1. Articles from Lihong V. Wang

    1-17 of 17
    1. Photoacoustic and optical coherence tomography of epilepsy with high temporal and spatial resolution and dual optical contrasts

      Photoacoustic and optical coherence tomography of epilepsy with high temporal and spatial resolution and dual optical contrasts

      Epilepsy mapping with high spatial and temporal resolution has great significance for both fundamental research on epileptic neurons and the clinical management of epilepsy. In this communication, we demonstrate for the first time in vivo epilepsy mapping with high spatial and temporal resolution and dual optical contrasts in an animal model. Through the variations of a depthresolved optical coherence tomography signal with optical scattering contrast, we observed that epileptic neuron activities modulated the optical refractive index of epileptic neurons and their surrounding tissue. Simultaneously, through neurovasculature coupling mechanisms and optical absorption contrast, we used photoacoustic signals to document the hemodynamic ...

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    2. A 2.5-mm diameter probe for photoacoustic and ultrasonic endoscopy

      A 2.5-mm diameter probe for photoacoustic and ultrasonic endoscopy

      We have created a 2.5-mm outer diameter integrated photo-acoustic and ultrasonic mini-probe which can be inserted into a standard video endoscope’s instrument channel. A small-diameter focused ultrasonic transducer made of PMN-PT provides adequate signal sensitivity, and enables miniaturization of the probe. Additionally, this new endoscopic probe utilizes the same scanning mirror and micromotor-based built-in actuator described in our previous reports; however, the length of the rigid distal section of the new probe has been further reduced to ~35 mm. This paper describes the technical details of the mini-probe and presents experimental results that both quantify the imaging performance ...

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    3. Investigation of Neovascularization in Three-Dimensional Porous Scaffolds In Vivo by a Combination of Multiscale Photoacoustic Microscopy and Optical Coherence Tomography

      Investigation of Neovascularization in Three-Dimensional Porous Scaffolds In Vivo by a Combination of Multiscale Photoacoustic Microscopy and Optical Coherence Tomography

      It is a grand challenge to visualize and assess in vivo neovascularization in a three-dimensional (3D) scaffold non-invasively, together with high spatial resolution and deep penetration depth. Here we used multiscale photoacoustic microscopy (PAM), including acoustic-resolution PAM (AR-PAM) and optical-resolution PAM (OR-PAM), to chronically monitor neovascularization in an inverse opal scaffold implanted in a mouse model up to six weeks by taking advantage of the optical absorption contrast intrinsic to hemoglobin molecules in red blood cells. By combining with optical coherence tomography (OCT) based on optical scattering contrast, we also demonstrated the capability to simultaneously image and analyze the vasculature ...

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    4. Three-dimensional Optical-resolution Photoacoustic Microscopy

      Three-dimensional Optical-resolution Photoacoustic Microscopy
      Optical microscopy, providing valuable insights at the cellular and organelle levels, has been widely recognized as an enabling biomedical technology. As the mainstays of in vivo three-dimensional (3-D) optical microscopy, single-/multi-photon fluorescence microscopy and optical coherence tomography (OCT) have demonstrated their extraordinary sensitivities to fluorescence and optical scattering contrasts, respectively. However, the optical absorption contrast of biological tissues, which encodes essential physiological/pathological information, has not yet been assessable. The emergence of biomedical photoacoustics has led to a new branch of optical microscopy optical-resolution photoacoustic microscopy (OR-PAM)(1), where the optical irradiation is focused to the diffraction limit to ...
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    5. In vivo, dual-modality imaging of mouse eyes: optical coherence tomography and photoacoustic microscopy within a single instrument

      In vivo, dual-modality imaging of mouse eyes: optical coherence tomography and photoacoustic microscopy within a single instrument
      Optical-resolution photoacoustic microscopy (OR-PAM) provides superb optical absorption contrast for red blood cells (RBCs), which makes it ideal for in vivo microvasculature imaging. In comparison, optical coherence tomography (OCT), widely used for tissue microstructure imaging, provides high optical scattering contrast. The two contrast mechanisms are highly complementary. In this work, we combined OR-PAM and OCT into a single, dual-modality imaging instrument for in vivo mouse eye imaging. We demonstrated in vivo dual-modality imaging of the anterior segment of mouse eyes with laser pulse energy within the ANSI laser safety standard.
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    6. Fast-scanning reflection-mode integrated optical-coherence and photoacoustic microscopy

