The Experts below are selected from a list of 82149 Experts worldwide ranked by ideXlab platform
Ruikang K Wang - One of the best experts on this subject based on the ideXlab platform.
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evaluating changes of blood flow in retina choroid and outer choroid in rats in response to elevated intraocular pressure by 1300 nm swept source oct
Microvascular Research, 2019Co-Authors: Shaozhen Song, William O Cepurna, John C Morrison, Ruikang K WangAbstract:Abstract We report the development of a 1300 nm swept-source optical coherence tomography (SS-OCT) system specifically designed to perform OCT Imaging and optical microangiography (OMAG) in rat eyes in vivo and its use in evaluating the effects of intraocular pressure (IOP) elevation on ocular circulation. The swept laser is operated in single longitude mode with a 90 nm bandwidth centered at 1300 nm and 200 kHz A-line rate, providing remarkable sensitivity fall-off performance along the Imaging Depth, a larger field of view of 2.5 × 2.5 mm2 (approximately 35°), and more time-efficient Imaging acquisition. The advantage of the SS-OCT/OMAG is highlighted by an increased Imaging Depth of the entire posterior thickness of optic nerve head (ONH) and its surrounding vascular anatomy, to include, for the first time in vivo, the vasculature at the scleral opening, allowing visualization of the circle of Zinn-Haller and posterior ciliary arteries (PCAs). Furthermore, the capillary-level resolution angiograms achieved at the retinal and choroidal layers over a larger field of view enable a significantly improved quantification of the response of vascular area density (VAD) to elevated IOP. The results indicate that reduction in perfusion of the choroid in response to elevated IOP is delayed compared to that seen in the retina; while choroidal VAD doesn't reach 50% of baseline until ~70 mmHg, the same effect is seen for the retinal VAD at ~60 mmHg. The superior image quality offered by SS-OCT may allow more comprehensive investigation of IOP-related ocular perfusion changes and their pathological roles in glaucomatous optic nerve damage.
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high resolution 1050 nm spectral domain retinal optical coherence tomography at 120 khz a scan rate with 6 1 mm Imaging Depth
Biomedical Optics Express, 2013Co-Authors: Lin An, Doug Malchow, Peng Li, Ruikang K WangAbstract:We report a newly developed high speed 1050nm spectral domain optical coherence tomography (SD-OCT) system for Imaging posterior segment of human eye. The system is capable of an axial resolution at ~10 µm in air, an Imaging Depth of 6.1 mm in air, a system sensitivity fall-off at ~6 dB/3mm and an Imaging speed of 120,000 A-scans per second. We experimentally demonstrate the system’s capability to perform phase-resolved Imaging of dynamic blood flow within retina, indicating high phase stability of the SDOCT system. Finally, we show an example that uses this newly developed system to image posterior segment of human eye with a large view of view (10 × 9 mm2), providing detailed visualization of microstructural features from anterior retina to posterior choroid. The demonstrated system parameters and Imaging performances are comparable to those that a typical 1 µm swept source OCT would deliver for retinal Imaging.
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extended Imaging Depth to 12 mm for 1050 nm spectral domain optical coherence tomography for Imaging the whole anterior segment of the human eye at 120 khz a scan rate
Journal of Biomedical Optics, 2013Co-Authors: Gongpu Lan, Doug Malchow, Murray A Johnstone, Ruikang K WangAbstract:ABSTRACT. We demonstrate a 1050-nm spectral domain optical coherence tomography (OCT) system with a 12 mm Imaging Depth in air, a 120 kHz A-scan rate and a 10 μm axial resolution for anterior-segment Imaging of human eye, in which a new prototype InGaAs linescan camera with 2048 active-pixel photodiodes is employed to record OCT spectral interferograms in parallel. Combined with the full-range complex technique, we show that the system delivers comparable Imaging performance to that of a swept-source OCT with similar system specifications.
