1. Articles from Cheng-Kuang Lee

    1-22 of 22
    1. Optical coherence tomography-guided laser microsurgery for blood coagulation with continuous-wave laser diode

      Optical coherence tomography-guided laser microsurgery for blood coagulation with continuous-wave laser diode

      Blood coagulation is the clotting and subsequent dissolution of the clot following repair to the damaged tissue. However, inducing blood coagulation is difficult for some patients with homeostasis dysfunction or during surgery. In this study, we proposed a method to develop an integrated system that combines optical coherence tomography (OCT) and laser microsurgery for blood coagulation. Also, an algorithm for positioning of the treatment location from OCT images was developed. With OCT scanning, 2D/3D OCT images and angiography of tissue can be obtained simultaneously, enabling to noninvasively reconstruct the morphological and microvascular structures for real-time monitoring of changes in ...

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    2. Investigation of temporal vascular effects induced by focused ultrasound treatment with speckle-variance optical coherence tomography

      Investigation of temporal vascular effects induced by focused ultrasound treatment with speckle-variance optical coherence tomography

      Focused ultrasound (FUS) can be used to locally and temporally enhance vascular permeability, improving the efficiency of drug delivery from the blood vessels into the surrounding tissue. However, it is difficult to evaluate in real time the effect induced by FUS and to noninvasively observe the permeability enhancement. In this study, speckle-variance optical coherence tomography (SVOCT) was implemented for the investigation of temporal effects on vessels induced by FUS treatment. With OCT scanning, the dynamic change in vessels during FUS exposure can be observed and studied. Moreover, the vascular effects induced by FUS treatment with and without the presence of ...

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    3. Two-Level Optical Coherence Tomography Scheme for Suppressing Spectral Saturation Artifacts

      Two-Level Optical Coherence Tomography Scheme for Suppressing Spectral Saturation Artifacts

      We demonstrate a novel method for reducing saturation artifacts in spectral-domain optical coherence tomography (SD-OCT) systems. This method is based on a two-level SD-OCT system with a dual-line charge-coupled device (CCD) camera. We compensate the saturated signal detected by the first line using the unsaturated signal detected by the second line. The Fourier transform of the compensated spectrum shows effective suppression of saturation artifacts. This method was also successfully performed on phantom material and skin on a human finger. Our method causes neither back-scattering power loss nor signal-to-noise ratio (SNR) degradation. The only difference between the traditional system and our ...

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    4. A pseudo-spectrum reconstruction method for reducing saturation artifact inspectral-domain optical coherence tomography

      A pseudo-spectrum reconstruction method for reducing saturation artifact inspectral-domain optical coherence tomography

      Saturation artifact is a significant image noise due to the limited detectable maximum light intensity of the CCD camera in the spectrometer module of spectral-domain optical coherence tomography (SD-OCT). This effect makes the OCT image appear with saturation noise in certain areas along with even more obvious vertical lines of noise. The unwanted artifacts cover the real sample structure information and can render the image unclear. This artifact problem is significant when using highly focused objective lenses for improving image transverse resolution. In this study, we developed a parabolic-based reconstruction method to estimate the saturated parts of the measured spectra ...

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    5. Mirror image suppression method

      Mirror image suppression method

      A mirror image suppression method adapted to an optical coherence tomography (OCT) system is provided. The mirror image suppression method includes the following steps: obtaining a tomography image of an object to be tested by using the OCT system; calculating one real image signal obtained from an n.sup.th specific-mode scan for a specific pixel of the tomography image based on image signals obtained from an (n-1).sup.th and the n.sup.th specific-mode scans; obtaining one real image signal of each of a plurality of pixels in the tomography image based on the calculation in the step ...

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    6. Quantitative observation of focused-ultrasound-induced vascular leakage and deformation via fluorescein angiography and optical coherence tomography

      Quantitative observation of focused-ultrasound-induced vascular leakage and deformation via fluorescein angiography and optical coherence tomography

      Focused ultrasound (FUS) is a recently discovered noninvasive technique for local and temporal enhancement of vascular permeability, which facilitates drug delivery from the vessels into the surrounding tissue. However, exposure to FUS at a high intensity may cause permanent damage. To investigate the effects of the FUS treatment on blood vessels, we propose to use fluorescein angiography (FA) and optical coherence tomography (OCT) for real-time observation of the diffusion of fluorescence dye from blood vessels and to evaluate the morphological changes of the vessels in vivo . With time-resolved FA imaging, the relationship between the exposed power and the improved permeability ...

