OHSU Receives NIH Grant ffor Optical Coherence Tomography-Aided Differential Diagnosis and Treatment of Irregular Corneas
...nce Tomography-Aided Differential Diagnosis and Treatment of Irregular Corneas. The principal investigator is Yan Li. The program began in 2018 and ends in 2023. Below is a summary of the proposed work.
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Multimodal endoscopy for colorectal cancer detection by optical coherence tomography and near-infrared fluorescence imaging
While colonoscopy is the gold standard for diagnosis and classification of colorectal cancer (CRC), its sensitivity and specificity are operator-dependent and are especially poor for small and flat lesions. Contemporary imaging modalities, such as optical coherence tomography (OCT) and near-infrared (NIR) fluorescence, have been investigated to visualize microvasculature and morphological changes for detecting early stage CRC in the gastrointestinal (GI) tract. In our study, we developed a multimodal endoscopic system ...
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Visual Optics Postdoctoral/Research Fellow Opening at Oregon Health & Science University
... independently and with team members. To apply, please contact Professors David Huang ( huangd@ohsu.edu ) and Yan Li ( liyan@ohsu.edu ). A postdoctoral research fellow position is available in the Center for Ophthalmic O...
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1.7 micron optical coherence tomography for vaginal tissue characterization in vivo
Objectives Optical coherence tomography (OCT) can noninvasively visualize in vivo tissue microstructure with high spatial resolution that approaches the histologic level. Currently, OCT studies in gynecology are few and limited to a conventional 1.3m center wavelength swept light source which provides high spatial resolution but limited penetration depth. Here, we present a novel endoscopic OCT system with improved penetration depth and high resolution. Methods A novel endoscopic OCT system ...
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Deep imaging in highly scattering media by combining reflection matrix measurement with Bessel-like beam based optical coherence tomography
Multiple scattering in biomedical tissue limits the imaging depth within a range of 12mm for conventional optical imaging techniques. To extend the imaging depth into the scattering medium, a computational method based on the reflection matrix measurement has been developed to retrieve the singly back-scattered signal light from the dominant detrimental multiple-scattered background. After applying singular value decomposition on the measured matrix in the post-process, the target image underneath the ...
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Multimodality endoscopic optical coherence tomography and fluorescence imaging technology for visualization of layered architecture and subsurface microvasculature
Endoscopic imaging technologies, such as endoscopic optical coherence tomography (OCT) and near-infrared fluorescence, have been used to investigate vascular and morphological changes as hallmarks of early cancer in the gastrointestinal tract. Here we developed a high-speed multimodality endoscopic OCT and fluorescence imaging system. Using this system, the architectural morphology and vasculature of the rectum wall were obtained simultaneously from a Sprague Dawley rat in vivo . This multimodality imaging strategy in ...
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Optical coherence tomography angiography of a pigmented Fuchs' adenoma (age-related hyperplasia of the nonpigmented ciliary body epithelium) masquerading as a ciliary body melanoma
Purpose To report a case of age-related hypertrophy of the nonpigmented ciliary epithelium (ARH-NPCE) clinically resembling a ciliary body melanoma and report the optical coherence tomography angiography (OCTA) findings associated with this lesion. Observations A 51-year-old male was referred for evaluation of a deeply pigmented ciliary body mass with extension through the iris root. Iridocyclectomy was performed due to concern for ciliary body melanoma. Histopathologic analysis was instead consistent with ...
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Imaging of Iris Lesions With High-Speed Optical Coherence Tomography
n BACKGROUND AND OBJECTIVES:To image and measure iris tumors with optical coherence tomography (OCT). n PATIENTS AND METHODS:High-speed(2,000 4,000 axial-scan/sec and 416 frames/sec) 1.3-micron wavelength anterior segment OCT prototypes were used to image 6 eyes of 6 patients with a variety of iris lesions, including focal iris nevus, diffuse iris nevus, amelanotic iris nevus, iris melanocytosis, and iris melanoma. OCT images were ...
