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Zhang J, Nguyen T, Potsaid B, Jayaraman V, Burgner C, Chen S, Li J, Liang K, Cable A, Traverso G, Mashimo H, Fujimoto JG. Multi-MHz MEMS-VCSEL swept-source optical coherence tomography for endoscopic structural and angiographic imaging with miniaturized brushless motor probes. Biomed Opt Express 2021; 12:2384-2403. [PMID: 33996236 PMCID: PMC8086463 DOI: 10.1364/boe.420394] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Revised: 03/10/2021] [Accepted: 03/18/2021] [Indexed: 05/02/2023]
Abstract
Swept source optical coherence tomography (SS-OCT) enables volumetric imaging of subsurface structure. However, applications requiring wide fields of view (FOV), rapid imaging, and higher resolutions have been challenging because multi-MHz axial scan (A-scan) rates are needed. We describe a microelectromechanical systems vertical cavity surface-emitting laser (MEMS-VCSEL) SS-OCT technology for A-scan rates of 2.4 and 3.0 MHz. Sweep to sweep calibration and resampling are performed using dual channel acquisition of the OCT signal and a Mach Zehnder interferometer signal, overcoming inherent optical clock limitations and enabling higher performance. We demonstrate ultrahigh speed structural SS-OCT and OCT angiography (OCTA) imaging of the swine gastrointestinal tract using a suite of miniaturized brushless motor probes, including a 3.2 mm diameter micromotor OCT catheter, a 12 mm diameter tethered OCT capsule, and a 12 mm diameter widefield OCTA probe. MEMS-VCSELs promise to enable ultrahigh speed SS-OCT with a scalable, low cost, and manufacturable technology, suitable for a diverse range of imaging applications.
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Affiliation(s)
- Jason Zhang
- Department of Electrical Engineering and Computer Science, Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
- These authors contributed equally to this work
| | - Tan Nguyen
- Department of Electrical Engineering and Computer Science, Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
- These authors contributed equally to this work
| | - Benjamin Potsaid
- Department of Electrical Engineering and Computer Science, Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
- Advanced Imaging Group, Thorlabs Inc., Newton, NJ 07860, USA
| | | | | | - Siyu Chen
- Department of Electrical Engineering and Computer Science, Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Jinxi Li
- Department of Electrical Engineering and Computer Science, Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Kaicheng Liang
- Department of Electrical Engineering and Computer Science, Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Alex Cable
- Advanced Imaging Group, Thorlabs Inc., Newton, NJ 07860, USA
| | - Giovanni Traverso
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
- Division of Gastroenterology, Massachusetts General Hospital, Boston, MA 02114, USA
- Division of Gastroenterology, Brigham and Women’s Hospital, Boston, MA 02115, USA
- Harvard Medical School, Boston, MA 02115, USA
| | - Hiroshi Mashimo
- Harvard Medical School, Boston, MA 02115, USA
- Veterans Affairs Boston Healthcare System, Boston, MA 02132, USA
| | - James G. Fujimoto
- Department of Electrical Engineering and Computer Science, Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
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2
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Elefante A, Giglio M, Sampaolo A, Menduni G, Patimisco P, Passaro VMN, Wu H, Rossmadl H, Mackowiak V, Cable A, Tittel FK, Dong L, Spagnolo V. Dual-Gas Quartz-Enhanced Photoacoustic Sensor for Simultaneous Detection of Methane/Nitrous Oxide and Water Vapor. Anal Chem 2019; 91:12866-12873. [PMID: 31500409 DOI: 10.1021/acs.analchem.9b02709] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The development of a dual-gas quartz-enhanced photoacoustic (QEPAS) sensor capable of simultaneous detection of water vapor and alternatively methane or nitrous oxide is reported. A diode laser and a quantum cascade laser (QCL) excited independently and simultaneously both the fundamental and the first overtone flexural mode of the quartz tuning fork (QTF), respectively. The diode laser targeted a water absorption line located at 7181.16 cm-1 (1.392 μm), while the QCL emission wavelength is centered at 7.71 μm and was tuned to target two strong absorption lines of methane and nitrous oxide, located at 1297.47 and 1297.05 cm-1, respectively. Two sets of microresonator tubes were positioned, respectively, at the antinode points of the fundamental and the first overtone flexural modes of the QTF to enhance the QEPAS signal-to-noise ratio. Detection limits of 18 ppb for methane, 5 ppb for nitrous oxide and 20 ppm for water vapor have been achieved at a lock-in integration time of 100 ms.
