1. Articles from Yingtian Pan

    1-23 of 23
    1. Cerebral capillary flow imaging by wavelength‐division‐multiplexing swept‐source optical Doppler tomography

      Cerebral capillary flow imaging by wavelength‐division‐multiplexing swept‐source optical Doppler tomography

      Swept‐source optical coherence tomography has demonstrated the unique advantages for fast imaging rate and long imaging distance, however, limited axial resolution and complex phase noises restrict swept‐source optical coherence Doppler tomography (SS‐ODT) for quantitative capillary blood flow imaging in the deep cortices. Here, the wavelength‐division‐multiplexing optical Doppler tomography (WDM‐ODT) method, which divides a single interferogram into multiple phase‐correlated interferograms, is proposed to effectively enhance the sensitivity for cerebral capillary flow imaging. Both flow phantom and in vivo mouse brain imaging studies show that WDM‐ODT is able to significantly suppress background phase noise ...

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    2. Volumetric Doppler angle correction for ultrahigh-resolution optical coherence Doppler tomography

      Volumetric Doppler angle correction for ultrahigh-resolution optical coherence Doppler tomography

      Ultrahigh-resolution optical coherence Doppler tomography (μODT) demonstrates great potential for quantitative blood flow imaging owing to its large field of view and capillary resolution. However, μODT only detects the axial flow velocity and requires Doppler angle correction to retrieve the absolute velocity. Although methods for Doppler angle tracking of single or few large vessels have been reported, a method that enables angle correction of the entire 3D microvascular networks remains a challenge. Here, we present a method based on eigenvalue analysis of 3D Hessian matrix to retrieve the orientation of each tubular vessel. As the algorithm is voxel based, it ...

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    3. High-speed swept source optical coherence Doppler tomography for deep brain microvascular imaging

      High-speed swept source optical coherence Doppler tomography for deep brain microvascular imaging

      Noninvasive microvascular imaging using optical coherence Doppler tomography (ODT) has shown great promise in brain studies; however, high-speed microcirculatory imaging in deep brain remains an open quest. A high-speed 1.3 μm swept-source ODT (SS-ODT) system is reported which was based on a 200 kHz vertical-cavity-surface-emitting laser. Phase errors induced by sweep-trigger desynchronization were effectively reduced by spectral phase encoding and instantaneous correlation among the A-scans. Phantom studies have revealed a significant reduction in phase noise, thus an enhancement of minimally detectable flow down to 268.2 μm/s. Further in vivo validation was performed, in which 3D cerebral-blood-flow (CBF ...

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    4. Ultrasensitive quantification of 3D cerebral capillary blood flow network dynamics

      Ultrasensitive quantification of 3D cerebral capillary blood flow network dynamics

      Ultra-high resolution optical Doppler coherence tomography (μODT) is a promising tool for brain functional imaging. However, its sensitivity for detecting slow flows in capillary beds may limit its utility in visualizing and quantifying subtle changes in brain microcirculation. To address this limitation, we developed a novel method called contrast-enhanced μODT (c-μODT) in which intralipid is injected into mouse tail vein to enhance μODT detection sensitivity. We demonstrate that after intralipid injection, the flow detection sensitivity of μODT is dramatically enhanced by 230% as quantified by the fill factor (FF) of microvasculature. More importantly, we show that c-μODT preserves ...

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    5. Ultrasensitive detection of 3D cerebral microvascular network dynamics in vivo

      Ultrasensitive detection of 3D cerebral microvascular network dynamics in vivo

      Despite widespread applications of multiphoton microscopy in microcirculation, its small field of view and inability to instantaneously quantify cerebral blood flow velocity (CBFv) in vascular networks limit its utility in investigating the heterogeneous responses to brain stimulations. Optical Doppler tomography (ODT) provides 3D images of CBFv networks, but it suffers poor sensitivity for measuring capillary flows. Here we report on a new method, contrast-enhanced ODT with Intralipid that significantly improves quantitative CBFv imaging of capillary networks by obviating the errors from long latency between flowing red blood cells (low hematocrit ~ 20% in capillaries). This enhanced sensitivity allowed us to measure ...

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    6. Optical coherence Doppler tomography for quantitative cerebral blood flow imaging

      Optical coherence Doppler tomography for quantitative cerebral blood flow imaging

      Optical coherence Doppler tomography (ODT) is a promising neurotechnique that permits 3D imaging of the cerebral blood flow (CBF) network; however, quantitative CBF velocity (CBFv) imaging remains challenging. Here we present a simple phase summation method to enhance slow capillary flow detection sensitivity without sacrificing dynamic range for fast flow and vessel tracking to improve angle correction for absolute CBFv quantification. Flow phantom validation indicated that the CBFv quantification accuracy increased from 15% to 91% and the coefficient of variation (CV) decreased 9.3-fold;in vivo mouse brain validation showed that CV decreased 4.4-/10.8- fold for venular ...

