1. Articles from Jun Zhang

    1-24 of 45 1 2 »
    1. Classification of Salivary Gland Tumors Based on Quantitative Optical Coherence Tomography

      Classification of Salivary Gland Tumors Based on Quantitative Optical Coherence Tomography

      Background and Objectives Visual inspection is the primary diagnostic method for oral diseases, and its accuracy of diagnosis mainly depends on surgeons’ experience. Histological examination is still the golden standard, but it is invasive and time‐consuming. In order to address these issues, as a noninvasive imaging technique, optical coherence tomography (OCT) can differentiate oral tissue with advantages of real‐time, in situ , and high resolution. The aim of this study is to explore optimal quantitative parameters in OCT images to distinguish different salivary gland tumors. Study Design/Materials and Methods OCT images of four salivary gland tumors were obtained ...

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    2. The vessel density of the superficial retinal capillary plexus as a new biomarker in cerebral small vessel disease: an optical coherence tomography angiography study

      The vessel density of the superficial retinal capillary plexus as a new biomarker in cerebral small vessel disease: an optical coherence tomography angiography study

      Background: Optical coherence tomography angiography (OCTA) is a novel and noninvasive technique for the quantitative assessment of retinal microvascular perfusion. Since the retinal and cerebral small vessels share similar embryological origins, anatomical features, and physiological properties, altered retinal microvasculature might provide a new perspective on the mechanisms of cerebral small vessel disease (CSVD). Objective: We aimed to evaluate retinal vessel density (VD) in patients with CSVD using OCTA and identify associations with cerebral magnetic resonance imaging (MRI) markers and cognitive function. Methods: We prospectively recruited 47 CSVD patients and 30 healthy controls (HCs) to participate in the study. All participants ...

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    3. Dynamic-range compression and contrast enhancement in swept-source optical coherence tomography systems with a frequency gain compensation amplifier

      Dynamic-range compression and contrast enhancement in swept-source optical coherence tomography systems with a frequency gain compensation amplifier

      Significance: Optical coherence tomography (OCT) has been widely used in clinical studies. However, the image quality of OCT decreases with increasing imaging depth since the light is rapidly attenuated in biological tissues. Aim: We present a compensation approach to preserve weak high-frequency signals from deep structures and compress the dynamic range of the detected signal for superior analog-to-digital conversion and image display capability. Approach: A homemade frequency gain compensation amplifier is designed and fabricated to amplify the electrical signal from a balanced photodetector and compensate for the signal attenuation in swept-source OCT (SSOCT). Results: It is demonstrated in imaging various ...

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    4. Integrated Multifunctional Laryngoscope for Medical Diagnosis and Treatment

      Integrated Multifunctional Laryngoscope for Medical Diagnosis and Treatment

      Laryngeal lesions can cause great inconvenience to patients. Early diagnosis and corresponding treatments are critical to the survival of patients. However, the diagnosis and precise removal of tumors remain a challenge under the use of a white light laryngoscope. In this work, an integrated, multifunctional laryngoscope was designed and tested for the imaging evaluation and precision laser surgery for laryngeal tissue. This integrated diagnostic and therapeutic endoscopic system included two imaging modes (i.e., optical coherence tomography and white light endoscopy) and a laser ablation treatment mode. The endoscope had a common-path design to ensure that the same position could ...

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    5. Identification of oral cancer in OCT images based on an optical attenuation model

      Identification of oral cancer in OCT images based on an optical attenuation model

      Surgery is still the first choice to treat oral cancer, where it is important to detect surgical margins in order to reduce cancer recurrence and maintain oral-maxillofacial function simultaneously. As a non-invasive and in situ imaging technique, optical coherence tomography (OCT) can obtain images close to the resolution of histopathology, which makes it have great potential in intraoperative diagnosis. However, it is not enough to find surgical margins accurately just observing OCT images directly and qualitatively. The purpose of this study is to identify oral cancer in OCT images by investigating the quantitative difference of cancer and non-cancer tissue. Based ...

