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Watson JJ, Hecht R, Tao YK. Optimization of handheld spectrally encoded coherence tomography and reflectometry for point-of-care ophthalmic diagnostic imaging. JOURNAL OF BIOMEDICAL OPTICS 2024; 29:076006. [PMID: 39050778 PMCID: PMC11267400 DOI: 10.1117/1.jbo.29.7.076006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/10/2024] [Revised: 06/28/2024] [Accepted: 07/08/2024] [Indexed: 07/27/2024]
Abstract
Significance Handheld optical coherence tomography (HH-OCT) systems enable point-of-care ophthalmic imaging in bedridden, uncooperative, and pediatric patients. Handheld spectrally encoded coherence tomography and reflectometry (HH-SECTR) combines OCT and spectrally encoded reflectometry (SER) to address critical clinical challenges in HH-OCT imaging with real-time en face retinal aiming for OCT volume alignment and volumetric correction of motion artifacts that occur during HH-OCT imaging. Aim We aim to enable robust clinical translation of HH-SECTR and improve clinical ergonomics during point-of-care OCT imaging for ophthalmic diagnostics. Approach HH-SECTR is redesigned with (1) optimized SER optical imaging for en face retinal aiming and retinal tracking for motion correction, (2) a modular aluminum form factor for sustained alignment and probe stability for longitudinal clinical studies, and (3) one-handed photographer-ergonomic motorized focus adjustment. Results We demonstrate an HH-SECTR imaging probe with micron-scale optical-optomechanical stability and use it for in vivo human retinal imaging and volumetric motion correction. Conclusions This research will benefit the clinical translation of HH-SECTR for point-of-care ophthalmic diagnostics.
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Affiliation(s)
- Jacob J. Watson
- Vanderbilt University, Department of Biomedical Engineering, Nashville, Tennessee, United States
| | - Rachel Hecht
- Vanderbilt University, Department of Biomedical Engineering, Nashville, Tennessee, United States
| | - Yuankai K. Tao
- Vanderbilt University, Department of Biomedical Engineering, Nashville, Tennessee, United States
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2
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Han T, Yang L, Tang Y, Chen C, Ma C, Liu Z, Ding Z. Long range topography by dispersion unmatched spectral-domain interferometry based on virtually imaged phased array modes. OPTICS LETTERS 2024; 49:2281-2284. [PMID: 38691699 DOI: 10.1364/ol.517249] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/29/2023] [Accepted: 03/24/2024] [Indexed: 05/03/2024]
Abstract
We propose to realize a long range topography by dispersion unmatched spectral-domain interferometry based on virtually imaged phased array (VIPA) modes. By filtering the continuous spectrum of a supercontinuum source through a side-entrance Fabry-Perot etalon configured at two input angles, two groups of VIPA modes are generated. A method based on unmatched dispersion is proposed for non-aliasing reconstruction of the true depth from the interference spectrum under-sampled at two groups of VIPA modes. With the high spectral resolution provided by the VIPA modes instead of the grating-based spectrometer, only a 10 dB falloff in sensitivity over a range of 10 mm was demonstrated. The feasibility of the proposed method was confirmed by topography of a sample of gauge blocks and a model of three-dimensional (3D) printed tooth. The occlusal surface of the tooth model was further quantitatively evaluated, demonstrating its potential application in long range 3D topography.
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3
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Liu CJ, Smith JT, Wang Y, Ouellette JN, Rogers JD, Oliner JD, Szulczewski M, Wait E, Brown W, Wax A, Eliceiri KW, Rafter J. Assessing cell viability with dynamic optical coherence microscopy. BIOMEDICAL OPTICS EXPRESS 2024; 15:1408-1417. [PMID: 38495713 PMCID: PMC10942685 DOI: 10.1364/boe.509835] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/02/2023] [Revised: 01/23/2024] [Accepted: 01/23/2024] [Indexed: 03/19/2024]
Abstract
Assessing cell viability is important in many fields of research. Current optical methods to assess cell viability typically involve fluorescent dyes, which are often less reliable and have poor permeability in primary tissues. Dynamic optical coherence microscopy (dOCM) is an emerging tool that provides label-free contrast reflecting changes in cellular metabolism. In this work, we compare the live contrast obtained from dOCM to viability dyes, and for the first time to our knowledge, demonstrate that dOCM can distinguish live cells from dead cells in murine syngeneic tumors. We further demonstrate a strong correlation between dOCM live contrast and optical redox ratio by metabolic imaging in primary mouse liver tissue. The dOCM technique opens a new avenue to apply label-free imaging to assess the effects of immuno-oncology agents, targeted therapies, chemotherapy, and cell therapies using live tumor tissues.
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Affiliation(s)
- Chao J. Liu
- Elephas Biosciences
Corporation, 1 Erdman Place, Madison, WI 53717, USA
| | - Jason T. Smith
- Elephas Biosciences
Corporation, 1 Erdman Place, Madison, WI 53717, USA
| | - Yuanbo Wang
- Elephas Biosciences
Corporation, 1 Erdman Place, Madison, WI 53717, USA
| | | | - Jeremy D. Rogers
- Department of Ophthalmology and Visual
Sciences, University of Wisconsin Madison,
2828 Marshall Ct, Madison, WI 53705, USA
| | | | | | - Eric Wait
- Elephas Biosciences
Corporation, 1 Erdman Place, Madison, WI 53717, USA
| | - William Brown
- Lumedica Inc.,
404 Hunt Street, Suite 510, Durham, NC 27701, USA
| | - Adam Wax
- Lumedica Inc.,
404 Hunt Street, Suite 510, Durham, NC 27701, USA
| | - Kevin W. Eliceiri
- Center for Quantitative Cell
Imaging, 1675 Observatory Drive, Madison, WI 53706,
USA
| | - John Rafter
- Elephas Biosciences
Corporation, 1 Erdman Place, Madison, WI 53717, USA
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4
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Jelly ET, Steelman ZA, Zhang H, Chu KK, Cotton CC, Eluri S, Shaheen NJ, Wax A. Next-generation endoscopic probe for detection of esophageal dysplasia using combined OCT and angle-resolved low-coherence interferometry. BIOMEDICAL OPTICS EXPRESS 2024; 15:1943-1958. [PMID: 38495690 PMCID: PMC10942713 DOI: 10.1364/boe.515469] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Revised: 02/08/2024] [Accepted: 02/17/2024] [Indexed: 03/19/2024]
Abstract
Angle-resolved low-coherence interferometry (a/LCI) is an optical technique that enables depth-specific measurements of nuclear morphology, with applications to detecting epithelial cancers in various organs. Previous a/LCI setups have been limited by costly fiber-optic components and large footprints. Here, we present a novel a/LCI instrument incorporating a channel for optical coherence tomography (OCT) to provide real-time image guidance. We showcase the system's capabilities by acquiring imaging data from in vivo Barrett's esophagus patients. The main innovation in this geometry lies in implementing a pathlength-matched single-mode fiber array, offering substantial cost savings while preserving signal fidelity. A further innovation is the introduction of a specialized side-viewing probe tailored for esophageal imaging, featuring miniature optics housed in a custom 3D-printed enclosure attached to the tip of the endoscope. The integration of OCT guidance enhances the precision of tissue targeting by providing real-time morphology imaging. This novel device represents a significant advancement in clinical translation of an enhanced screening approach for esophageal precancer, paving the way for more effective early-stage detection and intervention strategies.
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Affiliation(s)
- Evan T. Jelly
- Department of Biomedical Engineering, Duke University, Durham, North Carolina 27708, USA
| | - Zachary A. Steelman
- Department of Biomedical Engineering, Duke University, Durham, North Carolina 27708, USA
| | - Haoran Zhang
- Department of Biomedical Engineering, Duke University, Durham, North Carolina 27708, USA
| | - Kengyeh K. Chu
- Department of Biomedical Engineering, Duke University, Durham, North Carolina 27708, USA
| | - Cary C. Cotton
- Center for Esophageal Diseases and Swallowing, University of North Carolina, Chapel Hill, North Carolina 27599, USA
| | - Swathi Eluri
- Center for Esophageal Diseases and Swallowing, University of North Carolina, Chapel Hill, North Carolina 27599, USA
| | - Nicholas J. Shaheen
- Center for Esophageal Diseases and Swallowing, University of North Carolina, Chapel Hill, North Carolina 27599, USA
| | - Adam Wax
- Department of Biomedical Engineering, Duke University, Durham, North Carolina 27708, USA
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5
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Urizar MP, Gambra E, de Castro A, de la Peña Á, Pascual D, Cetinkaya O, Marcos S, Curatolo A. Long-range frequency-domain optical delay line based on a spinning tilted mirror for low-cost ocular biometry. BIOMEDICAL OPTICS EXPRESS 2023; 14:6521-6541. [PMID: 38420323 PMCID: PMC10898555 DOI: 10.1364/boe.501889] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Revised: 10/25/2023] [Accepted: 10/27/2023] [Indexed: 03/02/2024]
Abstract
Optical biometers are routinely used to measure intraocular distances in ophthalmic applications such as cataract surgery planning or myopia monitoring. However, due to their high cost and reduced transportability, access to them for screening and surgical planning is still limited in low-resource and remote settings. To increase patients' access to optical biometry we propose a novel low-cost frequency-domain optical delay line (FD-ODL) based on an inexpensive stepper motor spinning a tilted mirror, for integration into a time-domain (TD)-biometer, amenable to a compact footprint. In the proposed FD-ODL, the axial scan range and the A-scan rate are decoupled from one another, as the former only depends on the spinning mirror tilt angle, while the A-scan rate only depends on the motor shaft rotational speed. We characterized the scanning performance and specifications for two spinning mirror tilt angles, and compared them to those of the standard, more expensive FD-ODL implementation, employing a galvanometric scanner for group delay generation. A prototype of the low-cost FD-ODL with a 1.5 deg tilt angle, resulting in an axial scan range of 6.61 mm and an A-scan rate of 10 Hz was experimentally implemented and integrated in a dual sample beam optical low-coherence reflectometry (OLCR) setup with a detour unit to replicate the measurement window around the anterior segment and the retina. The intraocular distances of a model eye were measured with the proposed low-cost biometer and found to be in good agreement with those acquired by a custom swept-source optical coherence tomography (SS-OCT) system and two commercial biometers, validating our novel design.
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Affiliation(s)
- María Pilar Urizar
- 2EyesVision S.L., Madrid, Spain
- Instituto de Óptica ‘Daza de Valdés’, Consejo Superior de Investigaciones Científicas (IO, CSIC), Madrid, Spain
| | | | - Alberto de Castro
- Instituto de Óptica ‘Daza de Valdés’, Consejo Superior de Investigaciones Científicas (IO, CSIC), Madrid, Spain
| | - Álvaro de la Peña
- Instituto de Óptica ‘Daza de Valdés’, Consejo Superior de Investigaciones Científicas (IO, CSIC), Madrid, Spain
| | - Daniel Pascual
- Instituto de Óptica ‘Daza de Valdés’, Consejo Superior de Investigaciones Científicas (IO, CSIC), Madrid, Spain
| | - Onur Cetinkaya
- International Centre for Translational Eye Research (ICTER), and Institute of Physical Chemistry, Polish Academy of Sciences (IPC-PAS), Warsaw, Poland
| | - Susana Marcos
- Instituto de Óptica ‘Daza de Valdés’, Consejo Superior de Investigaciones Científicas (IO, CSIC), Madrid, Spain
- The Institute of Optics and Flaum Eye Institute, Center for Visual Sciences, University of Rochester, New York, USA
| | - Andrea Curatolo
- Instituto de Óptica ‘Daza de Valdés’, Consejo Superior de Investigaciones Científicas (IO, CSIC), Madrid, Spain
- International Centre for Translational Eye Research (ICTER), and Institute of Physical Chemistry, Polish Academy of Sciences (IPC-PAS), Warsaw, Poland
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6
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Fang Q, Castro-Urrea FA, Haederle F, Sanderson RW, Silva D, A Cowling W, Kennedy BF. In vivo characterisation of field pea stem wall thickness using optical coherence tomography. PLANT METHODS 2023; 19:105. [PMID: 37821949 PMCID: PMC10566190 DOI: 10.1186/s13007-023-01075-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Accepted: 08/31/2023] [Indexed: 10/13/2023]
Abstract
BACKGROUND Modern field pea breeding faces a significant challenge in selecting lines with strong stems that resist lodging. Traditional methods of assessing stem strength involve destructive mechanical tests on mature stems after natural senescence, such as measuring stem flexion, stem buckling or the thickness of dry stems when compressed, but these measurements may not correspond to the strength of stems in the living plant. Optical coherence tomography (OCT) can be used as a noncontact and nondestructive method to measure stem wall thickness in living plants by acquiring two- or three-dimensional images of living plant tissue. RESULTS In this proof-of-principle study, we demonstrated in vivo characterisation of stem wall thickness using OCT, with the measurement corrected for the refractive index of the stem tissue. This in vivo characterisation was achieved through real-time imaging of stems, with an acquisition rate of 13 milliseconds per two-dimensional, cross-sectional OCT image. We also acquired OCT images of excised stems and compared the accuracy of in vivo OCT measurements of stem wall thickness with ex vivo results for 10 plants each of two field pea cultivars, Dunwa and Kaspa. In vivo OCT measurements of stem wall thickness have an average percent error of - 3.1% when compared with ex vivo measurements. Additionally, we performed in vivo measurements of both stem wall thickness and stem width at various internode positions on the two cultivars. The results revealed that Dunwa had a uniform stem wall thickness across different internode positions, while Kaspa had a significantly negative slope of [Formula: see text]0.0198 mm/node. Both cultivars exhibited an increase in stem width along the internode positions; however, Dunwa had a rate of increase of 0.1844 mm/node, which is three times higher than that of Kaspa. CONCLUSIONS Our study has demonstrated the efficacy of OCT for accurate measurement of the stem wall thickness of live field pea. Moreover, OCT shows that the trends of stem wall thickness and stem width along the internode positions are different for the two cultivars, Dunwa and Kaspa, potentially hinting at differences in their stem strength. This rapid, in vivo imaging method provides a useful tool for characterising physical traits critical in breeding cultivars that are resistant to lodging.
