1. Jonathan J. Liu

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    1. Mentioned In 49 Articles

    2. OCT angiography calculation with optimized signal processing

      OCT angiography calculation with optimized signal processing
      Methods and systems for angiographic imaging with optical coherence tomography (OCT) are described using ratio-based and angiographic deviation based calculations. In using these calculations to determine motion, arbitrary interframe permutations may be used, post-calculated, non-linear results for projection visualization may be averaged, poor matches may be eliminated on an A-line by A-line basis, windowing functions may be used to improve results, partial spectrums may be used when capturing data, and ...
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    3. Microscope-Integrated Intraoperative Ultrahigh-Speed Swept-Source Optical Coherence Tomography for Widefield Retinal and Anterior Segment Imaging

      Microscope-Integrated Intraoperative Ultrahigh-Speed Swept-Source Optical Coherence Tomography for Widefield Retinal and Anterior Segment Imaging
      BACKGROUND AND OBJECTIVE: To demonstrate the feasibility of retinal and anterior segment intraoperative widefield imaging using an ultrahigh-speed, swept-source optical coherence tomography (SS-OCT) surgical microscope attachment. PATIENTS AND METHODS: A prototype post-objective SS-OCT using a 1,050-nm wavelength, 400 kHz A-scan rate, vertical cavity surface-emitting laser (VCSEL) light source was integrated to a commercial ophthalmic surgical microscope after the objective. Each widefield OCT data set was acquired in 3 seconds ...
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    4. Assessment of the radiofrequency ablation dynamics of esophageal tissue with optical coherence tomography

      Assessment of the radiofrequency ablation dynamics of esophageal tissue with optical coherence tomography
      Radiofrequency ablation (RFA) is widely used for the eradication of dysplasia and the treatment of early stage esophageal carcinoma in patients with Barretts esophagus (BE). However, there are several factors, such as variation of BE epithelium (EP) thickness among individual patients and varying RFA catheter-tissue contact, which may compromise RFA efficacy. We used a high-speed optical coherence tomography (OCT) system to identify and monitor changes in the esophageal tissue architecture ...
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    5. Three Dimensional Enhanced Imaging of Vitreoretinal Interface in Diabetic Retinopathy Using Swept Source Optical Coherence Tomography

      Three Dimensional Enhanced Imaging of Vitreoretinal Interface in Diabetic Retinopathy Using Swept Source Optical Coherence Tomography
      Purpose To analyze the vitreoretinal interface in diabetic eyes using three-dimensional wide-field volumes acquired using high-speed, long-wavelength swept-source optical coherence tomography (SS-OCT). Design Prospective cross-sectional study. Methods Fifty-six diabetic patients (88 eyes) and 11 healthy non-diabetic controls (22 eyes) were recruited. Up to eight SS-OCT volumes were acquired for each eye. A registration algorithm removed motion artifacts and merged multiple SS-OCT volumes to improve signal. Vitreous visualization was enhanced using ...
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    6. Characterization of Choroidal Layers in Normal Aging Eyes Using Enface Swept-Source Optical Coherence Tomography

      Characterization of Choroidal Layers in Normal Aging Eyes Using Enface Swept-Source Optical Coherence Tomography
      Purpose To characterize qualitative and quantitative features of the choroid in normal eyes using enface swept-source optical coherence tomography (SS-OCT). Methods Fifty-two eyes of 26 consecutive normal subjects were prospectively recruited to obtain multiple three-dimensional 12x12mm volumetric scans using a long-wavelength high-speed SS-OCT prototype. A motion-correction algorithm merged multiple SS-OCT volumes to improve signal. Retinal pigment epithelium (RPE) was segmented as the reference and enface images were extracted at varying ...
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    7. Systems Engineer Position Opening at Topcon Medical Systems in Oakland, New Jersey

      Systems Engineer Position Opening at Topcon Medical Systems in Oakland, New Jersey
      An exciting opportunity for a highly motivated system engineer to work creatively within a dedicated RD laboratory (Topcon Advanced Biomedical Imaging Laboratory, Oakland, NJ) contributing to interdisciplinary projects with global impact. Primary responsibilities include system development for ophthalmic imaging devices, supporting both prototype and commercial system development efforts. The position requires diverse engineering and programming experience including system integration, data acquisition and test equipment control, signal and image processing, and ...
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    8. Cardiac-Gated En Face Doppler Measurement of Retinal Blood Flow Using Swept Source Optical Coherence Tomography at 100,000 Axial Scans per Second