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    7. Evaluation of Moisture-Related Attenuation Coefficient and Water Diffusion Velocity in Human Skin Using Optical Coherence Tomography

      Evaluation of Moisture-Related Attenuation Coefficient and Water Diffusion Velocity in Human Skin Using Optical Coherence Tomography

      In this study, time-resolved optical coherence tomography (OCT) scanning images of the process of water diffusion in the skin that illustrate the enhancement in the backscattered intensities due to the increased water concentration are presented. In our experiments, the water concentration in the skin was increased by soaking the hand in water, and the same region of the skin was scanned and measured with the OCT system and a commercial moisture monitor every three minutes. To quantitatively analyze the moisture-related optical properties and the velocity of water diffusion in human skin, the attenuation coefficients of the skin, including the epidermis ...

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    8. Noninvasive imaging of heart chamber in Drosophila with dual-beam optical coherence tomography

      Noninvasive imaging of heart chamber in Drosophila with dual-beam optical coherence tomography

      The heart chamber of an adult Drosophila is approximately 2 mm long and 0.5 mm wide, and the interwall separation of different heart portions during systole and diastole range from tens of micrometers to hundreds of micrometers. Furthermore, the heart chamber has a curved structure, which results in the larger differences in depth between the different heart portions. However, applying the wavelength calibration process before Fourier transform in an optical coherence tomography (OCT) system may cause degradation in system sensitivity and longitudinal resolution when the optical path difference between the reference and sample arms increases, which makes imaging the ...

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    9. Diagnosis of oral precancer with optical coherence tomography

      Diagnosis of oral precancer with optical coherence tomography

      A procedure for computer analyzing an optical coherence tomography (OCT) image of normal and precancerous oral mucosae is demonstrated to reasonably plot the boundary between epithelium (EP) and lamina propria (LP) layers, determine the EP thickness, and estimate the range of dysplastic cell distribution based on standard deviation (SD) mapping. In this study, 54 normal oral mucosa, 39 oral mild dysplasia, and 44 oral moderate dysplasia OCT images are processed for evaluating the diagnosis statistics. Based on SD mapping in an OCT image, it is found that the laterally average range percentages of 70% SD maximum level in the EP ...

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    10. Motion-insensitive optical coherence tomography based micro-angiography

      Motion-insensitive optical coherence tomography based micro-angiography
      An improved image processing procedure for suppressing the phase noise due to a motion artifact acquired during optical coherence tomography scanning and effectively illustrating the blood vessel distribution in a living tissue is demonstrated. This new processing procedure and the widely used procedure for micro-angiography application are based on the selection of high-frequency components in the spatial-frequency spectrum of B-mode scanning (x-space), which are contributed from the image portions of moving objects. However, by switching the processing order between the x-space and k-space, the new processing procedure shows the superior function of effectively suppressing the phase noise due to a ...
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    11. Method for analyzing mucosa samples with optical coherence tomography

      Method for analyzing mucosa samples with optical coherence tomography

      A method for analyzing mucosa structure with optical coherence tomography (OCT) is provided, and includes: (a) scanning a mucosa sample with optical coherence tomography; (b) choosing a lateral range from a two- or three-dimensional OCT image and analyzing all the A-scan intensity profiles in the lateral range; (c) calculating three indicators in each A-scan intensity profile, including the standard deviation for a certain depth range below the sample surface, the exponential decay constant of the spatial-frequency spectrum and the epithelium thickness under the condition that the basement membrane is identifiable; and (d) using the three indicators of each A-scan intensity ...