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Affiliation(s)
- Qi Fang
- Department of Electrical, Electronic & Computer Engineering, School of Engineering, The University of Western Australia, Crawley, WA, 6009, Australia.
- Centre for Medical Research, BRITElab, Harry Perkins Institute of Medical Research, QEII Medical Centre, The University of Western Australia, Crawley, WA, 6009, Australia.
| | - Felipe A Castro-Urrea
- The UWA Institute of Agriculture, The University of Western Australia, Crawley, WA, 6009, Australia
- School of Agriculture and Environment, The University of Western Australia, Crawley, WA, 6009, Australia
| | - Felix Haederle
- Department of Electrical, Electronic & Computer Engineering, School of Engineering, The University of Western Australia, Crawley, WA, 6009, Australia
| | - Rowan W Sanderson
- Department of Electrical, Electronic & Computer Engineering, School of Engineering, The University of Western Australia, Crawley, WA, 6009, Australia
- Centre for Medical Research, BRITElab, Harry Perkins Institute of Medical Research, QEII Medical Centre, The University of Western Australia, Crawley, WA, 6009, Australia
| | - Dilusha Silva
- Department of Electrical, Electronic & Computer Engineering, School of Engineering, The University of Western Australia, Crawley, WA, 6009, Australia
- The UWA Institute of Agriculture, The University of Western Australia, Crawley, WA, 6009, Australia
| | - Wallace A Cowling
- The UWA Institute of Agriculture, The University of Western Australia, Crawley, WA, 6009, Australia
- School of Agriculture and Environment, The University of Western Australia, Crawley, WA, 6009, Australia
| | - Brendan F Kennedy
- Department of Electrical, Electronic & Computer Engineering, School of Engineering, The University of Western Australia, Crawley, WA, 6009, Australia
- Centre for Medical Research, BRITElab, Harry Perkins Institute of Medical Research, QEII Medical Centre, The University of Western Australia, Crawley, WA, 6009, Australia
- Australian Research Council Centre for Personalised Therapeutics Technologies, Melbourne, VIC, Australia
- Institute of Physics, Nicolaus Copernicus University, Torun, Poland
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7
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Zhang Z, Yang X, Zhao Z, Zeng F, Ye S, Baldock SJ, Lin H, Hardy JG, Zheng Y, Shen Y. Rapid imaging and product screening with low-cost line-field Fourier domain optical coherence tomography. Sci Rep 2023; 13:10809. [PMID: 37402736 DOI: 10.1038/s41598-023-37646-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Accepted: 06/25/2023] [Indexed: 07/06/2023] Open
Abstract
Fourier domain optical coherence tomography (FD-OCT) is a well-established imaging technique that provides high-resolution internal structure images of an object at a fast speed. Modern FD-OCT systems typically operate at speeds of 40,000-100,000 A-scans/s, but are priced at least tens of thousands of pounds. In this study, we demonstrate a line-field FD-OCT (LF-FD-OCT) system that achieves an OCT imaging speed of 100,000 A-scan/s at a hardware cost of thousands of pounds. We demonstrate the potential of LF-FD-OCT for biomedical and industrial imaging applications such as corneas, 3D printed electronics, and printed circuit boards.
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Affiliation(s)
- Zijian Zhang
- Department of Electrical Engineering and Electronics, University of Liverpool, Liverpool, L69 3GJ, UK
- Department of Eye and Vision Sciences, University of Liverpool, Liverpool, L7 8TX, UK
| | - Xingyu Yang
- Department of Electrical Engineering and Electronics, University of Liverpool, Liverpool, L69 3GJ, UK
| | - Zhiyi Zhao
- Department of Electrical Engineering and Electronics, University of Liverpool, Liverpool, L69 3GJ, UK
| | - Feng Zeng
- Department of Electrical Engineering and Electronics, University of Liverpool, Liverpool, L69 3GJ, UK
| | - Sicong Ye
- Department of Electrical Engineering and Electronics, University of Liverpool, Liverpool, L69 3GJ, UK
| | - Sara J Baldock
- Department of Chemistry, Lancaster University, Lancaster, LA1 4YB, UK
| | - Hungyen Lin
- School of Engineering, Lancaster University, Lancaster, LA1 4YW, UK
- Materials Science Institute, Lancaster University, Lancaster, LA1 4YB, UK
| | - John G Hardy
- Department of Chemistry, Lancaster University, Lancaster, LA1 4YB, UK
- Materials Science Institute, Lancaster University, Lancaster, LA1 4YB, UK
| | - Yalin Zheng
- Department of Eye and Vision Sciences, University of Liverpool, Liverpool, L7 8TX, UK.
| | - Yaochun Shen
- Department of Electrical Engineering and Electronics, University of Liverpool, Liverpool, L69 3GJ, UK.
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Cerrotta S, Torga JR, Morel EN. Long-range frequency domain low-coherence interferometry detector for industrial applications. JOURNAL OF THE OPTICAL SOCIETY OF AMERICA. A, OPTICS, IMAGE SCIENCE, AND VISION 2023; 40:C16-C21. [PMID: 37132947 DOI: 10.1364/josaa.478870] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
A low-cost long-range frequency domain low-coherence interferometry (LCI) detector is presented: time Fourier domain LCI (TFD-LCI). Combining ideas of time domain and frequency domain techniques, the TFD-LCI detects the analog Fourier transform of the optical interference signal with no limitation for the maximum optical path, measuring the thickness of several centimeters with micrometer resolution. A complete characterization of the technique is presented with a mathematical demonstration, simulations, and experimental results. An evaluation of repeatability and accuracy is also included. Measurements of small and large monolayer and multilayer thicknesses were done. Characterization of the internal and external thicknesses of industrial products such as transparent packages and glass windshield is presented, showing the potentiality of TFD-LCI for industrial applications.
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9
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Faubert AC, Larina IV, Wang S. Open-source, highly efficient, post-acquisition synchronization for 4D dual-contrast imaging of the mouse embryonic heart over development with optical coherence tomography. BIOMEDICAL OPTICS EXPRESS 2023; 14:163-181. [PMID: 36698661 PMCID: PMC9842004 DOI: 10.1364/boe.475027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Revised: 11/18/2022] [Accepted: 11/19/2022] [Indexed: 05/28/2023]
Abstract
Dynamic imaging of the beating embryonic heart in 3D is critical for understanding cardiac development and defects. Optical coherence tomography (OCT) plays an important role in embryonic heart imaging with its unique imaging scale and label-free contrasts. In particular, 4D (3D + time) OCT imaging enabled biomechanical analysis of the developing heart in various animal models. While ultrafast OCT systems allow for direct volumetric imaging of the beating heart, the imaging speed remains limited, leading to an image quality inferior to that produced by post-acquisition synchronization. As OCT systems become increasingly available to a wide range of biomedical researchers, a more accessible 4D reconstruction method is required to enable the broader application of OCT in the dynamic, volumetric assessment of embryonic heartbeat. Here, we report an open-source, highly efficient, post-acquisition synchronization method for 4D cardiodynamic and hemodynamic imaging of the mouse embryonic heart. Relying on the difference between images to characterize heart wall movements, the method provides good sensitivity to the cardiac activity when aligning heartbeat phases, even at early stages when the heart wall occupies only a small number of pixels. The method works with a densely sampled single 3D data acquisition, which, unlike the B-M scans required by other methods, is readily available in most commercial OCT systems. Compared with an existing approach for the mouse embryonic heart, this method shows superior reconstruction quality. We present the robustness of the method through results from different embryos with distinct heart rates, ranging from 1.24 Hz to 2.13 Hz. Since the alignment process operates on a 1D signal, the method has a high efficiency, featuring sub-second alignment time while utilizing ∼100% of the original image files. This allows us to achieve repeated, dual-contrast imaging of mouse embryonic heart development. This new, open-source method could facilitate research using OCT to study early cardiogenesis.
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Affiliation(s)
- Andre C. Faubert
- Department of Biomedical Engineering, Stevens Institute of Technology, Hoboken, NJ 07030, USA
| | - Irina V. Larina
- Department of Integrative Physiology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Shang Wang
- Department of Biomedical Engineering, Stevens Institute of Technology, Hoboken, NJ 07030, USA
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Rasheed HA, Davis T, Morales E, Fei Z, Grassi L, De Gainza A, Nouri-Mahdavi K, Caprioli J. DDLSNet: A Novel Deep Learning-Based System for Grading Funduscopic Images for Glaucomatous Damage. OPHTHALMOLOGY SCIENCE 2022; 3:100255. [PMID: 36619716 PMCID: PMC9813574 DOI: 10.1016/j.xops.2022.100255] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Revised: 10/03/2022] [Accepted: 11/03/2022] [Indexed: 11/13/2022]
Abstract
Purpose To report an image analysis pipeline, DDLSNet, consisting of a rim segmentation (RimNet) branch and a disc size classification (DiscNet) branch to automate estimation of the disc damage likelihood scale (DDLS). Design Retrospective observational. Participants RimNet and DiscNet were developed with 1208 and 11 536 optic disc photographs (ODPs), respectively. DDLSNet performance was evaluated on 120 ODPs from the RimNet test set, for which the DDLS scores were graded by clinicians. Reproducibility was evaluated on a group of 781 eyes, each with 2 ODPs taken within 4 years apart. Methods Disc damage likelihood scale calculation requires estimation of optic disc size, provided by DiscNet (VGG19 network), and the minimum rim-to-disc ratio (mRDR) or absent rim width (ARW), provided by RimNet (InceptionV3/LinkNet segmentation model). To build RimNet's dataset, glaucoma specialists marked optic disc rim and cup boundaries on ODPs. The "ground truth" mRDR or ARW was calculated. For DiscNet's dataset, corresponding OCT images provided "ground truth" disc size. Optic disc photographs were split into 80/10/10 for training, validation, and testing, respectively, for RimNet and DiscNet. DDLSNet estimation was tested against manual grading of DDLS by clinicians with the average score used as "ground truth." Reproducibility of DDLSNet grading was evaluated by repeating DDLS estimation on a dataset of nonprogressing paired ODPs taken at separate times. Main Outcome Measures The main outcome measure was a weighted kappa score between clinicians and the DDLSNet pipeline with agreement defined as ± 1 DDLS score difference. Results RimNet achieved an mRDR mean absolute error (MAE) of 0.04 (± 0.03) and an ARW MAE of 48.9 (± 35.9) degrees when compared to clinician segmentations. DiscNet achieved 73% (95% confidence interval [CI]: 70%, 75%) classification accuracy. DDLSNet achieved an average weighted kappa agreement of 0.54 (95% CI: 0.40, 0.68) compared to clinicians. Average interclinician agreement was 0.52 (95% CI: 0.49, 0.56). Reproducibility testing demonstrated that 96% of ODP pairs had a difference of ≤ 1 DDLS score. Conclusions DDLSNet achieved moderate agreement with clinicians for DDLS grading. This novel approach illustrates the feasibility of automated ODP grading for assessing glaucoma severity. Further improvements may be achieved by increasing the number of incomplete rims sample size, expanding the hyperparameter search, and increasing the agreement of clinicians grading ODPs.
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Affiliation(s)
- Haroon Adam Rasheed
- University of California Los Angeles David Geffen School of Medicine, Los Angeles, California
| | - Tyler Davis
- Department of Computer Science, University of California Los Angeles, Los Angeles, California
| | - Esteban Morales
- Glaucoma Division, Jules Stein Eye Institute, Los Angeles, California
| | - Zhe Fei
- University of California Los Angeles Jonathan and Karin Fielding School of Public Health, Los Angeles, California,Department of Biostatistics, University of California Los Angeles, Los Angeles, California
| | - Lourdes Grassi
- Glaucoma Division, Jules Stein Eye Institute, Los Angeles, California
| | | | | | - Joseph Caprioli
- Glaucoma Division, Jules Stein Eye Institute, Los Angeles, California,Correspondence: Joseph Caprioli, MD, Glaucoma Division, Jules Stein Eye Institute, 100 Stein Plaza, Los Angeles, CA 90095.