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multifunctional Imaging of human retina and choroid with 1050 nm spectral domain optical coherence tomography at 92 khz line scan rate
Journal of Biomedical Optics, 2011Co-Authors: Ruikang K WangAbstract:The light source at ∼1-μm wavelength is attractive for enhanced Imaging Depth in retinal optical coherence tomography (OCT). In this paper, we report on a 1050-nm spectral domain OCT system, combined with optical microangiography that operates at a 92-kHz line scan rate for multifunctional Imaging of the human eye, delivering the volumetric Imaging of microstructure and microvasculature within retina and choroid.
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signal degradation by multiple scattering in optical coherence tomography of dense tissue a monte carlo study towards optical clearing of biotissues
Physics in Medicine and Biology, 2002Co-Authors: Ruikang K WangAbstract:Multiple scattering is a major source that limits light penetration into biotissues, thereby preventing visualization of the deep microstructures for high-resolution optical Imaging techniques. The optical clearing approach is a new adventure in biomedical optics for manipulating the optical properties of tissue; for example, the scattering coefficient and the degree of forward scattering of photons, by the use of the chemical administration method in order to improve the optical Imaging Depth, particularly for the recently developed optical coherence tomography (OCT). This paper investigates systematically how the multiple scattering affects signal attenuation and localization in general, and how the alterations of optical properties of tissue enhance the optical Imaging Depth and signal localization in particular, by the use of Monte Carlo simulations through the separate considerations of the least scattered photons (LSP) and multiple scattered photons (MSP). The LSP are those photons that contribute to the precise OCT signal, i.e. localization, and the MSP are those that degrade the OCT signal. It is shown that with either the reduction of the scattering coefficient or the increase of the degree of forward scattering, signal localization and Imaging Depth for OCT is enhanced. Whilst the increase of the anisotropic factor of the medium is more efficient in improving signal localization, it introduces more scattering events for the photons travelling within the tissue for both the LSP and MSP. It is also found that the OCT Imaging resolution is almost reduced exponentially with the increase of the probing Depth as opposed to the claimed system resolution. We demonstrate that optical clearing could be a useful tool to improve the Imaging resolution when the light progressively penetrates the high scattering medium. Experimental results are also presented to show intuitively how multiple scattering affects OCT signal profiles by the use of intralipid solution and healthy human whole blood, representing moderately and highly scattering media respectively.
Lihong V Wang - One of the best experts on this subject based on the ideXlab platform.
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photoacoustic microscopy and computed tomography from bench to bedside
Annual Review of Biomedical Engineering, 2014Co-Authors: Lihong V Wang, Liang GaoAbstract:Photoacoustic Imaging (PAI) of biological tissue has seen immense growth in the past decade, providing unprecedented spatial resolution and functional information at Depths in the optical diffusive regime. PAI uniquely combines the advantages of optical excitation and those of acoustic detection. The hybrid Imaging modality features high sensitivity to optical absorption and wide scalability of spatial resolution with the desired Imaging Depth. Here we first summarize the fundamental principles underpinning the technology, then highlight its practical implementation, and finally discuss recent advances toward clinical translation.
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optical clearing aided photoacoustic microscopy with enhanced resolution and Imaging Depth
Optics Letters, 2013Co-Authors: Yong Zhou, Junjie Yao, Lihong V WangAbstract:Due to strong light scattering in tissue, both the spatial resolution and maximum penetration Depth of optical-resolution photoacoustic microscopy (OR-PAM) deteriorate sharply with Depth. To reduce tissue scattering, we propose to use glycerol as an optical clearing agent in OR-PAM. Our results show that the Imaging performance of OR-PAM can be greatly enhanced by optical clearing both in vitro and in vivo.
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photoacoustic microscopy in tissue engineering
Materials Today, 2013Co-Authors: Xin Cai, Yu Shrike Zhang, Younan Xia, Lihong V WangAbstract:Photoacoustic tomography (PAT) is an attractive modality for noninvasive, volumetric Imaging of scattering media such as biological tissues. By choosing the ultrasonic detection frequency, PAT enables scalable spatial resolution with an Imaging Depth of up to ∼7 cm while maintaining a high Depth-to-resolution ratio of ∼200 and consistent optical absorption contrasts. Photoacoustic microscopy (PAM), the microscopic embodiment of PAT, aims to image at millimeter Depth and micrometer-scale resolution. PAM is well-suited for characterizing three-dimensional scaffold-based samples, including scaffolds themselves, cells, and blood vessels, both qualitatively and quantitatively. Here we review our previous work on applications of PAM in tissue engineering and then discuss its future developments.
