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Meleppat RK, Valente D, Lee S, Jonnal RS, Doble N, Zawadzki RJ. On-axis full-field swept-source optical coherence tomography for murine retinal imaging. OPTICS LETTERS 2024; 49:4630-4633. [PMID: 39146121 DOI: 10.1364/ol.531116] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2024] [Accepted: 07/19/2024] [Indexed: 08/17/2024]
Abstract
A full-field swept-source optical coherence tomography (FF-SS-OCT) for in vivo murine retinal imaging is demonstrated. The on-axis FF-SS-OCT system was built in a Mach-Zehnder interferometer configuration employing a tunable laser source with an adjustable sweep rate and sweep range in conjunction with a fast 2D-CMOS camera. A large field retinal (coherent) illumination was accomplished using an imaging interface comprised of a short-focal length imaging lens and a contact lens. The magnification between the camera and retina (spatial sampling) was appropriately chosen to record the microscopic structural features of the retina in the image. A pupil stop was employed in the detection path to reject unwanted backscattering from the mouse eye and other sources and limit aberrations distorting the retinal images. In vivo mouse retinal imaging was performed at a sweep rate of 150 Hz to acquire volumes unaffected by the system vibrations, which predominated at lower frequencies. Operating the FF-SS-OCT at this speed yielded an effective axial scan rate of 20 million A-scans/s and a field of view of 820 × 410 µm (24.12° × 12.06°). High-quality retinal B-scans and enface images of the retina were obtained with the SS-FF-OCT, revealing all major retinal layers and vascular plexuses.
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2
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Ke M, Kumar A, Ansbæk TE, Leitgeb RA. Wide Dynamic Range Digital Aberration Measurement and Fast Anterior-Segment OCT Imaging †. SENSORS (BASEL, SWITZERLAND) 2024; 24:5161. [PMID: 39204856 PMCID: PMC11359324 DOI: 10.3390/s24165161] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/22/2024] [Revised: 07/26/2024] [Accepted: 08/08/2024] [Indexed: 09/04/2024]
Abstract
Ocular aberrometry with a wide dynamic range for assessing vision performance and anterior segment imaging that provides anatomical details of the eye are both essential for vision research and clinical applications. Defocus error is a major limitation of digital wavefront aberrometry (DWA), as the blurring of the detected point spread function (PSF) significantly reduces the signal-to-noise ratio (SNR) beyond the ±3 D range. With the aid of Badal-like precompensation of defocus, the dynamic defocus range of the captured aberrated PSFs can be effectively extended. We demonstrate a dual-modality MHz VCSEL-based swept-source OCT (SS-OCT) system with easy switching between DWA and OCT imaging modes. The system is capable of measuring aberrations with defocus dynamic range of 20 D as well as providing fast anatomical imaging of the anterior segment at an A-scan rate of 1.6 MHz.
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Affiliation(s)
- Mengyuan Ke
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, 1090 Wien, Austria;
| | | | | | - Rainer A. Leitgeb
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, 1090 Wien, Austria;
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3
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Viqar M, Madjarova V, Stoykova E, Nikolov D, Khan E, Hong K. Transfer Learning-Based Approach for Thickness Estimation on Optical Coherence Tomography of Varicose Veins. MICROMACHINES 2024; 15:902. [PMID: 39064413 PMCID: PMC11279361 DOI: 10.3390/mi15070902] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2024] [Revised: 07/06/2024] [Accepted: 07/09/2024] [Indexed: 07/28/2024]
Abstract
In-depth mechanical characterization of veins is required for promising innovations of venous substitutes and for better understanding of venous diseases. Two important physical parameters of veins are shape and thickness, which are quite challenging in soft tissues. Here, we propose the method TREE (TransfeR learning-based approach for thicknEss Estimation) to predict both the segmentation map and thickness value of the veins. This model incorporates one encoder and two decoders which are trained in a special manner to facilitate transfer learning. First, an encoder-decoder pair is trained to predict segmentation maps, then this pre-trained encoder with frozen weights is paired with a second decoder that is specifically trained to predict thickness maps. This leverages the global information gained from the segmentation model to facilitate the precise learning of the thickness model. Additionally, to improve the performance we introduce a sensitive pattern detector (SPD) module which further guides the network by extracting semantic details. The swept-source optical coherence tomography (SS-OCT) is the imaging modality for saphenous varicose vein extracted from the diseased patients. To demonstrate the performance of the model, we calculated the segmentation accuracy-0.993, mean square error in thickness (pixels) estimation-2.409 and both these metrics stand out when compared with the state-of-art methods.