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11
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Prediction of textile pilling resistance using optical coherence tomography. Sci Rep 2022; 12:18341. [PMID: 36316394 PMCID: PMC9622826 DOI: 10.1038/s41598-022-23230-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Accepted: 10/27/2022] [Indexed: 11/06/2022] Open
Abstract
This paper describes a new method of textile pilling prediction, based on multivariate analysis of the spatial layer above the surface. The original idea of the method is the acquisition of 3D fabric image using optical coherence tomography (OCT) with infrared light, which allows for the fabric fuzz visualization with high sensitivity. The pilling layer, reconstructed with the resolution of [Formula: see text], includes reliable textural information related to the amount of loose fibers and bunches appearing as a result of abrasion. Pilling intensity was assigned by supervised classification of the textural features using both linear (PLS-DA - partial least squares discriminant analysis, LDA - linear discriminant analysis) and non-linear (SVM - support vector machine) classifiers. The results demonstrated that the method is more suitable for fabrics after short-term abrasion, when the fuzz prevails over tangled fibers in the pilling layer. In that case, pilling grades were predicted with [Formula: see text] accuracy, sensitivity and specificity (for SVM model). The validation accuracy of the tested models after machine abrasion achieves lower values (up to [Formula: see text] for LDA model). With our method, we clearly showed that OCT can be used to quantitatively trace appearance changes of fabric samples due to test abrasion.
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12
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Esophageal OCT Imaging Using a Paddle Probe Externally Attached to Endoscope. Dig Dis Sci 2022; 67:4805-4812. [PMID: 35084606 PMCID: PMC10015416 DOI: 10.1007/s10620-021-07372-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Accepted: 12/18/2021] [Indexed: 12/14/2022]
Abstract
BACKGROUND AND AIMS Endoscopic surveillance of Barrett's esophagus (BE) by white light examination is insufficient to diagnose dysplastic change. In this work, we describe an optical imaging method to obtain high-resolution cross-sectional imaging using a paddle-shaped probe affixed to the endoscope tip. METHODS We integrated Optical Coherence Tomography (OCT), an optical imaging method that produces cross-sectional images, into a paddle probe attached to video endoscope. We acquired images of esophageal epithelium from patients undergoing routine upper GI endoscopy. Images were classified by a reviewer blinded to patient identity and condition, and these results were compared with clinical diagnosis. RESULTS We successfully captured epithelial OCT images from 30 patients and identified features consistent with both squamous epithelium and Barrett's esophagus. Our blinded image reviewer classified BE versus non-BE with 91.5% accuracy (65/71 image regions), including sensitivity of 84.6% for BE (11/13) and a specificity of 93.1% (54/58). However, in 16 patients, intubation of the probe into the esophagus could not be achieved. CONCLUSIONS A paddle probe is a feasible imaging format for acquiring cross-sectional OCT images from the esophagus and can provide a structural assessment of BE and non-BE tissue. Probe form factor is the current limiting obstacle, but could be addressed by further miniaturization.
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13
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Kendall WY, Bordas J, Mirminachi S, Joseph A, Roper J, Wax A. Spectroscopic optical coherence tomography for classification of colorectal cancer in a mouse model. JOURNAL OF BIOPHOTONICS 2022; 15:e202100387. [PMID: 35338763 DOI: 10.1002/jbio.202100387] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Revised: 03/16/2022] [Accepted: 03/17/2022] [Indexed: 06/14/2023]
Abstract
Noninvasive diagnosis of the malignant potential of colon polyps can improve prevention of colorectal cancer without the need for time-consuming and expensive biopsies. This study examines the use of spectroscopic optical coherence tomography (OCT) to classify tissue from genetically engineered mouse models of early-stage adenoma (APC) and advanced adenocarcinoma (AKP) in which tumors are induced in the distal colon. The optical tissue properties of scattering power and scattering attenuation coefficient are evaluated by analyzing the imaging data collected from tissues. Classifications are generated using 2D linear discriminant analysis with high levels of discrimination obtained. The overall classification accuracy obtained was 91.5%, with 100% sensitivity and 96.7% specificity in separating tumors from benign tissue, and 77.8% sensitivity and 99.4% specificity in separating adenocarcinoma from nonmalignant tissue. Thus, this study demonstrates the clinical potential of using spectroscopic OCT for rapid detection of colon adenoma and colorectal cancer.
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Affiliation(s)
- Wesley Y Kendall
- Department of Biomedical Engineering, Duke University, Durham, North Carolina, USA
| | - Julianna Bordas
- Department of Biomedical Engineering, Duke University, Durham, North Carolina, USA
| | | | - Abel Joseph
- Department of Gastroenterology, Duke Medicine, Durham, North Carolina, USA
| | - Jatin Roper
- Department of Gastroenterology, Duke Medicine, Durham, North Carolina, USA
| | - Adam Wax
- Department of Biomedical Engineering, Duke University, Durham, North Carolina, USA
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14
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English S, Barrett KM, Freeman WD, Demaerschalk BM, Dumitrascu O. Improving the Telemedicine Evaluation of Patients With Acute Vision Loss: A Call to Eyes. Neurology 2022; 99:381-386. [PMID: 35764399 DOI: 10.1212/wnl.0000000000200969] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Accepted: 05/26/2022] [Indexed: 11/15/2022] Open
Abstract
Acute vision loss related to cerebral or retinal ischemia is a time-sensitive emergency with potential treatment options including intravenous or intraarterial thrombolysis and mechanical thrombectomy. However, patients either present in delayed fashion or present to an emergency department that lacks the subspecialty expertise to recognize and treat these conditions in a timely fashion. Moreover, healthcare systems in the United States are becoming increasingly reliant on telestroke and teleneurology services for acute neurologic care, making accurate diagnosis of acute vision loss even more challenging due to critical limitations to the remote video evaluation, including the inability to perform routine ophthalmoscopy. The COVID-19 pandemic has led to a greater reliance on telemedicine services and helped to accelerate the development of novel tools and care pathways to improve remote ophthalmologic evaluation, but these tools have yet to be adapted for use in the remote evaluation of acute vision loss. Permanent vision loss can be disabling for patients and efforts must be made to increase and improve early diagnosis and management. Herein, the authors outline the importance of improving acute ophthalmologic diagnosis, outline key limitations and barriers to the current video-based teleneurology assessments, highlight opportunities to leverage new tools to enhance the remote assessment of vision loss, and propose new avenues to improve access to emergent ophthalmology subspeciality.
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Affiliation(s)
- Stephen English
- Department of Neurology, Mayo Clinic College of Medicine and Science, Jacksonville, Florida
| | - Kevin M Barrett
- Department of Neurology, Mayo Clinic College of Medicine and Science, Jacksonville, Florida
| | - William D Freeman
- Departments of Neurology and Critical Care Medicine, Mayo Clinic College of Medicine and Science, Jacksonville, Florida
| | - Bart M Demaerschalk
- Department of Neurology and Center for Digital Health, Mayo Clinic College of Medicine and Science, Phoenix, Arizona
| | - Oana Dumitrascu
- Departments of Neurology and Ophthalmology, Mayo Clinic College of Medicine and Science, Phoenix, Arizona
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15
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Samadi S, Mohazzab M, Dargahi J, Narayanswamy S. Design of a Linear Wavenumber Spectrometer for Line Scanning Optical Coherence Tomography with 50 mm Focal Length Cylindrical Optics. SENSORS 2022; 22:s22093278. [PMID: 35590968 PMCID: PMC9104028 DOI: 10.3390/s22093278] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Revised: 04/21/2022] [Accepted: 04/22/2022] [Indexed: 11/17/2022]
Abstract
Optical coherence tomography (OCT) has a wide range of uses in bioimaging and nondestructive testing. Larger bandwidth light sources have recently been implemented to enhance measurement resolution. Increased bandwidth has a negative impact on spectral nonlinearity in k space, notably in the case of spectral domain OCT (SD-OCT). This nonlinearity reduces the depth-dependent signal sensitivity of the spectrometers. A grating and prism combination is extensively used for linearizing. In an earlier study, we used a combination of the reflective grating and prism, as well as a cylindrical mirror with a radius of 180 mm, to achieve a high SR ratio with low nonlinearity. A creative design for a spectrometer with a cylindrical mirror of radius 50 mm, a light source with a center wavelength of 830 ± 100 nm (μm−1 − 6.756 μm−1 in k-space), and a grating of 1600 lines/mm is presented in this work. The design optimization is performed using MATLAB and ZEMAX. In the proposed design, the nonlinearity error reduced from 157∘× μm to 10.75∘× μm within the wavenumber range considered. The sensitivity research revealed that, with the new design, the SR ratio is extremely sensitive to the imaging optics’ angles. To resolve this, a spectrometer based on Grism is introduced. We present a Grism-based spectrometer with an optimized SR ratio of 0.97 and nonlinearity of 0.792∘× μm (Δθ/Δk). According to the sensitivity study, the Grism-based spectrometer is more robust.
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Affiliation(s)
- Sevin Samadi
- Department of Mechanical, Industrial and Aerospace Engineering (MIAE), Concordia University, Montreal, QC H3G 1M8, Canada; (S.S.); (S.N.)
| | - Masoud Mohazzab
- Seurat Technologies Inc., 70 Chestnut st, Andover, MA 01810, USA;
| | - Javad Dargahi
- Department of Mechanical, Industrial and Aerospace Engineering (MIAE), Concordia University, Montreal, QC H3G 1M8, Canada; (S.S.); (S.N.)
- Correspondence:
| | - Sivakumar Narayanswamy
- Department of Mechanical, Industrial and Aerospace Engineering (MIAE), Concordia University, Montreal, QC H3G 1M8, Canada; (S.S.); (S.N.)
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16
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Miao Y, Song J, Hsu D, Ng R, Jian Y, Sarunic MV, Ju MJ. Numerical calibration method for a multiple spectrometer-based OCT system. BIOMEDICAL OPTICS EXPRESS 2022; 13:1685-1701. [PMID: 35414988 PMCID: PMC8973183 DOI: 10.1364/boe.450942] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Revised: 02/14/2022] [Accepted: 02/17/2022] [Indexed: 06/14/2023]
Abstract
The present paper introduces a numerical calibration method for the easy and practical implementation of multiple spectrometer-based spectral-domain optical coherence tomography (SD-OCT) systems. To address the limitations of the traditional hardware-based spectrometer alignment across more than one spectrometer, we applied a numerical spectral calibration algorithm where the pixels corresponding to the same wavelength in each unit are identified through spatial- and frequency-domain interferometric signatures of a mirror sample. The utility of dual spectrometer-based SD-OCT imaging is demonstrated through in vivo retinal imaging at two different operation modes with high-speed and dual balanced acquisitions, respectively, in which the spectral alignment is critical to achieve improved retinal image data without any artifacts caused by misalignment of the spectrometers.
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Affiliation(s)
- Yusi Miao
- Department of Ophthalmology and Visual Sciences, University of British Columbia, Vancouver, BC, Canada
| | - Jun Song
- School of Biomedical Engineering, University of British Columbia, Vancouver, BC, Canada
| | - Destiny Hsu
- School of Engineering Science, Simon Fraser University, Burnaby, BC, Canada
| | - Ringo Ng
- School of Engineering Science, Simon Fraser University, Burnaby, BC, Canada
| | - Yifan Jian
- Casey Eye Institute, Oregon Health and Science University, Portland, Oregon 97239, USA
| | - Marinko V. Sarunic
- School of Engineering Science, Simon Fraser University, Burnaby, BC, Canada
- Institute of Ophthalmology, University College London, London, UK
- Department of Medical Physics and Biomedical Engineering, University College London, London, UK
| | - Myeong Jin Ju
- Department of Ophthalmology and Visual Sciences, University of British Columbia, Vancouver, BC, Canada
- School of Biomedical Engineering, University of British Columbia, Vancouver, BC, Canada
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17
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Rank EA, Agneter A, Schmoll T, Leitgeb RA, Drexler W. Miniaturizing optical coherence tomography. TRANSLATIONAL BIOPHOTONICS 2022. [DOI: 10.1002/tbio.202100007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Affiliation(s)
- Elisabet A. Rank
- Center for Medical Physics and Biomedical Engineering Medical University of Vienna Vienna Austria
| | - Anja Agneter
- Center for Medical Physics and Biomedical Engineering Medical University of Vienna Vienna Austria
| | - Tilman Schmoll
- Center for Medical Physics and Biomedical Engineering Medical University of Vienna Vienna Austria
- Carl Zeiss Meditec, Inc. Dublin California USA
| | - Rainer A. Leitgeb
- Center for Medical Physics and Biomedical Engineering Medical University of Vienna Vienna Austria
| | - Wolfgang Drexler
- Center for Medical Physics and Biomedical Engineering Medical University of Vienna Vienna Austria
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18
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Phu J, Masselos K, Sullivan-Mee M, Kalloniatis M. Glaucoma Suspects: The Impact of Risk Factor-Driven Review Periods on Clinical Load, Diagnoses, and Healthcare Costs. Transl Vis Sci Technol 2022; 11:37. [PMID: 35089311 PMCID: PMC8802015 DOI: 10.1167/tvst.11.1.37] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose To model the healthcare impact (clinical attendance time and financial cost) and clinical outcomes (glaucoma diagnoses) of different risk factor–driven review frequencies for glaucoma suspect patients up until the point of discharge or diagnosis. Methods Medical records of 494 glaucoma suspects were examined to extract the clinical diagnosis. Two criteria for review periods were defined, based on contrasting stringency from established clinical guidelines: American Academy of Ophthalmology (AAO), more stringent/less frequent; and the Australian National Health and Medical Research Council (NHMRC), less stringent/more frequent. We used these data to model patient outcomes and healthcare costs using a Markov model. Results The less stringent/more frequent criterion resulted in more high-risk glaucoma suspects requiring more frequent review compared with the more stringent/less frequent criterion. Across the 15 Markov cycles (7.5 years), the less stringent/more frequent review criterion resulted in 6.6% more diagnoses and fewer overall clinical visits (14.7%) and reduced cost per diagnosis by 12% to 32% (P < 0.0001). The number of glaucoma diagnoses made using each criterion converged at 2.5 to 3 years. Conclusions The stringency of risk assessments for glaucoma suspects impacts review periods and therefore clinical load, healthcare costs, and diagnosis rates. Using current testing methods, more frequent review periods appear advantageous for diagnostic efficiency, with both lower clinic load and lower cost up until the point of discharge or glaucoma diagnosis. Translational Relevance A less stringent criterion for assessing the risk of developing glaucoma potentially offers a more cost-effective method for reviewing glaucoma suspects, especially within the first 2.5 years.