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    7. Cerebral blood flow imaged with ultrahigh-resolution optical coherence angiography and Doppler tomography

      Cerebral blood flow imaged with ultrahigh-resolution optical coherence angiography and Doppler tomography

      Speckle contrast based optical coherence angiography (OCA) and optical coherence Doppler tomography (ODT) have been applied to image cerebral blood flow previously. However, the contrast mechanisms of these two methods are not fully studied. Here, we present both flow phantom and in vivo animal experiments using ultrahigh-resolution OCA (μOCA) and ODT (μODT) to investigate the flow sensitivity differences between these two methods. Our results show that the high sensitivity of μOCA for visualizing minute vasculature (e.g., slow capillary beds) is due to the enhancement by random Brownian motion of scatterers (e.g., red and white blood cells) within the ...

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    8. Characterization of dynamic physiology of the bladder by optical coherence tomography

      Characterization of dynamic physiology of the bladder by optical coherence tomography

      Because of its high spatial resolution and noninvasive imaging capabilities, optical coherence tomography has been used to characterize the morphological details of various biological tissues including urinary bladder and to diagnose their alternations (e.g., cancers). In addition to static morphology, the dynamic features of tissue morphology can provide important information that can be used to diagnose the physiological and functional characteristics of biological tissues. Here, we present the imaging studies based on optical coherence tomography to characterize motion related physiology and functions of rat bladder detrusor muscles and compared the results with traditional biomechanical measurements. Our results suggest that ...

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    9. Optical detection of brain function: simultaneous imaging of cerebral vascular response, tissue metabolism, and cellular activity in vivo

      Optical detection of brain function: simultaneous imaging of cerebral vascular response, tissue metabolism, and cellular activity in vivo

      It is known that a remaining challenge for functional brain imaging is to distinguish the coupling and decoupling effects among neuronal activity, cerebral metabolism, and vascular hemodynamics, which highlights the need for new tools to enable simultaneous measures of these three properties in vivo. Here, we review current neuroimaging techniques and their prospects and potential limitations for tackling this challenge. We then report a novel dual-wavelength laser speckle imaging (DW-LSI) tool developed in our labs that enables simultaneous imaging of cerebral blood flow (CBF), cerebral blood volume, and tissue hemoglobin oxygenation, which allows us to monitor neurovascular and tissue metabolic ...

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    10. High-resolution imaging diagnosis of human fetal membrane by three-dimensional optical coherence tomography

      High-resolution imaging diagnosis of human fetal membrane by three-dimensional optical coherence tomography
      Microscopic chorionic pseudocyst (MCP) arising in the chorion leave of the human fetal membrane (FM) is a clinical precursor for preeclampsia which may progress to fatal medical conditions (e.g., abortion) if left untreated. To examine the utility of three-dimensional (3D) optical coherence tomography (OCT) for noninvasive delineation of the morphology of human fetal membranes and early clinical detection of MCP, 60 human FM specimens were acquired from 10 different subjects undergoing term cesarean delivery for an ex vivo feasibility study. Our results showed that OCT was able to identify the four-layer architectures of human FMs consisting of high-scattering decidua ...
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    11. Enhancing Detection of Bladder Carcinoma In Situ by 3-Dimensional Optical Coherence Tomography

      Enhancing Detection of Bladder Carcinoma In Situ by 3-Dimensional Optical Coherence Tomography
      Purpose: We examined the usefulness of 3-dimensional optical coherence tomography to enhance the diagnosis of urothelial carcinoma in situ.Materials and Methods: By expressing SV40T antigen with uroplakin II promoter, carcinoma in situ readily develops in SV40T transgenic mice at about ages 8 to 20 weeks and then frank high grade papillary carcinoma develops in bladder epithelium. We examined 10 control and 40 SV40T mice during weeks 8 to 20 after birth by parallel en face white light imaging and 3-dimensional optical coherence tomography, and compared results with histology findings. We applied quantitative analysis of computer aided detection to 3-dimensional ...
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    12. On the possibility of time-lapse ultrahigh-resolution optical coherence tomography for bladder cancer grading

      has been recently demonstrated that the cellular details of bladder epithelium embedded in speckle noise can be uncovered with time-lapse ultrahigh-resolution optical coherence tomography (TL-uOCT) by proper time-lapse frame averaging that takes advantage of cellular micromotion in fresh biological tissue ex vivo. Here, spectral-domain 3-D TL-uOCT is reported to further improve the image fidelity, and new experimental evidence is presented to differentiate normal and cancerous nuclei of rodent bladder epithelia. Results of animal cancer study reveal that despite a slight overestimation (e.g., <10%) of nuclear size (DN) to histological evaluation, TL-uOCT is capable of distinguishing normal (DN7 µm) and ...
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    13. Diagnosis of Bladder Cancer With Microelectromechanical Systems-based Cystoscopic Optical Coherence Tomography