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Affiliation(s)
- Arianna Elefante
- State Key Laboratory of Quantum Optics and Quantum Optics Devices, Institute of Laser Spectroscopy , Shanxi University , Taiyuan 030006 , China.,PolySense Lab - Dipartimento Interateneo di Fisica , University and Politecnico of Bari , Via Amendola 173 , Bari , Italy
| | - Marilena Giglio
- State Key Laboratory of Quantum Optics and Quantum Optics Devices, Institute of Laser Spectroscopy , Shanxi University , Taiyuan 030006 , China.,PolySense Lab - Dipartimento Interateneo di Fisica , University and Politecnico of Bari , Via Amendola 173 , Bari , Italy
| | - Angelo Sampaolo
- State Key Laboratory of Quantum Optics and Quantum Optics Devices, Institute of Laser Spectroscopy , Shanxi University , Taiyuan 030006 , China.,PolySense Lab - Dipartimento Interateneo di Fisica , University and Politecnico of Bari , Via Amendola 173 , Bari , Italy
| | - Giansergio Menduni
- PolySense Lab - Dipartimento Interateneo di Fisica , University and Politecnico of Bari , Via Amendola 173 , Bari , Italy.,Photonics Research Group, Dipartimento di Ingegneria Elettrica e dell'informazione , Politecnico di Bari , Via Orabona 4 , Bari , 70126 , Italy
| | - Pietro Patimisco
- State Key Laboratory of Quantum Optics and Quantum Optics Devices, Institute of Laser Spectroscopy , Shanxi University , Taiyuan 030006 , China.,PolySense Lab - Dipartimento Interateneo di Fisica , University and Politecnico of Bari , Via Amendola 173 , Bari , Italy
| | - Vittorio M N Passaro
- Photonics Research Group, Dipartimento di Ingegneria Elettrica e dell'informazione , Politecnico di Bari , Via Orabona 4 , Bari , 70126 , Italy
| | - Hongpeng Wu
- State Key Laboratory of Quantum Optics and Quantum Optics Devices, Institute of Laser Spectroscopy , Shanxi University , Taiyuan 030006 , China
| | - Hubert Rossmadl
- Thorlabs GmbH , Hans-Boeckler-Straße 6 , 85221 Dachau , Germany
| | | | - Alex Cable
- Thorlabs, Inc. , 56 Sparta Ave. , Newton , 07860 , United States
| | - Frank K Tittel
- Department of Electrical and Computer Engineering , Rice University , Houston , Texas 77005 , United States
| | - Lei Dong
- State Key Laboratory of Quantum Optics and Quantum Optics Devices, Institute of Laser Spectroscopy , Shanxi University , Taiyuan 030006 , China
| | - Vincenzo Spagnolo
- State Key Laboratory of Quantum Optics and Quantum Optics Devices, Institute of Laser Spectroscopy , Shanxi University , Taiyuan 030006 , China.,PolySense Lab - Dipartimento Interateneo di Fisica , University and Politecnico of Bari , Via Amendola 173 , Bari , Italy
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3
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Lu CD, Waheed NK, Witkin A, Baumal CR, Liu JJ, Potsaid B, Joseph A, Jayaraman V, Cable A, Chan K, Duker JS, Fujimoto JG. Microscope-Integrated Intraoperative Ultrahigh-Speed Swept-Source Optical Coherence Tomography for Widefield Retinal and Anterior Segment Imaging. Ophthalmic Surg Lasers Imaging Retina 2019; 49:94-102. [PMID: 29443358 DOI: 10.3928/23258160-20180129-03] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Accepted: 12/18/2017] [Indexed: 11/20/2022]
Abstract
BACKGROUND AND OBJECTIVE To demonstrate the feasibility of retinal and anterior segment intraoperative widefield imaging using an ultrahigh-speed, swept-source optical coherence tomography (SS-OCT) surgical microscope attachment. PATIENTS AND METHODS A prototype post-objective SS-OCT using a 1,050-nm wavelength, 400 kHz A-scan rate, vertical cavity surface-emitting laser (VCSEL) light source was integrated to a commercial ophthalmic surgical microscope after the objective. Each widefield OCT data set was acquired in 3 seconds (1,000 × 1,000 A-scans, 12 × 12 mm2 for retina and 10 × 10 mm2 for anterior segment). RESULTS Intraoperative SS-OCT was performed in 20 eyes of 20 patients. In six of seven membrane peels and five of seven rhegmatogenous retinal detachment repair surgeries, widefield retinal imaging enabled evaluation pre- and postoperatively. In all seven cataract cases, anterior imaging evaluated the integrity of the posterior lens capsule. CONCLUSIONS Ultrahigh-speed SS-OCT enables widefield intraoperative viewing in the posterior and anterior eye. Widefield imaging visualizes ocular structures and pathology without requiring OCT realignment. [Ophthalmic Surg Lasers Imaging Retina. 2018;49:94-102.].
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Patimisco P, Sampaolo A, Giglio M, Dello Russo S, Mackowiak V, Rossmadl H, Cable A, Tittel FK, Spagnolo V. Tuning forks with optimized geometries for quartz-enhanced photoacoustic spectroscopy. Opt Express 2019; 27:1401-1415. [PMID: 30696206 DOI: 10.1364/oe.27.001401] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
We report on the design, realization, and performance of novel quartz tuning forks (QTFs) optimized for quartz-enhanced photoacoustic spectroscopy (QEPAS). Starting from a QTF geometry designed to provide a fundamental flexural in-plane vibrational mode resonance frequency of ~16 kHz, with a quality factor of 15,000 at atmospheric pressure, two novel geometries have been realized: a QTF with T-shaped prongs and a QTF with prongs having rectangular grooves carved on both surface sides. The QTF with grooves showed the lowest electrical resistance, while the T-shaped prongs QTF provided the best photoacoustic response in terms of signal-to-noise ratio (SNR). When acoustically coupled with a pair of micro-resonator tubes, the T-shaped QTF provides a SNR enhancement of a factor of 60 with respect to the bare QTF, which represents a record value for mid-infrared QEPAS sensing.
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Patimisco P, Sampaolo A, Mackowiak V, Rossmadl H, Cable A, Tittel FK, Spagnolo V. Loss Mechanisms Determining the Quality Factors in Quartz Tuning Forks Vibrating at the Fundamental and First Overtone Modes. IEEE Trans Ultrason Ferroelectr Freq Control 2018; 65:1951-1957. [PMID: 29994396 DOI: 10.1109/tuffc.2018.2853404] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Quartz tuning forks (QTFs) are piezo-transducers that have been implemented for numerous applications, such as chemical gas sensing, atomic force microscopy, rheology, and industrial process control. The most important parameter for QTFs' sensing application is the resonance quality factor (Q-factor). An experimental investigation and theoretical analysis of the influence of QTFs' geometries on the Q-factor of the flexural fundamental and first overtone resonance modes are reported. The resonance frequencies and related Q-factors for five different QTFs have been measured. The QTF response was recorded at different air pressures to investigate the influence of the surrounding medium on the Q-factor. A data analysis demonstrated that air viscous damping is the dominant energy dissipation mechanism for both flexural modes. Thermoelastic and support losses are additional contributions that depend on the QTF geometry. A study of the QTF damping mechanism dependence upon the prong geometry is also provided.