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integrated optical and acoustic resolution photoacoustic microscopy based on an optical fiber bundle
Optics Letters, 2013Co-Authors: Wenxin Xing, Konstantin Maslov, Lidai Wang, Lihong V WangAbstract:Photoacoustic microscopy (PAM), whose spatial resolution and maximum Imaging Depth are both scalable, has made great progress in recent years. However, each PAM system currently achieves only one resolution with an associated maximum Imaging Depth. Here, we present an integrated optical-resolution (OR) and acoustic-resolution (AR) PAM system implemented by delivering light via an optical fiber bundle. A single fiber core is used to deliver light for OR illumination in order to achieve a small spot size and hence high lateral resolution, whereas all the fiber cores are used to deliver more energy for AR illumination. Most other components are shared by the OR and AR Imaging. The lateral resolution can be seamlessly switched between 2.2 and 40 μm as the maximum Imaging Depth is switched between 1.3 and 3.0 mm. The system enables automatically coregistered higher-resolution OR and deeper AR photoacoustic Imaging.
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photoacoustic tomography in vivo Imaging from organelles to organs
Science, 2012Co-Authors: Lihong V WangAbstract:Photoacoustic tomography (PAT) can create multiscale multicontrast images of living biological structures ranging from organelles to organs. This emerging technology overcomes the high degree of scattering of optical photons in biological tissue by making use of the photoacoustic effect. Light absorption by molecules creates a thermally induced pressure jump that launches ultrasonic waves, which are received by acoustic detectors to form images. Different implementations of PAT allow the spatial resolution to be scaled with the desired Imaging Depth in tissue while a high Depth-to-resolution ratio is maintained. As a rule of thumb, the achievable spatial resolution is on the order of 1/200 of the desired Imaging Depth, which can reach up to 7 centimeters. PAT provides anatomical, functional, metabolic, molecular, and genetic contrasts of vasculature, hemodynamics, oxygen metabolism, biomarkers, and gene expression. We review the state of the art of PAT for both biological and clinical studies and discuss future prospects.
Xiaowei Zhuang - One of the best experts on this subject based on the ideXlab platform.
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isotropic three dimensional super resolution Imaging with a self bending point spread function
Nature Photonics, 2014Co-Authors: Joshua C Vaughan, Xiaowei ZhuangAbstract:By exploiting a self-bending point spread function based on Airy beams, a three-dimensional super-resolution fluorescence Imaging is realized. A three-dimensional localization precision in the range 10–15 nm was obtained at an Imaging Depth of 3 µm from ∼2,000 photons per localization.
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isotropic three dimensional super resolution Imaging with a self bending point spread function
Nature Photonics, 2014Co-Authors: Joshua C Vaughan, Xiaowei Zhuang, Shu JiaAbstract:Airy beams maintain their intensity profiles over a large propagation distance without substantial diffraction and exhibit lateral bending during propagation1,2,3,4,5. This unique property has been exploited for the micromanipulation of particles6, the generation of plasma channels7 and the guidance of plasmonic waves8, but has not been explored for high-resolution optical microscopy. Here, we introduce a self-bending point spread function (SB-PSF) based on Airy beams for three-dimensional super-resolution fluorescence Imaging. We designed a side-lobe-free SB-PSF and implemented a two-channel detection scheme to enable unambiguous three-dimensional localization of fluorescent molecules. The lack of diffraction and the propagation-dependent lateral bending make the SB-PSF well suited for precise three-dimensional localization of molecules over a large Imaging Depth. Using this method, we obtained super-resolution Imaging with isotropic three-dimensional localization precision of 10–15 nm over a 3 µm Imaging Depth from ∼2,000 photons per localization. By exploiting a self-bending point spread function based on Airy beams, a three-dimensional super-resolution fluorescence Imaging is realized. A three-dimensional localization precision in the range 10–15 nm was obtained at an Imaging Depth of 3 µm from ∼2,000 photons per localization.