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Affiliation(s)
- Maryam Viqar
- Institute of Optical Materials and Technologies, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria;
- Faculty of Information Technology and Communication Sciences, Tampere University, 33720 Tampere, Finland
| | - Violeta Madjarova
- Institute of Optical Materials and Technologies, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria;
| | - Elena Stoykova
- Institute of Optical Materials and Technologies, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria;
| | - Dimitar Nikolov
- Department of Vascular Surgery, Sofiamed University Hospital, 1797 Sofia, Bulgaria;
| | - Ekram Khan
- Department of Electronics Engineering, Aligarh Muslim University, Aligarh 202001, India;
| | - Keehoon Hong
- Electronics and Telecommunications Research Institute, 218 Gajeong-ro, Yuseong-gu, Daejeon 34129, Republic of Korea;
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4
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Ambrósio R, Esporcatte LPG, de Carvalho KA, Salomão MQ, Pereira-Souza AL, Lopes BT, Machado AP, Marschall S. Combined Rotating Ultra-High-Resolution Spectral Domain OCT and Scheimpflug Imaging for In Vivo Corneal Optical Biopsy. Diagnostics (Basel) 2024; 14:1455. [PMID: 39001345 PMCID: PMC11241082 DOI: 10.3390/diagnostics14131455] [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: 04/30/2024] [Revised: 06/24/2024] [Accepted: 06/27/2024] [Indexed: 07/16/2024] Open
Abstract
PURPOSE This article introduces the Pentacam® Cornea OCT (optical coherence tomography). This advanced corneal imaging system combines rotating ultra-high-resolution spectral domain OCT with sub- 2-micron axial resolution and Scheimpflug photography. The purpose of this study is to present the first experience with the instrument and its potential for corneal diagnostics, including optical biopsy. METHODS In this prospective study, the Pentacam® Cornea OCT was used to image the corneas of seven patients. The novel wide-angle pericentric scan system enables optimal OCT imaging performance for the corneal layer structure over the entire width of the cornea, including the limbal regions. A detailed analysis of the resulting images assessed the synergism between the OCT and Scheimpflug photography. RESULTS The Pentacam® Cornea OCT demonstrated significantly improved image resolution and ability to individualize corneal layers with high quality. There is a synergism between the OCT high-definition signal to individualize details on the cornea and Scheimpflug photography to detect and quantify corneal scattering. The noncontact exam was proven safe, user-friendly, and effective for enabling optical biopsy. CONCLUSIONS Pentacam® Cornea OCT is an advancement in corneal imaging technology. The ultra-high-resolution spectral domain OCT and Scheimpflug photography provide unprecedented detail and resolution, enabling optical biopsy and improving the understanding of corneal pathology. Further studies are necessary to compare and analyze the tomographic reconstructions of the cornea with the different wavelengths, which may provide helpful information for diagnosing and managing corneal diseases.
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Affiliation(s)
- Renato Ambrósio
- Rio de Janeiro Corneal Tomography and Biomechanics Study Group, Rio de Janeiro 20520-050, Brazil
- Instituto de Olhos Renato Ambrósio, Rio de Janeiro 20520-050, Brazil
- Department of Ophthalmology, Federal University of São Paulo, São Paulo 04021-001, Brazil
- Brazilian Artificial Intelligence Networking in Medicine-BrAIN, Rio de Janeiro 20520-050, Brazil
- Brazilian Artificial Intelligence Networking in Medicine-BrAIN, Maceió 57072-900, Brazil
- Department of Ophthalmology, Federal University the State of Rio de Janeiro (UNIRIO), Rio de Janeiro 20520-050, Brazil
| | - Louise Pellegrino G Esporcatte
- Rio de Janeiro Corneal Tomography and Biomechanics Study Group, Rio de Janeiro 20520-050, Brazil
- Instituto de Olhos Renato Ambrósio, Rio de Janeiro 20520-050, Brazil
- Department of Ophthalmology, Federal University of São Paulo, São Paulo 04021-001, Brazil
| | - Karolyna Andrade de Carvalho
- Rio de Janeiro Corneal Tomography and Biomechanics Study Group, Rio de Janeiro 20520-050, Brazil
- Instituto de Olhos Renato Ambrósio, Rio de Janeiro 20520-050, Brazil
| | - Marcella Q Salomão
- Rio de Janeiro Corneal Tomography and Biomechanics Study Group, Rio de Janeiro 20520-050, Brazil
- Instituto de Olhos Renato Ambrósio, Rio de Janeiro 20520-050, Brazil
- Department of Ophthalmology, Federal University of São Paulo, São Paulo 04021-001, Brazil
- Instituto Benjamin Constant, Rio de Janeiro 22290-255, Brazil
| | | | - Bernardo T Lopes
- Rio de Janeiro Corneal Tomography and Biomechanics Study Group, Rio de Janeiro 20520-050, Brazil
- School of Engineering, University of Liverpool, Liverpool L69 3GH, UK
| | - Aydano P Machado
