1. Articles from Jia Qin

    1-11 of 11
    1. Using a dual-tree complex wavelet transform for denoising an optical coherence tomography angiography blood vessel image

      Using a dual-tree complex wavelet transform for denoising an optical coherence tomography angiography blood vessel image

      High image quality is of great importance for precise diagnosis and therapeutics of eye disease in clinic. A human retina OCT angiography (OCTA) image can be extracted from multiple OCT B-scans to visualize the distribution of blood vessels. However, OCTA suffer from the degeneration of image quality due to inherent Gaussian noise of the OCT system while the blood vessel’s signal is extracted. The degeneration of the noise in OCTA image will be more conducive to the evaluation of abnormal and normal blood vessels in the human eye. To precisely assist diagnosis and therapeutics in clinic by reducing the ...

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    2. Spectrometer calibration with reduced dispersion for optical coherence tomography

      Spectrometer calibration with reduced dispersion for optical coherence tomography

      A wavelength calibration method is proposed for Fourier domain optical coherence tomography. In the present study, the wavelength remapping procedure is based on the spectral phase function determined by the calibration signal. To accomplish high accuracy feature for wavelength calibration, a common-path interferometer is employed. Two autocorrelation interferograms generated from the common-path interferometer are utilized as the calibration signals. The advantage of the interferometer proposed here is that the accurate optical path difference of the calibration signals could be acquired easily. The wavelength distribution in the spectrometer was deduced with the phase signal. The approach was compared to a wavelength-determined ...

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    3. High Resolution Imaging in male germ cell associated kinase (MAK)-related Retinal Degeneration

      High Resolution Imaging in male germ cell associated kinase (MAK)-related Retinal Degeneration

      Purpose To describe the characteristics of MAK -related retinal degeneration using optical coherence tomography angiography (OCTA) and adaptive optics scanning laser ophthalmoscopy (AOSLO). Design Cross-sectional study. Methods Six patients with rod-cone degeneration and disease-causing mutations in MAK were evaluated with visual acuity, spectral domain OCT, confocal AOSLO and OCTA. Foveal avascular zone (FAZ) area, vessel densities and perfusion densities of the superficial capillary plexus (SCP) and deep capillary plexus (DCP) in the central macula in all 6 patients were compared with 5 normal subjects. Cone spacing was measured in 4 patients from AOSLO images and compared with 37 normal subjects ...

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    4. Wide velocity range Doppler optical microangiography using optimized step-scanning protocol with phase variance mask

      Wide velocity range Doppler optical microangiography using optimized step-scanning protocol with phase variance mask

      We propose a simple and optimized method for acquiring a wide velocity range of blood flow using Doppler optical microangiography. After characterizing the behavior of the scanner in the fast scan axis, a step-scanning protocol is developed by utilizing repeated A-scans at each step. Multiple velocity range images are obtained by the high-pass filtering and Doppler processing of complex signals between A-scans within each step with different time intervals. A phase variance mask is then employed to segment meaningful Doppler flow signals from noisy phase background. The technique is demonstrated by imaging in vivo mouse brain with skull left intact ...

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    5. Label-free optical lymphangiography: development of an automatic segmentation method applied to optical coherence tomography to visualize lymphatic vessels using Hessian filters

      Label-free optical lymphangiography: development of an automatic segmentation method applied to optical coherence tomography to visualize lymphatic vessels using Hessian filters

      Lymphatic vessels are a part of the circulatory system that collect plasma and other substances that have leaked from the capillaries into interstitial fluid (lymph) and transport lymph back to the circulatory system. Since lymph is transparent, lymphatic vessels appear as dark hallow vessel-like regions in optical coherence tomography (OCT) cross sectional images. We propose an automatic method to segment lymphatic vessel lumen from OCT structural cross sections using eigenvalues of Hessian filters. Compared to the existing method based on intensity threshold, Hessian filters are more selective on vessel shape and less sensitive to intensity variations and noise. Using this ...

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    6. Super-resolution spectral estimation of optical micro-angiography for quantifying blood flow within microcirculatory tissue beds in vivo

      Super-resolution spectral estimation of optical micro-angiography for quantifying blood flow within microcirculatory tissue beds in vivo

      In this paper, we propose a super-resolution spectral estimation technique to quantify microvascular hemodynamics using optical microangiography (OMAG) based on optical coherence tomography (OCT). The proposed OMAG technique uses both amplitude and phase information of the OCT signals which makes it sensitive to the axial and transverse flows. The scanning protocol for the proposed method is identical to three-dimensional ultrahigh sensitive OMAG, and is applicable for in vivo measurements. In contrast to the existing capillary flow quantification methods, the proposed method is less sensitive to tissue motion and does not have aliasing problems due fast flow within large blood vessels ...

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    7. Uniform enhancement of optical micro-angiography images using Rayleigh contrast-limited adaptive histogram equalization

      Uniform enhancement of optical micro-angiography images using Rayleigh contrast-limited adaptive histogram equalization

      Optical microangiography is an imaging technology that is capable of providing detailed functional blood flow maps within microcirculatory tissue beds in vivo . Some practical issues however exist when displaying and quantifying the microcirculation that perfuses the scanned tissue volume. These issues include: (I) Probing light is subject to specular reflection when it shines onto sample. The unevenness of the tissue surface makes the light energy entering the tissue not uniform over the entire scanned tissue volume. (II) The biological tissue is heterogeneous in nature, meaning the scattering and absorption properties of tissue would attenuate the probe beam. These physical limitations ...