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    6. Multi-modal Anterior Eye Imager Combining Ultra-High Resolution OCT and Microvascular Imaging for Structural and Functional Evaluation of the Human Eye

      Multi-modal Anterior Eye Imager Combining Ultra-High Resolution OCT and Microvascular Imaging for Structural and Functional Evaluation of the Human Eye

      To establish complementary information for the diagnosis and evaluation of ocular surface diseases, we developed a multi-modal, non-invasive optical imaging platform by combining ultra-high resolution optical coherence tomography (UHR-OCT) with a microvascular imaging system based on slit-lamp biomicroscopy. Our customized UHR-OCT module achieves an axial resolution of ≈2.9 μm in corneal tissue with a broadband light source and an A-line acquisition rate of 24 kHz with a line array CCD camera. The microvascular imaging module has a lateral resolution of 3.5 μm under maximum magnification of ≈187.5× with an imaging rate of 60 frames/s, which is ...

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    7. Rapid, High-Resolution, Label-Free, and 3-Dimensional Imaging to Differentiate Colorectal Adenomas and Non-Neoplastic Polyps With Micro-Optical Coherence Tomography

      Rapid, High-Resolution, Label-Free, and 3-Dimensional Imaging to Differentiate Colorectal Adenomas and Non-Neoplastic Polyps With Micro-Optical Coherence Tomography

      INTRODUCTION: “ Resectanddiscard ” paradigmisoneofthemainstrategiestodealwithcolorectaldiminutivepolyps after optical diagnosis. However, there are risks that unrecognized potentially malignant lesions are discarded without accurate diagnosis. The purpose of this study is to validate the potential of micro- optical coherence tomography ( m OCT) to improve the diagnostic accuracy of colorectal lesions and help endoscopists make better clinical decision without additional pathology costs. METHODS: RESULTS: DISCUSSION: Fresh tissue samples were obtained from patients with colorectal polyps or colorectal cancer who received endoscopic therapy or laparoscopic surgery. These samples were instantly imaged by m OCT and then sent to pathological evaluation. Then, m OCT images were compared with ...

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    8. Correction of saturation effects in endoscopic swept-source optical coherence tomography based on dual-channel detection

      Correction of saturation effects in endoscopic swept-source optical coherence tomography based on dual-channel detection

      Saturation artifacts that are commonly observed in endoscopic swept-source optical coherence tomography (SSOCT) images cause image degradation and loss of image information. We present work on the correction of saturation effects in endoscopic SSOCT imaging. This method utilizes a broadband power divider with excellent pick-off flatness to divide the detected interference signal into the two channels of an analog-to-digital converter. Based on the precise calibration of the splitting ratio between the two channels, the maximum measurable signal power of the system was drastically increased by using the low level signal in one channel to correct the saturated signal in the ...

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    9. Dynamically focused optical coherence tomography for endoscopic applications

      Dynamically focused optical coherence tomography for endoscopic applications

      We report a demonstration of a small liquid-filled polymer lens that may be used to dynamically provide scanning depth focus for endoscopic optical coherence tomography (OCT) applications. The focal depth of the lens is controlled by changing the hydraulic pressure within the lens, enabling dynamic focal depth control without the need for articulated parts. The 1 mm diameter lens is shown to have resolving power of 5 μm, and can enable depth scans of 2.5 mm, making it suitable for use with OCT-enabled optical biopsy applications.

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    10. Contrast improvement for swept source optical coherence tomography image of sub-surface tissue

      Contrast improvement for swept source optical coherence tomography image of sub-surface tissue

      Swept source optical coherence tomography (SSOCT) is an attractive biological imaging technology due to its advantages of simple setup and high imaging speed. As the light intensity attenuated rapidly in high scattering biological tissues, the contrast of OCT image will drop with depth. In this paper a new method was introduced to compensate the attenuation of imaging contrast in SSOCT. The interference signal was divided into two channels of analog to digital converter (ADC) with a splitting ratio of 1:5. The higher level signal in one channel was used to reconstruct deeper structure of tissue and the lower level ...

