1. Articles from Yu Chen

    1-24 of 75 1 2 3 4 »
    1. Evaluation of the normal airway morphology using optical coherence tomography

      Evaluation of the normal airway morphology using optical coherence tomography

      Background The anatomical location of small airways, the distribution of airway cartilage and their correlation with ageing have not been well elucidated. Objective To explore the morphological characteristics of small airways in vivo , and how airway structural changes correlate with age using endobronchial optical coherence tomography (EB-OCT). Methods We recruited 112 subjects with peripheral pulmonary nodules. Participants underwent computed tomography, spirometry, and EB-OCT measurements. We measured the airway internal diamaeter (D mean ), inner area (Ai), airway wall area percentage (Aw%) and the thickness of airway cartilage. EB-OCT airway structural characteristics at different age intervals were analyzed, and the association between ...

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    2. PhD Student and Postdoctoral Associate Positions at the University of Massachusetts

      PhD Student and Postdoctoral Associate Positions at the University of Massachusetts

      We are looking for highly motivated individuals to join the Biophotonics Imaging Laboratory at UMass Amherst and Worcester. Our lab has interdisciplinary biomedical engineering research programs focusing on the development of novel optical imaging methods for biomedical applications, including functional neuroimaging, early cancer detection, transplant organ evaluation, and tissue engineering. Our optical imaging technologies include optical coherence tomography (OCT), multi-photon microscopy (MPM), fluorescence molecular imaging (FMI), laminar optical tomography (LOT), and endoscopy. A detailed description of our research can be found at: http://blog.umd.edu/biophotonics/research/ Candidates with experiences on biomedical engineering, optical engineering, and/or electrical/mechanical ...

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    3. Significances of spirometry and impulse oscillometry for detecting small airway disorders assessed with endobronchial optical coherence tomography in COPD

      Significances of spirometry and impulse oscillometry for detecting small airway disorders assessed with endobronchial optical coherence tomography in COPD

      Background: Spirometry confers limited value for identifying small-airway disorders (SADs) in early-stage COPD, which can be detected with impulse oscillometry (IOS) and endobronchial optical coherence tomography (EB-OCT). Whether IOS is useful for reflecting small-airway morphological abnormalities in COPD remains unclear. Objectives: To compare the diagnostic value of spirometry and IOS for identifying SADs in heavy-smokers and COPD based on the objective assessment with EB-OCT. Methods: We recruited 59 COPD patients (stage I, n=17; stage II, n=18; stage III–IV, n=24), 26 heavy-smokers and 21 never-smokers. Assessments of clinical characteristics, spirometry, IOS and EB-OCT were performed. Receiver operation ...

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    4. Depth-resolved mapping of muscular bundles in myocardium pulmonary junction using optical coherence tomography

      Depth-resolved mapping of muscular bundles in myocardium pulmonary junction using optical coherence tomography

      Atrial fibrillation (AF) is the most common cardiac arrhythmia and has high patient morbidity. One of the root causes of AF is initiating triggers from atrial myocardium extending into the pulmonary veins. Visualizing the muscular bundles of myocardial extension is essential to guide the catheter radio-frequency ablation and confirm the curative tissue necrosis thereafter. We applied optical coherence tomography (OCT) for direct visualization of cardial muscle extension in myocardium pulmonary junction. Two perspectives (cross-sectional and en face images) are presented for imaging myocardial extensions. The results demonstrated that cross-sectional images can quickly locate the myocardium pulmonary junction. And en face ...

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    5. 3D mesoscopic fluorescence tomography for imaging micro-distribution of antibody-photon absorber conjugates during near infrared photoimmunotherapy in vivo

      3D mesoscopic fluorescence tomography for imaging micro-distribution of antibody-photon absorber conjugates during near infrared photoimmunotherapy in vivo

      As a novel low-side-effect cancer therapy, photo-immunotherapy (PIT) is based on conjugating monoclonal antibody (mAb) with a near-infrared (NIR) phthalocyanine dye IRDye700DX (IR 700). IR700 is not only fluorescent to be used as an imaging agent, but also phototoxic. When illuminating with NIR light, PIT can induce highly-selective cancer cell death while leaving most of tumor blood vessels unharmed, leading to an effect termed super-enhanced permeability and retention (SUPR), which can significantly improve the effectiveness of anti-cancer drug. Currently, the therapeutic effects of PIT are monitored using 2D macroscopic fluorescence reflectance imager, which lacks the resolution and depth information to ...