- Department of Ophthalmology, Federal University of São Paulo, São Paulo 04021-001, Brazil
- Brazilian Artificial Intelligence Networking in Medicine-BrAIN, Rio de Janeiro 20520-050, Brazil
- Brazilian Artificial Intelligence Networking in Medicine-BrAIN, Maceió 57072-900, Brazil
- Computing Institute, Federal University of Alagoas, Maceió 57072-900, Brazil
| | - Sebastian Marschall
- Department of Research & Development, OCULUS, Optikgeräte GmbH, 35578 Wetzlar, Germany
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Chen K, Swanson S, Bizheva K. Line-field dynamic optical coherence tomography platform for volumetric assessment of biological tissues. BIOMEDICAL OPTICS EXPRESS 2024; 15:4162-4175. [PMID: 39022542 PMCID: PMC11249681 DOI: 10.1364/boe.527797] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/17/2024] [Revised: 05/31/2024] [Accepted: 05/31/2024] [Indexed: 07/20/2024]
Abstract
Dynamic optical coherence tomography (dOCT) utilizes time-dependent signal intensity fluctuations to enhance contrast in OCT images and indirectly probe physiological processes in cells. Majority of the dOCT studies published so far are based on acquisition of 2D images (B-scans or C-scans) by utilizing point-scanning Fourier domain (spectral or swept-source) OCT or full-field OCT respectively, primarily due to limitations in the image acquisition rate. Here we introduce a novel, high-speed spectral domain line-field dOCT (SD-LF-dOCT) system and image acquisition protocols designed for fast, volumetric dOCT imaging of biological tissues. The imaging probe is based on an exchangeable afocal lens pair that enables selection of combinations of transverse resolution (from 1.1 µm to 6.4 µm) and FOV (from 250 × 250 µm2 to 1.4 × 1.4 mm2), suitable for different biomedical applications. The system offers axial resolution of ∼ 1.9 µm in biological tissue, assuming an average refractive index of 1.38. Maximum sensitivity of 90.5 dB is achieved for 3.5 mW optical imaging power at the tissue surface and maximum camera acquisition rate of 2,000 fps. Volumetric dOCT images acquired with the SD-LF-dOCT system from plant tissue (cucumber), animal tissue (mouse liver) and human prostate carcinoma spheroids allow for volumetric visualization of the tissues' cellular and sub-cellular structures and assessment of cellular motility.
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Affiliation(s)
- Keyu Chen
- Department of Physics and Astronomy, University of Waterloo, Waterloo N2 L 3G1, ON, Canada
| | - Stephanie Swanson
- Department of Physics and Astronomy, University of Waterloo, Waterloo N2 L 3G1, ON, Canada
| | - Kostadinka Bizheva
- Department of Physics and Astronomy, University of Waterloo, Waterloo N2 L 3G1, ON, Canada
- School of Optometry and Vision Sciences, University of Waterloo, Waterloo, ON, Canada
- System Design Engineering Department, University of Waterloo, Waterloo, ON, Canada
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6
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Schulte B, Göb M, Singh AP, Lotz S, Draxinger W, Heimke M, Pieper M, Heinze T, Wedel T, Rahlves M, Huber R, Ellrichmann M. High-resolution rectoscopy using MHz optical coherence tomography: a step towards real time 3D endoscopy. Sci Rep 2024; 14:4672. [PMID: 38409328 PMCID: PMC10897148 DOI: 10.1038/s41598-024-55338-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2023] [Accepted: 02/22/2024] [Indexed: 02/28/2024] Open
Abstract
Colonoscopy and endoscopic ultrasound play pivotal roles in the assessment of rectal diseases, especially rectal cancer and inflammatory bowel diseases. Optical coherence tomography (OCT) offers a superior depth resolution, which is a critical factor for individualizing the therapeutic concept and evaluating the therapy response. We developed two distinct rectoscope prototypes, which were integrated into a 1300 nm MHz-OCT system constructed at our facility. The rapid rotation of the distal scanning probe at 40,000 revolutions per minute facilitates a 667 Hz OCT frame rate, enabling real-time endoscopic imaging of large areas. The performance of these OCT-rectoscopes was assessed in an ex vivo porcine colon and a post mortem human in-situ colon. The OCT-rectoscope consistently distinguished various layers of the intestinal wall, identified gut-associated lymphatic tissue, and visualized a rectal polyp during the imaging procedure with 3D-reconstruction in real time. Subsequent histological examination confirmed these findings. The body donor was preserved using an ethanol-glycerol-lysoformin-based technique for true-to-life tissue consistency. We could demonstrate that the novel MHZ-OCT-rectoscope effectively discriminates rectal wall layers and crucial tissue characteristics in a post mortem human colon in-situ. This real-time-3D-OCT holds promise as a valuable future diagnostic tool for assessing disease state and therapy response on-site in rectal diseases.
