1. Articles from Peijun Gong

    1-14 of 14
    1. Jones matrix‐based speckle‐decorrelation angiography using polarization‐sensitive optical coherence tomography

      Jones matrix‐based speckle‐decorrelation angiography using polarization‐sensitive optical coherence tomography

      We show that polarization‐sensitive optical coherence tomography angiography (PS‐OCTA) based on full Jones matrix assessment of speckle decorrelation offers improved contrast and depth of vessel imaging over conventional OCTA. We determine how best to combine the individual Jones matrix elements and compare the resulting image quality to that of a conventional OCT scanner by co‐locating and imaging the same skin locations with closely matched scanning setups. Vessel projection images from finger and forearm skin demonstrate the benefits of Jones matrix‐based PS‐OCTA. Our study provides a promising starting point and a useful reference for future pre ...

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    2. Parametric imaging of attenuation by optical coherence tomography: review of models, methods, and clinical translation

      Parametric imaging of attenuation by optical coherence tomography: review of models, methods, and clinical translation

      Significance: Optical coherence tomography (OCT) provides cross-sectional and volumetric images of backscattering from biological tissue that reveal the tissue morphology. The strength of the scattering, characterized by an attenuation coefficient, represents an alternative and complementary tissue optical property, which can be characterized by parametric imaging of the OCT attenuation coefficient. Over the last 15 years, a multitude of studies have been reported seeking to advance methods to determine the OCT attenuation coefficient and developing them toward clinical applications. Aim: Our review provides an overview of the main models and methods, their assumptions and applicability, together with a survey of preclinical ...

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    3. Short-time series optical coherence tomography angiography and its application to cutaneous microvasculature

      Short-time series optical coherence tomography angiography and its application to cutaneous microvasculature

      We present a new optical coherence tomography (OCT) angiography method for imaging tissue microvasculature in vivo based on the characteristic frequency-domain flow signature in a short time series of a single voxel. The angiography signal is generated by Fourier transforming the OCT signal time series from a given voxel in multiple acquisitions and computing the average magnitude of non-zero (high-pass) frequency components. Larger temporal variations of the OCT signal caused by blood flow result in higher values of the average magnitude in the frequency domain compared to those from static tissue. Weighting of the signal by the inverse of the ...

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    4. Label‐free volumetric imaging of conjunctival collecting lymphatics ex vivo by optical coherence tomography lymphangiography

      Label‐free volumetric imaging of conjunctival collecting lymphatics ex vivo by optical coherence tomography lymphangiography

      We employ optical coherence tomography (OCT) and optical coherence microscopy (OCM) to study conjunctival lymphatics in porcine eyes ex vivo . This study is a precursor to the development of in vivo imaging of the collecting lymphatics for potentially guiding and monitoring glaucoma filtration surgery. OCT scans at 1300 nm and higher‐resolution OCM scans at 785 nm reveal the lymphatic vessels via their optical transparency. Equivalent signal characteristics are also observed from blood vessels largely free of blood (and devoid of flow) in the ex vivo conjunctiva. In our lymphangiography, vessel networks were segmented by compensating the depth attenuation in ...

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    5. Axial Length Variation Impacts on Superficial Retinal Vessel Density and Foveal Avascular Zone Area Measurements Using Optical Coherence Tomography Angiography

      Axial Length Variation Impacts on Superficial Retinal Vessel Density and Foveal Avascular Zone Area Measurements Using Optical Coherence Tomography Angiography

      Purpose : To evaluate the impact of image magnification correction on superficial retinal vessel density (SRVD) and foveal avascular zone area (FAZA) measurements using optical coherence tomography angiography (OCTA). Methods : Participants with healthy retinas were recruited for ocular biometry, refraction, and RTVue XR Avanti OCTA imaging with the 3 × 3-mm protocol. The foveal and parafoveal SRVD and FAZA were quantified with custom software before and after correction for magnification error using the Littman and the modified Bennett formulae. Relative changes between corrected and uncorrected SRVD and FAZA were calculated. Results : Forty subjects were enrolled and the median (range) age of the ...

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    6. In vivo label-free lymphangiography of cutaneous lymphatic vessels in human burn scars using optical coherence tomography

      In vivo label-free lymphangiography of cutaneous lymphatic vessels in human burn scars using optical coherence tomography

      We present an automated, label-free method for lymphangiography of cutaneous lymphatic vessels in humans in vivo using optical coherence tomography (OCT). This method corrects for the variation in OCT signal due to the confocal function and sensitivity fall-off of a spectral-domain OCT system and utilizes a single-scattering model to compensate for A-scan signal attenuation to enable reliable thresholding of lymphatic vessels. A segment-joining algorithm is then incorporated into the method to mitigate partial-volume effects with small vessels. The lymphatic vessel images are augmented with images of the blood vessel network, acquired from the speckle decorrelation with additional weighting to differentiate ...

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    7. 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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    8. Investigation of optical attenuation imaging using optical coherence tomography for monitoring of scars undergoing fractional laser treatment

      Investigation of optical attenuation imaging using optical coherence tomography for monitoring of scars undergoing fractional laser treatment

      En face 2D OCT attenuation coefficient map of a treated immature scar derived from the pre-treatment (top) and the post-treatment (bottom) scans. (Vasculature (black) is masked out.) The scale bars are 0.5 mm. We demonstrate the use of the near-infrared attenuation coefficient, measured using optical coherence tomography (OCT), in longitudinal assessment of hypertrophic burn scars undergoing fractional laser treatment. The measurement method incorporates blood vessel detection by speckle decorrelation and masking, and a robust regression estimator to produce 2D en face parametric images of the attenuation coefficient of the dermis. Through reliable co-location of the field of view across ...