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    6. Optical coherence tomography and computer-aided diagnosis of a murine model of chronic kidney disease

      Optical coherence tomography and computer-aided diagnosis of a murine model of chronic kidney disease

      Chronic kidney disease (CKD) is characterized by a progressive loss of renal function over time. Histopathological analysis of the condition of glomeruli and the proximal convolutional tubules over time can provide valuable insights into the progression of CKD. Optical coherence tomography (OCT) is a technology that can analyze the microscopic structures of a kidney in a nondestructive manner. Recently, we have shown that OCT can provide real-time imaging of kidney microstructures in vivo without administering exogenous contrast agents. A murine model of CKD induced by intravenous Adriamycin (ADR) injection is evaluated by OCT. OCT images of the rat kidneys have ...

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    7. Multi-shaping technique reduces sidelobe magnitude in optical coherence tomography

      Multi-shaping technique reduces sidelobe magnitude in optical coherence tomography

      Shaping methods that are commonly used in Fourier-domain optical coherence tomography (FD-OCT) can suppress sidelobe artifacts in the axial direction, but they typically broaden the mainlobe of the point spread function (PSF) and reduce the axial resolution. To improve OCT image quality without this tradeoff, we have developed a multi-shaping technique that reduces the axial sidelobe magnitude dramatically and achieves better axial resolution than conventional shaping methods. This technique is robust and compatible in various FD-OCT imaging systems. Testing of multi-shaping in three experimental settings shows that it reduced the axial sidelobe contribution by more than 8 dB and improved ...

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    8. Monitoring Kidney Microanatomy Changes During Ischemia-Reperfusion Process Using Texture Analysis of OCT Images

      Monitoring Kidney Microanatomy Changes During Ischemia-Reperfusion Process Using Texture Analysis of OCT Images

      Impact Statement: Tubular diameter has been developed previously as a potential biomarker for the transplant kidney. However, the tubular lumens were segmented out based on an empirically-determined threshold. In our study, a fully automatic texture analysis algorithm has been developed for OCT image analysis of kidney microanatomy during ischemia-reperfusion process. Our method can potentially be applicable in evaluating the status of donor kidneys prior to and after their transplantation. Abstract: Kidney ischemia-reperfusion (I/R) accounts for the majority of acute kidney injury cases, whose consequences are commonly encountered after kidney transplantation. Optical coherence tomography (OCT) has been applied to image ...

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    9. Postdoctoral Fellow, Bioengineering at University of Maryland - College Park

      Postdoctoral Fellow, Bioengineering at University of Maryland - College Park

      We are seeking a postdoctoral fellow to pursue research on developing novel optical imaging devices and applications on cancer diagnosis, functional brain imaging and tissue engineering. Candidates must hold a Ph.D. in engineering, physics, or related fields and have prior experience with Optics, OCT, Microscopy (e.g. fluorescence, confocal, Two-photon), and image analysis software development. Experience with cell culture and/or animals experiments is a plus. Please submit a cover letter with a brief description of research experience, interests, and career goals (≤ 2 pages), CV with complete list of publications, and contact information for 3 references in a single ...

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    10. 3D in vivo imaging with extended-focus optical coherence microscopy

      3D in vivo imaging with extended-focus optical coherence microscopy

      Optical coherence microscopy (OCM) has unique advantages of non-invasive 3D imaging without the need of exogenous labels for studying biological samples. However, the imaging depth of this technique is limited by the tradeoff between the depth of focus (DOF) and high lateral resolution in Gaussian optics. To overcome this limitation, we have developed an extended-focus OCM (xf-OCM) imaging system using quasi-Bessel beam illumination to extend the DOF to ∼100 μm, about 3-fold greater than standard OCM. High lateral resolution of 1.6 μm ensured detailed identification of structures within live animal samples. The insensitivity to spherical aberrations strengthened the capability ...