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Affiliation(s)
- Berenice Schulte
- Interdisciplinary Endoscopy, Medical Department 1, University Hospital Schleswig-Holstein, Campus Kiel, Kiel, Germany
| | - Madita Göb
- Institute of Biomedical Optics, University of Luebeck, Luebeck, Germany
| | | | - Simon Lotz
- Institute of Biomedical Optics, University of Luebeck, Luebeck, Germany
| | | | - Marvin Heimke
- Center of Clinical Anatomy, Institute of Anatomy, Christian-Albrechts University Kiel, Kiel, Germany
| | - Mario Pieper
- Institute of Anatomy, University of Luebeck, Luebeck, Germany
- Airway Research Center North (ARCN), German Center for Lung Research (DZL), Luebeck, Germany
| | - Tillmann Heinze
- Center of Clinical Anatomy, Institute of Anatomy, Christian-Albrechts University Kiel, Kiel, Germany
| | - Thilo Wedel
- Center of Clinical Anatomy, Institute of Anatomy, Christian-Albrechts University Kiel, Kiel, Germany
| | - Maik Rahlves
- Institute of Biomedical Optics, University of Luebeck, Luebeck, Germany
| | - Robert Huber
- Institute of Biomedical Optics, University of Luebeck, Luebeck, Germany
| | - Mark Ellrichmann
- Interdisciplinary Endoscopy, Medical Department 1, University Hospital Schleswig-Holstein, Campus Kiel, Kiel, Germany.
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7
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Singh AP, Göb M, Ahrens M, Eixmann T, Schulte B, Schulz-Hildebrandt H, Hüttmann G, Ellrichmann M, Huber R, Rahlves M. Virtual Hall sensor triggered multi-MHz endoscopic OCT imaging for stable real-time visualization. OPTICS EXPRESS 2024; 32:5809-5825. [PMID: 38439298 DOI: 10.1364/oe.514636] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2023] [Accepted: 01/18/2024] [Indexed: 03/06/2024]
Abstract
Circumferential scanning in endoscopic imaging is crucial across various disciplines, and optical coherence tomography (OCT) is often the preferred choice due to its high-speed, high-resolution, and micron-scale imaging capabilities. Moreover, real-time and high-speed 3D endoscopy is a pivotal technology for medical screening and precise surgical guidance, among other applications. However, challenges such as image jitter and non-uniform rotational distortion (NURD) are persistent obstacles that hinder real-time visualization during high-speed OCT procedures. To address this issue, we developed an innovative, low-cost endoscope that employs a brushless DC motor for scanning, and a sensorless technique for triggering and synchronizing OCT imaging with the scanning motor. This sensorless approach uses the motor's electrical feedback (back electromotive force, BEMF) as a virtual Hall sensor to initiate OCT image acquisition and synchronize it with a Fourier Domain Mode-Locked (FDML)-based Megahertz OCT system. Notably, the implementation of BEMF-triggered OCT has led to a substantial reduction in image jitter and NURD (<4 mrad), thereby opening up a new window for real-time visualization capabilities. This approach suggests potential benefits across various applications, aiming to provide a more accurate, deployable, and cost-effective solution. Subsequent studies can explore the adaptability of this system to specific clinical scenarios and its performance under practical endoscopic conditions.