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    9. Optical coherence tomography for longitudinal monitoring of vasculature in scars treated with laser fractionation - Gong - 2015 - Journal of Biophotonics - Wiley Online Library

      Optical coherence tomography for longitudinal monitoring of vasculature in scars treated with laser fractionation - Gong - 2015 - Journal of Biophotonics - Wiley Online Library

      En face optical coherence tomography vasculature images pre-treatment (top) and ˜20 weeks after the first laser treatment (bottom) of a mature burn scar. Arrows mark the same vessel pattern. This study presents the first in vivo longitudinal assessment of scar vasculature in ablative fractional laser treatment using optical coherence tomography (OCT). A method based on OCT speckle decorrelation was developed to visualize and quantify the scar vasculature over the treatment period. Through reliable co-location of the imaging field of view across multiple imaging sessions, and compensation for motion artifact, the study was able to track the same scar tissue over ...

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    10. Imaging of skin birefringence for human scar assessment using polarization-sensitive optical coherence tomography aided by vascular masking

      Imaging of skin birefringence for human scar assessment using polarization-sensitive optical coherence tomography aided by vascular masking

      We demonstrate the in vivo assessment of human scars by parametric imaging of birefringence using polarization-sensitive optical coherence tomography (PS-OCT). Such in vivo assessment is subject to artifacts in the detected birefringence caused by scattering from blood vessels. To reduce these artifacts, we preprocessed the PS-OCT data using a vascular masking technique. The birefringence of the remaining tissue regions was then automatically quantified. Results from the scars and contralateral or adjacent normal skin of 13 patients show a correspondence of birefringence with scar type: the ratio of birefringence of hypertrophic scars to corresponding normal skin is 2.2 ± 0.2 ...

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    11. Assessment of human burn scars with optical coherence tomography by imaging the attenuation coefficient of tissue after vascular masking

      Assessment of human burn scars with optical coherence tomography by imaging the attenuation coefficient of tissue after vascular masking

      The formation of burn-scar tissue in human skin profoundly alters, among other things, the structure of the dermis. We present a method to characterize dermal scar tissue by the measurement of the near-infrared attenuation coefficient using optical coherence tomography (OCT). To generate accurate en face parametric images of attenuation, we found it critical to first identify (using speckle decorrelation) and mask the tissue vasculature from the three-dimensional OCT data. The resulting attenuation coefficients in the vasculature-masked regions of the dermis of human burn-scar patients are lower in hypertrophic ( 3.8 ± 0.4     mm − 1 ) and normotrophic ( 4.2 ± 0.9 ...

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    12. Feature Of The Week 12/17/12: University of Western Australia Investigates Quantitative Assessment of Burn Scars Using OCT

      Feature Of The Week 12/17/12: University of Western Australia Investigates Quantitative Assessment of Burn Scars Using OCT

      In scars arising from burns, objective assessment of vascularity is important in the early identification of pathological scarring, and in the assessment of progression and treatment response. We demonstrate the first clinical assessment and automated quantification of vascularity in cutaneous burn scars of human patients in vivo that uses optical coherence tomography (OCT). Scar microvasculature was delineated in three-dimensional OCT images using speckle decorrelation. The diameter and area density of blood vessels were automatically quantified. A substantial increase was observed in the measured density of vasculature in hypertrophic scar tissues (38%) when compared against normal, unscarred skin (22%). A proliferation ...

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    13. In vivo assessment of human burn scars through automated quantification of vascularity using optical coherence tomography

      In vivo assessment of human burn scars through automated quantification of vascularity using optical coherence tomography

      In scars arising from burns, objective assessment of vascularity is important in the early identification of pathological scarring, and in the assessment of progression and treatment response. We demonstrate the first clinical assessment and automated quantification of vascularity in cutaneous burn scars of human patients in vivo that uses optical coherence tomography (OCT). Scar microvasculature was delineated in three-dimensional OCT images using speckle decorrelation. The diameter and area density of blood vessels were automatically quantified. A substantial increase was observed in the measured density of vasculature in hypertrophic scar tissues (38%) when compared against normal, unscarred skin (22%). A proliferation ...

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    1-14 of 14
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  2. Topics in the News

    1. (14 articles) University of Western Australia
    2. (14 articles) David D. Sampson
    3. (9 articles) Robert A. McLaughlin
    4. (3 articles) Qiang Wang
    5. (2 articles) Karol Karnowski
    6. (2 articles) Brendan F. Kennedy
    7. (1 articles) Erasmus University
    8. (1 articles) Daniël M. de Bruin
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    In vivo assessment of human burn scars through automated quantification of vascularity using optical coherence tomography Feature Of The Week 12/17/12: University of Western Australia Investigates Quantitative Assessment of Burn Scars Using OCT Assessment of human burn scars with optical coherence tomography by imaging the attenuation coefficient of tissue after vascular masking Imaging of skin birefringence for human scar assessment using polarization-sensitive optical coherence tomography aided by vascular masking Optical coherence tomography for longitudinal monitoring of vasculature in scars treated with laser fractionation - Gong - 2015 - Journal of Biophotonics - Wiley Online Library Optical coherence tomography angiography for longitudinal monitoring of vascular changes in human cutaneous burns Investigation of optical attenuation imaging using optical coherence tomography for monitoring of scars undergoing fractional laser treatment Optical coherence tomography in the assessment of acute changes in cutaneous vascular diameter induced by heat stress In vivo label-free lymphangiography of cutaneous lymphatic vessels in human burn scars using optical coherence tomography Short-time series optical coherence tomography angiography and its application to cutaneous microvasculature Optical coherence tomography features of neovascularization in proliferative diabetic retinopathy: a systematic review Retinal microvascular metrics in untreated essential hypertensives using optical coherence tomography angiography