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    11. Optical coherence microscopy with extended focus for in vivo embryonic imaging

      Optical coherence microscopy with extended focus for in vivo embryonic imaging

      Optical coherence microscopy (OCM) has unique advantages of high-resolution volumetric imaging without relying on exogenous labels or dyes. It combines the coherence-gated depth discrimination of optical coherence tomography (OCT) with the high lateral resolution of confocal microscopy, offering an excellent balance between the resolutions and imaging depth. However, as the lateral resolution becomes higher, the imaging depth of OCM decreases and its three-dimensional imaging capability is greatly degraded. To overcome this limitation, we used amplitude apodization to create quasi-Bessel beam illumination in order to extend the depth of focus. The lateral and axial resolutions of our OCM system were measured ...

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    12. Phase variance optical coherence microscopy for label-free imaging of the developing vasculature in zebrafish embryos

      Phase variance optical coherence microscopy for label-free imaging of the developing vasculature in zebrafish embryos

      A phase variance optical coherence microscope (pvOCM) has been created to image blood flow in the microvasculature of zebrafish embryos, without the use of exogenous labels. The pvOCM imaging system has axial and lateral resolutions of 2.8    μ m 2.8  μm in tissue and imaging depth of more than 100    μ m 100  μm . Images of 2 to 5 days postfertilization zebrafish embryos identified the detailed anatomical structure based on OCM intensity contrast. Phase variance contrast offered visualization of blood flow in the arteries, veins, and capillaries. The pvOCM images of the vasculature were confirmed by direct comparisons with fluorescence ...

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    13. Depth-resolved imaging of colon tumor using optical coherence tomography and fluorescence laminar optical tomography

      Depth-resolved imaging of colon tumor using optical coherence tomography and fluorescence laminar optical tomography

      Early detection of neoplastic changes remains a critical challenge in clinical cancer diagnosis and treatment. Many cancers arise from epithelial layers such as those of the gastrointestinal (GI) tract. Current standard endoscopic technology is difficult to detect the subsurface lesions. In this research, we investigated the feasibility of a novel multi-modal optical imaging approach including high-resolution optical coherence tomography (OCT) and high-sensitivity fluorescence laminar optical tomography (FLOT) for structural and molecular imaging. The C57BL/6J-Apc Min /J mice were imaged using OCT and FLOT, and the correlated histopathological diagnosis was obtained. Quantitative structural (scattering coefficient) and molecular (relative enzyme activity ...

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    14. Imaging Spinal Structures With Polarization-Sensitive Optical Coherence Tomography

      Imaging Spinal Structures With Polarization-Sensitive Optical Coherence Tomography

      Impact Statement: We investigate polarization-sensitive optical coherence tomography (PS-OCT) to obtain both intensity and polarization contrast images of in vivo and ex vivo spinal structures like subcutaneous fat, supraspinous ligament, interspinous ligament, ligamentum flavum, dura, and spinal cord in a piglet model. The PS-OCT can provide enhanced contrast characteristic structures compared to the intensity OCT; therefore it has the potential for guidance in spine interventional procedures. Abstract: We investigate polarization-sensitive optical coherence tomography (PS-OCT) to obtain both intensity and polarization contrast images of in vivo and ex vivo spinal structures like subcutaneous fat, supraspinous ligament, interspinous ligament, ligamentum flavum, dura ...

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    15. Measuring Airway Remodeling in Patients with Different COPD Staging Using Endobronchial Optical Coherence Tomography

      Measuring Airway Remodeling in Patients with Different COPD Staging Using Endobronchial Optical Coherence Tomography

      Background Although forced expiratory volume in one second (FEV 1 ) remains the gold standard for staging COPD, the association between airway remodeling and airflow limitation remains unclear. Objective Endobronchial optical coherence tomography (EB-OCT) was performed to assess the association between disorders of large- and medium-to-small-sized airways and COPD staging. We also evaluated small-airway architecture in heavy-smokers with normal FEV 1 (S NL ) and healthy never-smokers. Methods We recruited 48 COPD patients (stage Ⅰ, n=14; stage Ⅱ, n=15; stage Ⅲ-Ⅳ, n=19), 21 S NL , and 17 healthy never-smokers. Smoking history inquiry, spirometry, chest computed tomography, bronchoscopy and EB-OCT ...

