1. Articles from jigang wu

    1-14 of 14
    1. Three-dimensional endoscopic OCT using sparse sampling with a miniature magnetic-driven scanning probe

      Three-dimensional endoscopic OCT using sparse sampling with a miniature magnetic-driven scanning probe

      We propose to apply sparse sampling and compressive sensing (CS) reconstruction in three-dimensional (3D) endoscopic optical coherence tomography (OCT) to reduce the amount of data required in the imaging process. We used a homemade miniature side-imaging magnetic-driven scanning probe with an outer diameter of 1.4 mm in a 1310 nm swept-source OCT system to acquire two-dimensional (2D) circumferential cross-sectional images of an ex vivo pigeon trachea sample. 3D imaging is then achieved by reconstruction from the multiple 2D images acquired while pulling the sample with a translation stage. Given a total translation distance, we achieved sparse sampling by randomizing ...

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    2. A 2.8-mm-diameter scanhead for multispectral photoacoustic microscopy and optical coherence tomography

      A 2.8-mm-diameter scanhead for multispectral photoacoustic microscopy and optical coherence tomography

      An endoscopic probe with high resolution and multiple contrasts provides useful diagnostic information. For example, a miniature probe capable of multimodal imaging including photoacoustic imaging, optical coherence tomography (OCT), and ultrasound has been reported. However, microscale resolution is only realized in OCT modality in the probe, which may restrict the applications where high resolutions for multiple contrasts are required. Here, we present an approach to construct a miniature scanhead with 2.8 mm in diameter that achieves high-resolution multispectral photoacoustic microscopy (PAM) and OCT. The method realizes high resolution of ∼10 μm for both PAM and OCT. We experimentally demonstrate ...

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    3. Endoscopic optical coherence tomography using compressive sensing

      Endoscopic optical coherence tomography using compressive sensing

      Conventionally endoscopic OCT images are reconstructed by uniform sampling in both axial and transverse direction of the image. To shorten the scanning time and reduce the acquisition data, we propose to sparsely sample the axial scans and use compressive sensing (CS) to reconstruct the full endoscopic OCT image with randomly chosen axial scans that are much less than conventional Nyquist criteria requirement. And we study the ratio of sparse sampling numerically and experimentally that are required to reconstruct acceptable OCT images. We demonstrate that the OCT image acquisition time can be significantly reduced because of much less acquired data.

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    4. Miniaturized magnetic-driven scanning probe for endoscopic optical coherence tomography

      Miniaturized magnetic-driven scanning probe for endoscopic optical coherence tomography

      We designed and implemented a magnetic-driven scanning (MDS) probe for endoscopic optical coherence tomography (OCT). The probe uses an externally-driven tiny magnet in the distal end to achieve unobstructed 360-degree circumferential scanning at the side of the probe. The design simplifies the scanning part inside the probe and thus allows for easy miniaturization and cost reduction. We made a prototype probe with an outer diameter of 1.4 mm and demonstrated its capability by acquiring OCT images of ex vivo trachea and artery samples from a pigeon. We used a spectrometer-based Fourier-domain OCT system and the system sensitivity with our ...

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    5. Miniaturized endoscopic probe for optical coherence tomography with a tiny magnet driving device

      Miniaturized endoscopic probe for optical coherence tomography with a tiny magnet driving device

      This paper proposes an endoscopic probe for optical coherence tomography (OCT) applying on side-imaging of internal organs. The probe consists of single-mode fiber, a gradient-index (GRIN) lens, and a mirror of cylindrical wedge shape attaching to a magnetized metal piece by epoxy with a short steel wire. For OCT scanning, we use magnetic field generated by a larger magnet externally to drive the rotation of the magnetized metal. Compare with other probes, our probe design has two distinct advantages: 1) The exit beam will be unobstructed during 360 degree circumference scanning because there are no connecting wires in the scanning ...

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    6. Optical imaging techniques in microfluidics and their applications

      Optical imaging techniques in microfluidics and their applications

      Microfluidic devices have undergone rapid development in recent years and provide a lab-on-a-chip solution for many biomedical and chemical applications. Optical imaging techniques are essential in microfluidics for observing and extracting information from biological or chemical samples. Traditionally, imaging in microfluidics is achieved by bench-top conventional microscopes or other bulky imaging systems. More recently, many novel compact microscopic techniques have been developed to provide a low-cost and portable solution. In this review, we provide an overview of optical imaging techniques used in microfluidics followed with their applications. We first discuss bulky imaging systems including microscopes and interferometer-based techniques, then we ...

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    7. Congratulations to Jian Ren from Caltech a Winner of a 2012 Student Travel Grant Award

      Congratulations to Jian Ren from  Caltech a Winner of a 2012 Student Travel Grant Award
      Jian Ren from the California Institute of Technology is one of four winners of the OCT News 2012 student travel grant awards (see prior announcement Here). Below is a summary of his work. Glaucoma is one type of ophthalmic diseases, where ocular hypertension damages optical nerve, making it the second leading cause of blindness worldwide. One major cause of Open Angle Glaucoma is the poor outflow of aqueous humor through the Trabecular Meshwork (TM). Potential treatments include the micro-bypass stents, which are implanted in the TM and shunt fluid directly to the Schlemm’s Canal (SC) to reduce intraocular pressure ...
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    8. Feature Of The Week 5/1/11: Caltech Researchers Develop an OCT Needle Probe for Investigating Open Angle Glaucoma