Joshua C Vaughan - One of the best experts on this subject based on the ideXlab platform.
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isotropic three dimensional super resolution Imaging with a self bending point spread function
Nature Photonics, 2014Co-Authors: Joshua C Vaughan, Xiaowei ZhuangAbstract:By exploiting a self-bending point spread function based on Airy beams, a three-dimensional super-resolution fluorescence Imaging is realized. A three-dimensional localization precision in the range 10–15 nm was obtained at an Imaging Depth of 3 µm from ∼2,000 photons per localization.
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isotropic three dimensional super resolution Imaging with a self bending point spread function
Nature Photonics, 2014Co-Authors: Joshua C Vaughan, Xiaowei Zhuang, Shu JiaAbstract:Airy beams maintain their intensity profiles over a large propagation distance without substantial diffraction and exhibit lateral bending during propagation1,2,3,4,5. This unique property has been exploited for the micromanipulation of particles6, the generation of plasma channels7 and the guidance of plasmonic waves8, but has not been explored for high-resolution optical microscopy. Here, we introduce a self-bending point spread function (SB-PSF) based on Airy beams for three-dimensional super-resolution fluorescence Imaging. We designed a side-lobe-free SB-PSF and implemented a two-channel detection scheme to enable unambiguous three-dimensional localization of fluorescent molecules. The lack of diffraction and the propagation-dependent lateral bending make the SB-PSF well suited for precise three-dimensional localization of molecules over a large Imaging Depth. Using this method, we obtained super-resolution Imaging with isotropic three-dimensional localization precision of 10–15 nm over a 3 µm Imaging Depth from ∼2,000 photons per localization. By exploiting a self-bending point spread function based on Airy beams, a three-dimensional super-resolution fluorescence Imaging is realized. A three-dimensional localization precision in the range 10–15 nm was obtained at an Imaging Depth of 3 µm from ∼2,000 photons per localization.
Doug Malchow - One of the best experts on this subject based on the ideXlab platform.
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high resolution 1050 nm spectral domain retinal optical coherence tomography at 120 khz a scan rate with 6 1 mm Imaging Depth
Biomedical Optics Express, 2013Co-Authors: Lin An, Doug Malchow, Peng Li, Ruikang K WangAbstract:We report a newly developed high speed 1050nm spectral domain optical coherence tomography (SD-OCT) system for Imaging posterior segment of human eye. The system is capable of an axial resolution at ~10 µm in air, an Imaging Depth of 6.1 mm in air, a system sensitivity fall-off at ~6 dB/3mm and an Imaging speed of 120,000 A-scans per second. We experimentally demonstrate the system’s capability to perform phase-resolved Imaging of dynamic blood flow within retina, indicating high phase stability of the SDOCT system. Finally, we show an example that uses this newly developed system to image posterior segment of human eye with a large view of view (10 × 9 mm2), providing detailed visualization of microstructural features from anterior retina to posterior choroid. The demonstrated system parameters and Imaging performances are comparable to those that a typical 1 µm swept source OCT would deliver for retinal Imaging.
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extended Imaging Depth to 12 mm for 1050 nm spectral domain optical coherence tomography for Imaging the whole anterior segment of the human eye at 120 khz a scan rate
Journal of Biomedical Optics, 2013Co-Authors: Gongpu Lan, Doug Malchow, Murray A Johnstone, Ruikang K WangAbstract:ABSTRACT. We demonstrate a 1050-nm spectral domain optical coherence tomography (OCT) system with a 12 mm Imaging Depth in air, a 120 kHz A-scan rate and a 10 μm axial resolution for anterior-segment Imaging of human eye, in which a new prototype InGaAs linescan camera with 2048 active-pixel photodiodes is employed to record OCT spectral interferograms in parallel. Combined with the full-range complex technique, we show that the system delivers comparable Imaging performance to that of a swept-source OCT with similar system specifications.