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Patimisco P, Sampaolo A, Giglio M, Mackowiak V, Rossmadl H, Gross B, Cable A, Tittel FK, Spagnolo V. Octupole electrode pattern for tuning forks vibrating at the first overtone mode in quartz-enhanced photoacoustic spectroscopy. Opt Lett 2018; 43:1854-1857. [PMID: 29652382 DOI: 10.1364/ol.43.001854] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2018] [Accepted: 03/17/2018] [Indexed: 06/08/2023]
Abstract
The design, realization, and performance analysis of an octupole electrode pattern configuration intended for the optimization of the charge collection efficiency in quartz tuning forks (QTFs) vibrating at the first overtone in-plane flexural mode is reported. Two QTFs having the same geometry, but differing in the electrode pattern deposited on the QTF prongs, have been realized in order to study the influence of the electrode pattern on the resonance quality factor and electrical resistance. A standard quadrupole pattern (optimized for the fundamental mode) and an octupole electrode layout have been implemented. Although both QTFs show the same resonance quality factor for the first overtone, the octupole pattern provides a reduction of the QTF electrical resistance by more than four times. The sensing performance of the two QTFs has been compared by employing them in a mid-IR quartz-enhanced photoacoustic sensor (QEPAS) system targeting a water absorption line. When operating at the first overtone mode, the QTF with an octupole electrode pattern provides a QEPAS signal more than two times higher with respect to the QTF employing the standard quadrupole configuration.
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7
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Liang K, Wang Z, Ahsen OO, Lee HC, Potsaid BM, Jayaraman V, Cable A, Mashimo H, Li X, Fujimoto JG. Cycloid scanning for wide field optical coherence tomography endomicroscopy and angiography in vivo. Optica 2018; 5:36-43. [PMID: 29682598 PMCID: PMC5909979 DOI: 10.1364/optica.5.000036] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Accepted: 11/27/2017] [Indexed: 05/18/2023]
Abstract
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 endoscopic imaging. We demonstrate a new cycloid scanner in a tethered capsule for ultrahigh speed, side-viewing optical coherence tomography (OCT) endomicroscopy in vivo. The cycloid capsule incorporates two scanners: a piezoelectrically actuated resonant fiber scanner to perform a precision, small FOV, fast scan and a micromotor scanner to perform a wide FOV, slow scan. Together these scanners distally scan the beam circumferentially in a 2D cycloid pattern, generating an unwrapped 1 mm × 38 mm strip FOV. Sequential strip volumes can be acquired with proximal pullback to image centimeter-long regions. Using ultrahigh speed 1.3 μm wavelength swept-source OCT at a 1.17 MHz axial scan rate, we imaged the human rectum at 3 volumes/s. Each OCT strip volume had 166 × 2322 axial scans with 8.5 μm axial and 30 μm transverse resolution. We further demonstrate OCT angiography at 0.5 volumes/s, producing volumetric images of vasculature. In addition to OCT applications, cycloid scanning promises to enable precision 2D optical scanning for other imaging modalities, including fluorescence confocal and nonlinear microscopy.
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Affiliation(s)
- Kaicheng Liang
- Department of Electrical Engineering and Computer Science, Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Zhao Wang
- Department of Electrical Engineering and Computer Science, Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Osman O. Ahsen
- Department of Electrical Engineering and Computer Science, Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Hsiang-Chieh Lee
- Department of Electrical Engineering and Computer Science, Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Benjamin M. Potsaid
- Department of Electrical Engineering and Computer Science, Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
- Thorlabs, Newton, New Jersey 07860, USA
| | | | | | - Hiroshi Mashimo
- Veterans Affairs Boston Healthcare System, Boston, Massachusetts 02130, USA
- Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Xingde Li
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, Maryland 21218, USA
| | - James G. Fujimoto
- Department of Electrical Engineering and Computer Science, Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
- Corresponding author:
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8
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Singh M, Raghunathan R, Piazza V, Davis-Loiacono AM, Cable A, Vedakkan TJ, Janecek T, Frazier MV, Nair A, Wu C, Larina IV, Dickinson ME, Larin KV. Applicability, usability, and limitations of murine embryonic imaging with optical coherence tomography and optical projection tomography. Biomed Opt Express 2016; 7:2295-310. [PMID: 27375945 PMCID: PMC4918583 DOI: 10.1364/boe.7.002295] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2016] [Revised: 05/09/2016] [Accepted: 05/10/2016] [Indexed: 05/17/2023]
Abstract
We present an analysis of imaging murine embryos at various embryonic developmental stages (embryonic day 9.5, 11.5, and 13.5) by optical coherence tomography (OCT) and optical projection tomography (OPT). We demonstrate that while OCT was capable of rapid high-resolution live 3D imaging, its limited penetration depth prevented visualization of deeper structures, particularly in later stage embryos. In contrast, OPT was able to image the whole embryos, but could not be used in vivo because the embryos must be fixed and cleared. Moreover, the fixation process significantly altered the embryo morphology, which was quantified by the volume of the eye-globes before and after fixation. All of these factors should be weighed when determining which imaging modality one should use to achieve particular goals of a study.
