmonology, Urology
    2. Business News:

      Acquisition, Clinical Trials, Funding, Other Business News, Partnership, Patents
    3. Technology:

      Broadband Sources, Probes, Tunable Sources
    4. Miscellaneous:

      Jobs & Studentships, Student Theses, Textbooks
  2. Topics in the News

    1. (14 articles) University of British Columbia
    2. (6 articles) Myeong Jin Ju
    3. (2 articles) University of Tsukuba
    4. (2 articles) Simon Fraser University
    5. (2 articles) Yoshiaki Yasuno
    6. (1 articles) UC Irvine
    7. (1 articles) University of Ulsan
    8. (1 articles) Petra E. Wilder-Smith
    9. (1 articles) Tatiana Krasieva
    10. (1 articles) Zhongping Chen
  3. Popular Articles

  4. Picture Gallery

    High-speed spectral domain 
optical coherence tomography using 
non-uniform fast Fourier transform Multiscale multimodal imaging with multiphoton microscopy and optical coherence tomography Selection of convolution kernel in non-uniform fast Fourier transform for Fourier domain optical coherence tomography Multimodal optical imaging with multiphoton microscopy and optical coherence tomography Characterizing refractive index and thickness of biological tissues using combined multiphoton microscopy and optical coherence tomography Corneal imaging and refractive index measurement using a combined multiphoton microscopy and optical coherence tomography system Tri-modal microscopy with multiphoton and optical coherence microscopy/tomography for multi-scale and multi-contrast imaging Advanced multi-contrast Jones matrix optical coherence tomography for Doppler and polarization sensitive imaging Three-dimensional volumetric human meibomian gland investigation using polarization-sensitive optical coherence tomography Heterogeneity of Neointimal Healing Following Biodegradable-polymer Drug-Eluting Coronary Stent Implantation Swept-source and multimodal OCT technologies offer clinical advantages Early vascular response of ultra-thin bioresorbable polymer sirolimus-eluting stents assessed by optical frequency domain imaging: the EVALUATION study