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      Mentions: Wei Wang
    16. Multi-modality Optical Imaging of Rat Kidney Dysfunction: In Vivo Response to Various Ischemia Times

      Multi-modality Optical Imaging of Rat Kidney Dysfunction: In Vivo Response to Various Ischemia Times

      We observed in vivo kidney dysfunction with various ischemia times at 30, 75, 90, and 120 min using multi-modality optical imaging: optical coherence tomography (OCT), Doppler OCT (DOCT), and two-photon microscopy (TPM). We imaged the renal tubule lumens and glomerulus at several areas of each kidney before, during, and after ischemia of 5-month-old female Munich-Wistar rats. For animals with 30 and 75 min ischemia times, we observed that all areas were recovered after ischemia, that tubule lumens were re-opened and the blood flow of the glomerulus was re-established. For animals with 90 and 120 min ischemia times, we observed unrecovered ...

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    17. Research Associate Position in OCT at the University of Maryland

      Research Associate Position in OCT at the University of Maryland

      Position description: A Postdoctoral Research Associate position is available at the University of Maryland, College Park. Research projects include intraoperative imaging of transplant kidney viability using OCT in collaboration with Georgetown University Medical Center, and development of automatic image processing algorithm to predict organ viability. Required expertise: Ph.D. in physics, electrical engineering, optical engineering, or biomedical/bioengineering. Hand-on experience on optical and electronic instrumentation and strong programming skills (Matlab, Labview, and C++). Prior research expertise on OCT and image processing. Application: Interested candidates should submit Curriculum vitae with a list of contact information of 3 references by email to ...

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    18. Optical Coherence Tomography of the Aging Kidney

      Optical Coherence Tomography of the Aging Kidney

      Objectives: The aging kidney exhibits a progressive decline in renal function with characteristic histopathologic changes and is a risk factor for renal transplant. However, the degree to which the kidney exhibits this decline depends on several factors that vary from one individual to the next. Optical coherence tomography is an evolving noninvasive imaging technology that has recently been used to evaluate acute tubular necrosis of living-human donor kidneys before their transplant. With the increasing use of kidneys from older individuals, it is important to determine whether optical coherence tomography also can distinguish the histopathology associated with aging. Materials and Methods ...

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    19. Validation of Human Small Airway Measurements Using Endobronchial Optical Coherence Tomography

      Validation of Human Small Airway Measurements Using Endobronchial Optical Coherence Tomography

      PURPOSE: To evaluate the usefulness of endobronchial optical coherence tomography (EB-OCT) in assessing small airways morphology in vivo. METHODS: Twelve patients with pulmonary nodules scheduled for lung resection underwent spirometry, multidetector computed tomography (MDCT) and EB-OCT. We measured Dmean (mean luminal diameter), Ai (inner luminal area), Aw (airway wall area) and Aw% [Aw/(Ai+Aw) ×100%] from the 3rd to 5th generation bronchi of RB9 segment by MDCT. Dmean, Ai, Aw and Aw% from the 3rd to 9th generation bronchi of RB9 segment were measured by EB-OCT and histology. The correlations of these 4 parameters, measured by the three methods ...

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    20. OCT imaging of myocardium extending to pulmonary vein

      OCT imaging of myocardium extending to pulmonary vein

      In this study, we propose to use optical coherence tomography to enable a direct visualization of myocardium extending into the pulmonary vein (PV). The results showed that there are obvious differences in the morphology of myocardium and fibrous tissue in the transition region of myocardial sleeve, which is in agreement with the histological analysis. In addition, the myocardial area in transition point has three layers in the depth of 1 mm, and the depth-resolved myocardial fiber show different orientation in the different layers. This characteristic was applied for segmentation of the structures of myocardium extending into PV.

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    21. Label-free imaging of developing vasculature in zebrafish with phase variance optical coherence microscopy

      Label-free imaging of developing vasculature in zebrafish with phase variance optical coherence microscopy

      A phase variance optical coherence microscope (pvOCM) has been created to visualize blood flow in the vasculature of zebrafish embryos, without using exogenous labels. The pvOCM imaging system has axial and lateral resolutions of 2 μm in tissue, and imaging depth of more than 100 μm. Imaging of 2–5 days post-fertilization zebrafish embryos identified the detailed structures of somites, spinal cord, gut and notochord based on intensity contrast. Visualization of the blood flow in the aorta, veins and intersegmental vessels was achieved with phase variance contrast. The pvOCM vasculature images were confirmed with corresponding fluorescence microscopy of a zebrafish ...