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    11. Suppression of saturation artifacts in swept source optical coherence tomography using dual channel detection

      Suppression of saturation artifacts in swept source optical coherence tomography using dual channel detection

      A technique to suppress saturation artifacts in swept source optical coherence tomography (SSOCT) system was presented. The detected signal was split into two channels of a high speed data acquisition card with two levels by a power divider. The signal in one channel with higher level was used to reconstruct OCT images and the signal in the other channel with lower level was used to compensate the saturated signal in the first channel by calibrating the splitting ratio between the two channels. Based on dual channel detection, this technique can enhance the dynamic range of SSOCT system and remove saturation ...

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    12. Trimodality imaging system and intravascular endoscopic probe: combined optical coherence tomography, fluorescence imaging and ultrasound imaging

      Trimodality imaging system and intravascular endoscopic probe: combined optical coherence tomography, fluorescence imaging and ultrasound imaging

      In this Letter, we present a trimodality imaging system and an intravascular endoscopic probe for the detection of early-stage atherosclerotic plaques. The integrated system is able to acquire optical coherence tomography (OCT), fluorescence, and ultrasound images and simultaneously display them in real time. A trimodality intravascular endoscopic probe of 1.2 mm in diameter and 7 mm in length was fabricated based on a dual-modality optical probe that integrates OCT and fluorescence imaging functions and a miniature ultrasound transducer. The probe is capable of rotating at up to 600 rpm. Ex vivo images from rabbit aorta and human coronary arteries ...

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    13. Integrated IVUS-OCT for Real-Time Imaging of Coronary Atherosclerosis

      Integrated IVUS-OCT for Real-Time Imaging of Coronary Atherosclerosis

      Accurate assessment of atherosclerotic plaque characteristics and the subsequent tailoring of optimal therapy holds great promise for preventing acute coronary syndromes (ACS) and life-threatening sequelae 1 . Combined use of optical coherence tomography (OCT) and intravascular ultrasound (IVUS) was proposed as a potential method for accurate assessment of plaque characteristics and vulnerability ( 2 , ). However, significant challenges remain in trying to adapt an integrated OCT-IVUS system for clinical applications. We report here a fully integrated intracoronary OCT-IVUS imaging technique to visualize atherosclerotic plaque in living animals and human coronary arteries from cadavers with high resolution and deep penetration capability simultaneously.

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    14. Feature Of The Week 11/24/13 : Miniature OCT/IVUS probe for automatically co-registered three-dimensional intracoronary imaging with real-time display

      Feature Of The Week 11/24/13 : Miniature OCT/IVUS probe for automatically co-registered three-dimensional intracoronary imaging with real-time display

      Combined use of intravascular ultrasound (IVUS) and optical coherence tomography (OCT) holds the potential of combining the strengths of both imaging modalities and improving the diagnostic accuracy of atherosclerotic plaque vulnerability. In this manuscript, we reported a co-registered intracoronary OCT-IVUS system and catheter with real-time imaging and polar-coordinate displaying capability, well-suited for clinical utilization in guiding interventional cardiologists. With an eventual goal of clinical use in humans, this novel catheter design and modified software are poised to strengthen the ability to diagnose vulnerable plaques in patients in real-time. We upgraded our old designs in the following aspects. 1) This novel ...

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    15. Miniature optical coherence tomography-ultrasound probe for automatically coregistered three-dimensional intracoronary imaging with real-time display

      Miniature optical coherence tomography-ultrasound probe for automatically coregistered three-dimensional intracoronary imaging with real-time display

      We have developed a novel miniature integrated optical coherence tomography (OCT)-intravascular ultrasound (IVUS) probe, with a 1.5-mm-long rigid part and 0.9-mm outer diameter, for real-time intracoronary imaging of atherosclerotic plaques and guiding of interventional procedures. By placing the OCT ball lens and IVUS transducer back-to-back at the same axial position, this probe can provide automatically coregistered, coaxial OCT-IVUS imaging. To demonstrate its real-time capability, three-dimensional OCT-IVUS imaging of a pig’s coronary artery displaying in polar coordinates, as well as images of three major types of atherosclerotic plaques in human cadaver coronary segments, were obtained using this ...

