1. Articles mentioning both Harvard University and Massachusetts Institute of Technology

    1-24 of 114 1 2 3 4 5 »
    1. Extended Coherence Length and Depth Ranging Using a Fourier-Domain Mode-Locked Frequency Comb and Circular Interferometric Ranging

      Extended Coherence Length and Depth Ranging Using a Fourier-Domain Mode-Locked Frequency Comb and Circular Interferometric Ranging
      Fourier-domain mode locking has been a popular laser design for high-speed optical-frequency-domain imaging (OFDI), but achieving long coherence lengths, and therefore imaging range, has been challenging. The narrow linewidth of a Fourier-domain mode-locked (FDML) frequency-comb (FC) laser could provide an attractive platform for high-speed as well as long-range OFDI. Unfortunately, aliasing artifacts arising from signals beyond the principal measurement depth of the free spectral range have prohibited the use of ...
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    2. A Mechanical Approach for Smooth Surface Fitting to Delineate Vessel Walls in Optical Coherence Tomography Images

      A Mechanical Approach for Smooth Surface Fitting to Delineate Vessel Walls in Optical Coherence Tomography Images
      Automated analysis of vascular imaging techniques is limited by the inability to precisely determine arterial borders. Intravascular optical coherence tomography (OCT) offers unprecedented detail of artery wall structure and composition, but does not provide consistent visibility of the outer border of the vessel due to limited penetration depth. Existing interpolation and surface fitting methods prove insufficient to accurately fill the gaps between the irregularly-spaced and sometimes unreliably-identified visible segments of ...
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    3. Computer-Aided Analysis of Gland-Like Subsurface Hyposcattering Structures in Barrett’s Esophagus Using Optical Coherence Tomography

      Computer-Aided Analysis of Gland-Like Subsurface Hyposcattering Structures in Barrett’s Esophagus Using Optical Coherence Tomography
      (1) Background: Barretts esophagus (BE) is a complication of chronic gastroesophageal reflux disease and is a precursor to esophageal adenocarcinoma. The clinical implication of subsurface glandular structures of Barretts esophagus is not well understood. Optical coherence tomography (OCT), also known as volumetric laser endomicroscopy (VLE), can assess subsurface glandular structures, which appear as subsurface hyposcattering structures (SHSs). The aim of this study is to develop a computer-aided algorithm and apply ...
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    4. Optic axis mapping with catheter-based polarization-sensitive optical coherence tomography

      Optic axis mapping with catheter-based polarization-sensitive optical coherence tomography
      Birefringence offers an intrinsic contrast mechanism related to the microstructure and arrangement of fibrillary tissue components. Here we present a reconstruction strategy to recover not only the scalar amount of birefringence, but also its optic axis orientation as a function of depth in tissue from measurements with catheter-based polarization-sensitive optical coherence tomography. A polarization symmetry constraint, intrinsic to imaging in the backscatter direction, facilitates the required compensation for wavelength-dependent transmission ...
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    5. Extended coherence length and depth ranging using a Fourier domain mode-locked frequency comb and circular interferometric ranging

      Extended coherence length and depth ranging using a Fourier domain mode-locked frequency comb and circular interferometric ranging
      Fourier domain mode-locking (FDML) has been a popular laser design for high speed optical frequency domain imaging (OFDI) but achieving long coherence lengths, and therefore imaging range, has been challenging. The narrow instantaneous linewidth of a frequency comb (FC) FDML laser could provide an attractive platform for high speed as well as long range OFDI. Unfortunately, aliasing artifacts arising from signals beyond the principle measurement depth of the free spectral ...
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    6. Feature Of The Week 10/08/2018: Clinical Utility of Ultrahigh-Speed Endoscopic Optical Coherence Tomography in Gastroenterology

      Feature Of The Week 10/08/2018: Clinical Utility of Ultrahigh-Speed Endoscopic Optical Coherence Tomography in Gastroenterology
      ...enesis. For more information see recent Article1 , Article2 , and Article3 . Courtesy Osman O. Ahsen from the Massachusetts Institute of Technology . Barrett’s esophagus (BE) surveillance is limited by biopsy sampling er...
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    7. Volumetric non-local-means based speckle reduction for optical coherence tomography