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    22. Optical Coherence Tomographic Elastography Reveals Mesoscale Shear Strain Inhomogeneities in the Annulus Fibrosus

      Optical Coherence Tomographic Elastography Reveals Mesoscale Shear Strain Inhomogeneities in the Annulus Fibrosus

      Study Design. Basic science study using in vitro tissue testing and imaging to characterize local strains in annulus fibrosus (AF) tissue. Objective. To characterize mesoscale strain inhomogeneities between lamellar and inter-/translamellar (ITL) matrix compartments during tissue shear loading. Summary of Background Data. The intervertebral disc (IVD) is characterized by significant heterogeneities in tissue structure and plays a critical role in load distribution and force transmission in the spine. In particular, the AF possesses a lamellar architecture interdigitated by a complex network of extracellular matrix components that form a distinct ITL compartment. Currently, there is not a firm understanding of ...

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    23. Validation of human small-airway measurements using endobronchial optical coherence tomography: an observational study

      Validation of human small-airway measurements using endobronchial optical coherence tomography: an observational study

      Background Small-airway remodelling is the cardinal pathological feature underlying chronic obstructive pulmonary disease (COPD). Identification of early-stage pathological changes is crucial for the diagnosis, treatment, and prognosis of respiratory diseases. Our study aimed to investigate the usefulness of endobronchial optical coherence tomography (EB-OCT) in assessment of small-airways morphology in patients with pulmonary nodules who were scheduled for lung resection surgery (four had COPD, four were smokers with normal lung function, and four were life-long non-smokers). Patients with respiratory diseases other than COPD were excluded. Methods 12 patients with pulmonary nodules scheduled for lung resection underwent spirometry, multidetector CT (MDCT), and ...

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      Mentions: Yu Chen Wei Wang
    24. Validation of human small airway measurements using endobronchial optical coherence tomography

      Validation of human small airway measurements using endobronchial optical coherence tomography

      Background Small airway remodeling is the cardinal feature underlying chronic airway diseases. There is no modality which identifies small airway pathological changes, which is crucial for early diagnosis, efficacy and prognostic assessment. Objective To evaluate the usefulness of endobronchial optical coherence tomography (EB-OCT) in assessing small airways morphology in vivo . Methods Twelve patients with pulmonary nodules scheduled for lung resection underwent spirometry, multi-detector computed tomography (MDCT) and EB-OCT. We measured D mean (mean luminal diameter), Ai (inner luminal area), Aw (airway wall area) and Aw% [Aw/(Ai + Aw) × 100%] from the 3rd to 5th generation bronchi of RB9 segment by ...

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    Effects of axial resolution improvement on optical coherence tomography (OCT) imaging of gastrointestinal tissues Feature Of The Week 9/6/09: Automated Quantification of Microstructural Dimensions of the Human Kidney using Optical Coherence Tomography Investigation of pore structure and cell distribution in EH-PEG hydrogel scaffold using optical coherence tomography and fluorescence microscopy Cellular resolution ex vivo imaging of gastrointestinal tissues with optical coherence microscopy Optical Coherence Tomography of Human Kidney Congratulations to Chia-Pin Liang From the University of Maryland a Winner of a 2012 Student Travel Grant Award Research Associate Position in OCT at the University of Maryland Repeatability and Reproducibility of Axial and Lateral Measurements on Handheld Optical Coherence Tomography Systems Compared with Tabletop System Bleb Morphology Using Anterior-Segment Optical Coherence Tomography after Ahmed Glaucoma Valve Surgery with Tenon Capsule Resection Utility of optical coherence tomography angiography in pregnancy-associated central serous chorioretinopathy Multimodal Imaging at Depth Using Innovations in Raman Spectroscopy and Optical Coherence Tomography Convolutional neural network-based automatic detection of follicle cells in ovarian tissue using optical coherence tomography