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Affiliation(s)
- Jack Phu
- Centre for Eye Health, University of New South Wales, Kensington, NSW, Australia.,School of Optometry and Vision Science, University of New South Wales, Kensington, NSW, Australia
| | - Katherine Masselos
- Centre for Eye Health, University of New South Wales, Kensington, NSW, Australia.,Prince of Wales Hospital Ophthalmology Department, Randwick, NSW, Australia
| | | | - Michael Kalloniatis
- Centre for Eye Health, University of New South Wales, Kensington, NSW, Australia.,School of Optometry and Vision Science, University of New South Wales, Kensington, NSW, Australia
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19
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Labkovich M, Paul M, Kim E, A. Serafini R, Lakhtakia S, Valliani AA, Warburton AJ, Patel A, Zhou D, Sklar B, Chelnis J, Elahi E. Portable hardware & software technologies for addressing ophthalmic health disparities: A systematic review. Digit Health 2022; 8:20552076221090042. [PMID: 35558637 PMCID: PMC9087242 DOI: 10.1177/20552076221090042] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Accepted: 03/09/2022] [Indexed: 11/19/2022] Open
Abstract
Vision impairment continues to be a major global problem, as the WHO estimates
2.2 billion people struggling with vision loss or blindness. One billion of
these cases, however, can be prevented by expanding diagnostic capabilities.
Direct global healthcare costs associated with these conditions totaled $255
billion in 2010, with a rapid upward projection to $294 billion in 2020.
Accordingly, WHO proposed 2030 targets to enhance integration and
patient-centered vision care by expanding refractive error and cataract
worldwide coverage. Due to the limitations in cost and portability of adapted
vision screening models, there is a clear need for new, more accessible vision
testing tools in vision care. This comparative, systematic review highlights the
need for new ophthalmic equipment and approaches while looking at existing and
emerging technologies that could expand the capacity for disease identification
and access to diagnostic tools. Specifically, the review focuses on portable
hardware- and software-centered strategies that can be deployed in remote
locations for detection of ophthalmic conditions and refractive error.
Advancements in portable hardware, automated software screening tools, and big
data-centric analytics, including machine learning, may provide an avenue for
improving ophthalmic healthcare.
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Affiliation(s)
- Margarita Labkovich
- Department of Medical Education, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Megan Paul
- Department of Medical Education, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Eliott Kim
- Department of Medical Education, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Randal A. Serafini
- Department of Medical Education, Icahn School of Medicine at Mount Sinai, New York, NY, USA
- Nash Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | | | - Aly A Valliani
- Department of Medical Education, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Andrew J Warburton
- Department of Medical Education, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Aashay Patel
- Department of Medical Education, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Davis Zhou
- Department of Ophthalmology, New York Eye and Ear Infirmary of Mount Sinai, New York, NY, USA
| | - Bonnie Sklar
- Department of Ophthalmology, Wills Eye Hospital, Philadelphia, PA, USA
| | - James Chelnis
- Department of Ophthalmology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Ebrahim Elahi
- Department of Ophthalmology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
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20
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Das AV, Narayanan R, Rani PK. Effect of COVID-19 Pandemic on Presentation of Patients With Diabetic Retinopathy in a Multitier Ophthalmology Network in India. Cureus 2021; 13:e19148. [PMID: 34873499 PMCID: PMC8631499 DOI: 10.7759/cureus.19148] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/30/2021] [Indexed: 01/15/2023] Open
Abstract
OBJECTIVE This study aimed to describe the demographics and clinical profile of patients with diabetic retinopathy (DR) presenting during the novel coronavirus disease 2019 (COVID-19) lockdown and unlock phases in India. METHODS This hospital-based cross-sectional study included patients presenting from March 25, 2019, to March 31, 2021. All patients who presented with DR were included as cases. The data were collected using an electronic medical record system. RESULTS In total, 88,012 patients diagnosed with retinal diseases were presented to the network and included for analysis. There were 21,271 (24%) DR patients during the study period and the majority were men (71%) from the urban area (45%). An increasing number of patients with proliferative DR (56%), sight-threatening DR (79%), need for vitreoretinal procedures (31%), and intravitreal injections (19%) were seen during the lockdown (phase one-four). There was a significant increase in the number of patients with blindness in pre-lockdown (20%), lockdown (32%), and post-lockdown (26%). Patterns of sight-threatening DR and blindness were similar in both fresh and follow-up patients. CONCLUSION The presentation of DR patients in hospital is evolving because of the COVID-19 pandemic. The footfalls of patients during the unlock (phase 1-10) regained to two-thirds of the pre-COVID-19 level. There was an increase in patients with sight-threatening DR and the need for vitreoretinal surgery and intravitreal injections during the lockdown (phase 1-4).
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Affiliation(s)
- Anthony V Das
- Department of eyeSmart Electronic Medical Record (EMR) and AEye, L. V. Prasad Eye Institute, Hyderabad, IND
| | - Raja Narayanan
- Department of Vitreoretinal Diseases, L. V. Prasad Eye Institute, Hyderabad, IND
| | - Padmaja K Rani
- Department of Vitreoretinal Diseases/Tele-Ophthalmology, L. V. Prasad Eye Institute, Hyderabad, IND
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21
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Jelly ET, Zhao Y, Chu KK, Price H, Crose M, Steelman ZA, Wax A. Deep imaging with 1.3 µm dual-axis optical coherence tomography and an enhanced depth of focus. BIOMEDICAL OPTICS EXPRESS 2021; 12:7689-7702. [PMID: 35003860 PMCID: PMC8713684 DOI: 10.1364/boe.438621] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Revised: 10/01/2021] [Accepted: 11/03/2021] [Indexed: 06/14/2023]
Abstract
For many clinical applications, such as dermatology, optical coherence tomography (OCT) suffers from limited penetration depth due primarily to the highly scattering nature of biological tissues. Here, we present a novel implementation of dual-axis optical coherence tomography (DA-OCT) that offers improved depth penetration in skin imaging at 1.3 µm compared to conventional OCT. Several unique aspects of DA-OCT are examined here, including the requirements for scattering properties to realize the improvement and the limited depth of focus (DOF) inherent to the technique. To overcome this limitation, our approach uses a tunable lens to coordinate focal plane selection with image acquisition to create an enhanced DOF for DA-OCT. This improvement in penetration depth is quantified experimentally against conventional on-axis OCT using tissue phantoms and mouse skin. The results presented here suggest the potential use of DA-OCT in situations where a high degree of scattering limits depth penetration in OCT imaging.
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Affiliation(s)
- Evan T. Jelly
- Department of Biomedical Engineering, Duke University, Durham, NC 27708, USA
| | - Yang Zhao
- Department of Biomedical Engineering, Duke University, Durham, NC 27708, USA
| | - Kengyeh K. Chu
- Department of Biomedical Engineering, Duke University, Durham, NC 27708, USA
| | - Hillel Price
- Department of Biomedical Engineering, Duke University, Durham, NC 27708, USA
| | | | - Zachary A. Steelman
- Department of Biomedical Engineering, Duke University, Durham, NC 27708, USA
| | - Adam Wax
- Department of Biomedical Engineering, Duke University, Durham, NC 27708, USA
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22
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Abid A, Duval R, Rezende F, Boutopoulos C. A Smart Vitrector Equipped by a Fiber-Based OCT Sensor Mitigates Intentional Attempts at Creating Iatrogenic Retinal Breaks During Vitrectomy in Pigs. Transl Vis Sci Technol 2021; 10:19. [PMID: 34767622 PMCID: PMC8590174 DOI: 10.1167/tvst.10.13.19] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose The occurrence of iatrogenic retinal breaks (RB) in pars plana vitrectomy (PPV) is a complication that compromises the overall efficacy of the surgery. A subset of iatrogenic RB occurs when the retina (rather than the vitreous gel) is cut accidentally by the vitrector. We developed a smart vitrector that can detect in real-time potential iatrogenic RB and activate promptly a PPV machine response to prevent them. Methods We fabricated the smart vitrectors by attaching a miniaturized fiber-based OCT sensor on commercial vitrectors (25G). The system's response time to an iatrogenic RB onset was measured and compared to the literature reported physiologically limited response time of the average surgeon. Two surgeons validated its ability to prevent simulated iatrogenic RB by performing PPV in pigs. Note that the system is meant to control the PPV machine and requires no visual or audio signal interpretation by the surgeons. Results We found that the response time of the system (28.9 ± 6.5 ms) is 11 times shorter compared to the literature reported physiologically limited reaction time of the average surgeon (P < 0.0001). Ex vivo validation (porcine eyes) showed that the system prevents 78.95% (15/19) (95% confidence interval [CI] 54.43–93.95) of intentional attempts at creating RB, whereas in vivo validation showed that the system, prevents 55.68% (30/54) (95% CI 41.40–69.08), and prevents or mitigates 70.37% (38/54) (95% CI 56.39–82.02) of such attempts. A subset of failures was classified as “early stop” (i.e., false positive), having a prevalence of 5.26% (1/19) in ex vivo tests and 24.07% (13/54) in in vivo tests. Conclusions Our results indicate the smart vitrector can prevent iatrogenic RB by providing seamless intraoperative feedback to the PPV machine. Importantly, the use of the smart vitrector requires no modifications of the established PPV procedure. It can mitigate a significant proportion of iatrogenic RB and thus improve the overall efficacy of the surgery. Translational Relevance Potential clinical adoption of the smart vitrector can reduce the incidence of iatrogenic RB in PPV and thus increase the therapeutic outcome of the surgery.
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Affiliation(s)
- Alexandre Abid
- Institute of Biomedical Engineering, University of Montreal, Montreal, Quebec, Canada.,Maisonneuve-Rosemont Hospital Research Centre, Montreal, Quebec, Canada
| | - Renaud Duval
- Maisonneuve-Rosemont Hospital, Montreal, Quebec, Canada.,Department of Ophthalmology, University of Montreal, Montreal, Quebec, Canada
| | - Flavio Rezende
- Maisonneuve-Rosemont Hospital, Montreal, Quebec, Canada.,Department of Ophthalmology, University of Montreal, Montreal, Quebec, Canada
| | - Christos Boutopoulos
- Institute of Biomedical Engineering, University of Montreal, Montreal, Quebec, Canada.,Maisonneuve-Rosemont Hospital Research Centre, Montreal, Quebec, Canada.,Department of Ophthalmology, University of Montreal, Montreal, Quebec, Canada
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23
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Abstract
PURPOSE OF REVIEW The COVID-19 public health emergency accelerated the adoption of telemedicine in neuro-ophthalmology. This review surveys the current telemedicine landscape and discusses associated limitations and opportunities. RECENT FINDINGS Logistic considerations and regulatory changes related to the COVID-19 pandemic have spurred a proliferation of tele-neuro-ophthalmic practice. One significant benefit of telemedicine is increased access to the limited number of neuro-ophthalmologists in the country. Certain elements of the neuro-ophthalmic examination can be ascertained during a video visit or through the use of mobile applications. However, data quality can be limited and more direct evaluation of the fundus currently requires the implementation of imaging techniques, such as fundus photography and/or optical coherence tomography. For cases that require it, a 'hybrid' model can be adopted in which patients physically present to designated locations for testing and subsequently participate in televisit with the physician to discuss the assessment and plan. SUMMARY Telemedicine provides an alternate pathway for patients to access the limited resource of neuro-ophthalmic care, and it will likely persist beyond the current COVID-19 pandemic. It has some limitations currently but continued progress in technologic, legal, and reimbursement strategies will hopefully facilitate further adoption.