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8
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Burhan S, Detrez N, Rewerts K, Strenge P, Buschschlüter S, Kren J, Hagel C, Bonsanto MM, Brinkmann R, Huber R. Phase unwrapping for MHz optical coherence elastography and application to brain tumor tissue. BIOMEDICAL OPTICS EXPRESS 2024; 15:1038-1058. [PMID: 38404346 PMCID: PMC10890849 DOI: 10.1364/boe.510020] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/24/2023] [Revised: 12/15/2023] [Accepted: 12/17/2023] [Indexed: 02/27/2024]
Abstract
During neuro-oncologic surgery, phase-sensitive optical coherence elastography (OCE) can be valuable for distinguishing between healthy and diseased tissue. However, the phase unwrapping process required to retrieve the original phase signal is a challenging and critical task. To address this issue, we demonstrate a one-dimensional unwrapping algorithm that recovers the phase signal from a 3.2 MHz OCE system. With a processing time of approximately 0.11 s per frame on the GPU, multiple 2π wraps are detected and corrected. By utilizing this approach, exact and reproducible information on tissue deformation can be obtained with pixel accuracy over the entire acquisition time. Measurements of brain tumor-mimicking phantoms and human ex vivo brain tumor samples verified the algorithm's reliability. The tissue samples were subjected to a 200 ms short air pulse. A correlation with histological findings confirmed the algorithm's dependability.
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Affiliation(s)
- Sazgar Burhan
- Institut für Biomedizinische Optik, Universität zu Lübeck, Peter-Monnik-Weg 4, 23562 Lübeck, Germany
| | - Nicolas Detrez
- Medizinisches Laserzentrum Lübeck GmbH, Peter-Monnik-Weg 4, 23562 Lübeck, Germany
| | - Katharina Rewerts
- Institut für Biomedizinische Optik, Universität zu Lübeck, Peter-Monnik-Weg 4, 23562 Lübeck, Germany
| | - Paul Strenge
- Medizinisches Laserzentrum Lübeck GmbH, Peter-Monnik-Weg 4, 23562 Lübeck, Germany
| | | | - Jessica Kren
- Klinik für Neurochirurgie, Universitätsklinikum Schleswig-Holstein, Campus Lübeck, Ratzeburger Allee 160, 23562 Lübeck, Germany
| | - Christian Hagel
- Institut für Neuropathologie, Universitätsklinikum Hamburg-Eppendorf, Martinistrasse 52, 20251 Hamburg, Germany
| | - Matteo Mario Bonsanto
- Institut für Neuropathologie, Universitätsklinikum Hamburg-Eppendorf, Martinistrasse 52, 20251 Hamburg, Germany
| | - Ralf Brinkmann
- Institut für Biomedizinische Optik, Universität zu Lübeck, Peter-Monnik-Weg 4, 23562 Lübeck, Germany
- Medizinisches Laserzentrum Lübeck GmbH, Peter-Monnik-Weg 4, 23562 Lübeck, Germany
| | - Robert Huber
- Institut für Biomedizinische Optik, Universität zu Lübeck, Peter-Monnik-Weg 4, 23562 Lübeck, Germany
- Medizinisches Laserzentrum Lübeck GmbH, Peter-Monnik-Weg 4, 23562 Lübeck, Germany
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9
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Klufts M, Jiménez AM, Lotz S, Bashir MA, Pfeiffer T, Mlynek A, Wieser W, Chamorovskiy A, Bradu A, Podoleanu A, Huber R. 828 kHz retinal imaging with an 840 nm Fourier domain mode locked laser. BIOMEDICAL OPTICS EXPRESS 2023; 14:6493-6508. [PMID: 38420314 PMCID: PMC10898573 DOI: 10.1364/boe.504302] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Revised: 11/08/2023] [Accepted: 11/16/2023] [Indexed: 03/02/2024]
Abstract
This paper presents a Fourier domain mode locked (FDML) laser centered around 840 nm. It features a bidirectional sweep repetition rate of 828 kHz and a spectral bandwidth of 40 nm. An axial resolution of ∼9.9 µm in water and a 1.4 cm sensitivity roll-off are achieved. Utilizing a complex master-slave (CMS) recalibration method and due to a sufficiently high sensitivity of 84.6 dB, retinal layers of the human eye in-vivo can be resolved during optical coherence tomography (OCT) examination. The developed FDML laser enables acquisition rates of 3D-volumes with a size of 200 × 100 × 256 voxels in under 100 milliseconds. Detailed information on the FDML implementation, its challenging design tasks, and OCT images obtained with the laser are presented in this paper.