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Affiliation(s)
- Manmohan Singh
- Department of Biomedical Engineering, University of Houston, 3605 Cullen Boulevard, Houston, 77204, USA
| | - Raksha Raghunathan
- Department of Biomedical Engineering, University of Houston, 3605 Cullen Boulevard, Houston, 77204, USA
| | - Victor Piazza
- Molecular Physiology and Biophysics, Baylor College of Medicine, One Baylor Plaza, Houston, 77584, USA
| | | | - Alex Cable
- Thorlabs, Inc., 56 Sparta Ave., Newton, 07860, USA
| | - Tegy J. Vedakkan
- Molecular Physiology and Biophysics, Baylor College of Medicine, One Baylor Plaza, Houston, 77584, USA
| | - Trevor Janecek
- Department of Biomedical Engineering, University of Houston, 3605 Cullen Boulevard, Houston, 77204, USA
| | - Michael V. Frazier
- Department of Biomedical Engineering, University of Houston, 3605 Cullen Boulevard, Houston, 77204, USA
| | - Achuth Nair
- Department of Biomedical Engineering, University of Houston, 3605 Cullen Boulevard, Houston, 77204, USA
| | - Chen Wu
- Department of Biomedical Engineering, University of Houston, 3605 Cullen Boulevard, Houston, 77204, USA
| | - Irina V. Larina
- Molecular Physiology and Biophysics, Baylor College of Medicine, One Baylor Plaza, Houston, 77584, USA
| | - Mary E. Dickinson
- Molecular Physiology and Biophysics, Baylor College of Medicine, One Baylor Plaza, Houston, 77584, USA
| | - Kirill V. Larin
- Department of Biomedical Engineering, University of Houston, 3605 Cullen Boulevard, Houston, 77204, USA
- Molecular Physiology and Biophysics, Baylor College of Medicine, One Baylor Plaza, Houston, 77584, USA
- Department of Electrical Engineering, Samara National Research University, Samara, 34 Moskovskoye sh., 443086, Russia
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Salem R, Jiang Z, Liu D, Pafchek R, Gardner D, Foy P, Saad M, Jenkins D, Cable A, Fendel P. Mid-infrared supercontinuum generation spanning 1.8 octaves using step-index indium fluoride fiber pumped by a femtosecond fiber laser near 2 µm. Opt Express 2015; 23:30592-30602. [PMID: 26698692 DOI: 10.1364/oe.23.030592] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
A nearly two-octave wide coherent mid-infrared supercontinuum is demonstrated in a dispersion-engineered step-index indium fluoride fiber pumped near 2 µm. The pump source is an all-fiber femtosecond laser with 100 fs pulse width, 570 mW average power and 50 MHz repetition rate. The supercontinuum spectrum spans from 1.25 µm to 4.6 µm. Numerical modelling of the supercontinuum spectra show good agreement with the measurements. The coherence of the supercontinuum is calculated using a numerical model and shows a high degree of coherence across the generated bandwidth allowing it to be used for frequency comb applications.
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10
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Liang K, Traverso G, Lee HC, Ahsen OO, Wang Z, Potsaid B, Giacomelli M, Jayaraman V, Barman R, Cable A, Mashimo H, Langer R, Fujimoto JG. Ultrahigh speed en face OCT capsule for endoscopic imaging. Biomed Opt Express 2015; 6:1146-63. [PMID: 25909001 PMCID: PMC4399656 DOI: 10.1364/boe.6.001146] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2014] [Revised: 03/02/2015] [Accepted: 03/02/2015] [Indexed: 05/18/2023]
Abstract
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 advancing the capsule while scanning the distal high-speed micromotor. Circumferential en face OCT was demonstrated in living swine at 250 Hz frame rate and 1 MHz A-scan rate using a MEMS tunable VCSEL light source at 1300 nm. Cross-sectional and en face OCT views of the upper and lower gastrointestinal tract were generated with precision distal pneumatic longitudinal actuation as well as proximal manual longitudinal actuation. These devices could enable clinical studies either as an adjunct to endoscopy, attached to an endoscope, or as a swallowed tethered capsule for non-endoscopic imaging without sedation. The combination of ultrahigh speed imaging and distal scanning capsule technology could enable both screening and surveillance applications.
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Affiliation(s)
- Kaicheng Liang
- Department of Electrical Engineering & Computer Science and Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge MA,
USA
| | - Giovanni Traverso
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge MA,
USA
- Division of Gastroenterology, Massachusetts General Hospital, Boston MA,
USA
- Harvard Medical School, Boston MA,
USA
| | - Hsiang-Chieh Lee
- Department of Electrical Engineering & Computer Science and Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge MA,
USA
| | - Osman Oguz Ahsen
- Department of Electrical Engineering & Computer Science and Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge MA,
USA
| | - Zhao Wang
- Department of Electrical Engineering & Computer Science and Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge MA,
USA
| | - Benjamin Potsaid
- Department of Electrical Engineering & Computer Science and Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge MA,
USA
- Advanced Imaging Group, Thorlabs Inc., Newton NJ,
USA
| | - Michael Giacomelli
- Department of Electrical Engineering & Computer Science and Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge MA,
USA
| | | | - Ross Barman
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge MA,
USA
| | - Alex Cable
- Advanced Imaging Group, Thorlabs Inc., Newton NJ,
USA
| | - Hiroshi Mashimo
- Harvard Medical School, Boston MA,
USA
- Veterans Affairs Boston Healthcare System, Boston MA,
USA
| | - Robert Langer
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge MA,
USA
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge MA,
USA
| | - James G. Fujimoto
- Department of Electrical Engineering & Computer Science and Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge MA,
USA
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Wang Z, Lee HC, Ahsen OO, Lee B, Choi W, Potsaid B, Liu J, Jayaraman V, Cable A, Kraus MF, Liang K, Hornegger J, Fujimoto JG. Depth-encoded all-fiber swept source polarization sensitive OCT. Biomed Opt Express 2014; 5:2931-49. [PMID: 25401008 PMCID: PMC4230879 DOI: 10.1364/boe.5.002931] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2014] [Revised: 07/23/2014] [Accepted: 07/24/2014] [Indexed: 05/18/2023]
Abstract
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 demonstrated systems design for both ophthalmic and catheter-based PS-OCT. For ophthalmic imaging, we used an optical clock frequency doubling method to extend the imaging range of a commercially available short cavity light source to improve polarization depth-encoding. For catheter based imaging, we demonstrated 200 kHz PS-OCT imaging using a MEMS-tunable vertical cavity surface emitting laser (VCSEL) and a high speed micromotor imaging catheter. The system was demonstrated in human retina, finger and lip imaging, as well as ex vivo swine esophagus and cardiovascular imaging. The all-fiber PS-OCT is easier to implement and maintain compared to previous PS-OCT systems and can be more easily translated to clinical applications due to its robust design.
