1. Ecole Polytechnique Fédérale de Lausanne

    0 Comments Leave a Comment

    1-15 of 29 1 2 »
    1. Mentioned In 29 Articles

    2. Imaging of cortical structures and microvasculature using extended-focus optical coherence tomography at 1.3  μm

      Imaging of cortical structures and microvasculature using extended-focus optical coherence tomography at 1.3  μm
      Extended-focus optical coherence tomography (xf-OCT) is a variant of optical coherence tomography (OCT) wherein the illumination and/or detection modes are engineered to provide a constant diffractionless lateral resolution over an extended depth of field (typically 3 to 10 10 the Rayleigh range). xf-OCT systems operating at 800 nm have been devised and used in the past to image brain structures at high-resolution in vivo , but are limited to 500 ...
      Read Full Article
    3. In vivo high-resolution cortical imaging with extended-focus optical coherence microscopy in the visible-NIR wavelength range

      In vivo high-resolution cortical imaging with extended-focus optical coherence microscopy in the visible-NIR wavelength range
      Visible light optical coherence tomography has shown great interest in recent years for spectroscopic and high-resolution retinal and cerebral imaging. Here, we present an extended-focus optical coherence microscopy system operating from the visible to the near-infrared wavelength range for high axial and lateral resolution imaging of cortical structures in vivo . The system exploits an ultrabroad illumination spectrum centered in the visible wavelength range ( c =650nm, 250nm) offering a submicron axial ...
      Read Full Article
    4. Interferometric synthetic aperture microscopy for extended focus optical coherence microscopy

      Interferometric synthetic aperture microscopy for extended focus optical coherence microscopy
      Optical coherence microscopy (OCM) is an interferometric technique providing 3D images of biological samples with micrometric resolution and penetration depth of several hundreds of micrometers. OCM differs from optical coherence tomography (OCT) in that it uses a high numerical aperture (NA) objective to achieve high lateral resolution. However, the high NA also reduces the depth-of-field (DOF), scaling with 1/NA 2 . Interferometric synthetic aperture microscopy (ISAM) is a computed imaging ...
      Read Full Article
    5. Optical coherence microscopy system having a filter for suppressing a specular light contribution

      Optical coherence microscopy system having a filter for suppressing a specular light contribution
      The invention relates to an optical coherence microscopy system for fast, phase resolved imaging by means of optical coherence microscopy with decoupled illumination and detection apertures, producing a dark-field effect with an enhanced optical contrast. The setup uses a light source with an appropriate temporal coherence, an interferometer and an array detector combined with a spectrometer. The dark-field effect is produced by optical filter means in the illumination and detection ...
      Read Full Article
    6. Massively parallel data processing for quantitative total flow imaging with optical coherence microscopy and tomography

      Massively parallel data processing for quantitative total flow imaging with optical coherence microscopy and tomography
      We present an application of massively parallel processing of quantitative flow measurements data acquired using spectral optical coherence microscopy (SOCM). The need for massive signal processing of these particular datasets have been a major hurdle for many applications based on SOCM. In view of this difficulty, we implemented and adapted quantitative total flow estimation algorithms on graphics processing units (GPU) and achieved a 150 fold reduction in processing time when ...
      Read Full Article
    7. Extended-focus optical coherence microscopy for high-resolution imaging of the murine brain

      Extended-focus optical coherence microscopy for high-resolution imaging of the murine brain
      We propose a new method and optical instrumentation for mouse brain imaging based on extended-focus optical coherence microscopy. This in vivo imaging technique allows the evaluation of the cytoarchitecture at cellular level and the circulation system dynamics in three dimensions. This minimally invasive and non-contact approach is performed without the application of contrasting agents. The optical design achieved a resolution of 2.2 m over a distance of 800 m ...
      Read Full Article
    8. Imaging of the stroke-related changes in the vascular system of the mouse brain with the use of extended focus Optical Coherence Microscopy

      Imaging of the stroke-related changes in the vascular system of the mouse brain with the use of extended focus Optical Coherence Microscopy
      We used Optical Coherence Microscopy (OCM) to monitor structural and functional changes due to ischemic stroke in small animals brains in vivo. To obtain lateral resolution of 2.2 m over the range of 600 m we used extended focus configuration of OCM instrument involving Bessel beam. It provided access to detailed 3D information about the changes in brain vascular system up to the level of capillaries across I and ...
      Read Full Article
    9. Subsurface ablation of atherosclerotic plaque using ultrafast laser pulses

      Subsurface ablation of atherosclerotic plaque using ultrafast laser pulses
      We perform subsurface ablation of atherosclerotic plaque using ultrafast pulses. Excised mouse aortas containing atherosclerotic plaque were ablated with ultrafast near-infrared (NIR) laser pulses. Optical coherence tomography (OCT) was used to observe the ablation result, while the physical damage was inspected in histological sections. We characterize the effects of incident pulse energy on surface damage, ablation hole size, and filament propagation. We find that it is possible to ablate plaque ...
      Read Full Article
    10. Visible light optical coherence correlation spectroscopy