      Fast-scanning reflection-mode integrated optical-coherence and photoacoustic microscopy
      We previously demonstrated that multimodal microscopy combining photoacoustic microscopy and optical coherence tomography can provide comprehensive insight into biological tissue at µm-level resolution by exploiting both optical absorption and scattering contrasts. Recently, we have developed a second-generation integrated photoacoustic and optical-coherence microscope, which can potentially be adapted for clinical applications. In this new system, we can perform photoacoustic and optical-coherence imaging simultaneously at a speed of 5,000 A-lines per second with real-time on-screen display. Also, both modalities now work in reflection mode instead of transmission mode, allowing easy access to various anatomical locations of interest. Imaging of skin and ...
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    7. Photoacoustic imaging and characterization of the microvasculature

      Photoacoustic imaging and characterization of the microvasculature
      Photoacoustic (optoacoustic) tomography, combining optical absorption contrast and highly scalable spatial resolution (from micrometer optical resolution to millimeter acoustic resolution), has broken through the fundamental penetration limit of optical ballistic imaging modalities—including confocal microscopy, two-photon microscopy, and optical coherence tomography—and has achieved high spatial resolution at depths down to the diffusive regime. Optical absorption contrast is highly desirable for microvascular imaging and characterization because of the presence of endogenous strongly light-absorbing hemoglobin. We focus on the current state of microvascular imaging and characterization based on photoacoustics. We first review the three major embodiments of photoacoustic tomography: microscopy, computed ...
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    8. In vivo photoacoustic tomography and its clinical application.

      High-resolution volumetric optical imaging modalities, such as confocal microscopy, two-photon microscopy, and optical coherence tomography, have become increasingly important in biomedicine. However, due to strong light scattering, the penetration depths of these imaging modalities are limited to the optical transport mean free path (1 mm) in biological tissues. Photoacoustic imaging, an emerging hybrid modality that can provide strong endogenous and exogenous optical absorption contrasts with high ultrasonic spatial resolution, has overcome the fundamental depth limitation while maintaining high spatial resolution. The image resolution, as well as the maximum imaging depth, is scalable with ultrasonic frequency within the reach of diffuse ...
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    9. Three-dimensional combined photoacoustic and optical coherence microscopy for in vivo microcirculation studies

      Three-dimensional combined photoacoustic and optical coherence microscopy for in vivo microcirculation studies
      Photoacoustic microscopy is predominantly sensitive to optical absorption, while optical coherence tomography relies on optical backscattering. Integrating their complementary contrasts can provide comprehensive information about biological tissue. We have developed a dual-modality microscope that combines the two for studying microcirculation. Three-dimensional imaging of microvasculature and its local environment has been demonstrated at micrometer-order resolution using endogenous contrast in vivo.
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    10. Nanoparticles for photoacoustic imaging

      Nanoparticles have been designed and applied as contrast enhancers in various optical imaging techniques, such as optical coherence tomography, fluorescence imaging, and optical reflectance microscopy. As an emerging hybrid imaging modality, photoacoustic imaging (PAI) has also benefited from the application of these nanoparticle-based contrast agents. We review this rapidly growing field and describe the applications of nanoparticles in PAI. Particular focus is given to nanoparticles whose absorption mechanism is based on surface plasmon resonance, including gold nanoshells, nanorods, and nanocages. Dye-embedded nanoparticles are also reviewed. Specifically, the design and application of each nanoparticle-based contrast agent in relation to the field ...
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    11. In-vivo imaging of microcirculation using integrated photoacoustic and optical-coherence microscopy

      Photoacoustic imaging and optical coherence tomography have complementary imaging contrasts. Photoacoustic imaging is sensitive to optical absorption, thus is able to generate detailed maps of deep microvasculature in vivo. Optical coherence tomography exploits the optical scattering contrast, and can provide real-time, micrometer-resolution imaging of tissue. We integrate an optical-resolution photoacoustic microscopy and a spectral-domain optical coherence tomography into a single system. Our preliminary experiments showed that it could be a valuable imaging tool for microcirculation studies in vivo.
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    12. Prospects of photoacoustic tomography

      Commercially available high-resolution three-dimensional optical imaging modalities—including confocal microscopy, two-photon microscopy, and optical coherence tomography—have fundamentally impacted biomedicine. Unfortunately, such tools cannot penetrate biological tissue deeper than the optical transport mean free path (~1 mm in the skin). Photoacoustic tomography, which combines strong optical contrast and high ultrasonic resolution in a single modality, has broken through this fundamental depth limitation and achieved superdepth high-resolution optical imaging. In parallel, radio frequency-or microwave-induced thermoacoustic tomography is being actively developed to combine radio frequency or microwave contrast with ultrasonic resolution. In this Vision 20/20 article, the prospects of photoacoustic tomography ...
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    13. Photoacoustic microscopy at super depths