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Affiliation(s)
- Zhao Wang
- Department of Electrical Engineering and Computer Science and Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Hsiang-Chieh Lee
- Department of Electrical Engineering and Computer Science and Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Osman Oguz Ahsen
- Department of Electrical Engineering and Computer Science and Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - ByungKun Lee
- Department of Electrical Engineering and Computer Science and Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - WooJhon Choi
- Department of Electrical Engineering and Computer Science and Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Benjamin Potsaid
- Department of Electrical Engineering and Computer Science and Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA, USA
- Advanced Imaging Group, Thorlabs, Inc., Newton, NJ, USA
| | - Jonathan Liu
- Department of Electrical Engineering and Computer Science and Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA, USA
| | | | - Alex Cable
- Department of Electrical Engineering and Computer Science and Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA, USA
- Advanced Imaging Group, Thorlabs, Inc., Newton, NJ, USA
| | - Martin F. Kraus
- Pattern Recognition Lab and School of Advanced Optical Technologies, University Erlangen-Nürnberg, Erlangen, Germany
| | - Kaicheng Liang
- Department of Electrical Engineering and Computer Science and Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Joachim Hornegger
- Pattern Recognition Lab and School of Advanced Optical Technologies, University Erlangen-Nürnberg, Erlangen, Germany
| | - James G. Fujimoto
- Department of Electrical Engineering and Computer Science and Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA, USA
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Ahsen OO, Tao YK, Potsaid BM, Sheikine Y, Jiang J, Grulkowski I, Tsai TH, Jayaraman V, Kraus MF, Connolly JL, Hornegger J, Cable A, Fujimoto JG. Swept source optical coherence microscopy using a 1310 nm VCSEL light source. Opt Express 2013; 21:18021-33. [PMID: 23938673 PMCID: PMC3756222 DOI: 10.1364/oe.21.018021] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2013] [Revised: 07/08/2013] [Accepted: 07/12/2013] [Indexed: 05/18/2023]
Abstract
We demonstrate high speed, swept source optical coherence microscopy (OCM) using a MEMS tunable vertical cavity surface-emitting laser (VCSEL) light source. The light source had a sweep rate of 280 kHz, providing a bidirectional axial scan rate of 560 kHz. The sweep bandwidth was 117 nm centered at 1310 nm, corresponding to an axial resolution of 13.1 µm in air, corresponding to 8.1 µm (9.6 µm spectrally shaped) in tissue. Dispersion mismatch from different objectives was compensated numerically, enabling magnification and field of view to be easily changed. OCM images were acquired with transverse resolutions between 0.86 µm - 3.42 µm using interchangeable 40X, 20X and 10X objectives with ~600 µm x 600 µm, ~1 mm x 1 mm and ~2 mm x 2 mm field-of-view (FOV), respectively. Parasitic variations in path length with beam scanning were corrected numerically. These features enable swept source OCM to be integrated with a wide range of existing scanning microscopes. Large FOV mosaics were generated by serially acquiring adjacent overlapping microscopic fields and combining them in post-processing. Fresh human colon, thyroid and kidney specimens were imaged ex vivo and compared to matching histology sections, demonstrating the ability of OCM to image tissue specimens.
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Affiliation(s)
- Osman O Ahsen
- Department of Electrical Engineering & Computer Science and Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA, USA
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Jayaraman V, Cole G, Robertson M, Burgner C, John D, Uddin A, Cable A. Rapidly swept, ultra-widely-tunable 1060 nm MEMS-VCSELs. Electron Lett 2012; 48:1331-1333. [PMID: 23520409 PMCID: PMC3601947 DOI: 10.1049/el.2012.3180] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Demonstrated are 1060 nm microelectromechanical-systems-based tunable vertical-cavity surface-emitting lasers (MEMS-VCSELs) with a 100 nm continuous tuning range under repetitively scanned operation at rates beyond 500 kHz and a 90 nm continuous tuning range under static operation. These devices employ a thin strained InGaAs multiple quantum well active region integrated with a fully oxidised GaAs/AlxOy bottom mirror and a suspended dielectric top mirror. The devices are optically pumped via 850 nm light. These ultra-widely tunable lasers represent the first MEMS-VCSELs reported in this wavelength range, and are ideally suited for application in ophthalmic swept-source optical coherence tomography.
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Affiliation(s)
- V. Jayaraman
- Praevium Research Inc., 5266 Hollister Avenue, Suite 224, Santa Barbara, CA 93111, USA
| | - G.D. Cole
- Advanced Optical Microsystems, 1243 West El Camino Real, Mountain View, CA 94040, USA
| | - M. Robertson
- Praevium Research Inc., 5266 Hollister Avenue, Suite 224, Santa Barbara, CA 93111, USA
| | - C. Burgner
- Praevium Research Inc., 5266 Hollister Avenue, Suite 224, Santa Barbara, CA 93111, USA
| | - D. John
- Praevium Research Inc., 5266 Hollister Avenue, Suite 224, Santa Barbara, CA 93111, USA
| | - A. Uddin
- Praevium Research Inc., 5266 Hollister Avenue, Suite 224, Santa Barbara, CA 93111, USA
| | - A. Cable
- Thorlabs, 56 Sparta Ave, Newton, NJ 07860, USA
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Jayaraman V, Cole GD, Robertson M, Uddin A, Cable A. High-sweep-rate 1310 nm MEMS-VCSEL with 150 nm continuous tuning range. Electron Lett 2012; 48:867-869. [PMID: 23976788 PMCID: PMC3749789 DOI: 10.1049/el.2012.1552] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Microelectromechanical-systems-based vertical-cavity surface-emitting lasers (MEMS-VCSELs) capable of a 150 nm continuous tuning range near 1310 nm are demonstrated. These devices employ a thin optically pumped active region structure with large free-spectral range, which promotes wide and continuous tuning. To achieve VCSEL emission at 1310 nm, a wide-gain-bandwidth indium phosphide-based multiple quantum well active region is combined with a wide-bandwidth fully oxidised GaAs-based mirror through wafer bonding, with tuning enabled by a suspended dielectric top mirror. These devices are capable of being scanned over the entire tuning range at frequencies up to 500 kHz, making them ideal for applications such as swept source optical coherence tomography and high-speed transient spectroscopy.