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    16. Imaging and quantifying Brownian motion of micro- and nanoparticles using phase-resolved Doppler variance optical coherence tomography

      Imaging and quantifying Brownian motion of micro- and nanoparticles using phase-resolved Doppler variance optical coherence tomography

      Different types and sizes of micro- and nanoparticles have been synthesized and developed for numerous applications. It is crucial to characterize the particle sizes. Traditional dynamic light scattering, a predominant method used to characterize particle size, is unable to provide depth resolved information or imaging functions. Doppler variance optical coherence tomography (OCT) measures the spectral bandwidth of the Doppler frequency shift due to the Brownian motion of the particles utilizing the phase-resolved approach and can provide quantitative information about particle size. Spectral bandwidths of Doppler frequency shifts for various sized particles were quantified and were demonstrated to be inversely proportional ...

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    17. Imaging and quantifying Brownian motion of micro- and nanoparticles using phase-resolved Doppler variance optical coherence tomography

      Imaging and quantifying Brownian motion of micro- and nanoparticles using phase-resolved Doppler variance optical coherence tomography

      Different types and sizes of micro- and nanoparticles have been synthesized and developed for numerous applications. It is crucial to characterize the particle sizes. Traditional dynamic light scattering, a predominant method used to characterize particle size, is unable to provide depth resolved information or imaging functions. Doppler variance optical coherence tomography (OCT) measures the spectral bandwidth of the Doppler frequency shift due to the Brownian motion of the particles utilizing the phase-resolved approach and can provide quantitative information about particle size. Spectral bandwidths of Doppler frequency shifts for various sized particles were quantified and were demonstrated to be inversely proportional ...

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    18. High-speed upper-airway imaging using full-range optical coherence tomography

      High-speed upper-airway imaging using full-range optical coherence tomography

      Obstruction in the upper airway can often cause reductions in breathing or gas exchange efficiency and lead to rest disorders such as sleep apnea. Imaging diagnosis of the obstruction region has been accomplished using computed tomography (CT) and magnetic resonance imaging (MRI). However CT requires the use of ionizing radiation, and MRI typically requires sedation of the patient to prevent motion artifacts. Long-range optical coherence tomography (OCT) has the potential to provide high-speed three-dimensional tomographic images with high resolution and without the use of ionizing radiation. In this paper, we present work on the development of a long-range OCT endoscopic ...

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    19. Phase-resolved acoustic radiation force optical coherence elastography

      Phase-resolved acoustic radiation force optical coherence elastography

      Many diseases involve changes in the biomechanical properties of tissue, and there is a close correlation between tissue elasticity and pathology. We report on the development of a phase-resolved acoustic radiation force optical coherence elastography method (ARF-OCE) to evaluate the elastic properties of tissue. This method utilizes chirped acoustic radiation force to produce excitation along the sample’s axial direction, and it uses phase-resolved optical coherence tomography (OCT) to measure the vibration of the sample. Under 500-Hz square wave modulated ARF signal excitation, phase change maps of tissue mimicking phantoms are generated by the ARF-OCE method, and the resulting Young ...

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    20. Endoscopic long range fourier domain optical coherence tomography (LR-FD-OCT)

      Endoscopic long range fourier domain optical coherence tomography (LR-FD-OCT)

      An endoscopic swept-source Fourier Domain optical coherence tomographic system (FDOCT system) for imaging of tissue structure includes a Fourier Domain mode locked (FDML), high speed, narrow line-width, wavelength swept source, an OCT interferometer having a sample arm, a reference arm, a detection arm, and a source arm coupled to the swept source, an endoscopic probe coupled to the sample arm, and a data processing circuit coupled to the detection arm. The swept source includes a long optic fiber functioning as a cavity, a high optical gain lasing module, and a tunable narrow bandwidth bandpass filter for wavelength selection combined to ...

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    21. Intravascular atherosclerotic imaging with combined fluorescence and optical coherence tomography probe based on a double-clad fiber combiner

      Intravascular atherosclerotic imaging with combined fluorescence and optical coherence tomography probe based on a double-clad fiber combiner

      We developed a multimodality fluorescence and optical coherence tomography probe based on a double-clad fiber (DCF) combiner. The probe is composed of a DCF combiner, grin lens, and micromotor in the distal end. An integrated swept-source optical coherence tomography and fluorescence intensity imaging system was developed based on the combined probe for the early diagnoses of atherosclerosis. This system is capable of real-time data acquisition and processing as well as image display. For fluorescence imaging, the inflammation of atherosclerosis and necrotic core formed with the annexin V–conjugated Cy5.5 were imaged. Ex vivo imaging of New Zealand white rabbit ...