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24
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Leitgeb R, Placzek F, Rank E, Krainz L, Haindl R, Li Q, Liu M, Andreana M, Unterhuber A, Schmoll T, Drexler W. Enhanced medical diagnosis for dOCTors: a perspective of optical coherence tomography. JOURNAL OF BIOMEDICAL OPTICS 2021; 26:JBO-210150-PER. [PMID: 34672145 PMCID: PMC8528212 DOI: 10.1117/1.jbo.26.10.100601] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Accepted: 09/23/2021] [Indexed: 05/17/2023]
Abstract
SIGNIFICANCE After three decades, more than 75,000 publications, tens of companies being involved in its commercialization, and a global market perspective of about USD 1.5 billion in 2023, optical coherence tomography (OCT) has become one of the fastest successfully translated imaging techniques with substantial clinical and economic impacts and acceptance. AIM Our perspective focuses on disruptive forward-looking innovations and key technologies to further boost OCT performance and therefore enable significantly enhanced medical diagnosis. APPROACH A comprehensive review of state-of-the-art accomplishments in OCT has been performed. RESULTS The most disruptive future OCT innovations include imaging resolution and speed (single-beam raster scanning versus parallelization) improvement, new implementations for dual modality or even multimodality systems, and using endogenous or exogenous contrast in these hybrid OCT systems targeting molecular and metabolic imaging. Aside from OCT angiography, no other functional or contrast enhancing OCT extension has accomplished comparable clinical and commercial impacts. Some more recently developed extensions, e.g., optical coherence elastography, dynamic contrast OCT, optoretinography, and artificial intelligence enhanced OCT are also considered with high potential for the future. In addition, OCT miniaturization for portable, compact, handheld, and/or cost-effective capsule-based OCT applications, home-OCT, and self-OCT systems based on micro-optic assemblies or photonic integrated circuits will revolutionize new applications and availability in the near future. Finally, clinical translation of OCT including medical device regulatory challenges will continue to be absolutely essential. CONCLUSIONS With its exquisite non-invasive, micrometer resolution depth sectioning capability, OCT has especially revolutionized ophthalmic diagnosis and hence is the fastest adopted imaging technology in the history of ophthalmology. Nonetheless, OCT has not been completely exploited and has substantial growth potential-in academics as well as in industry. This applies not only to the ophthalmic application field, but also especially to the original motivation of OCT to enable optical biopsy, i.e., the in situ imaging of tissue microstructure with a resolution approaching that of histology but without the need for tissue excision.
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Affiliation(s)
- Rainer Leitgeb
- Medical University of Vienna, Center for Medical Physics and Biomedical Engineering, Vienna, Austria
- Medical University of Vienna, Christian Doppler Laboratory OPTRAMED, Vienna, Austria
| | - Fabian Placzek
- Medical University of Vienna, Center for Medical Physics and Biomedical Engineering, Vienna, Austria
| | - Elisabet Rank
- Medical University of Vienna, Center for Medical Physics and Biomedical Engineering, Vienna, Austria
| | - Lisa Krainz
- Medical University of Vienna, Center for Medical Physics and Biomedical Engineering, Vienna, Austria
| | - Richard Haindl
- Medical University of Vienna, Center for Medical Physics and Biomedical Engineering, Vienna, Austria
| | - Qian Li
- Medical University of Vienna, Center for Medical Physics and Biomedical Engineering, Vienna, Austria
| | - Mengyang Liu
- Medical University of Vienna, Center for Medical Physics and Biomedical Engineering, Vienna, Austria
| | - Marco Andreana
- Medical University of Vienna, Center for Medical Physics and Biomedical Engineering, Vienna, Austria
| | - Angelika Unterhuber
- Medical University of Vienna, Center for Medical Physics and Biomedical Engineering, Vienna, Austria
| | - Tilman Schmoll
- Medical University of Vienna, Center for Medical Physics and Biomedical Engineering, Vienna, Austria
- Carl Zeiss Meditec, Inc., Dublin, California, United States
| | - Wolfgang Drexler
- Medical University of Vienna, Center for Medical Physics and Biomedical Engineering, Vienna, Austria
- Address all correspondence to Wolfgang Drexler,
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25
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Ji X, Mojahed D, Okawachi Y, Gaeta AL, Hendon CP, Lipson M. Millimeter-scale chip-based supercontinuum generation for optical coherence tomography. SCIENCE ADVANCES 2021; 7:eabg8869. [PMID: 34533990 PMCID: PMC8448444 DOI: 10.1126/sciadv.abg8869] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Supercontinuum sources for optical coherence tomography (OCT) have raised great interest as they provide broad bandwidth to enable high resolution and high power to improve imaging sensitivity. Commercial fiber-based supercontinuum systems require high pump powers to generate broad bandwidth and customized optical filters to shape/attenuate the spectra. They also have limited sensitivity and depth performance. We introduce a supercontinuum platform based on a 1-mm2 Si3N4 photonic chip for OCT. We directly pump and efficiently generate supercontinuum near 1300 nm without any postfiltering. With a 25-pJ pump pulse, we generate a broadband spectrum with a flat 3-dB bandwidth of 105 nm. Integrating the chip into a spectral domain OCT system, we achieve 105-dB sensitivity and 1.81-mm 6-dB sensitivity roll-off with 300-μW optical power on sample. We image breast tissue to demonstrate strong imaging performance. Our chip will pave the way toward portable OCT and incorporating integrated photonics into optical imaging technologies.
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Affiliation(s)
- Xingchen Ji
- Department of Electrical Engineering, Columbia University, New York, NY 10027, USA
| | - Diana Mojahed
- Department of Electrical Engineering, Columbia University, New York, NY 10027, USA
- Department of Biomedical Engineering, Columbia University, New York, NY 10027, USA
| | - Yoshitomo Okawachi
- Department of Applied Physics and Applied Mathematics, Columbia University, New York, NY 10027, USA
| | - Alexander L. Gaeta
- Department of Applied Physics and Applied Mathematics, Columbia University, New York, NY 10027, USA
| | - Christine P. Hendon
- Department of Electrical Engineering, Columbia University, New York, NY 10027, USA
- Corresponding author. (M.L.); (C.P.H.)
| | - Michal Lipson
- Department of Electrical Engineering, Columbia University, New York, NY 10027, USA
- Corresponding author. (M.L.); (C.P.H.)
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Abstract
PURPOSE OF REVIEW Diabetic retinopathy (DR) is one of the leading causes of vision loss worldwide. Although screening and early treatment guidelines for DR have significantly reduced the disease burden, restrictions related to the COVID-19 pandemic have changed real-world practice patterns in the management of DR. This review summarizes evolving guidelines and outcomes of the treatment of DR in the setting of the pandemic. RECENT FINDINGS Intravitreal injections for DR have decreased significantly globally during the pandemic, ranging from approximately 30 to nearly 100% reduction, compared to corresponding timepoints in 2019. Most studies on functional outcomes show a decrease in visual acuity on delayed follow-up. Changing practice patterns in the management of DR has led to fewer intravitreal injections and overall reduction in visual acuity on follow-up. As COVID variants emerge, it will be necessary to continue evaluating practice guidelines.
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Affiliation(s)
- Ishrat Ahmed
- grid.21107.350000 0001 2171 9311Wilmer Eye Institute, Johns Hopkins University, 600 N. Wolfe Street, Maumenee 726, Baltimore, MD 21287 USA
| | - T. Y. Alvin Liu
- grid.21107.350000 0001 2171 9311Wilmer Eye Institute, Johns Hopkins University, 600 N. Wolfe Street, Maumenee 726, Baltimore, MD 21287 USA
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27
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Jelly ET, Kwun J, Schmitz R, Farris AB, Steelman ZA, Sudan DL, Knechtle SJ, Wax A. Optical coherence tomography of small intestine allograft biopsies using a handheld surgical probe. JOURNAL OF BIOMEDICAL OPTICS 2021; 26:JBO-210108R. [PMID: 34561973 PMCID: PMC8461564 DOI: 10.1117/1.jbo.26.9.096008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/05/2021] [Accepted: 09/08/2021] [Indexed: 06/13/2023]
Abstract
SIGNIFICANCE The current gold standard for monitoring small intestinal transplant (IT) rejection is endoscopic visual assessment and biopsy of suspicious lesions; however, these lesions are only superficially visualized by endoscopy. Invasive biopsies provide a coarse sampling of tissue health without depicting the true presence and extent of any pathology. Optical coherence tomography (OCT) presents a potential alternative approach with significant advantages over traditional white-light endoscopy. AIM The aim of our investigation was to evaluate OCT performance in distinguishing clinically relevant morphological features associated with IT graft failure. APPROACH OCT was applied to evaluate the small bowel tissues of two rhesus macaques that had undergone IT of the ileum. The traditional assessment from routine histological observation was compared with OCT captured using a handheld surgical probe during the days post-transplant and subsequently was compared with histophaology. RESULTS The reported OCT system was capable of identifying major biological landmarks in healthy intestinal tissue. Following IT, one nonhuman primate (NHP) model suffered a severe graft ischemia, and the second NHP graft failed due to acute cellular rejection. OCT images show visual evidence of correspondence with histological signs of IT rejection. CONCLUSIONS Results suggest that OCT imaging has significant potential to reveal morphological changes associated with IT rejection and to improve patient outcomes overall.
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Affiliation(s)
- Evan T. Jelly
- Duke University, Department of Biomedical Engineering, Durham, North Carolina, United States
| | - Jean Kwun
- Duke University Medical Center, Duke Transplant Center, Department of Surgery, Durham, United States
| | - Robin Schmitz
- Duke University Medical Center, Duke Transplant Center, Department of Surgery, Durham, United States
| | - Alton B. Farris
- Emory University, Department of Pathology, Atlanta, Georgia, United States
| | - Zachary A. Steelman
- Duke University, Department of Biomedical Engineering, Durham, North Carolina, United States
| | - Debra L. Sudan
- Duke University Medical Center, Duke Transplant Center, Department of Surgery, Durham, United States
| | - Stuart J. Knechtle
- Duke University Medical Center, Duke Transplant Center, Department of Surgery, Durham, United States
| | - Adam Wax
- Duke University, Department of Biomedical Engineering, Durham, North Carolina, United States
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28
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Song G, Jelly ET, Chu KK, Kendall WY, Wax A. A review of low-cost and portable optical coherence tomography. PROGRESS IN BIOMEDICAL ENGINEERING (BRISTOL, ENGLAND) 2021; 3:032002. [PMID: 37645660 PMCID: PMC10465117 DOI: 10.1088/2516-1091/abfeb7] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/31/2023]
Abstract
Optical coherence tomography (OCT) is a powerful optical imaging technique capable of visualizing the internal structure of biological tissues at near cellular resolution. For years, OCT has been regarded as the standard of care in ophthalmology, acting as an invaluable tool for the assessment of retinal pathology. However, the costly nature of most current commercial OCT systems has limited its general accessibility, especially in low-resource environments. It is therefore timely to review the development of low-cost OCT systems as a route for applying this technology to population-scale disease screening. Low-cost, portable and easy to use OCT systems will be essential to facilitate widespread use at point of care settings while ensuring that they offer the necessary imaging performances needed for clinical detection of retinal pathology. The development of low-cost OCT also offers the potential to enable application in fields outside ophthalmology by lowering the barrier to entry. In this paper, we review the current development and applications of low-cost, portable and handheld OCT in both translational and research settings. Design and cost-reduction techniques are described for general low-cost OCT systems, including considerations regarding spectrometer-based detection, scanning optics, system control, signal processing, and the role of 3D printing technology. Lastly, a review of clinical applications enabled by low-cost OCT is presented, along with a detailed discussion of current limitations and outlook.
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Affiliation(s)
- Ge Song
- Author to whom any correspondence should be addressed.
| | | | - Kengyeh K Chu
- Department of Biomedical Engineering, Duke University, Durham, NC 27708, United States of America
| | - Wesley Y Kendall
- Department of Biomedical Engineering, Duke University, Durham, NC 27708, United States of America
| | - Adam Wax
- Department of Biomedical Engineering, Duke University, Durham, NC 27708, United States of America
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29
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Yin X, Zhu Y, Hu J. 3D Fingerprint Recognition based on Ridge-Valley-Guided 3D Reconstruction and 3D Topology Polymer Feature Extraction. IEEE TRANSACTIONS ON PATTERN ANALYSIS AND MACHINE INTELLIGENCE 2021; 43:1085-1091. [PMID: 31675315 DOI: 10.1109/tpami.2019.2949299] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
An automated fingerprint recognition system (AFRS) for 3D fingerprints is essential and highly promising for biometric security. Despite the progress in developing 3D AFRSs, achieving high-quality real-time reconstruction and high-accuracy recognition of 3D fingerprints remain two challenging issues. To address them, we propose a robust 3D AFRS based on ridge-valley (RV)-guided 3D fingerprint reconstruction and 3D topology polymer (TTP) feature extraction. The former considers the unique fingerprint characteristics of the RV and achieves real-time reconstruction. Unlike traditional triangulation-based methods that establish correspondences between points by cross-correlation-based searching, we propose to establish RV correspondences (RVCs) between ridges/valleys by defining and calculating a RVC matrix based on the topology of RV curves. To enhance depth reconstruction, curve-based smoothing is proposed to refine our novel RV disparity map. The TTP feature codes the 3D topology by projecting the 3D minutiae onto multiple planes and extracting their corresponding 2D topologies and has proven to be effective and efficient for 3D fingerprint recognition. Comprehensive experimental results demonstrate that our method outperforms the state-of-the-art methods in terms of both reconstruction and recognition accuracy. Also, due to its very short running time, it is appropriate for practical applications.