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Affiliation(s)
- V Jayaraman
- Praevium Research, Inc., 5266 Hollister Avenue, Suite 224, Santa Barbara, CA 93111, USA
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15
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Abstract
PURPOSE To determine histopathological status of living human kidneys in real time and a noninvasive fashion would be a significant advancement in renal disease diagnosis. Recently we reported that optical coherence tomography has the requisite high spatial resolution to noninvasively determine histopathological changes in rodent kidneys with microm scale resolution. We established whether optical coherence tomography could 1) effectively penetrate the connective tissue capsule surrounding human kidneys, 2) provide a global survey of the human renal surface and 3) determine histopathological changes in human renal microstructure. MATERIALS AND METHODS Using a high speed optical coherence tomography system equipped with a frequency swept laser light source (1.3 microm wavelength) we obtained cross-sectional images of 4 ex vivo human kidneys. All scanned sections underwent subsequent conventional light microscopic histological analysis, allowing direct comparisons. RESULTS Optical coherence tomography enabled characterization of the tubules, glomeruli and cortical vessels with a penetration depth of up to 2 mm and 10 microm spatial resolution. We surveyed and imaged an entire human kidney within minutes in a noninvasive fashion. Acquired optical coherence tomography images documented histopathological changes in the tubules, glomeruli and interstitium that closely matched the conventional histological observations. CONCLUSIONS Optical coherence tomography resolution and low cost, and the versatility of the probes required for imaging acquisition make this optical technology a promising modality to diagnose renal pathology.
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Affiliation(s)
- Maristela L Onozato
- Division of Nephrology and Hypertension, Cardiovascular Kidney Institute, Georgetown University Medical Center, Washington, DC, USA
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Yuan S, Roney CA, Wierwille J, Chen CW, Xu B, Griffiths G, Jiang J, Ma H, Cable A, Summers RM, Chen Y. Co-registered optical coherence tomography and fluorescence molecular imaging for simultaneous morphological and molecular imaging. Phys Med Biol 2010; 55:191-206. [PMID: 20009192 DOI: 10.1088/0031-9155/55/1/011] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Optical coherence tomography (OCT) provides high-resolution, cross-sectional imaging of tissue microstructure in situ and in real time, while fluorescence molecular imaging (FMI) enables the visualization of basic molecular processes. There is a great deal of interest in combining these two modalities so that the tissue's structural and molecular information can be obtained simultaneously. This could greatly benefit biomedical applications such as detecting early diseases and monitoring therapeutic interventions. In this research, an optical system that combines OCT and FMI was developed. The system demonstrated that it could co-register en face OCT and FMI images with a 2.4 x 2.4 mm(2) field-of-view. The transverse resolutions of OCT and FMI of the system are both approximately 10 microm. Capillary tubes filled with fluorescent dye Cy 5.5 in different concentrations under a scattering medium are used as the phantom. En face OCT images of the phantoms were obtained and successfully co-registered with FMI images that were acquired simultaneously. A linear relationship between FMI intensity and dye concentration was observed. The relationship between FMI intensity and target fluorescence tube depth measured by OCT images was also observed and compared with theoretical modeling. This relationship could help in correcting reconstructed dye concentration. Imaging of colon polyps of the APC(min) mouse model is presented as an example of biological applications of this co-registered OCT/FMI system.
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Affiliation(s)
- Shuai Yuan
- Fischell Department of Bioengineering, University of Maryland, College Park, MD 20742, USA
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17
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Li Q, Onozato ML, Andrews PM, Chen CW, Paek A, Naphas R, Yuan S, Jiang J, Cable A, Chen Y. Automated quantification of microstructural dimensions of the human kidney using optical coherence tomography (OCT). Opt Express 2009; 17:16000-16. [PMID: 19724599 DOI: 10.1364/oe.17.016000] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Optical coherence tomography (OCT) is a rapidly emerging imaging modality that can non-invasively provide cross-sectional, high-resolution images of tissue morphology in situ and in real-time. We previously demonstrated that OCT is capable of visualizing characteristic kidney anatomic structures, including blood vessels, uriniferous tubules, glomeruli, and renal capsules on a Munich-Wistar rat model. Because the viability of a donor kidney is closely correlated with its tubular morphology, and a large amount of image datasets are expected when using OCT to scan the entire kidney to provide a global assessment of its viability, it is necessary to develop automatic image analysis methods to quantify the spatially-resolved morphometric parameters such as tubular diameter to provide potential diagnostic information. In this study, we imaged the human kidney in vitro and quantified the diameters of hollow structures such as blood vessels and uriniferous tubules automatically. The microstructures were first segmented from cross-sectional OCT images. Then the spatially-isolated region-of-interest (ROI) was automatically selected to quantify its dimension. This method enables the automatic selection and quantification of spatially-resolved morphometric parameters. The quantification accuracy was validated, and measured features are in agreement with known kidney morphology. This work can enable studies to determine the clinical utility of OCT for kidney imaging, as well as studies to evaluate kidney morphology as a biomarker for assessing kidney's viability prior to transplantation.
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Affiliation(s)
- Qian Li
- Fischell Department of Bioengineering and Department of Electrical and Computer Engineering, University of Maryland, College Park, MD 20742, USA
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18
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Yuan S, Li Q, Jiang J, Cable A, Chen Y. Three-dimensional coregistered optical coherence tomography and line-scanning fluorescence laminar optical tomography. Opt Lett 2009; 34:1615-7. [PMID: 19488125 DOI: 10.1364/ol.34.001615] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
We present a combined optical coherence tomography (OCT) and line-scanning fluorescence laminar optical tomography (FLOT) system. This hybrid system enables coregistered structural and molecular imaging in 3D with 10-100 microm resolution and millimeter-scale imaging depth. Experimental results on a capillary phantom with fluorescence dye Cy5.5 using an OCT/FLOT imaging system have been demonstrated.