      Photoacoustic microscopy at super depths
      Combining light and ultrasound in a single hybrid technology enables multiscale, high-resolution imaging deep into biological tissue. With their ability to sense rich optical contrast in living tissue using harmless nonionizing radiation, commercial high-resolution 3D optical imaging techniques—such as confocal microscopy, two-photon microscopy, and optical coherence tomography—have had a fundamental impact on biomedicine. These techniques, which are collectively known as ballistic imaging, depend on unscattered or minimally scattered photons. Its utility notwithstanding, ballistic imaging also has several limitations. In particular, diffraction constrains its resolution, and because living tissue scatters light, ballistic imaging techniques are unable to penetrate deeper ...
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    14. In vivo burn imaging using Mueller optical coherence tomography

      Miloš Todorovic, Shuliang Jiao, Jun Ai, David Pereda-Cubián, George Stoica, Lihong V. Wang. We report on the use of a high-speed, fiber-based Mueller-matrix optical coherence tomography system with continuous source-polarization modulation for in vivo burn depth evaluation and healing monitoring. A homemade hand-held probe with integrated optical scanning and beam delivering optics was ... [Opt. Express 16, 10279-10284 (2008)]
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    15. Optical coherence computed tomography

      Li Li and Lihong V. Wang We proposed a novel time-resolved optical tomography, optical coherence computed tomography. It married the key concepts of time-resolved diffuse optical tomography and optical coherence tomography. Both ballistic and multiple-scattered photons were measured at multiple source-detection positions by ... [Proc. SPIE Int. Soc. Opt. Eng. 6855, 68550H (2008)] published Wed Feb 6, 2008.
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    16. Optical coherence computed tomography

      Li Li and Lihong V. Wang Optical Imaging Laboratory, Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, Missouri 63130, USA A time-resolved optical tomography, optical coherence computed tomography, is proposed to bridge the gap between diffuse optical tomography and optical coherence tomography. Both ballistic and multiple-scattered photons are measured at multiple source-detection positions by low-coherence interferometry providing a temporal resolution smalle
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    17. Biomedical Optics: Principles and Imaging (Book)

      Biomedical Optics: Principles and Imaging (Book)
      This entry-level textbook, covering the area of tissue optics, is based on the lecture notes for a graduate course (Bio-optical Imaging) that has been taught six times by the authors at Texas A&M University. After the fundamentals of photon transport in biological tissues are established, various optical imaging techniques for biological tissues are covered. The imaging modalities include ballistic imaging, quasi-ballistic imaging (optical coherence tomography), diffusion imaging, and ultrasound-aided hybrid imaging. The basic physics and engineering of each imaging technique are emphasized.
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    1-17 of 17
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  2. Topics in the News

    1. (17 articles) Lihong V. Wang
    2. (16 articles) Washington University in St. Louis
    3. (8 articles) Li Li
    4. (6 articles) Konstantin I. Maslov
    5. (2 articles) Geng Ku
    6. (2 articles) Thorlabs
    7. (2 articles) Kyungpook National University
    8. (2 articles) University of Washington
    9. (2 articles) Jeehyun Kim
    10. (2 articles) Ruchire Eranga Wijesinghe
    11. (2 articles) Mansik Jeon
    12. (1 articles) Harvard University
    13. (1 articles) Massachusetts General Hospital
    14. (1 articles) David Pereda Cubián
    15. (1 articles) Shuliang Jiao
    16. (1 articles) University of Ulsan
    17. (1 articles) Tokyo Medical & Dental University
    18. (1 articles) University of Toronto
    19. (1 articles) Yasunori Sumi
    20. (1 articles) Ali M. Fard
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    Three-dimensional combined photoacoustic and optical coherence microscopy for in vivo microcirculation studies Biomedical Optics: Principles and Imaging (Book) Photoacoustic imaging and characterization of the microvasculature In vivo, dual-modality imaging of mouse eyes: optical coherence tomography and photoacoustic microscopy within a single instrument Three-dimensional Optical-resolution Photoacoustic Microscopy Investigation of Neovascularization in Three-Dimensional Porous Scaffolds In Vivo by a Combination of Multiscale Photoacoustic Microscopy and 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 Relative retinal flow velocity detection using optical coherence tomography angiography imaging Comparison of Optical Flow Ratio and Fractional Flow Ratio in Stent-Treated Arteries Immediately After Percutaneous Coronary Intervention Spaceflight Associated Neuro-Ocular Syndrome (SANS): A Systematic Review and Future Directions Retinal Thickness and Microvascular Pattern in Early Parkinson's Disease