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Affiliation(s)
- Marie Klufts
- Institute of Biomedical Optics, University of Lübeck, Lübeck 23562, Germany
| | | | - Simon Lotz
- Institute of Biomedical Optics, University of Lübeck, Lübeck 23562, Germany
| | | | | | | | | | | | - Adrian Bradu
- School of Physical Sciences, University of Kent, Canterbury CT2 7NH, United Kingdom
| | - Adrian Podoleanu
- School of Physical Sciences, University of Kent, Canterbury CT2 7NH, United Kingdom
| | - Robert Huber
- Institute of Biomedical Optics, University of Lübeck, Lübeck 23562, Germany
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10
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Wolfgang M, Kern A, Deng S, Stranzinger S, Liu M, Drexler W, Leitgeb R, Haindl R. Ultra-high-resolution optical coherence tomography for the investigation of thin multilayered pharmaceutical coatings. Int J Pharm 2023; 643:123096. [PMID: 37268027 DOI: 10.1016/j.ijpharm.2023.123096] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Revised: 05/25/2023] [Accepted: 05/26/2023] [Indexed: 06/04/2023]
Abstract
Optical Coherence Tomography (OCT) has recently gained attention as a promising technology for in-line monitoring of pharmaceutical film-coating processes for (single-layered) tablet coatings and end-point detection with commercial systems. An increasing interest in the investigation of multiparticulate dosage forms with mostly multi-layered coatings below 20 µm final film thickness demands advancement in OCT technology for pharmaceutical imaging. We present an ultra-high-resolution (UHR-) OCT and investigate its performance based on three different multiparticulate dosage forms with different layer structures (one single-layered, two multi-layered) with layer thicknesses in a range from 5 to 50 µm. The achieved system resolution of 2.4 µm (axial) and 3.4 µm (lateral, both in air) enables the assessment of defects, film thickness variability and morphological features within the coating, previously unattainable using OCT. Despite the high transverse resolution, the provided depth of field was found sufficient to reach the core region of all dosage forms under test. We further demonstrate an automated segmentation and evaluation of UHR-OCT images for coating thicknesses, where human experts struggle using today's standard OCT systems.
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Affiliation(s)
| | - Alice Kern
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | - Shiyu Deng
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | | | - Mengyang Liu
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria; Singapore Eye Research Institute, Singapore National Eye Centre, Singapore, Singapore
| | - Wolfgang Drexler
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | - Rainer Leitgeb
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria; Christian Doppler Laboratory OPTRAMED, Medical University of Vienna, Vienna, Austria.
| | - Richard Haindl
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria; School of Chemistry, Chemical Engineering and Biotechnology, Nanyang Technological University, 62 Nanyang Drive, Singapore, Singapore; Singapore Eye Research Institute, Singapore National Eye Centre, Singapore, Singapore
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11
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Feng X, Li GY, Yun SH. Ultra-wideband optical coherence elastography from acoustic to ultrasonic frequencies. Nat Commun 2023; 14:4949. [PMID: 37587178 PMCID: PMC10432526 DOI: 10.1038/s41467-023-40625-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Accepted: 07/31/2023] [Indexed: 08/18/2023] Open
Abstract
Visualizing viscoelastic waves in materials and tissues through noninvasive imaging is valuable for analyzing their mechanical properties and detecting internal anomalies. However, traditional elastography techniques have been limited by a maximum wave frequency below 1-10 kHz, which hampers temporal and spatial resolution. Here, we introduce an optical coherence elastography technique that overcomes the limitation by extending the frequency range to MHz. Our system can measure the stiffness of hard materials including bones and extract viscoelastic shear moduli for polymers and hydrogels in conventionally inaccessible ranges between 100 Hz and 1 MHz. The dispersion of Rayleigh surface waves across the ultrawide band allowed us to profile depth-dependent shear modulus in cartilages ex vivo and human skin in vivo with sub-mm anatomical resolution. This technique holds immense potential as a noninvasive measurement tool for material sciences, tissue engineering, and medical diagnostics.
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Affiliation(s)
- Xu Feng
- Harvard Medical School and Wellman Center for Photomedicine, Massachusetts General Hospital, 50 Blossom St. BAR-8, Boston, MA, 02114, USA
| | - Guo-Yang Li
- Harvard Medical School and Wellman Center for Photomedicine, Massachusetts General Hospital, 50 Blossom St. BAR-8, Boston, MA, 02114, USA
| | - Seok-Hyun Yun
- Harvard Medical School and Wellman Center for Photomedicine, Massachusetts General Hospital, 50 Blossom St. BAR-8, Boston, MA, 02114, USA.
- Harvard-MIT Health Sciences and Technology, Cambridge, MA, 02139, USA.