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Affiliation(s)
- Shuai Yuan
- Fischell Department of Bioengineering, University of Maryland, College Park, Maryland 20742, USA
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Li Q, Onozato M, Andrews PM, Paek A, Duttaroy A, Shirmahamoodi B, Jiang J, Cable A, Chen Y. Three-dimensional high-resolution optical coherence tomography (OCT) imaging of human kidney. Annu Int Conf IEEE Eng Med Biol Soc 2009; 2009:5741-5743. [PMID: 19963648 DOI: 10.1109/iembs.2009.5332600] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Optical coherence tomography (OCT) is a rapidly emerging imaging modality that can non-invasively provide cross-sectional, high-resolution images of tissue morphology in situ and in real-time. Previous studies have demonstrated that OCT is capable of accurately visualizing the pathological changes in the living kidney in vivo using the Munich-Wistar rat model. In this work, we establish, for the first time, the capability of OCT to image the intact human kidney ex vivo. Characteristic kidney anatomic structures including the blood vessels, uriniferous tubules, glomeruli, and kidney capsules can be readily discerned. The diameter and volume parameters of these structures can also be automatically quantified. These two parameters may be critical in clinical applications such as the assessment of the donor kidney's viability prior to transplantation, or image the kidney responses to ischemic insult.
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Affiliation(s)
- Qian Li
- Fischell Department of Bioengineering, University of Maryland, College Park, MD 20742, USA
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20
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Larina IV, Sudheendran N, Ghosn M, Jiang J, Cable A, Larin KV, Dickinson ME. Live imaging of blood flow in mammalian embryos using Doppler swept-source optical coherence tomography. J Biomed Opt 2008; 13:060506. [PMID: 19123647 DOI: 10.1117/1.3046716] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Studying hemodynamic changes during early mammalian embryonic development is critical for further advances in prevention, diagnostics, and treatment of congenital cardiovascular (CV) birth defects and diseases. Doppler optical coherence tomography (OCT) has been shown to provide sensitive measurements of blood flow in avian and amphibian embryos. We combined Doppler swept-source optical coherence tomography (DSS-OCT) and live mouse embryo culture to analyze blood flow dynamics in early embryos. SS-OCT structural imaging was used for the reconstruction of embryo morphology and the orientation of blood vessels, which is required for calculating flow velocity from the Doppler measurements. Spatially and temporally resolved blood flow profiles are presented for the dorsal aorta and a yolk sac vessel in a 9.5-day embryo. We demonstrate that DSS-OCT can be successfully used for structural analysis and spatially and temporally resolved hemodynamic measurements in developing early mammalian embryos.
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Affiliation(s)
- Irina V Larina
- Baylor College of Medicine, Molecular Physiology and Biophysics, One Baylor Plaza, Houston, Texas 77584, USA
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21
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Potsaid B, Gorczynska I, Srinivasan VJ, Chen Y, Jiang J, Cable A, Fujimoto JG. Ultrahigh speed spectral / Fourier domain OCT ophthalmic imaging at 70,000 to 312,500 axial scans per second. Opt Express 2008; 16:15149-69. [PMID: 18795054 PMCID: PMC2743204 DOI: 10.1364/oe.16.015149] [Citation(s) in RCA: 224] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
We demonstrate ultrahigh speed spectral / Fourier domain optical coherence tomography (OCT) using an ultrahigh speed CMOS line scan camera at rates of 70,000 - 312,500 axial scans per second. Several design configurations are characterized to illustrate trade-offs between acquisition speed, resolution, imaging range, sensitivity and sensitivity roll-off performance. Ultrahigh resolution OCT with 2.5 - 3.0 micron axial image resolution is demonstrated at approximately 100,000 axial scans per second. A high resolution spectrometer design improves sensitivity roll-off and imaging range performance, trading off imaging speed to 70,000 axial scans per second. Ultrahigh speed imaging at >300,000 axial scans per second with standard image resolution is also demonstrated. Ophthalmic OCT imaging of the normal human retina is investigated. The high acquisition speeds enable dense raster scanning to acquire densely sampled volumetric three dimensional OCT (3D-OCT) data sets of the macula and optic disc with minimal motion artifacts. Imaging with approximately 8 - 9 micron axial resolution at 250,000 axial scans per second, a 512 x 512 x 400 voxel volumetric 3D-OCT data set can be acquired in only approximately 1.3 seconds. Orthogonal registration scans are used to register OCT raster scans and remove residual axial eye motion, resulting in 3D-OCT data sets which preserve retinal topography. Rapid repetitive imaging over small volumes can visualize small retinal features without motion induced distortions and enables volume registration to remove eye motion. Cone photoreceptors in some regions of the retina can be visualized without adaptive optics or active eye tracking. Rapid repetitive imaging of 3D volumes also provides dynamic volumetric information (4D-OCT) which is shown to enhance visualization of retinal capillaries and should enable functional imaging. Improvements in the speed and performance of 3D-OCT volumetric imaging promise to enable earlier diagnosis and improved monitoring of disease progression and response to therapy in ophthalmology, as well as have a wide range of research and clinical applications in other areas.