      Visible light optical coherence correlation spectroscopy
      Optical coherence correlation spectroscopy (OCCS) allows studying kinetic processes at the single particle level using the backscattered light of nanoparticles. We extend the possibilities of this technique by increasing its signal-to-noise ratio by a factor of more than 25 and by generalizing the method to solutions containing multiple nanoparticle species. We applied these improvements by measuring protein adsorption and formation of a protein monolayer on superparamagnetic iron oxide nanoparticles under ...
      Read Full Article
    11. Quantitative cerebral blood flow imaging with extended-focus optical coherence microscopy

      Quantitative cerebral blood flow imaging with extended-focus optical coherence microscopy
      Quantitative three-dimensional blood flow imaging is a valuable technique to investigate the physiology of the brain. Two-photon microscopy (2PM) allows quantification of the local blood flow velocity with micrometric resolution by performing repeated line scans, but prohibitively long measurement times would be required to apply this technique to full three-dimensional volumes. By multiplexing the image acquisition over depth, Fourier domain optical coherence tomography (FDOCT) enables quantification of blood flow velocities ...
      Read Full Article
    12. Quantitative lateral and axial flow imaging with optical coherence microscopy and tomography

      Quantitative lateral and axial flow imaging with optical coherence microscopy and tomography
      Optical coherence tomography (OCT) and optical coherence microscopy (OCM) allow the acquisition of quantitative three-dimensional axial flow by estimating the Doppler shift caused by moving scatterers. Measuring the velocity of red blood cells is currently the principal application of these methods. In many biological tissues, blood flow is often perpendicular to the optical axis, creating the need for a quantitative measurement of lateral flow. Previous work has shown that lateral ...
      Read Full Article
    13. Experimental study of z resolution in acousto-optical coherence tomography using random phase jumps on ultrasound and light

      Experimental study of z resolution in acousto-optical coherence tomography using random phase jumps on ultrasound and light
      Acousto-optical coherence tomography (AOCT) is a variant of acousto-optic imaging (also called ultrasound modulated optical tomography) that makes possible to get resolution along the ultrasound propagation axis z . We present here AOCT experimental results, and we study how the z resolution depends on time step between phase jumps Tϕ , or on the correlation length z . By working at low resolution, we perform a quantitative comparison of the z measurements with ...
      Read Full Article
    14. Label-Free Imaging of Cerebral β-Amyloidosis with Extended-Focus Optical Coherence Microscopy

      Label-Free Imaging of Cerebral β-Amyloidosis with Extended-Focus Optical Coherence Microscopy
      ...y of Molecular and Cellular Biology of Alzheimer's Disease, Brain Mind Institute and School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH1015 Lausanne, Switzerland; 2. ^2Laboratoire d'optique Biom...
      Read Full Article
    15. Zero-crossing approach to high-resolution reconstruction in frequency-domain optical-coherence tomography

      Zero-crossing approach to high-resolution reconstruction in frequency-domain optical-coherence tomography
      We address the problem of high-resolution reconstruction in frequency-domain optical-coherence tomography (FDOCT). The traditional method employed uses the inverse discrete Fourier transform, which is limited in resolution due to the Heisenberg uncertainty principle. We propose a reconstruction technique based on zero-crossing (ZC) interval analysis. The motivation for our approach lies in the observation that, for a multilayered specimen, the backscattered signal may be expressed as a sum of sinusoids, and ...
      Read Full Article
    16. Fast three-dimensional imaging of gold nanoparticles in living cells with photothermal optical lock-in Optical Coherence Microscopy

      Fast three-dimensional imaging of gold nanoparticles in living cells with photothermal optical lock-in Optical Coherence Microscopy
      We introduce photothermal optical lock-in Optical Coherence Microscopy (poli-OCM), a volumetric imaging technique, which combines the depth sectioning of OCM with the high sensitivity of photothermal microscopy while maintaining the fast acquisition speed inherent to OCM. We report on the detection of single 40 nm gold particles with a 0.5 m lateral and 2 m axial resolution over a 50 m depth of field and the three-dimensional localization of ...
      Read Full Article
    17. 1-15 of 29 1 2 »
  1. Categories

    1. Applications:

      Art, Cardiology, Dentistry, Dermatology, Developmental Biology, Gastroenterology, Gynecology, Microscopy, NDE/NDT, Neurology, Oncology, Ophthalmology, Other Non-Medical, Otolaryngology, Pulmonology, Urology
    2. Business News:

      Acquisition, Clinical Trials, Funding, Other Business News, Partnership, Patents
    3. Technology:

      Broadband Sources, Probes, Tunable Sources
    4. Miscellaneous:

      Jobs & Studentships, Student Theses, Textbooks
  2. About Ecole Polytechnique Fédérale de Lausanne

    Ecole Polytechnique Fédérale de Lausanne

    Biomedical Imaging Group at the Ecole Polytechnique Fédérale de Lausanne.  The biomedical imaging group pursues research on the development of new algorithms and mathematical tools for the advanced processing of medical and biological images. Topics of interest are image reconstruction, multi-modal imaging, image analysis and visualization. Research efforts are taking place at two complementary levels: 1) the fundamental and mathematical aspects of imaging and 2)  application-oriented projects in collaboration with researchers in medicine and biology.