1. Articles from Martin F. Kraus

    25-30 of 30 « 1 2
    1. Split-spectrum amplitude-decorrelation angiography with optical coherence tomography

      Split-spectrum amplitude-decorrelation angiography with optical coherence tomography

      Amplitude decorrelation measurement is sensitive to transverse flow and immune to phase noise in comparison to Doppler and other phase-based approaches. However, the high axial resolution of OCT makes it very sensitive to the pulsatile bulk motion noise in the axial direction. To overcome this limitation, we developed split-spectrum amplitude-decorrelation angiography (SSADA) to improve the signal-to-noise ratio (SNR) of flow detection. The full OCT spectrum was split into several narrower bands. Inter-B-scan decorrelation was computed using the spectral bands separately and then averaged. The SSADA algorithm was tested on in vivo images of the human macula and optic nerve head ...

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    2. Speckle reduction in swept source optical coherence tomography images with slow-axis averaging

      Speckle reduction in swept source optical coherence tomography images with slow-axis averaging

      The effectiveness of speckle reduction using traditional frame averaging technique was limited in ultrahigh speed optical coherence tomography (OCT). As the motion between repeated frames was very small, the speckle pattern of the frames might be identical. This problem could be solved by averaging frames acquired at slightly different locations. The optimized scan range depended on the spot size of the laser beam, the smoothness of the boundary, and the homogeneity of the tissue. In this study we presented a method to average frames obtained within a narrow range along the slow-axis. A swept-source OCT with 100,000 Hz axial ...

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    3. Piezoelectric-transducer-based miniature catheter for ultrahigh-speed endoscopic optical coherence tomography

      Piezoelectric-transducer-based miniature catheter for ultrahigh-speed endoscopic optical coherence tomography

      We developed a piezoelectric-transducer- (PZT) based miniature catheter with an outer diameter of 3.5 mm for ultrahigh-speed endoscopic optical coherence tomography (OCT). A miniaturized PZT bender actuates a fiber and the beam is scanned through a GRIN lens and micro-prism to provide high-speed, side-viewing capability. The probe optics can be pulled back over a long distance to acquire three-dimensional (3D) data sets covering a large area. Imaging is performed with 11 μm axial resolution in air (8 μm in tissue) and 20 μm transverse resolution, at 960 frames per second with a Fourier domain mode-locked laser operating at 480 ...

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    4. Total retinal blood flow measurement with ultrahigh speed swept source/Fourier domain OCT

      Total retinal blood flow measurement with ultrahigh speed swept source/Fourier domain OCT

      Doppler OCT provides depth-resolved information on flow in biological tissues. In this article, we demonstrate ultrahigh speed swept source/Fourier domain OCT for visualization and quantitative assessment of retinal blood flow. Using swept laser technology, the system operated in the 1050-nm wavelength range at a high axial scan rate of 200 kHz. The rapid imaging speed not only enables volumetric imaging with high axial scan densities, but also enables measurement of high flow velocities in the central retinal vessels. Deep penetration in the optic nerve and lamina cribrosa was achieved by imaging at 1-µm wavelengths. By analyzing en-face images extracted ...

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    5. Retinal blood flow measurement with ultrahigh-speed swept-source / Fourier domain optical coherence tomography

      Retinal blood flow measurement with ultrahigh-speed swept-source / Fourier domain optical coherence tomography

      Doppler OCT is a functional extension of OCT that provides information on flow in biological tissues. We present a novel approach for total retinal blood flow assessment using ultrahigh speed Doppler OCT. A swept source / Fourier domain OCT system at 1050 nm was used for 3D imaging of the human retina. The high axial scan rate of 200 kHz allowed measuring the high flow velocities in the central retinal vessels. By analyzing en-face images extracted from 3D Doppler data sets, absolute flow for single vessels as well as total retinal blood flow can be measured using a simple and robust ...

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    6. Piezoelectric transducer based miniature catheter for ultrahigh speed endoscopic optical coherence tomography

      Piezoelectric transducer based miniature catheter for ultrahigh speed endoscopic optical coherence tomography

      We developed a piezoelectric transducer (PZT) based miniature catheter with an outer diameter of 3 mm for ultrahigh speed endoscopic optical coherence tomography (OCT) using Fourier domain modelocked (FDML) laser at a 480 kHz axial scan rate. The miniaturized PZT bender actuates a fiber to provide high scanning speed. The side-viewing probe can be pulled back for a long distance to acquire three-dimensional (3D) dataset covering a large area on the specimen. Operating with a high speed data acquisition (DAQ) system, OCT imaging with 6.5 mm imaging range, 10 μm axial resolution, 20 μm lateral resolution, and frame rate ...

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    25-30 of 30 « 1 2
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  2. Topics in the News

    1. (30 articles) Massachusetts Institute of Technology
    2. (30 articles) James G. Fujimoto
    3. (29 articles) Martin F. Kraus
    4. (21 articles) University of Erlangen
    5. (20 articles) Jonathan J. Liu
    6. (17 articles) Benjamin M. Potsaid
    7. (15 articles) Thorlabs
    8. (13 articles) Tufts University
    9. (13 articles) Jay S. Duker
    10. (9 articles) Ireneusz Grulkowski
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    Retinal blood flow measurement with ultrahigh-speed swept-source / Fourier domain optical coherence tomography Piezoelectric transducer based miniature catheter for ultrahigh speed endoscopic optical coherence tomography Total retinal blood flow measurement with ultrahigh speed swept source/Fourier domain OCT Piezoelectric-transducer-based miniature catheter for ultrahigh-speed endoscopic optical coherence tomography Speckle reduction in swept source optical coherence tomography images with slow-axis averaging Split-spectrum amplitude-decorrelation angiography with optical coherence tomography Ultrahigh speed endoscopic optical coherence tomography using micro-motor imaging catheter and VCSEL technology Automated lamina cribrosa microstructural segmentation in optical coherence tomography scans of healthy and glaucomatous eyes Feature Of The Week 2/16/14: En Face Enhanced-Depth Swept-Source Optical Coherence Tomography Features of Chronic Central Serous Chorioretinopath 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) Intravitreal Ranibizumab Monotherapy or Combined with Laser for Diabetic Macular Edema (OCT guided study) Prospective evaluation of drug eluting self‐apposing stent for the treatment of unprotected left main coronary artery disease: 1‐year results of the TRUNC study