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30
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Abstract
Optical coherence tomography (OCT) has become one of the most important techniques in ophthalmic diagnostics, as it is the only way to three-dimensionally visualize morphological changes in the layered structure of the retina at a high resolution. In addition, OCT is applied for countless medical and technical purposes. Recent developments pave the way for small-footprint OCT systems at significantly reduced costs, thereby extending possible use cases. Now, it appears increasingly likely that, in the near future, OCT will find its way into many more industrial and medical applications, including disease monitoring at home.
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Affiliation(s)
- Dierck Hillmann
- Institute of Biomedical Optics, University of Lübeck, Peter-Monnik-Weg 4, 23562, Lübeck, Germany.
- Thorlabs GmbH, Maria-Goeppert-Straße 9, 23562, Lübeck, Germany.
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31
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Rank EA, Sentosa R, Harper DJ, Salas M, Gaugutz A, Seyringer D, Nevlacsil S, Maese-Novo A, Eggeling M, Muellner P, Hainberger R, Sagmeister M, Kraft J, Leitgeb RA, Drexler W. Toward optical coherence tomography on a chip: in vivo three-dimensional human retinal imaging using photonic integrated circuit-based arrayed waveguide gratings. LIGHT, SCIENCE & APPLICATIONS 2021; 10:6. [PMID: 33402664 PMCID: PMC7785745 DOI: 10.1038/s41377-020-00450-0] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Revised: 11/14/2020] [Accepted: 12/03/2020] [Indexed: 05/19/2023]
Abstract
In this work, we present a significant step toward in vivo ophthalmic optical coherence tomography and angiography on a photonic integrated chip. The diffraction gratings used in spectral-domain optical coherence tomography can be replaced by photonic integrated circuits comprising an arrayed waveguide grating. Two arrayed waveguide grating designs with 256 channels were tested, which enabled the first chip-based optical coherence tomography and angiography in vivo three-dimensional human retinal measurements. Design 1 supports a bandwidth of 22 nm, with which a sensitivity of up to 91 dB (830 µW) and an axial resolution of 10.7 µm was measured. Design 2 supports a bandwidth of 48 nm, with which a sensitivity of 90 dB (480 µW) and an axial resolution of 6.5 µm was measured. The silicon nitride-based integrated optical waveguides were fabricated with a fully CMOS-compatible process, which allows their monolithic co-integration on top of an optoelectronic silicon chip. As a benchmark for chip-based optical coherence tomography, tomograms generated by a commercially available clinical spectral-domain optical coherence tomography system were compared to those acquired with on-chip gratings. The similarities in the tomograms demonstrate the significant clinical potential for further integration of optical coherence tomography on a chip system.
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Affiliation(s)
- Elisabet A Rank
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Waehringer Guertel 18-20/4 L, 1090, Vienna, Austria.
| | - Ryan Sentosa
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Waehringer Guertel 18-20/4 L, 1090, Vienna, Austria
| | - Danielle J Harper
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Waehringer Guertel 18-20/4 L, 1090, Vienna, Austria
| | - Matthias Salas
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Waehringer Guertel 18-20/4 L, 1090, Vienna, Austria
| | - Anna Gaugutz
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Waehringer Guertel 18-20/4 L, 1090, Vienna, Austria
| | - Dana Seyringer
- Research Centre for Microtechnology, Vorarlberg University of Applied Sciences, Hochschulstrasse 1, 6850, Dornbirn, Austria
| | - Stefan Nevlacsil
- AIT Austrian Institute of Technology GmbH, Gieffinggasse 4, 1210, Vienna, Austria
| | - Alejandro Maese-Novo
- AIT Austrian Institute of Technology GmbH, Gieffinggasse 4, 1210, Vienna, Austria
| | - Moritz Eggeling
- AIT Austrian Institute of Technology GmbH, Gieffinggasse 4, 1210, Vienna, Austria
| | - Paul Muellner
- AIT Austrian Institute of Technology GmbH, Gieffinggasse 4, 1210, Vienna, Austria
| | - Rainer Hainberger
- AIT Austrian Institute of Technology GmbH, Gieffinggasse 4, 1210, Vienna, Austria
| | | | - Jochen Kraft
- ams AG, Tobelbader Strasse 30, 8141, Premstaetten, Austria
| | - Rainer A Leitgeb
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Waehringer Guertel 18-20/4 L, 1090, Vienna, Austria
| | - Wolfgang Drexler
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Waehringer Guertel 18-20/4 L, 1090, Vienna, Austria
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Batabyal S, Kim S, Wright W, Mohanty S. Laser-assisted targeted gene delivery to degenerated retina improves retinal function. JOURNAL OF BIOPHOTONICS 2021; 14:e202000234. [PMID: 33026157 DOI: 10.1002/jbio.202000234] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Revised: 09/27/2020] [Accepted: 09/28/2020] [Indexed: 06/11/2023]
Abstract
Delivery of therapeutic genes into retina is proving to reverse degeneration and restore vision, however, viral vector-based gene delivery is prone to immunorejection, inflammatory/immune-response and nontargeted. Here, we report nonviral gene delivery and expression of opsin encoding genes in mouse retina in-vitro and in-vivo by use of pulsed femtosecond laser microbeam. In-vitro patch-clamp recording of the opsin-sensitized retinal cells and visually evoked in-vivo electrical recording from laser-transfected eye of mouse with degenerated retina showed functional response. The ultrafast laser-based naked gene delivery showed minimal damage and reliable expression of therapeutic opsin in cell membrane of the selected cells and in targeted retinal region. Laser-based "naked DNA gene therapy" in a spatially targeted manner will pave the way for treatment of inherited retinal diseases.
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Marques MJ, Green R, King R, Clement S, Hallett P, Podoleanu A. Sub-surface characterisation of latest-generation identification documents using optical coherence tomography. Sci Justice 2020; 61:119-129. [PMID: 33736844 DOI: 10.1016/j.scijus.2020.12.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Revised: 11/19/2020] [Accepted: 12/21/2020] [Indexed: 10/22/2022]
Abstract
The identification of individuals, particularly at international border crossings, coupled with the evolving sophistication of identity documents are issues that authorities must contend with. Particularly, the ability to distinguish legitimate from counterfeit documents, with high throughput, sensitivity, and selectivity is an ever-evolving challenge. Over the last decade, an increasing number of security features have been introduced by authorities in identification documents. The latest generation of travel documents (such as passports and national ID cards) forego paper substrates for several layers of polycarbonate, allowing security features to be embedded within the documents. These security features may contain information at either the superficial and sub-surface levels, thus increasing the document's resilience to counterfeiting. As the documents become harder to forge, so does the sophistication of forgery detection. There appears to be an unmet and evolving need to identify such sophisticated forgeries, in a non-destructive, high throughput manner. In this publication, we report on the application of optical coherence tomography (OCT) imaging on assessing security features in specimen passports and national ID cards. OCT allows sub-surface imaging of translucent structures, non-destructively enabling quantitative visualisation of embedded security features.
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Affiliation(s)
- Manuel J Marques
- Applied Optics Group, School of Physical Sciences, University of Kent, Canterbury CT2 7NH, United Kingdom.
| | - Robert Green
- Forensic Research Group, School of Physical Sciences, University of Kent, Canterbury CT2 7NH, United Kingdom
| | - Roberto King
- Foster and Freeman Ltd, Vale Park, 2 Vale Link, Evesham WR11 1TD, United Kingdom
| | - Simon Clement
- Foster and Freeman Ltd, Vale Park, 2 Vale Link, Evesham WR11 1TD, United Kingdom
| | - Peter Hallett
- Foster and Freeman Ltd, Vale Park, 2 Vale Link, Evesham WR11 1TD, United Kingdom
| | - Adrian Podoleanu
- Applied Optics Group, School of Physical Sciences, University of Kent, Canterbury CT2 7NH, United Kingdom
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34
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Atalar O, Millar DS, Wang P, Koike-Akino T, Kojima K, Orlik PV, Parsons K. Spectrally sparse optical coherence tomography. OPTICS EXPRESS 2020; 28:37798-37810. [PMID: 33379608 DOI: 10.1364/oe.409539] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Accepted: 11/18/2020] [Indexed: 06/12/2023]
Abstract
Swept-source optical coherence tomography (OCT) typically relies on expensive and complex swept-source lasers, the cost of which currently limits the suitability of OCT for new applications. In this work, we demonstrate spectrally sparse OCT utilizing randomly spaced low-bandwidth optical chirps, suitable for low-cost implementation with telecommunications grade devices. Micron scale distance estimation accuracy with a resolution of 40 μm at a standoff imaging distance greater than 10 cm is demonstrated using a stepped chirp approach with approximately 23% occupancy of 4 THz bandwidth. For imaging of sparse scenes, comparable performance to full bandwidth occupancy is verified for metallic targets.
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35
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Chopra R, Wagner SK, Keane PA. Optical coherence tomography in the 2020s-outside the eye clinic. Eye (Lond) 2020; 35:236-243. [PMID: 33168975 DOI: 10.1038/s41433-020-01263-6] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Revised: 10/20/2020] [Accepted: 10/27/2020] [Indexed: 11/09/2022] Open
Abstract
Optical coherence tomography (OCT) is a paragon of success in the translation of biophotonics science to clinical practice. OCT systems have become ubiquitous in eye clinics but access beyond this is limited by their cost, size and the skill required to operate the devices. Remarkable progress has been made in the development of OCT technology to improve the speed of acquisition, the quality of images and into functional extensions of OCT such as OCT angiography. However, more needs to be done to radically improve the access to OCT by addressing its limitations and enable penetration outside of typical clinical settings and into underserved populations. Beyond high-income countries, there are 6.5 billion people with similar eye-care needs, which cannot be met by the current generation of bulky, expensive and complex OCT systems. In addition, advancing the portability of this technology to address opportunities in point-of-care diagnostics, telemedicine and remote monitoring may aid development of personalised medicine. In this review, we discuss the major milestones in OCT hardware development to reach those beyond the eye clinic.
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Affiliation(s)
- Reena Chopra
- NIHR Biomedical Research Centre for Ophthalmology, Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, London, UK
| | - Siegfried K Wagner
- NIHR Biomedical Research Centre for Ophthalmology, Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, London, UK
| | - Pearse A Keane
- NIHR Biomedical Research Centre for Ophthalmology, Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, London, UK.
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36
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Hayashi J, Tagami J, Chan D, Sadr A. New bulk-fill composite system with high irradiance light polymerization: Integrity and degree of conversion. Dent Mater 2020; 36:1615-1623. [PMID: 33168226 DOI: 10.1016/j.dental.2020.10.012] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Revised: 09/05/2020] [Accepted: 10/06/2020] [Indexed: 01/05/2023]
Abstract
OBJECTIVE The study used optical coherence tomography (OCT) and micro Raman microscopy (mRM) to investigate internal defect (ID) and degree of conversion (DC) of two bulk-fill composite systems with high-irradiance or conventional light polymerization settings. METHODS The ID and DC of the new bulk-fill composites; Tetric PowerFill (PwrPst) and Tetric PowerFlow (PwrFlw) were compared with the predecessor bulk-fill composites; Tetric EvoCeram Bulkfill (EvoPst) and Tetric EvoFlow Bulkfill (EvoFlw), using LED light curing unit in two settings; normal (LED-Nrm: 1000 mW/cm2, 10-s) or PowerCure (LED-Pwr: 3000 mW/cm2, 3-s). ID formation was observed in bonded cylindrical composite cavities (4-mm depth, 3-mm diameter) using Yoshida Dental OCT. From the vertically projected 2D image, ID area percentage (ID-A%) was calculated. DC at the top and bottom and bottom/top DC ratio (DC-R%) of 4-mm thick discs was calculated using mRM. All data were statistically analyzed at significance level of α = 0.05. RESULTS Flowable composites in LED-Pwr showed smaller ID frequencies than other groups (PwrFlw: 0/8, EvoFlw: 2/8) (p < 0.05). Composite type significantly affected ID-A%, DC and DC-R% (p < 0.001), while light settings significantly affected ID-A% but not DC and DC-R% (p > 0.05). In both light settings, EvoPst showed the lowest DC-R% (<80%). SIGNIFICANCE Internal defect and degree of conversion of bulk-fill composites were affected by their composition and light settings. There was a tendency for less defects and better polymerization for the flowable bulk-fills. The new flowable bulk-fill composite with 3-seconds high irradiance light curing showed no defect formation.
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Affiliation(s)
- Juri Hayashi
- Department of Restorative Dentistry, Biomimetics Biomaterials Biophotonics Biomechanics & Technology Laboratory, School of Dentistry, University of Washington, 1959 NE Pacific Street, Seattle, WA 98195-7456, USA; Cariology and Operative Dentistry, Department of Restorative Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45, Yushima, Bunkyo-ku, Tokyo 113-8549, Japan
| | - Junji Tagami
- Cariology and Operative Dentistry, Department of Restorative Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45, Yushima, Bunkyo-ku, Tokyo 113-8549, Japan
| | - Daniel Chan
- Department of Restorative Dentistry, Biomimetics Biomaterials Biophotonics Biomechanics & Technology Laboratory, School of Dentistry, University of Washington, 1959 NE Pacific Street, Seattle, WA 98195-7456, USA
| | - Alireza Sadr
- Department of Restorative Dentistry, Biomimetics Biomaterials Biophotonics Biomechanics & Technology Laboratory, School of Dentistry, University of Washington, 1959 NE Pacific Street, Seattle, WA 98195-7456, USA.
