1. Articles from Osman Oguz Ahsen

    1-4 of 4
    1. Correction of circumferential and longitudinal motion distortion in high-speed catheter/endoscope-based optical coherence tomography

      Correction of circumferential and longitudinal motion distortion in high-speed catheter/endoscope-based optical coherence tomography

      Catheter/endoscope-based optical coherence tomography (OCT) is a powerful modality that visualizes structural information in luminal organs. Increases in OCT speed have reduced motion artifacts by enabling acquisition faster than or comparable to the time scales of physiological motion. However motion distortion remains a challenge because catheter/endoscope OCT imaging involves both circumferential and longitudinal scanning of tissue. This paper presents a novel image processing method to estimate and correct motion distortion in both the circumferential and longitudinal directions using a single en face image from a volumetric data set. The circumferential motion distortion is estimated and corrected using the ...

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    2. 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 µm axial resolution in tissue. The micromotor balloon catheter enables circumferential imaging of the esophagus at 240 frames per second (fps) with a ~30 µm (FWHM) spot size. Volumetric imaging is achieved by proximal pullback of the micromotor assembly within the balloon at 1.5 mm/sec ...

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    3. Ultrahigh speed en face OCT capsule for endoscopic imaging

      Ultrahigh speed en face OCT capsule for endoscopic imaging

      Depth resolved and en face OCT visualization in vivo may have important clinical applications in endoscopy. We demonstrate a high speed, two-dimensional (2D) distal scanning capsule with a micromotor for fast rotary scanning and a pneumatic actuator for precision longitudinal scanning. Longitudinal position measurement and image registration were performed by optical tracking of the pneumatic scanner. The 2D scanning device enables high resolution imaging over a small field of view and is suitable for OCT as well as other scanning microscopies. Large field of view imaging for screening or surveillance applications can also be achieved by proximally pulling back or ...

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    4. 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 polarization beam splitters and polarization controllers were used to remove the polarization ambiguity. A simplified post-processing algorithm was proposed for speckle noise reduction relaxing the demand for phase stability. We ...

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    1-4 of 4
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  2. Topics in the News

    1. (4 articles) Massachusetts Institute of Technology
    2. (3 articles) Thorlabs
    3. (3 articles) Praevium Research
    4. (2 articles) Harvard University
    5. (2 articles) Duke University
    6. (1 articles) University of Erlangen
    7. (1 articles) Brigham and Women’s Hospital
    8. (1 articles) Konyang University
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    Depth-encoded all-fiber swept source polarization sensitive OCT Ultrahigh speed en face OCT capsule for endoscopic imaging Circumferential optical coherence tomography angiography imaging of the swine esophagus using a micromotor balloon catheter Correction of circumferential and longitudinal motion distortion in high-speed catheter/endoscope-based optical coherence tomography Repeatability of Optical Coherence Tomography Angiography Measurements in Patients with Retinal Vein Occlusion Retinal Vascularization Analysis on Optical Coherence Tomography Angiography before and after Intraretinal or Subretinal Fluid Resorption in Exudative Age-Related Macular Degeneration: A Pilot Study Anterior‐segment optical coherence tomography of filtering blebs in the early postoperative period of ab externo SIBS microshunt implantation with mitomycin C: Morphological analysis and correlation with intraocular pressure reduction Combining artificial intelligence and robotics: a novel fully automated optical coherence tomography-based approach for eye disease screening Impact of fundus pigmentation on retinal layer visibility on investigational bedside optical coherence tomography in preterm infants Vascular morphology in facial solar lentigo assessed by optical coherence tomography angiography Macular vascular changes in pregnant women with gestational diabetes mellitus by optical coherence tomography angiography Feasibility of peripheral OCT imaging using a novel integrated SLO ultra-widefield imaging swept-source OCT device