      Volumetric non-local-means based speckle reduction for optical coherence tomography
      We present a novel tomographic non-local-means based despeckling technique, TNode, for optical coherence tomography. TNode is built upon a weighting similarity criterion derived for speckle in a three-dimensional similarity window. We present an implementation using a two-dimensional search window, enabling the despeckling of volumes in the presence of motion artifacts, and an implementation using a three-dimensional window with improved performance in motion-free volumes. We show that our technique provides effective ...
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    8. A Quantum Field Approach for Advancing Optical Coherence Tomography Part I: First Order Correlations, Single Photon Interference, and Quantum Noise

      A Quantum Field Approach for Advancing Optical Coherence Tomography Part I: First Order Correlations, Single Photon Interference, and Quantum Noise
      Optical coherence tomography has become an important imaging technology in cardiology and ophthalmology, with other applications under investigations. Major advances in optical coherence tomography (OCT) imaging are likely to occur through a quantum field approach to the technology. In this paper, which is the first part in a series on the topic, the quantum basis of OCT first order correlations is expressed in terms of full field quantization. Specifically first ...
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    9. Robust wavenumber and dispersion calibration for Fourier-domain optical coherence tomography

      Robust wavenumber and dispersion calibration for Fourier-domain optical coherence tomography
      Many Fourier-domain optical coherence tomography (FD-OCT) systems sample the interference fringes with a non-uniform wavenumber ( k ) interval, introducing a chirp to the signal that depends on the path length difference underlying each fringe. A dispersion imbalance between sample and reference arms also generates a chirp in the fringe signal which, in contrast, is independent of depth. Fringe interpolation to obtain a signal linear in k and compensate dispersion imbalance is ...
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    10. Radiometric model for coaxial single- and multimode optical emission from double-clad fiber

      Radiometric model for coaxial single- and multimode optical emission from double-clad fiber
      Double-clad fibers (DCFs) are versatile waveguides supporting a single-mode core surrounded by a multimode inner cladding. DCFs are increasingly used for multimodal biomedical applications, such as imaging or therapy, for which the core is typically used for coherent illumination and the inner cladding, to support a concurrent modality. Proper optimization is, however, critical to ensure high optical performance and requires accurate modeling of coaxial single- and multimode output beams. In ...
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    11. Cycloid scanning for wide field optical coherence tomography endomicroscopy and angiography in vivo

      Cycloid scanning for wide field optical coherence tomography endomicroscopy and angiography in vivo
      Devices that perform wide field-of-view (FOV) precision optical scanning are important for endoscopic assessment and diagnosis of luminal organ disease such as in gastroenterology. Optical scanning for in vivo endoscopic imaging has traditionally relied on one or more proximal mechanical actuators, limiting scan accuracy and imaging speed. There is a need for rapid and precise two-dimensional (2D) microscanning technologies to enable the translation of benchtop scanning microscopies to in vivo ...
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    12. Complex differential variance angiography with noise-bias correction for optical coherence tomography of the retina

      Complex differential variance angiography with noise-bias correction for optical coherence tomography of the retina
      Complex differential variance (CDV) provides phase-sensitive angiographic imaging for optical coherence tomography (OCT) with immunity to phase-instabilities of the imaging system and small-scale axial bulk motion. However, like all angiographic methods, measurement noise can result in erroneous indications of blood flow that confuse the interpretation of angiographic images. In this paper, a modified CDV algorithm that corrects for this noise-bias is presented. This is achieved by normalizing the CDV signal ...
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    13. Clinical Predictors for Lack of Favorable Vascular Response to Statin Therapy in Patients With Coronary Artery Disease: A Serial Optical Coherence Tomography Study

      Clinical Predictors for Lack of Favorable Vascular Response to Statin Therapy in Patients With Coronary Artery Disease: A Serial Optical Coherence Tomography Study
      Background Previous studies have demonstrated that statin therapy improves cardiac outcomes, probably by stabilizing thin‐cap fibroatheroma in patients with coronary artery disease. However, major adverse cardiac events still occur in some patients, despite statin therapy. The aim of this study is to identify clinical predictors for the lack of a favorable vascular response to statin therapy in patients with coronary artery disease. Methods and Results A total of 140 ...
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    14. Endoscopic forward-viewing optical coherence tomography and angiography with MHz swept source