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Soomro T, Shah N, Niestrata-Ortiz M, Yap T, Normando EM, Cordeiro MF. Recent advances in imaging technologies for assessment of retinal diseases. Expert Rev Med Devices 2020; 17:1095-1108. [PMID: 32885710 DOI: 10.1080/17434440.2020.1816167] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
INTRODUCTION Retinal imaging is a key investigation in ophthalmology. New devices continue to be created to keep up with the demand for better imaging modalities in this field. This review looks to highlight current trends and the future of retinal imaging. AREAS COVERED This review looks at the advances in topographical imaging, photoacoustic microscopy, optical coherence tomography and molecular imaging. There is future scoping on further advances in retinal imaging. EXPERT OPINION Retinal imaging continues to develop at a rapid pace to improve diagnosis and management of patients. We will see the development of big data to gain powerful insights and new technologies such as teleophthalmology mature in the future.
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Affiliation(s)
- Taha Soomro
- Imperial College Ophthalmology Research Group, Western Eye Hospital , 153-173 Marylebone Road, London, UK
| | - Neil Shah
- Imperial College Ophthalmology Research Group, Western Eye Hospital , 153-173 Marylebone Road, London, UK
| | - Magdalena Niestrata-Ortiz
- Imperial College Ophthalmology Research Group, Western Eye Hospital , 153-173 Marylebone Road, London, UK
| | - Timothy Yap
- Imperial College Ophthalmology Research Group, Western Eye Hospital , 153-173 Marylebone Road, London, UK
| | - Eduardo M Normando
- Imperial College Ophthalmology Research Group, Western Eye Hospital , 153-173 Marylebone Road, London, UK
| | - M Francesca Cordeiro
- Imperial College Ophthalmology Research Group, Western Eye Hospital , 153-173 Marylebone Road, London, UK
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Abstract
BACKGROUND Telehealth provides health care to a patient from a provider at a distant location. Before the COVID-19 pandemic, adoption of telehealth modalities was increasing slowly but steadily. During the public health emergency, rapid widespread telehealth implementation has been encouraged to promote patient and provider safety and preserve access to health care. EVIDENCE ACQUISITION Evidence was acquired from English language Internet searches of the medical and business literature and following breaking news on the COVID-19 pandemic and responses from health care stakeholders, including policymakers, payers, physicians, health care organizations, and patients. We also had extensive discussions with colleagues who are developing telehealth techniques relevant to neuro-ophthalmology. RESULTS Regulatory, legal, reimbursement, and cultural barriers impeded the widespread adoption of telehealth before the COVID-19 pandemic. With the increased use of telehealth in response to the public health emergency, we are rapidly accumulating experience and an evidence base identifying opportunities and challenges related to the widespread adoption of tele-neuro-ophthalmology. One of the major challenges is the current inability to adequately perform funduscopy remotely. CONCLUSIONS Telehealth is an increasingly recognized means of health care delivery. Tele-Neuro-Ophthalmology adoption is necessary for the sake of our patients, the survival of our subspecialty, and the education of our trainees and students. Telehealth does not supplant but supplements and complements in-person neuro-ophthalmologic care. Innovations in digital optical fundus photography, mobile vision testing applications, artificial intelligence, and principles of channel management will facilitate further adoption of tele-neuro-ophthalmology and bring the specialty to the leading edge of health care delivery.
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Li Z, Holamoge YV, Li Z, Zaid W, Osborn ML, Ramos A, Miller JT, Li Y, Yao S, Xu J. Detection and analysis of enamel cracks by ICG-NIR fluorescence dental imaging. Ann N Y Acad Sci 2020; 1475:52-63. [PMID: 32519363 DOI: 10.1111/nyas.14374] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2019] [Revised: 04/13/2020] [Accepted: 04/28/2020] [Indexed: 01/01/2023]
Abstract
Cracked teeth are the third most common cause of tooth loss, but there is no reliable imaging tool for the diagnosis of cracks. Here, we demonstrate the feasibility of indocyanine green near-infrared fluorescence (ICG-NIRF) dental imaging for the detection of enamel cracks and enamel-dentin cracks in vitro in the first (ICG-NIRF-I, 700-950 nm) and second (ICG-NIRF-II, 950-1700 nm) imaging windows with transmission excitation light, and compared ICG-NIRF with conventional NIR illumination-II (NIRi-II) and X-ray imaging. Dentin cracks were detected by CT scan, while most enamel cracks, undetectable under X-ray imaging, were clearly visible in NIR images. We found that ICG-NIRF-II detected cracks more effectively than NIRi-II, and that light orientation is an important factor for crack detection: an angled exposure obtained better image contrast of cracks than parallel exposure, as it created a shadow under the crack. Crack depth could be evaluated from the crack shadow in ICG-NIRF and NIRi-II images; from this shadow we could determine crack depth and discriminate enamel-dentin cracks from craze lines. Cracks could be observed clearly from ICG-NIRF images with 1-min ICG tooth immersion, although longer ICG immersion produced images with greater contrast. Overall, our data show that ICG-NIRF dental imaging is a useful tool for diagnosing cracked teeth at an early stage.
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Affiliation(s)
- Zhongqiang Li
- Division of Electrical and Computer Engineering, College of Engineering, Louisiana State University, Baton Rouge, Louisiana
| | - Yoshita V Holamoge
- Division of Electrical and Computer Engineering, College of Engineering, Louisiana State University, Baton Rouge, Louisiana
| | - Zheng Li
- Division of Electrical and Computer Engineering, College of Engineering, Louisiana State University, Baton Rouge, Louisiana
| | - Waleed Zaid
- Oral and Maxillofacial Surgery, School of Dentistry, Louisiana State University Health Science Center, Baton Rouge, Louisiana
| | - Michelle L Osborn
- Department of Comparative Biomedical Science, School of Veterinary Medicine, Louisiana State University, Baton Rouge, Louisiana
| | - Alexandra Ramos
- Department of Comparative Biomedical Science, School of Veterinary Medicine, Louisiana State University, Baton Rouge, Louisiana
| | - Jacob T Miller
- Division of Electrical and Computer Engineering, College of Engineering, Louisiana State University, Baton Rouge, Louisiana
| | - Yanping Li
- School of Environment and Sustainability, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Shaomian Yao
- Department of Comparative Biomedical Science, School of Veterinary Medicine, Louisiana State University, Baton Rouge, Louisiana
| | - Jian Xu
- Division of Electrical and Computer Engineering, College of Engineering, Louisiana State University, Baton Rouge, Louisiana
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Li K, Yang Z, Liang W, Shang J, Liang Y, Wan S. Low-cost, ultracompact handheld optical coherence tomography probe for in vivo oral maxillofacial tissue imaging. JOURNAL OF BIOMEDICAL OPTICS 2020; 25:1-13. [PMID: 32314560 PMCID: PMC7167599 DOI: 10.1117/1.jbo.25.4.046003] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2019] [Accepted: 04/01/2020] [Indexed: 05/13/2023]
Abstract
SIGNIFICANCE Optical coherence tomography (OCT) has proven useful for detecting various oral maxillofacial abnormalities. To apply it to clinical applications including biopsy guidance and routine screening, a handheld imaging probe is indispensable. OCT probes reported for oral maxillofacial imaging were either based on a bulky galvanometric mirror pair (not compact or long enough) or a distal-end microelectromechanical systems (MEMS) scanner (raised safety concerns), or adapted from fiber-optic catheters (ill-suited for oral cavity geometry). AIM To develop a handheld probe featuring great compactness and excellent maneuverability for oral maxillofacial tissue imaging. APPROACH A dual-axis MEMS scanner was deployed at the proximal end of the probe and the scanned beam was relayed to the distal end through a 4f configuration. Such design provides both a perfect dual-axis telecentric scan and excellent compactness. RESULTS A handheld probe with a rigid part 70 mm in length and 7 mm in diameter and weighing 25 g in total was demonstrated through both ex vivo and in vivo experiments, including structural visualization of various oral maxillofacial tissues and monitoring the recovery process of an oral mucosa canker sore. CONCLUSIONS The proposed probe exhibits excellent maneuverability and imaging performance showing great potential in clinical applications.
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Affiliation(s)
- Kaiyan Li
- Southeast University, School of Biological Science and Medical Engineering, Nanjing, Jiangsu, China
| | - Zihan Yang
- Nankai University, Institute of Modern Optics, Tianjin, China
| | - Wenxuan Liang
- Columbia University, Mortimer B. Zuckerman Mind Brain Behavior Institute, New York, United States
| | - Jianwei Shang
- Nankai University, Tianjin Stomatological Hospital, Hospital of Stomatology, Department of Oral Pathology, Tianjin, China
| | - Yanmei Liang
- Nankai University, Institute of Modern Optics, Tianjin, China
- Address all correspondence to Yanmei Liang, E-mail: ; Suiren Wan, E-mail:
| | - Suiren Wan
- Southeast University, School of Biological Science and Medical Engineering, Nanjing, Jiangsu, China
- Address all correspondence to Yanmei Liang, E-mail: ; Suiren Wan, E-mail:
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Oliver AA, Stinson JS, Osborne A, Taylor C, Goldman J, Kirkpatrick SJ. Comparison of optical microscopy and optical coherence tomography as quality assurance methods for evaluating lubricious hydrophilic coatings surrounding catheter shafts. J Biomed Mater Res B Appl Biomater 2020; 108:2538-2545. [PMID: 32078237 DOI: 10.1002/jbm.b.34585] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Revised: 01/13/2020] [Accepted: 02/02/2020] [Indexed: 11/10/2022]
Abstract
Cardiac catheters are a vital tool in medicine due to their widespread use in many minimally invasive procedures. To aid in advancing the catheter within the patient's vasculature, many catheters are coated with a lubricious hydrophilic coating (HPC). Although HPCs benefit patients, their delamination during use is a serious safety concern. Adverse health effects associated with HPC delamination include pulmonary and myocardial embolism, embolic stroke, infarction, and death. In order to improve patient outcomes, more consistent manufacturing methods and improved quality assurance techniques are needed to evaluate HPC medical devices. The present work investigates the efficacy of two novel methods to image and evaluate HPCs post-manufacturing, relative to industry-standard scanning electron microscopy (SEM)-based methods. We have shown that novel evaluation approaches based on optical microscopy (OM) and optical coherence tomography (OCT) are capable of imaging HPC layers and quantifying HPC thickness, saving hours of time relative to SEM sample preparation and imaging. Additionally, the nondestructive nature of OCT avoids damage and alteration to the HPC prior to imaging, leading to more reliable HPC thickness measurements. Overall, the work demonstrated the feasibility and advantages of using OM and OCT to image and measure HPC thickness relative to industry-standard SEM methods.
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Affiliation(s)
- Alexander A Oliver
- Department of Biomedical Engineering, Michigan Technological University, Houghton, Michigan
| | | | | | | | - Jeremy Goldman
- Department of Biomedical Engineering, Michigan Technological University, Houghton, Michigan
| | - Sean J Kirkpatrick
- Department of Biomedical Engineering, Michigan Technological University, Houghton, Michigan
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Almog IF, Chen F, Senova S, Fomenko A, Gondard E, Sacher WD, Lozano AM, Poon JKS. Full-field swept-source optical coherence tomography and neural tissue classification for deep brain imaging. JOURNAL OF BIOPHOTONICS 2020; 13:e201960083. [PMID: 31710771 PMCID: PMC7065632 DOI: 10.1002/jbio.201960083] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2019] [Revised: 10/19/2019] [Accepted: 11/06/2019] [Indexed: 05/28/2023]
Abstract
Optical coherence tomography can differentiate brain regions with intrinsic contrast and at a micron scale resolution. Such a device can be particularly useful as a real-time neurosurgical guidance tool. We present, to our knowledge, the first full-field swept-source optical coherence tomography system operating near a wavelength of 1310 nm. The proof-of-concept system was integrated with an endoscopic probe tip, which is compatible with deep brain stimulation keyhole neurosurgery. Neuroimaging experiments were performed on ex vivo brain tissues and in vivo in rat brains. Using classification algorithms involving texture features and optical attenuation, images were successfully classified into three brain tissue types.