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    12. Microvascular Imaging Using Swept-Source Optical Coherence Tomography with Single-Channel Acquisition

      Microvascular Imaging Using Swept-Source Optical Coherence Tomography with Single-Channel Acquisition
      This study proposes a new approach to improve the phase stability for swept-source optical coherence tomography (SS-OCT) with single-channel acquisition. This approach can improve the phase instability due to the A-scan trigger jitter from the swept source, or the asynchronization between the A-scan trigger and high-speed digitizer, which enables the visualization of vascular structures by SS-OCT. Aside from reducing the phase noise of the OCT system, only one channel is required for the A-scan trigger, data storage, and wavelength calibration by implementing the proposed approach. Finally, human skin was scanned in vivo to demonstrate the vascular images.
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    13. Method for suppressing the mirror image in Fourier-domain optical coherence tomography

      Method for suppressing the mirror image in Fourier-domain optical coherence tomography
      A method, novel to our knowledge, for effective mirror image suppression in Fourier-domain optical coherence tomography based on a phase shift between neighboring A-mode scans is demonstrated. By realizing that the phase shifts of the real and mirror images are mutually reversed and assuming that the real image intensities of the two successive A-mode scans are the same, we can solve a set of two coupled equations to obtain the real image signals. The images based on the scanning of a high-resolution spectral-domain optical coherence tomography system are processed to show effective mirror image suppression results. Compared with a similar ...
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    14. Observations of cardiac beating behaviors of wild-type and mutant Drosophilae with optical coherence tomography

      Observations of cardiac beating behaviors of wild-type and mutant Drosophilae with optical coherence tomography
      Time-resolved optical coherence tomography (OCT) scanning images of wild-type and mutant fruit flies (Drosophila melanogaster), illustrating the heartbeat patterns for evaluating their cardiac functions, are demonstrated. Based on the heartbeat patterns, the beat rate and the relative phase between the first two heart segments can be evaluated. The OCT scanning results of mutant flies with impaired proteasome function in cardiac muscles show irregular heartbeat patterns and systematically decreased average beat rates, when compared with the regular patterns of ∼4.97 beats/s in average beat rate of the wild-type. In both wild-type and proteasome mutant flies, the beatings at different ...
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    15. Defect detection and property evaluation of indium tin oxide conducting glass using optical coherence tomography

      Defect detection and property evaluation of indium tin oxide conducting glass using optical coherence tomography
      This study demonstrates a new approach for evaluating the properties of indium tin oxide (ITO) conducting glass and identifying defects using optical coherence tomography (OCT). A swept-source OCT system was implemented to scan the ITO conducting glass to enable two-dimensional or three-dimensional imaging. With OCT scanning, the defects can be clearly identified at various depths. Several parameters in addition to morphological information can be estimated simultaneously, including the thickness of the glass substrate, the refractive index, reflection coefficient, and transmission coefficient, all of which can be used to evaluate the quality of ITO conducting glass. This study developed a modified ...
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    16. Characterizing the localized surface plasmon resonance behaviors of Au nanorings and tracking their diffusion in bio-tissue with optical coherence tomography

      Characterizing the localized surface plasmon resonance behaviors of Au nanorings and tracking their diffusion in bio-tissue with optical coherence tomography
      , , , , , , Chou, , , , , The characterization results of the localized surface plasmon resonance (LSPR) of Au nanorings (NRs) with optical coherence tomography (OCT) are first demonstrated. Then, the diffusion behaviors of Au NRs in mouse liver samples tracked with OCT are shown. For such research, aqueous solutions of Au ... [Biomed. Opt. Express 1, 1059-1073 (2010)]
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    17. Clinical diagnosis of oral submucous fibrosis with optical coherence tomography

      A swept-source optical coherence tomography (SS-OCT) system with a specially designed probe is built for clinical scanning of oral submucous fibrosis (OSF) patients. By analysing 44 OSF cases of SS-OCT scanning results, two indicators, including epithelium (EP) thickness and standard deviation (SD) of A-mode scan intensity in the laminar propria (LP) layer, are found useful for real-time OSF diagnosis. Statistics show that sensitivity and specificity of LP SD can reach 84.1 and 95.5 %, respectively. Also, both sensitivity and specificity of EP thickness can reach 100 %.
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    18. Diagnosis of oral submucous fibrosis with optical coherence tomography

      The epithelium (EP) thickness and the standard deviation (SD) of A-mode scan intensity in the laminar propria (LP) layer are used as effective indicators for the diagnosis of oral submucous fibrosis (OSF) based on the noninvasive clinical scanning of a swept-source optical coherence tomography (OCT) system of ~6 µm in axial resolution (in tissue) and 103 dB in sensitivity. Compared with the corresponding parameters in healthy oral mucosal mucosa, in OSF mucosa, the EP thickness becomes smaller and the SD of A-mode scan intensity in the LP layer (LP SD) also becomes smaller. The LP SD can also be used ...