      Objectives To examine the utility and potential limitations of microelectromechanical systems-based spectral-domain cystoscopic optical coherence tomography (COCT) so as to improve the diagnosis of early bladder cancer. Methods An optical coherence tomography catheter was integrated into the single instrument channel of a 22F cystoscope to permit white-light-guided COCT over a large field of view (4.6 mm wide and 2.1 mm deep per scan at 8 frames/s) and 10-μm resolution. Intraoperative COCT diagnosis was performed in 56 patients, with a total of 110 lesions examined and compared with biopsied histology. Results The overall sensitivity of COCT (94%) was ...
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    14. Noninvasive and High-resolution Optical Monitoring of Healing of Diabetic Dermal Excisional Wounds Implanted with Biodegradable in situ Gelable Hydrogels

      Closure of diabetic dermal chronic wounds remains a clinical challenge. Implant-assisted healing is emerging as a potential class of therapy for dermal wound closure; this advancement has not been paralleled by the development in complementary diagnostic techniques to objectively monitor the wound healing process in conjunction with assessing/monitoring of implant efficacy. Biopsies provide the most objective morphological assessments of wound healing; however, they not only perpetuate the wound presence but also increase the risk of infection. A non-invasive and high-resolution imaging technique is highly desirable to provide objective longitudinal diagnosis of implant-assisted wound healing. We investigated the feasibility of ...
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    15. Optical Coherence Tomography Systems And Methods (Wo 2009/039303)

      Optical Coherence Tomography Systems And Methods (Wo 2009/039303)
      In general, in one aspect, the invention features a method that includes using an optical coherence tomography system to acquire a plurality of frames of a sample where each frame includes optical information about the composition of the sample through a section of the sample. The method further includes averaging over two or more of the frames to provide an image of the section of the sample where successive frames of the two or more frames are acquired with a time lapse of 0.05-0.7 seconds. Embodiments of the method may have unique advantages for endoscopic subcellular imaging. For ...
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    16. A digital frequency ramping method for enhancing doppler flow imaging in Fourier-domain optical coherence tomography

      A digital frequency ramping method for enhancing doppler flow imaging in Fourier-domain optical coherence tomography
      A digital frequency ramping method (DFRM) is proposed to improve the signal-to-noise ratio (SNR) of Doppler flow imaging in Fourier -domain optical coherence tomography (FDOCT). To examine the efficacy of DFRM for enhancing flow detection, computer simulation and tissue phantom study were conducted for phase noise reduction and flow quantification. In addition, the utility of this technique was validated in our in vivo clinical bladder imaging with endoscopic FDOCT. The Doppler flow images reconstructed by DFRM were compared with the counterparts by traditional Doppler FDOCT. The results demonstrate that DFRM enables real-time Doppler FDOCT imaging at significantly enhanced sensitivity without ...
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    17. Quantification of cocaine-induced cortical blood flow changes using laser speckle contrast imaging and Doppler optical coherence tomography

      Quantification of cocaine-induced cortical blood flow changes using laser speckle contrast imaging and Doppler optical coherence tomography

      We present a dual-imaging technique combining laser speckle contrast imaging and spectral-domain Doppler optical coherence tomography to enable quantitative characterization of local cerebral blood flow (CBF) changes in rat cortex in response to drug stimulus (e.g., cocaine) at high spatiotemporal resolutions. To examine the utility of this new technique, animal experiments were performed to study the influences of anesthetic regimes (e.g., isoflurane, α-chloralose) on the pharmadynamic effects of acute cocaine challenge. The results showed that cocaine-evoked CBF patterns (e.g., increases in α-chloralose and decreases in isoflurane regimes) were quantitatively characterized, thus rendering it a potentially useful tool ...