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Affiliation(s)
- Benjamin Potsaid
- Department of Electrical Engineering and Computer Science, and Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA 02139
- Advanced Imaging Group Thorlabs, Inc., Newton, NJ 07860
| | - Iwona Gorczynska
- Department of Electrical Engineering and Computer Science, and Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA 02139
- New England Eye Center and Tufts Medical Center, Tufts University, Boston, MA
| | - Vivek J. Srinivasan
- Department of Electrical Engineering and Computer Science, and Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA 02139
| | - Yueli Chen
- Department of Electrical Engineering and Computer Science, and Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA 02139
- New England Eye Center and Tufts Medical Center, Tufts University, Boston, MA
| | - James Jiang
- Advanced Imaging Group Thorlabs, Inc., Newton, NJ 07860
| | - Alex Cable
- Advanced Imaging Group Thorlabs, Inc., Newton, NJ 07860
| | - James G. Fujimoto
- Department of Electrical Engineering and Computer Science, and Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA 02139
- New England Eye Center and Tufts Medical Center, Tufts University, Boston, MA
- Corresponding Author:
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22
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Mariampillai A, Standish BA, Moriyama EH, Khurana M, Munce NR, Leung MK, Jiang J, Cable A, Wilson BC, Vitkin IA, Yang VXD. Speckle variance detection of microvasculature using swept-source optical coherence tomography. Opt Lett 2008; 33:1530-2. [PMID: 18594688 DOI: 10.1364/ol.33.001530] [Citation(s) in RCA: 410] [Impact Index Per Article: 25.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
We report on imaging of microcirculation by calculating the speckle variance of optical coherence tomography (OCT) structural images acquired using a Fourier domain mode-locked swept-wavelength laser. The algorithm calculates interframe speckle variance in two-dimensional and three-dimensional OCT data sets and shows little dependence to the Doppler angle ranging from 75 degrees to 90 degrees . We demonstrate in vivo detection of blood flow in vessels as small as 25 microm in diameter in a dorsal skinfold window chamber model with direct comparison with intravital fluorescence confocal microscopy. This technique can visualize vessel-size-dependent vascular shutdown and transient vascular occlusion during Visudyne photodynamic therapy and may provide opportunities for studying therapeutic effects of antivascular treatments without on exogenous contrast agent.
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Affiliation(s)
- Adrian Mariampillai
- Department of Medical Biophysics, University of Toronto, Toronto, M5G 2M9, Canada
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23
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Cable A, Nieman DC, Austin M, Hogen E, Utter AC. Validity of leg-to-leg bioelectrical impedance measurement in males. J Sports Med Phys Fitness 2001; 41:411-4. [PMID: 11533575] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/21/2023]
Abstract
BACKGROUND This study determined the validity of the leg-to-leg bioelectrical impedance analysis (BIA) system (Tanita Body Fat Analyzer, TBF 105, Tanita Corporation of America, Inc., Arlington Heights, IL) in estimating body composition in males. METHODS EXPERIMENTAL DESIGN Fat-free mass (FFM) was estimated using BIA and underwater weighing, and compared. SETTING Subjects were recruited from the community. PARTICIPANTS Heterogeneous group of males (N=192) was recruited, with a mean+/-SD age of 39.0+/-16.8 yrs; body mass index, 26.0+/-4.0 kg/m2, percent body fat, 18.1+/-8.9 percent. MEASURES Prior to BIA testing, subjects were required to adhere to standard BIA testing guidelines, and bioelectrical impedance was measured in subjects standing erect with bare feet on the analyzer's footpads, and wearing a swimsuit. Underwater weighing was conducted using standard procedures, with direct measurement of residual volume. RESULTS A Bland-Altman plot of difference between FFM measured by underwater weighing and BIA versus average FFM by the two methods showed no systematic difference (mean difference, 0.07+/-3.5 kg). FFM was estimated at 66.3+/-8.6 kg with underwater weighing, and 66.2+/-7.7 kg with BIA (r=0.92, p<0.001; SEE 3.5 kg). CONCLUSIONS These data indicate that the leg-to-leg bioelectrical impedance system accurately assesses FFM in a heterogenous group of males when compared to underwater weighing.
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Affiliation(s)
- A Cable
- Department of Health and Exercise Science, Appalachian State University, Boone, NC 28608, USA
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Abstract
Locus equations are linear regressions of the onset of F2 transitions on their offsets. These functions vowel-normalize the F2 transitions such that they are able to characterize consonantal place categories. The purpose of this research was to determine if compensatory articulation due to bite blocks would alter the normally linear relationship between F2 transition onset and offset frequencies or alter the differential slopes and y intercepts of locus equations as a function of stop place. Six speakers, three male and three female, each produced /bVt/, /dVt/, and /gVt/ tokens for ten vowel contexts under normal and bite block conditions. Extremely linear and practically identical scatterplots were obtained in the two speaking conditions. No adaptation to the bite blocks was found when comparing locus equations derived from the initial versus the final bite block trial. Results are discussed in relation to the "orderly output constraint," which postulates a perceptual function for linearly related F2 transition end points within consonantal place categories.
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Affiliation(s)
- H M Sussman
- University of Texas, Austin, Texas 78712, USA
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25
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Cable A, Prentiss M, Bigelow NP. Observations of sodium atoms in a magnetic molasses trap loaded by a continuous uncooled source. Opt Lett 1990; 15:507-509. [PMID: 19767991 DOI: 10.1364/ol.15.000507] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
We describe observations of atoms trapped in magnetic molasses made by using a simplified apparatus that is loaded by a continuous uncooled source of atoms. We also measured the cross section for collisions in which trapped sodium atoms are ejected from the trap by thermal sodium atoms and estimate that the cross section is 30 times larger than for collisions with other background thermal atoms.
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Prentiss M, Cable A, Bjorkholm JE, Chu S, Raab EL, Pritchard DE. Atomic-density-dependent losses in an optical trap. Opt Lett 1988; 13:452-454. [PMID: 19745929 DOI: 10.1364/ol.13.000452] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
We have observed that two-body collisions between cold sodium atoms confined within a magnetic-molasses optical trap lead to significant atomic-density-dependent trap losses. Such losses set an upper limit to the product of atomic density and confinement time that can be achieved in such a trap.
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Raab EL, Prentiss M, Cable A, Chu S, Pritchard DE. Trapping of neutral sodium atoms with radiation pressure. Phys Rev Lett 1987; 59:2631-2634. [PMID: 10035608 DOI: 10.1103/physrevlett.59.2631] [Citation(s) in RCA: 268] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
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Chu S, Hollberg L, Bjorkholm JE, Cable A, Ashkin A. Three-dimensional viscous confinement and cooling of atoms by resonance radiation pressure. Phys Rev Lett 1985; 55:48-51. [PMID: 10031677 DOI: 10.1103/physrevlett.55.48] [Citation(s) in RCA: 163] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
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