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Affiliation(s)
- Ilan Felts Almog
- Edward S. Rogers Sr. Department of Electrical and Computer EngineeringUniversity of TorontoTorontoOntarioCanada
- Krembil Research InstituteToronto Western HospitalTorontoOntarioCanada
| | - Fu‐Der Chen
- Edward S. Rogers Sr. Department of Electrical and Computer EngineeringUniversity of TorontoTorontoOntarioCanada
- Krembil Research InstituteToronto Western HospitalTorontoOntarioCanada
| | - Suhan Senova
- Krembil Research InstituteToronto Western HospitalTorontoOntarioCanada
- Department of NeurosurgeryCentre Hospitalier Universitaire Henri‐Mondor, APHPCréteilFrance
- INSERM Unit 955, Institut Mondor de Recherche Biomédicale, Université Paris‐EstCréteilFrance
| | - Anton Fomenko
- Krembil Research InstituteToronto Western HospitalTorontoOntarioCanada
| | - Elise Gondard
- Krembil Research InstituteToronto Western HospitalTorontoOntarioCanada
| | - Wesley D. Sacher
- Edward S. Rogers Sr. Department of Electrical and Computer EngineeringUniversity of TorontoTorontoOntarioCanada
- Max Planck Institute of Microstructure PhysicsHalleGermany
| | - Andres M. Lozano
- Krembil Research InstituteToronto Western HospitalTorontoOntarioCanada
- Division of Neurosurgery, Department of SurgeryToronto Western HospitalTorontoOntarioCanada
| | - Joyce K. S. Poon
- Edward S. Rogers Sr. Department of Electrical and Computer EngineeringUniversity of TorontoTorontoOntarioCanada
- Krembil Research InstituteToronto Western HospitalTorontoOntarioCanada
- Max Planck Institute of Microstructure PhysicsHalleGermany
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Che Hamzah J, Daka Q, Azuara-Blanco A. Home monitoring for glaucoma. Eye (Lond) 2019; 34:155-160. [PMID: 31772381 DOI: 10.1038/s41433-019-0669-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2019] [Revised: 09/25/2019] [Accepted: 10/09/2019] [Indexed: 11/09/2022] Open
Abstract
Glaucoma services are overwhelmed and struggling to accommodate current demand. Reducing the need for hospital based services would improve our ability to see those most at risk of vision loss, which could both reduce demand and improve patient outcomes. Digital technologies that provide opportunities for home monitoring of glaucoma progression have potential to contribute to solve these challenges and, potentially, improve glaucoma care. This article will review the literatures of well-established technologies that support home monitoring for glaucoma, specifically home tonometry (with rebound tonometry) and perimetry with Moorfields Motion Displacement Test and Melbourne Rapid Field.
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Affiliation(s)
- Jemaima Che Hamzah
- Department of Ophthalmology, Faculty of Medicine, Universiti Kebangsaan Malaysia, Kuala Lumpur, Malaysia
| | - Qëndresë Daka
- Department of Pathophysiology, Medical Faculty, University of Prishtina, Prishtinë, Kosovo
| | - Augusto Azuara-Blanco
- Centre for Public Health, School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast, Belfast, UK.
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Jelly ET, Steelman ZA, Wax A. Optical coherence tomography through a rigid borescope applied to quantification of articular cartilage thickness in a porcine knee model. OPTICS LETTERS 2019; 44:5590-5593. [PMID: 31730120 PMCID: PMC7558429 DOI: 10.1364/ol.44.005590] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
There exists an unmet need for an optical coherence tomography (OCT) delivery scheme that is simple, robust, and applicable to general surgical applications. To deliver the beam in a narrow form factor, optical borescopes present an attractive potential solution. We present a method for enabling endoscopic delivery of OCT using a handheld rigid borescope adapted to a low-cost OCT engine. The system reduces the distal profile of the scanner, enabling application of the system in otherwise hard-to-access regions. The clinical potential of this design is demonstrated through real-time quantification of articular cartilage thickness, a primary biomarker of joint health during osteoarthritis. This platform has the potential to enable use of OCT for real-time feedback during arthroscopic surgery.
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Affiliation(s)
- Evan T. Jelly
- Department of Biomedical Engineering, Duke University, Durham, NC 27708, USA
- Corresponding author:
| | - Zachary A. Steelman
- Department of Biomedical Engineering, Duke University, Durham, NC 27708, USA
| | - Adam Wax
- Department of Biomedical Engineering, Duke University, Durham, NC 27708, USA
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Measuring light scattering and absorption in corals with Inverse Spectroscopic Optical Coherence Tomography (ISOCT): a new tool for non-invasive monitoring. Sci Rep 2019; 9:14148. [PMID: 31578438 PMCID: PMC6775107 DOI: 10.1038/s41598-019-50658-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Accepted: 09/17/2019] [Indexed: 12/12/2022] Open
Abstract
The success of reef-building corals for >200 million years has been dependent on the mutualistic interaction between the coral host and its photosynthetic endosymbiont dinoflagellates (family Symbiodiniaceae) that supply the coral host with nutrients and energy for growth and calcification. While multiple light scattering in coral tissue and skeleton significantly enhance the light microenvironment for Symbiodiniaceae, the mechanisms of light propagation in tissue and skeleton remain largely unknown due to a lack of technologies to measure the intrinsic optical properties of both compartments in live corals. Here we introduce ISOCT (inverse spectroscopic optical coherence tomography), a non-invasive approach to measure optical properties and three-dimensional morphology of living corals at micron- and nano-length scales, respectively, which are involved in the control of light propagation. ISOCT enables measurements of optical properties in the visible range and thus allows for characterization of the density of light harvesting pigments in coral. We used ISOCT to characterize the optical scattering coefficient (μs) of the coral skeleton and chlorophyll a concentration of live coral tissue. ISOCT further characterized the overall micro- and nano-morphology of live tissue by measuring differences in the sub-micron spatial mass density distribution (D) that vary throughout the tissue and skeleton and give rise to light scattering, and this enabled estimates of the spatial directionality of light scattering, i.e., the anisotropy coefficient, g. Thus, ISOCT enables imaging of coral nanoscale structures and allows for quantifying light scattering and pigment absorption in live corals. ISOCT could thus be developed into an important tool for rapid, non-invasive monitoring of coral health, growth and photophysiology with unprecedented spatial resolution.
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Jones PR, Philippin H, Makupa WU, Burton MJ, Crabb DP. Severity of Visual Field Loss at First Presentation to Glaucoma Clinics in England and Tanzania. Ophthalmic Epidemiol 2019; 27:10-18. [PMID: 31517561 DOI: 10.1080/09286586.2019.1661499] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Purpose: To compare severity of visual field (VF) loss at first presentation in glaucoma clinics in England and Tanzania.Methods: Large archives of VF records from automated perimetry were used to retrospectively examine vision loss at first presentation in glaucoma clinics in Tanzania (N = 1,502) and England (N = 9,264). Mean deviation (MD) of the worse eye at the first hospital visit was used as an estimate of detectable VF loss severity.Results: In Tanzania, 44.7% {CI95%: 42.2, 47.2} of patients presented with severe VF loss (< -20 dB), versus 4.6% {4.1, 5.0} in England. If we consider late presentation to also include cases of advanced loss (-12.01 dB to -20 dB), then the proportion of patients presenting late was 58.1% {55.6, 60.6} and 14.0% {13.3, 14.7}, respectively. The proportion of late presentations was greater in Tanzania at all ages, but the difference was particularly pronounced among working-age adults, with 50.3% {46.9, 53.7} of 18-65-year-olds presenting with advanced or severe VF loss, versus 10.2% {9.3, 11.3} in England. In both countries, men were more likely to present late than women.Conclusions: Late presentation of glaucoma is a problem in England, and an even greater challenge in Tanzania. Possible solutions are discussed, including increased community eye-care, and a more proactive approach to case finding through the use of disruptive new technologies, such as low-cost, portable diagnostic aids.
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Affiliation(s)
- Pete R Jones
- Division of Optometry and Visual Science, School of Health Science, City, University of London, London, England
| | - Heiko Philippin
- International Centre for Eye Health, Faculty of Infectious & Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK.,Department of Ophthalmology, Kilimanjaro Christian Medical Centre, Moshi, Tanzania.,Eye Center, University Hospital Freiburg, Freiburg, Germany
| | - William U Makupa
- Department of Ophthalmology, Kilimanjaro Christian Medical Centre, Moshi, Tanzania
| | - Matthew J Burton
- International Centre for Eye Health, Faculty of Infectious & Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK
| | - David P Crabb
- Division of Optometry and Visual Science, School of Health Science, City, University of London, London, England
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Song G, Chu KK, Kim S, Crose M, Cox B, Jelly ET, Ulrich JN, Wax A. First Clinical Application of Low-Cost OCT. Transl Vis Sci Technol 2019; 8:61. [PMID: 31293815 PMCID: PMC6602122 DOI: 10.1167/tvst.8.3.61] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Accepted: 05/07/2019] [Indexed: 12/17/2022] Open
Abstract
Purpose We present the design of a new low-cost optical coherence tomography (OCT) system and compare its retinal imaging capabilities to a standard commercial system through a clinical study. Methods A spectral-domain OCT system was designed using various cost-reduction techniques to be low-cost, highly portable, and completely stand-alone. Clinical imaging was performed on 120 eyes of 60 patients (60 eyes of normal volunteers and 60 eyes with retinal disease) using both the low-cost OCT and a Heidelberg Engineering Spectralis OCT. Contrast-to-noise ratio (CNR) was measured from resulting images to determine system performance. Results The low-cost OCT system was successfully applied to clinical imaging of the retina. The system offers an axial resolution of 8.0 μm, a lateral resolution of 19.6 μm, and an imaging depth of 2.7 mm for a 6.6-mm field of view in the X and Y directions. Total cost is $5037, a significant size reduction compared to current commercial higher performance systems. Mean CNR value of low-cost OCT images is only 5.6% lower compared to the Heidelberg Spectralis. Conclusions The images captured with the low-cost OCT were of adequate resolution and allowed for clinical diagnostics. It offers comparable performance as a retinal screening tool at a fraction of the cost of current commercial systems. Translational Relevance Low-cost OCT has the potential to increase access to retinal imaging.
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Affiliation(s)
- Ge Song
- Department of Biomedical Engineering, Duke University, Durham, NC, USA
| | - Kengyeh K Chu
- Department of Biomedical Engineering, Duke University, Durham, NC, USA
| | - Sanghoon Kim
- Department of Biomedical Engineering, Duke University, Durham, NC, USA
| | - Michael Crose
- Department of Biomedical Engineering, Duke University, Durham, NC, USA
| | - Brian Cox
- Department of Biomedical Engineering, Duke University, Durham, NC, USA
| | - Evan T Jelly
- Department of Biomedical Engineering, Duke University, Durham, NC, USA
| | - J Niklas Ulrich
- Kittner Eye Center, University of North Carolina, Chapel Hill, NC, USA
| | - Adam Wax
- Department of Biomedical Engineering, Duke University, Durham, NC, USA
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Erfanzadeh M, Zhu Q. Photoacoustic imaging with low-cost sources; A review. PHOTOACOUSTICS 2019; 14:1-11. [PMID: 30923674 PMCID: PMC6423351 DOI: 10.1016/j.pacs.2019.01.004] [Citation(s) in RCA: 60] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2018] [Revised: 12/28/2018] [Accepted: 01/24/2019] [Indexed: 05/04/2023]
Abstract
Benefitting from advantages of optical and ultrasound imaging, photoacoustic imaging (PAI) has demonstrated potentials in a wide range of medical applications. In order to facilitate clinical applications of PAI and encourage its application in low-resource settings, research on low-cost photoacoustic imaging with inexpensive optical sources has gained attention. Here, we review the advances made in photoacoustic imaging with low-cost sources.
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Affiliation(s)
- Mohsen Erfanzadeh
- Department of Biomedical Engineering, University of Connecticut, Storrs, CT 06269, USA
| | - Quing Zhu
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO 63130, USA
- Department of Radiology, Washington University School of Medicine, St. Louis, MO 63110, USA
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Majumder S, Deen MJ. Smartphone Sensors for Health Monitoring and Diagnosis. SENSORS (BASEL, SWITZERLAND) 2019; 19:E2164. [PMID: 31075985 PMCID: PMC6539461 DOI: 10.3390/s19092164] [Citation(s) in RCA: 117] [Impact Index Per Article: 23.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Revised: 04/27/2019] [Accepted: 04/30/2019] [Indexed: 12/29/2022]
Abstract
Over the past few decades, we have witnessed a dramatic rise in life expectancy owing to significant advances in medical science and technology, medicine as well as increased awareness about nutrition, education, and environmental and personal hygiene. Consequently, the elderly population in many countries are expected to rise rapidly in the coming years. A rapidly rising elderly demographics is expected to adversely affect the socioeconomic systems of many nations in terms of costs associated with their healthcare and wellbeing. In addition, diseases related to the cardiovascular system, eye, respiratory system, skin and mental health are widespread globally. However, most of these diseases can be avoided and/or properly managed through continuous monitoring. In order to enable continuous health monitoring as well as to serve growing healthcare needs; affordable, non-invasive and easy-to-use healthcare solutions are critical. The ever-increasing penetration of smartphones, coupled with embedded sensors and modern communication technologies, make it an attractive technology for enabling continuous and remote monitoring of an individual's health and wellbeing with negligible additional costs. In this paper, we present a comprehensive review of the state-of-the-art research and developments in smartphone-sensor based healthcare technologies. A discussion on regulatory policies for medical devices and their implications in smartphone-based healthcare systems is presented. Finally, some future research perspectives and concerns regarding smartphone-based healthcare systems are described.
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Affiliation(s)
- Sumit Majumder
- Department of Electrical and Computer Engineering, McMaster University, Hamilton, ON L8S 4L8, Canada.
| | - M Jamal Deen
- Department of Electrical and Computer Engineering, McMaster University, Hamilton, ON L8S 4L8, Canada.
- School of Biomedical Engineering, McMaster University, Hamilton, ON L8S 4L8, Canada.
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