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12
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Wang C, Yin Z, He B, Chen Z, Hu Z, Shi Y, Zhang X, Zhang N, Jing L, Wang G, Xue P. Polarization-isolated stretched-pulse mode-locked swept laser for 10.3-MHz A-line rate optical coherence tomography. OPTICS LETTERS 2023; 48:4025-4028. [PMID: 37527109 DOI: 10.1364/ol.495786] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2023] [Accepted: 07/10/2023] [Indexed: 08/03/2023]
Abstract
Stretched-pulse mode-locked (SPML) lasing based on a chirped fiber Bragg grating (CFBG) has proven to be a powerful method to generate wavelength-swept lasers at speeds of tens of megahertz. However, light transmitted through the CFBG may lead to undesirable laser oscillation that disrupts the mechanism of the laser active mode locking in the theta ring cavity. In this Letter, we demonstrate a simple and low-cost approach to suppress the transmitted light and achieve an effective duty cycle of ∼100% with only one CFBG and no need for intra-cavity semiconductor optical amplifier (SOA) modulation, extra-cavity optical buffering, and post amplification. By utilizing polarization isolation of the bi-directional CFBG, a swept laser centered at 1305 nm, with repetition rate of 10.3 MHz, optical power of 84 mW, and 3 dB bandwidth of 109 nm, is demonstrated. Ultrahigh speed 3D optical coherence tomography (OCT) structural imaging of a human palm in vivo using this swept laser is also demonstrated. We believe that this ultrahigh speed swept laser will greatly promote the OCT technique for industrial and biomedical applications.
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13
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Asghari H. Visible wavelength time-stretch optical coherence tomography. OPTICS EXPRESS 2023; 31:24085-24096. [PMID: 37475244 DOI: 10.1364/oe.492753] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Accepted: 06/21/2023] [Indexed: 07/22/2023]
Abstract
Visible light optical coherence tomography (OCT) is an emerging non-invasive imaging modality that offers new opportunities for anatomical and functional imaging of biological tissues. Time-stretch dispersive Fourier transform, also known as photonic time-stretch, is an all-optical processing method that enables real-time Fourier transformation of ultrafast optical signals and allows for OCT at high A-scan rates. In this work, a working prototype of a photonic time-stretch OCT (TS-OCT) method in the visible wavelength region is proposed and experimentally demonstrated. The proposed visible-light TS-OCT system achieves unprecedented throughput of 100 giga voxels/second and OCT volume rate of 4,000 volumes/second and can be used to expand the range of applications of TS-OCT systems.
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14
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Nienhaus J, Matten P, Britten A, Scherer J, Höck E, Freytag A, Drexler W, Leitgeb RA, Schlegl T, Schmoll T. Live 4D-OCT denoising with self-supervised deep learning. Sci Rep 2023; 13:5760. [PMID: 37031338 PMCID: PMC10082772 DOI: 10.1038/s41598-023-32695-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Accepted: 03/31/2023] [Indexed: 04/10/2023] Open
Abstract
By providing three-dimensional visualization of tissues and instruments at high resolution, live volumetric optical coherence tomography (4D-OCT) has the potential to revolutionize ophthalmic surgery. However, the necessary imaging speed is accompanied by increased noise levels. A high data rate and the requirement for minimal latency impose major limitations for real-time noise reduction. In this work, we propose a low complexity neural network for denoising, directly incorporated into the image reconstruction pipeline of a microscope-integrated 4D-OCT prototype with an A-scan rate of 1.2 MHz. For this purpose, we trained a blind-spot network on unpaired OCT images using a self-supervised learning approach. With an optimized U-Net, only a few milliseconds of additional latency were introduced. Simultaneously, these architectural adaptations improved the numerical denoising performance compared to the basic setup, outperforming non-local filtering algorithms. Layers and edges of anatomical structures in B-scans were better preserved than with Gaussian filtering despite comparable processing time. By comparing scenes with and without denoising employed, we show that neural networks can be used to improve visual appearance of volumetric renderings in real time. Enhancing the rendering quality is an important step for the clinical acceptance and translation of 4D-OCT as an intra-surgical guidance tool.
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Affiliation(s)
- Jonas Nienhaus
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria.