      Cardiac-Gated En Face Doppler Measurement of Retinal Blood Flow Using Swept Source Optical Coherence Tomography at 100,000 Axial Scans per Second
      Purpose: To develop and demonstrate a cardiac gating method for repeatable in vivo measurement of total retinal blood flow (TRBF) in humans using en face Doppler optical coherence tomography (OCT) at commercially available imaging speeds. Methods: A prototype swept-source OCT system operating at 100 kHz axial scan rate was developed and interfaced with a pulse oximeter. Using the plethysmogram measured from the earlobe, Doppler OCT imaging of a 1.5 ...
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    9. AGREEMENT AND REPRODUCIBILITY OF RETINAL PIGMENT EPITHELIAL DETACHMENT VOLUMETRIC MEASUREMENTS THROUGH OPTICAL COHERENCE TOMOGRAPHY

      AGREEMENT AND REPRODUCIBILITY OF RETINAL PIGMENT EPITHELIAL DETACHMENT VOLUMETRIC MEASUREMENTS THROUGH OPTICAL COHERENCE TOMOGRAPHY
      Purpose: To assess the agreement and reproducibility of retinal pigment epithelial detachment (RPED) volumetric measurements using a commercially available optical coherence tomography software available for the Zeiss Cirrus HD-OCT. Methods: Twelve eyes of 10 patients with a diagnosis of neovascular age-related macular degeneration with RPED, seen at the New England Eye Center between October 2012 and December 2012, were enrolled in the study. Three separate scans per affected eye were ...
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    10. High-Speed Ultrahigh-Resolution OCT of Bruch's Membrane in Membranoproliferative Glomerulonephritis Type 2

      High-Speed Ultrahigh-Resolution OCT of Bruch's Membrane in Membranoproliferative Glomerulonephritis Type 2
      Membranoproliferative glomerulonephritis (MPGN) type 2 is characterized by electron-dense deposits in the glomerular basement membrane and drusen-like deposits in Bruch's membrane. Over time, atrophic changes in the retina and retinal pigment epithelium occur, which can progress to choroidal neovascularization (CNV). This report describes a patient with MPGN type 2 who developed progressive loss of vision secondary to CNV. High-speed ultrahigh-resolution optical coherence tomography (UHR-OCT) showed an irregular Bruch's ...
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    11. Depth-encoded all-fiber swept source polarization sensitive OCT

      Depth-encoded all-fiber swept source polarization sensitive OCT
      Polarization sensitive optical coherence tomography (PS-OCT) is a functional extension of conventional OCT and can assess depth-resolved tissue birefringence in addition to intensity. Most existing PS-OCT systems are relatively complex and their clinical translation remains difficult. We present a simple and robust all-fiber PS-OCT system based on swept source technology and polarization depth-encoding. Polarization multiplexing was achieved using a polarization maintaining fiber. Polarization sensitive signals were detected using fiber based ...
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    12. Optical coherence tomography angiography of optic nerve head and parafovea in multiple sclerosis

      Optical coherence tomography angiography of optic nerve head and parafovea in multiple sclerosis
      Aims To investigate swept-source optical coherence tomography (OCT) angiography in the optic nerve head (ONH) and parafoveal regions in patients with multiple sclerosis (MS). Methods Fifty-two MS eyes and 21 healthy control (HC) eyes were included. There were two MS subgroups: 38 MS eyes without an optic neuritis (ON) history (MS ON), and 14 MS eyes with an ON history (MS +ON). The OCT images were captured by high-speed 1050 ...
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    13. Feature Of The Week 4/2/14: A Compact High-Performance Hand-Held Device for Extending Ophthalmic OCT to New Points of Care (Narrated Presentation)

      Feature Of The Week 4/2/14: A Compact High-Performance Hand-Held Device for Extending Ophthalmic OCT to New Points of Care (Narrated Presentation)
      We developed an ultrahigh speed, handheld swept source optical coherence tomography (SS-OCT) ophthalmic instrument using a 2D MEMS mirror. A vertical cavity surface-emitting laser (VCSEL) operating at 1060 nm center wavelength yielded a 350 kHz axial scan rate and 10 m axial resolution in tissue. The long coherence length of the VCSEL enabled a 3.08 mm imaging range with minimal sensitivity roll-off in tissue. Two different designs with identical ...
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  2. About Jonathan J. Liu

    Jonathan J. Liu was a graduate student in the Laser Medicine and Medical Imaging Group at the Massachusetts Institute of Technology.