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    18. Enhancing Doppler Flow Imaging in Fourier-domain Optical Coherence Tomography

      Enhancing Doppler Flow Imaging in Fourier-domain Optical Coherence Tomography

      A digital frequency ramping method (DFRM) is proposed to improve the signal-to-noise ratio (SNR) of Doppler flow imaging in Fourier-domain optical coherence tomography (FDOCT). To examine the efficacy of DFRM for enhancing flow detection, computer simulation and tissue phantom study were conducted ... [Opt. Express 17, 3951-3963 (2009)]

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    19. High-resolution imaging diagnosis and staging of bladder cancer: comparison between optical coherence tomography and high-frequency ultrasound

      Zhijia Yuan, Zhenguo Wang, Rubin Pan et al. A comparative study between 1.3-[mu]m optical coherence tomography (OCT) and 40-MHz high-frequency ultrasound (HFUS) is presented to enhance imaging of bladder cancers ex vivo. A standard rat bladder cancer model in which transitional cell carcinoma (TCC) was induced by intravesical instillation of ... [J. Biomed. Opt. 13, 054007 (2008)] published Fri Sep 12, 2008.
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    20. Optical coherence Doppler tomography quantifies laser speckle contrast imaging for blood flow imaging in the rat cerebral cortex

      Optical coherence Doppler tomography quantifies laser speckle contrast imaging for blood flow imaging in the rat cerebral cortex

      A dual-imaging modality is demonstrated for high-resolution quantitative imaging of local cerebral blood flow in the rat cortex by combining simultaneous spectral-domain Doppler optical coherence tomography (SDOCT) and full-field laser speckle contrast imaging (LSCI). Preliminary studies in tissue flow phantom and cocaine-induced cerebral blood flow changes indicated that by correlating coregistered cortical arterial blood flow, the relative measurement of flow changes by LSCI could be accurately calibrated by the absolute flow imaging provided by SDOCT (least square fit, r2≈0.96). Quantitative LSCI of cerebral blood flow is crucial to the quantitative analyses of the spatiotemporal hemodynamics of functional brain ...

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    21. Assessment of Dermal Wound Repair after Collagen Implantation with Optical Coherence Tomography

      We present an animal study to examine the utility and potential limitations of optical coherence tomography (OCT) for noninvasive evaluation of biomaterial scaffold–assisted wound healing. The transverse and axial resolutions of the OCT system at the wavelength of 1.3 μm were 12 and 10 μm, respectively. A murine full-thickness transcutaneous wound model was employed, in which a 10 mm full-thickness wound was created on the back of each male Balb/cJ mouse and a porous collagen scaffold was implanted in the wound bed followed by coverage with a TegadermTM film. Sequential cross-sectional OCT scans were performed at different ...
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    22. Optical Coherence Tomography: A Noninvasive Method to Assess Wound Reepithelialization

      Background Accurate assessment of wound healing may require invasive tissue biopsies, limiting its clinical usefulness in humans. Optical coherence tomography (OCT) is a novel, high-resolution method using light reflection to obtain noninvasive cross sectional imaging of biological tissues. ObjectivesTo evaluate the utility of OCT for assessing wound reepithelialization in a porcine model. MethodsThe authors conducted an animal study with two domestic pigs. Excisional cutaneous wounds were created over the ventral surface of the animals using an electric dermatome set at a depth of 600 μm. The wounds were excised two or three days later and precisely marked to guide initial ...
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    23. Endoscopic optical coherence tomography based on a microelectromechanical mirror

      Endoscopic optical coherence tomography based on a microelectromechanical mirror
      An endoscopic optical coherence tomography (OCT) system based on a microelectromechanical mirror to facilitate lateral light scanning is described. The front-view OCT scope, adapted to the instrument channel of a commercial endoscopic sheath, allows real-time cross-sectional imaging of living biological tissue via direct endoscopic visual guidance. The transverse and axial resolutions of the OCT scope are roughly 20 and 10.2μm, respectively. Cross-sectional images of 500×1000 pixels covering an area of 2.9 mm×2.8 mm can be acquired at ~5 frames/s and with nearly 100-dB dynamic range. Applications in thickness measurement and bladder tissue imaging are ...
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    1-23 of 23
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    1. (22 articles) Yingtian Pan
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    Optical coherence Doppler tomography quantifies laser speckle contrast imaging for blood flow imaging in the rat cerebral cortex Enhancing Doppler Flow Imaging in Fourier-domain Optical Coherence Tomography Endoscopic optical coherence tomography based on a microelectromechanical mirror A digital frequency ramping method for enhancing doppler flow imaging in Fourier-domain optical coherence tomography Optical Coherence Tomography Systems And Methods (Wo 2009/039303) Enhancing Detection of Bladder Carcinoma In Situ by 3-Dimensional Optical Coherence Tomography The multi-spectral signal properties of multiple reference optical coherence tomography (Thesis) Calibration-free time-stretch optical coherence tomography with large imaging depth Does Projection Artifact Removal Improve Visualization of Images in Optical Coherence Tomography Angiography? Spectral‐domain optical coherence tomography of retinal vessels in Waldenström's macroglobulinemia Optical coherence tomography imaging of oral mucosa bullous diseases: a preliminary study The use of anterior segment optical coherence tomography (ASOCT) in demonstrating recurrence of vitreoretinal lymphoma (VRL) in the anterior vitreous