      Endoscopic forward-viewing optical coherence tomography and angiography with MHz swept source
      Endoscopic optical coherence tomography (OCT) instruments are mostly side viewing and rely on at least one proximal scan, thus limiting accuracy of volumetric imaging and en face visualization. Previous forward-viewing OCT devices had limited axial scan speeds. We report a forward-viewing fiber scanning 3D-OCT probe with 900 m field of view and 5 m transverse resolution, imaging at 1 MHz axial scan rate in the human gastrointestinal tract. The probe ...
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    15. Dynamic neointimal pattern after drug-eluting stent implantation defined by optical coherence tomography

      Dynamic neointimal pattern after drug-eluting stent implantation defined by optical coherence tomography
      Objectives: Certain neointimal patterns including neoatherosclerosis (NA) are known to be associated with poor clinical outcome. The prevalence and time course of different neointimal patterns have not been studied systematically. The aim of this study was to investigate the serial changes in neointimal pattern after drug-eluting stent implantation. Patients and methods: A total of 132 patients with 207 drug-eluting stents, who underwent two follow-up optical coherence tomography studies at 6 ...
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    16. 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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    17. 16  MHz wavelength-swept and wavelength-stepped laser architectures based on stretched-pulse active mode locking with a single continuously chirped fiber Bragg grating

      16  MHz wavelength-swept and wavelength-stepped laser architectures based on stretched-pulse active mode locking with a single continuously chirped fiber Bragg grating
      We demonstrate a novel high-speed and broadband laser architecture based on stretched pulse active mode locking that provides a wavelength-swept and wavelength-stepped output. The laser utilizes a single intracavity 8.3 meter chirped fiber Bragg grating to generate positive and negative dispersion, and can be operated with or without an intracavity fixed FabryPerot etalon to generate wavelength-swept and wavelength-stepped (frequency comb) outputs, respectively. Using a four-path delay line at the ...
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    18. Clinical Significance of Lipid-Rich Plaque Detected by Optical Coherence Tomography : A 4-Year Follow-Up Study

      Clinical Significance of Lipid-Rich Plaque Detected by Optical Coherence Tomography : A 4-Year Follow-Up Study
      Background Lipid-rich plaque (LRP) is thought to be a precursor to cardiac events. However, its clinical significance in coronary arteries has never been systematically investigated. Objectives This study investigated the prevalence and clinical significance of LRP in the nonculprit region of the target vessel in patients undergoing percutaneous coronary intervention (PCI). Methods The study included 1,474 patients from 20 sites across 6 countries undergoing PCI, who had optical coherence ...
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    19. Fully automated lumen segmentation of intracoronary optical coherence tomography images

      Fully automated lumen segmentation of intracoronary optical coherence tomography images
      Optical coherence tomography (OCT) provides high-resolution cross-sectional images of arterial luminal morphology. Traditionally lumen segmentation of OCT images is performed manually by expert observers; a laborious, time consuming effort, sensitive to inter-observer variability process. Although several automated methods have been developed, the majority cannot be applied in real time because of processing demands. To address these limitations we propose a new method for rapid image segmentation of arterial lumen borders ...
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    20. Beth Isreal Deaconess Medical Center Receives Grant for Intravascular Molecular-Structural Imaging of Coronary Stent Pathobiology

      Beth Isreal Deaconess Medical Center Receives Grant for Intravascular Molecular-Structural Imaging of Coronary Stent Pathobiology
      ...uctor in Medicine at Harvard Medical School, Boston, Massachusetts. He is a graduate of the MD-PhD program at Harvard Medical School and Massachusetts Institute of Technology, and has completed clinical training in medic...
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    21. In vivo label-free measurement of lymph flow velocity and volumetric flow rates using Doppler optical coherence tomography