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Intravascular Optical Coherence Tomography for Characterization of Atherosclerosis with a 1.7 Micron Swept-Source Laser
The main cause of acute coronary events, such as thrombosis, is the rupture of atherosclerotic plaques. Typical intravascular optical coherence tomography (IVOCT) imaging systems that utilize a 1.3m swept source laser are often used for identifying fibrous cap thickness of plaques, yet cannot provide adequate depth penetration to resolve the size of the lipid pool. Here, we present a novel IVOCT system with a 1.7m center wavelength swept ...
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Methods and systems to measure corneal epithelial thickness and power, stromal thickness, subepithelial corneal power and topography for disease diagnosis
This invention discloses methods and systems for measuring corneal epithelial thickness and power, stromal thickness, subepitheila corneal power and topography. The systems and methods disclosed herein are non-invasive, non-contact and automated imaging methods which preferably makes use of Fourier-domain optical tomography. Also disclosed herein are scanning patterns and image analysis methods for utilizing and analyzing Fourier-domain optical coherence tomography images to obtain information about conical epithelial and stromal properties as ...
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Extended axial imaging range, widefield swept source optical coherence tomography angiography
We developed a high-speed, swept source OCT system for widefield OCT angiography (OCTA) imaging. The system has an extended axial imaging range of 6.6 mm. An electrical lens is used for fast, automatic focusing. The recently developed split-spectrum amplitude and phase-gradient angiography allow high-resolution OCTA imaging with only two B-scan repetitions. An improved post-processing algorithm effectively removed trigger jitter artifacts and reduced noise in the flow signal. We demonstrated ...
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Distinguishing between contact lens warpage and ectasia: Usefulness of optical coherence tomography epithelial thickness mapping
Purpose To distinguish between corneal ectasia and contact lensrelated warpage by characteristic patterns on corneal topography and optical coherence tomography (OCT) epithelial thickness maps. Setting Casey Eye Institute, Portland, Oregon, USA. Design Prospective and retrospective case series. Methods Axial and mean power maps were obtained on corneal topography systems. Epithelial thickness maps were generated using RTVue OCT. A sector divider was applied to all maps. The locations of the minimum ...
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Non-invasive 3D imaging and measuring of anterior chamber angle of the eye
Embodiments of OCT measurement and analysis techniques described herein enable precise 3D anterior chamber angle measurement from major, pertinent landmarks in the eye. Such techniques result in a more reliable, quantifiable angle measurement technique that is both non-invasive and non-contact in nature, thereby improving clinical practicality, while improving patient comfort and care. For example, a method is provided for in vivo imaging of an eye, including taking a plurality of ...
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Fully integrated optical coherence tomography, ultrasound, and indocyanine green-based fluorescence tri-modality system for intravascular imaging
We present a tri-modality imaging system and fully integrated tri-modality probe for intravascular imaging. The tri-modality imaging system is able to simultaneously acquire optical coherence tomography (OCT), ultrasound (US), and fluorescence imaging. Moreover, for fluorescence imaging, we used the FDA-approved indocyanine green (ICG) dye as the contrast agent to target lipid-loaded macrophages. We conducted imaging from a male New Zealand white rabbit to evaluate the performance of the tri-modality system ...
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Optical Coherence Tomography Angiography Characteristics of Iris Melanocytic Tumors
Purpose To evaluate tumor vasculature with optical coherence tomography angiography (OCTA) in malignant iris melanomas and benign iris lesions. Design Cross-sectional observational clinical study. Participants Patients with iris lesions and healthy volunteers. Methods Eyes were imaged using OCTA systems operating at 1050- and 840-nm wavelengths. Three-dimensional OCTA scans were acquired. Iris melanoma patients treated with radiation therapy were imaged again after I-125 plaque brachytherapy at 6 and 18 months. Main ...
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About Yan Li
Yan Li is with the Center for Opthalmic Optics and Lasers. Dr. Yan Li earned her PhD in Biomedical Engineering from Case Western Reserve University. She is currently a senior research associate in the Department of Ophthalmology, Keck School of Medicine of USC. She received her master’s degree in Biomedical Engineering at the Zhejiang University, China, in 2000. Her research interests include medical image processing, optical coherence tomography for imaging the corneal and anterior segment of the eye, planning refractive surgeries, and guiding the treatment of anterior eye diseases with optical coherence tomography.