      Feature Of The Week 5/1/11: Caltech Researchers Develop an OCT Needle Probe for Investigating Open Angle Glaucoma
      Feature Of The Week 5/1/11: One major cause of Open Angle Glaucoma is the poor outflow of aqueous humor through the Trabecular Meshwork (TM). Potential treatments include the micro-bypass stents, which are implanted in the TM and shunt fluid directly to the Schlemm’s Canal (SC) to reduce intraocular pressure. Implanting the stent with the appropriate orientation near a major collector channel (CC) might maximize outflow of aqueous humor.As scleral tissue and the TM are not transparent to visible light, OCT using infrared light may be useful in visualizing and locating collector channels, hence could assist the ...
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    9. Ex vivo Optical Coherence Tomography Imaging of Collector Channels with a Scanning Endoscopic Probe

      Ex vivo Optical Coherence Tomography Imaging of Collector Channels with a Scanning Endoscopic Probe
      Abstract Purpose: To achieve high-fidelity optical coherence tomography (OCT) imaging of ex vivo collector channels (CCs) exiting Schlemm's canal (SC) using a paired angled rotating scanning endoscopic probe. Methods: An endoscopic probe was developed to guide an OCT laser beam onto human cadaver eye tissue samples to detect CCs. The prototype probe consisted of two gradient-index (GRIN) lenses, which were housed in two stainless steel needles respectively. The probe scanned the laser beam across a fan shape area by rotating the two GRIN lenses. We built a swept source based OCT system to provide the depth scans. Human cadaver ...
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    10. Manual-scanning optical coherence tomography probe based on position tracking

      Manual-scanning optical coherence tomography probe based on position tracking
      A method based on position tracking to reconstruct images for a manual-scanning optical coherence tomography (OCT) probe is proposed and implemented. The method employs several feature points on a hand-held probe and a camera to track the device’s pose. The continuous device poses tracking, and the collected OCT depth scans can then be combined to render OCT images. The tracking accuracy of the system was characterized to be about 6 um along two axes and 19 um along the third. A phantom target was used to validate the method. In addition, we report OCT images of a 54-stage Xenopus ...
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    11. Harmonically matched diffraction grating pair

      A method and device realize shallow gratings-based planar beam splitter/combiner. Non-trivial phase shifts between different ports of resulting interferometers are used to acquire full-field phase measurements. The non-trivial phase shifts between different ports of the planar beam splitter/combiner can be adjusted by simply shearing one grating with respect to the second grating. The two shallow diffraction gratings are harmonically-related and can be recorded on a single substrate for compact interferometric based schemes. During the recording process, the two gratings are aligned such that the grating planes and the grating vectors are parallel to that of each other. The ...
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    12. Coherence domain optical imaging techniques (Thesis)

      Coherence domain optical imaging techniques (Thesis)
      Coherence domain optical imaging techniques have been developing quickly in the past few decades after the invention of laser. In this thesis, I will report the imaging methods that constitute my research projects during these years of graduate studies, including paired-angle-rotation scanning (PARS) forward-imaging probe for optical coherence tomography (OCT), full-field phase imaging technique based on harmonically matched diffraction grating (G1G2 grating), and Fresnel zone plate (FZP) based optifluidic microscopy (OFM). Compared with conventional optical microscopy, the coherence domain optical imaging has many advantages and greatly extends the application of imaging techniques. OCT, based on low-coherence interferometry, is a high-resolution ...
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    13. Paired angled rotation scanning probes and methods of use

      Probes, and systems and methods for optically scanning a conical volume in front of a probe, for use with an imaging modality, such as Optical Coherence Tomography (OCT). A probe includes an optical fiber having a proximal end and a distal end and defining an axis, with the proximal end of the optical fiber being proximate a light source, and the distal end having a first angled surface. A refractive lens element is positioned proximate the distal end of the optical fiber. The lens element and the fiber end are both configured to separately rotate about the axis so as ...
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    14. Handheld forward-imaging needle endoscope for ophthalmic optical coherence tomography inspection

      Shuo Han, Marinko V. Sarunic, Jigang Wu et al. We report the narrowest to-date (21 gauge, 820-[mu]m-diam) handheld forward-imaging optical coherence tomography (OCT) needle endoscope and demonstrate its feasibility for ophthalmic OCT inspection. The probe design is based on paired-angle-rotation scanning (PARS), which enables a linear B-scan pat ... [J. Biomed. Opt. 13, 020505 (2008)] published Mon Apr 21, 2008.
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    1-14 of 14
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  2. Topics in the News

    1. (14 articles) Jigang Wu
    2. (9 articles) California Institute of Technology
    3. (8 articles) Changhuei Yang
    4. (6 articles) Shanghai Jiao Tong University
    5. (4 articles) University of Michigan
    6. (4 articles) Jian Ren
    7. (3 articles) Henrick K. Gille
    8. (1 articles) Tsinghua University
    9. (1 articles) University of Southern California
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    Manual-scanning optical coherence tomography probe based on position tracking Coherence domain optical imaging techniques (Thesis) Ex vivo Optical Coherence Tomography Imaging of Collector Channels with a Scanning Endoscopic Probe Feature Of The Week 5/1/11: Caltech Researchers Develop an OCT Needle Probe for Investigating Open Angle Glaucoma Congratulations to Jian Ren from  Caltech a Winner of a 2012 Student Travel Grant Award Optical imaging techniques in microfluidics and their applications Miniaturized magnetic-driven scanning probe for endoscopic optical coherence tomography Fantom Encore Sirolimus-eluting Bioresorbable Scaffold for Treatment of De-novo CAD: the ENCORE-I Study Assessment of Microcirculatory Dysfunction in Septic Shock Patients by OCTA OCT system used at home demonstrates potential for daily monitoring of AMD Optical Coherence Tomography Biomarkers of the Outer Blood—Retina Barrier in Patients with Diabetic Macular Oedema Retinal Boundary Segmentation in Stargardt Disease Optical Coherence Tomography Images Using Automated