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    22. An imaging-based approach to the evaluation of xerostomia

      An imaging-based approach to the evaluation of xerostomia

      Background and Objective Goal was to evaluate the potential of in vivo optical coherence tomography (OCT) imaging to determine the response of patients with xerostomia to a dry mouth toothpaste versus fluoride toothpaste placebo. Study Design/Materials and Methods Ten subjects with xerostomia participated in this double-blind, crossover, placebo-controlled study. After examination and OCT imaging, subjects used the first product for 15 days, followed by a 7-day washout period, and then they used the second product for 15 days. Data were acquired at 5-day intervals, also before and after the washout. Results Visual examination and tongue blade adhesion test did ...

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    23. Advances in a fully integrated intravascular OCT-ultrasound system for cardiovascular imaging

      Advances in a fully integrated intravascular OCT-ultrasound system for cardiovascular imaging

      Intracoronary optical coherence tomography (OCT) and intravascular ultrasound (IVUS) are two popular techniques for the detection and determination of atherosclerosis. IVUS allows visualization of plaques while also providing a large penetration depth to determine plaque volume. Intracoronary OCT provides the ability to capture microscopic features associated with high risk plaque. Traditionally to utilize the benefits of both modalities, separate probes and systems had to be used one at a time to image a vessel. We present work required to create a combined OCT IVUS system capable of simultaneous imaging to detect atherosclerotic plaques. A novel integrated probe of size 0 ...

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    24. Polarization-maintaining buffered Fourier domain mode-locked swept source for optical coherence tomography

      Polarization-maintaining buffered Fourier domain mode-locked swept source for optical coherence tomography
      A polarization-maintaining buffered Fourier domain mode-locked (FDML) swept source with a center wavelength of 1300 nm is demonstrated. The scanning rate of the buffered FDML swept source is doubled without sacrificing the output power of the swept source by combining two orthogonally polarized outputs with a polarization beam combiner. The stability of the swept source is improved because the polarization state of the laser beam inside the laser cavity is maintained without the use of any polarization controllers. The swept source is capable of an edge-to-edge tuning range of more than 150 nm and a FWHM range of 95 nm ...
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    1-24 of 45 1 2 »
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    1. (37 articles) Jun Zhang
    2. (32 articles) Zhongping Chen
    3. (31 articles) UC Irvine
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    5. (10 articles) Qifa Zhou
    6. (8 articles) K. Kirk Shung
    7. (7 articles) Gangjun Liu
    8. (6 articles) Sun Yat-Sen University
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    High-speed and wide bandwidth Fourier domain mode-locked wavelength swept laser with multiple SOAs High-dynamic-range quantitative phase imaging with spectral domain phase microscopy Integrated intravascular optical coherence tomography ultrasound imaging system Integrated intravascular optical coherence tomography (OCT) - ultrasound (US) imaging system A dual-modality probe utilizing intravascular ultrasound and optical coherence tomography for intravascular imaging applications Feature Of The Week 1/30/11: Development of Dual-Mode OCT and IVUS for Intravascular Imaging - A look at recent work from University of Southern California and UC Irvine Feature Of The Week 11/24/13 : Miniature OCT/IVUS probe for automatically co-registered three-dimensional intracoronary imaging with real-time display High performance OCTA enabled by combining features of shape, intensity, and complex decorrelation A Novel 3D Segmentation Approach for Extracting Retinal Layers from Optical Coherence Tomography Images Assessing the Outcomes of Focused Heating of the Skin by a Long-Pulsed 1064 nm Laser with an Integrated Scanner, Infrared Thermal Guidance, and Optical Coherence Tomography Albumin‐PEG‐Based Biomaterial for Laser‐Tissue Soldering and Its Real‐Time Monitoring With Swept‐Source Optical Coherence Tomography Asymmetric response to ranibizumab in mixed choroidal neovascularization in a neovascular age-related macular degeneration diagnosed on OCT angiography