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    8. Variable-range Doppler optical microangiography using stabilized step scanning and phase variance binarized mask

      Variable-range Doppler optical microangiography using stabilized step scanning and phase variance binarized mask

      Skipping various numbers of A-lines is effective to obtain multi-range velocimetry using Doppler optical coherence tomography (DOCT). High correlation between A-lines is a fundamental prerequisite for DOCT processing. Therefore, high oversampling is normally necessary, especially when skipping A-lines. That requires quite a long time of imaging, which might not be acceptable on some occasions. Step-scanning protocol, which captures repeated A-scans, has been employed for multi-range DOCT previously. We develop it by waiting for the scanner to stabilize, but not capturing continuously. In this way the cross-correlation of step scanning maintains almost constant for all the captured A-lines, and is higher ...

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    9. Quantifying Optical Microangiography Images Obtained from a Spectral Domain Optical Coherence Tomography System

      Quantifying Optical Microangiography Images Obtained from a Spectral Domain Optical Coherence Tomography System

      The blood vessel morphology is known to correlate with several diseases, such as cancer, and is important for describing several tissue physiological processes, like angiogenesis. Therefore, a quantitative method for characterizing the angiography obtained from medical images would have several clinical applications. Optical microangiography (OMAG) is a method for obtaining three-dimensional images of blood vessels within a volume of tissue. In this study we propose to quantify OMAG images obtained with a spectral domain optical coherence tomography system. A technique for determining three measureable parameters (the fractal dimension, the vessel length fraction, and the vessel area density) is proposed and ...

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    10. Supercontinuum light source enables in vivooptical microangiography of capillary vessels within tissue beds

      Supercontinuum light source enables in vivooptical microangiography of capillary vessels within tissue beds
      This Letter reports on the use of a supercontinuum light source to achieve ultrahigh resolution and ultrahigh sensitive optical microangiography (OMAG) imaging of microcirculations within tissue beds in vivo. After passing through a specially designed optical filter with a passband of 120 nm centered on 800 nm, the light source is coupled into an optic-fiber-based OMAG system that provides a measured axial resolution of ∼3 μm over a ranging distance of 2 mm. Within this ranging distance, the system gives an averaged signal-to-noise ratio of 87 dB and a sensitivity roll-off of 7 dB at an A-scan rate of 70 ...
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    11. Ultrahigh sensitive optical microangiography reveals depth-resolved microcirculation and its longitudinal response to prolonged ischemic event within skeletal muscles in mice

      Ultrahigh sensitive optical microangiography reveals depth-resolved microcirculation and its longitudinal response to prolonged ischemic event within skeletal muscles in mice

      The primary pathophysiology of peripheral arterial disease is associated with impaired perfusion to the muscle tissue in the lower extremities. The lack of effective pharmacologic treatments that stimulate vessel collateralization emphasizes the need for an imaging method that can be used to dynamically visualize depth-resolved microcirculation within muscle tissues. Optical microangiography (OMAG) is a recently developed label-free imaging method capable of producing three-dimensional images of dynamic blood perfusion within microcirculatory tissue beds at an imaging depth of up to ∼2 mm, with an unprecedented imaging sensitivity of blood flow at ∼4 μm/s. In this paper, we demonstrate the utility ...

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    1-11 of 11
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  2. Topics in the News

    1. (8 articles) University of Washington
    2. (8 articles) Ruikang K. Wang
    3. (5 articles) Zhongwei Zhi
    4. (3 articles) Siavash Yousefi
    5. (2 articles) Lin An
    6. (2 articles) Suzan Dziennis
    7. (2 articles) Roberto Reif
    8. (2 articles) Kyungpook National University
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    12. (2 articles) Mansik Jeon
    13. (1 articles) Oregon Health & Science University
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    Ultrahigh sensitive optical microangiography reveals depth-resolved microcirculation and its longitudinal response to prolonged ischemic event within skeletal muscles in mice Supercontinuum light source enables in vivooptical microangiography of capillary vessels within tissue beds Quantifying Optical Microangiography Images Obtained from a Spectral Domain Optical Coherence Tomography System Variable-range Doppler optical microangiography using stabilized step scanning and phase variance binarized mask Uniform enhancement of optical micro-angiography images using Rayleigh contrast-limited adaptive histogram equalization Super-resolution spectral estimation of optical micro-angiography for quantifying blood flow within microcirculatory tissue beds in vivo Label-free optical lymphangiography: development of an automatic segmentation method applied to optical coherence tomography to visualize lymphatic vessels using Hessian filters Wide velocity range Doppler optical microangiography using optimized step-scanning protocol with phase variance mask High Resolution Imaging in male germ cell associated kinase (MAK)-related Retinal Degeneration Spectrometer calibration with reduced dispersion for optical coherence tomography A Generic Framework for Fourier-Domain Optical Coherence Tomography Imaging: Software Architecture and Hardware Implementations Vision-Inspection-Synchronized Dual Optical Coherence Tomography for High-Resolution Real-Time Multidimensional Defect Tracking in Optical Thin Film Industry