      In vivo label-free measurement of lymph flow velocity and volumetric flow rates using Doppler optical coherence tomography
      Direct in vivo imaging of lymph flow is key to understanding lymphatic system function in normal and disease states. Optical microscopy techniques provide the resolution required for these measurements, but existing optical techniques for measuring lymph flow require complex protocols and provide limited temporal resolution. Here, we describe a Doppler optical coherence tomography platform that allows direct, label-free quantification of lymph velocity and volumetric flow rates. We overcome the challenge ...
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    22. Circumferential optical coherence tomography angiography imaging of the swine esophagus using a micromotor balloon catheter

      Circumferential optical coherence tomography angiography imaging of the swine esophagus using a micromotor balloon catheter
      We demonstrate a micromotor balloon imaging catheter for ultrahigh speed endoscopic optical coherence tomography (OCT) which provides wide area, circumferential structural and angiographic imaging of the esophagus without contrast agents. Using a 1310 nm MEMS tunable wavelength swept VCSEL light source, the system has a 1.2 MHz A-scan rate and ~8.5 m axial resolution in tissue. The micromotor balloon catheter enables circumferential imaging of the esophagus at 240 ...
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    23. An Elastic Second Skin

      An Elastic Second Skin
      We report the synthesis and application of an elastic, wearable crosslinked polymer layer (XPL) that mimics the properties of normal, youthful skin. XPL is made of a tunable polysiloxane-based material that can be engineered with specific elasticity, contractility, adhesion, tensile strength and occlusivity. XPL can be topically applied, rapidly curing at the skin interface without the need for heat- or light-mediated activation. In a pilot human study, we examined the ...
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    24. Intravascular fibrin molecular imaging improves the detection of unhealed stents assessed by optical coherence tomography in vivo

      Intravascular fibrin molecular imaging improves the detection of unhealed stents assessed by optical coherence tomography in vivo
      Aims Fibrin deposition and absent endothelium characterize unhealed stents that are at heightened risk of stent thrombosis. Optical coherence tomography (OCT) is increasingly used for assessing stent tissue coverage as a measure of healed stents, but cannot precisely identify whether overlying tissue represents physiological neointima. Here we assessed and compared fibrin deposition and persistence on bare metal stent (BMS) and drug-eluting stent (DES) using near-infrared fluorescence (NIRF) molecular imaging in ...
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    25. 1-24 of 114 1 2 3 4 5 »
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  2. Organizations in the News

    1. (63 articles) Massachusetts General Hospital
    2. (13 articles) Brigham and Women’s Hospital
    3. (9 articles) Beth Israel Deaconess Medical Center
    4. (7 articles) Tufts University
    5. (6 articles) Massachusetts Eye and Ear Infirmary
    6. (6 articles) University of Pittsburgh
    7. (5 articles) Massachusetts General Hospital OCT Registry
    8. (5 articles) University of Southern California
    9. (4 articles) Oregon Health & Science University
    10. (4 articles) Korea Advanced Institute of Science and Technology
    11. (4 articles) Stanford University
    12. (4 articles) National Institutes of Health
  3. People in the News

    1. (52 articles) James G. Fujimoto
    2. (26 articles) Brett E. Bouma
    3. (17 articles) Guillermo J. Tearney
    4. (17 articles) Hsiang-Chieh Lee
    5. (16 articles) Hiroshi Mashimo
    6. (16 articles) Tsung-Han Tsai
    7. (14 articles) Chao Zhou
    8. (13 articles) Zhao Wang
    9. (10 articles) Benjamin J. Vakoc
    10. (10 articles) Osman O. Ahsen
    11. (9 articles) Aaron D. Aguirre
    12. (9 articles) Desmond C. Adler
  4. OCT Companies in the News

    1. (11 articles) Thorlabs
    2. (10 articles) St. Jude Medical
    3. (6 articles) Praevium Research
    4. (4 articles) Carl Zeiss Meditec
    5. (3 articles) NinePoint Medical
    6. (2 articles) Optovue
    7. (2 articles) Topcon Medical Systems
    8. (1 articles) Cambridge Technology
    9. (1 articles) Tomey Corporation
    10. (1 articles) Heidelberg Engineering
    11. (1 articles) Bioptigen