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    19. Differentiating oral lesions in different carcinogenesis stages with optical coherence tomography

      A swept-source optical coherence tomography (SS-OCT) system is used to clinically scan oral lesions in different oral carcinogenesis stages, including normal oral mucosa control, mild dysplasia (MiD), moderate dysplasia (MoD), early-stage squamous cell carcinoma (ES-SCC), and well-developed SCC (WD-SCC), for diagnosis purpose. On the basis of the analyses of the SS-OCT images, the stages of dysplasia (MiD and MoD), and SCC (ES-SCC and WD-SCC) can be differentiated from normal control by evaluating the depth-dependent standard deviation (SD) values of lateral variations. In the dysplasia stage, the boundary between the epithelium (EP) and lamina propria (LP) layers can still be identified ...

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    20. Effective indicators for diagnosis of oral cancer using optical coherence tomography

      Effective indicators for diagnosis of oral cancer using optical coherence tomography

      C. C. Yang, Meng-Tsan Tsai, Hsiang-Chieh Lee, Cheng-Kuang Lee, Chuan-Hang Yu, Hsin-Ming Chen, Chun-Pin Chiang, Cheng-Chang Chang, Yih-Ming Wang, C. C. Yang A swept-source optical coherence tomography system is used to clinically scan oral precancer and cancer patients for statistically analyzing the effective indicators of diagnosis. Three indicators are considered, including the standard deviation (SD) of an A-mode scan signal profile, the ... [Opt. Express 16, 15847-15862 (2008)]

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    21. Delineation of an oral cancer lesion with swept-source optical coherence tomography

      We demonstrate the ex vivo imaging of an oral cancerous sample with a swept-source optical coherence tomography (SS-OCT) system. With the axial resolution of 8μm in free space and system sensitivity of 108dB, we can well distinguish the normal and abnormal tissue portions in a sample. In particular, we analyze the lateral variation of A-scan profiles to show two parameters of SS-OCT signal for delineating an oral cancer lesion. One of the parameters is the decay constant in the exponential fitting of the SS-OCT signal intensity along depth. This decay constant decreases as the A-scan point moves laterally ...

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    22. Measurement of the hemoglobin oxygen saturation level with spectroscopic spectral-domain optical coherence tomography

      We report the measurement of the hemoglobin (Hb) oxygen saturation level in human blood with a spectroscopic spectral-domain optical coherence tomography (SSD-OCT) system based on the crossover behavior of Hb and oxyhemoglobin (HbO_2) absorption coefficients around 800 nm. By calculating the ratio ... [Opt. Lett. 33, 416-418 (2008)]
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    1-22 of 22
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    Effective indicators for diagnosis of oral cancer using optical coherence tomography Characterizing the localized surface plasmon resonance behaviors of Au nanorings and tracking their diffusion in bio-tissue with optical coherence tomography Defect detection and property evaluation of indium tin oxide conducting glass using optical coherence tomography Observations of cardiac beating behaviors of wild-type and mutant Drosophilae with optical coherence tomography Microvascular Imaging Using Swept-Source Optical Coherence Tomography with Single-Channel Acquisition Post-Doctoral and Graduate Student Research Positions at the University of Illinois Urbana-Champaign Multiscale correlation of microvascular changes on optical coherence tomography angiography with retinal sensitivity in diabetic retinopathy Macrophage targeted theranostic strategy for accurate detection and rapid stabilization of the inflamed high-risk plaque PERSONALIZED CHARACTERISTICS OF MORPHOMETRIC AND FUNCTIONAL PARAMETERS OF RETINA IN ARTERIAL HYPERTENTION ACCORDING TO OPTICAL COHERENCE TOMOGRAPHY-ANGIOGRAPHY DATA Coherence function-encoded optical palpation Systems, methods, and media for multiple reference arm spectral domain optical coherence tomography Monitoring dissolution of a dosage form in progress during dissolution by low coherence interferometry