| | - Philipp Matten
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | - Anja Britten
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | - Julius Scherer
- 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
| | - Rainer A Leitgeb
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | - Thomas Schlegl
- 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, USA
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15
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Niederleithner M, de Sisternes L, Stino H, Sedova A, Schlegl T, Bagherinia H, Britten A, Matten P, Schmidt-Erfurth U, Pollreisz A, Drexler W, Leitgeb RA, Schmoll T. Ultra-Widefield OCT Angiography. IEEE TRANSACTIONS ON MEDICAL IMAGING 2023; 42:1009-1020. [PMID: 36383595 DOI: 10.1109/tmi.2022.3222638] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Optical Coherence Tomography Angiography (OCTA), a functional extension of OCT, has the potential to replace most invasive fluorescein angiography (FA) exams in ophthalmology. So far, OCTA's field of view is however still lacking behind fluorescence fundus photography techniques. This is problematic, because many retinal diseases manifest at an early stage by changes of the peripheral retinal capillary network. It is therefore desirable to expand OCTA's field of view to match that of ultra-widefield fundus cameras. We present a custom developed clinical high-speed swept-source OCT (SS-OCT) system operating at an acquisition rate 8-16 times faster than today's state-of-the-art commercially available OCTA devices. Its speed allows us to capture ultra-wide fields of view of up to 90 degrees with an unprecedented sampling density and hence extraordinary resolution by merging two single shot scans with 60 degrees in diameter. To further enhance the visual appearance of the angiograms, we developed for the first time a three-dimensional deep learning based algorithm for denoising volumetric OCTA data sets. We showcase its imaging performance and clinical usability by presenting images of patients suffering from diabetic retinopathy.
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16
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Koutsiaris AG, Batis V, Liakopoulou G, Tachmitzi SV, Detorakis ET, Tsironi EE. Optical Coherence Tomography Angiography (OCTA) of the eye: A review on basic principles, advantages, disadvantages and device specifications. Clin Hemorheol Microcirc 2022; 83:247-271. [PMID: 36502308 DOI: 10.3233/ch-221634] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Optical Coherence Tomography Angiography (OCTA) is a relatively new imaging technique in ophthalmology for the visualization of the retinal microcirculation and other tissues of the human eye. This review paper aims to describe the basic definitions and principles of OCT and OCTA in the most straightforward possible language without complex mathematical and engineering analysis. This is done to help health professionals of various disciplines improve their understanding of OCTA and design further clinical research more efficiently. First, the basic technical principles of OCT and OCTA and related terminology are described. Then, a list of OCTA advantages and disadvantages, with a special reference to blood flow quantification limitations. Finally, an updated list of the basic hardware and software specifications of some of the commercially available OCTA devices is presented.
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Affiliation(s)
- Aristotle G. Koutsiaris
- Medical Informatics Laboratory, Faculty of Medicine, School of Health Sciences, University of Thessaly, Biopolis, Larissa, Greece
| | - Vasilios Batis
- Jules Gonin Eye Hospital Lausanne, Switzerland
- Department of Ophthalmology, University Hospital of Heraklion, Crete, Greece
| | - Georgia Liakopoulou
- Medical Informatics Laboratory, Faculty of Medicine, School of Health Sciences, University of Thessaly, Biopolis, Larissa, Greece
| | | | | | - Evangelia E. Tsironi
- Department of Ophthalmology, University Hospital of Larissa, Faculty of Medicine, School of Health Sciences, University of Thessaly, Larissa, Greece
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17
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Xu L, Zhang L, Wang K, Liu C, Zhang C, Zhang X. Dual-comb based time-stretch optical coherence tomography for large and segmental imaging depth. OPTICS EXPRESS 2022; 30:39014-39024. [PMID: 36258452 DOI: 10.1364/oe.469795] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Accepted: 09/29/2022] [Indexed: 06/16/2023]
Abstract
Optical coherence tomography based on time-stretch enables high frame rate and high-resolution imaging for the inertia-free wavelength-swept mechanism. The fundamental obstacle is still the acquisition bandwidth's restriction on imaging depth. By introducing dual-comb with slightly different repetition rates, the induced Vernier effect is found to be capable of relieving the problem. In our work, a dual-comb based time-stretch optical coherence tomography is proposed and experimentally demonstrated, achieving a 1.5-m imaging depth and 200-kHz A-scan rate. Moreover, about a 33.4-µm resolution and 25-µm accuracy are achieved. In addition, by adjusting the frequency detuning of the dual-comb, the A-scan rate can be further boosted to video-rate imaging. With enlarged imaging depth, this scheme is promising for a wide range of applications, including light detection and ranging.
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18
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Image enhancement of wide-field retinal optical coherence tomography angiography by super-resolution angiogram reconstruction generative adversarial network. Biomed Signal Process Control 2022. [DOI: 10.1016/j.bspc.2022.103957] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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19
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Strenge P, Lange B, Draxinger W, Grill C, Danicke V, Theisen-Kunde D, Hagel C, Spahr-Hess S, Bonsanto MM, Handels H, Huber R, Brinkmann R. Differentiation of different stages of brain tumor infiltration using optical coherence tomography: Comparison of two systems and histology. Front Oncol 2022; 12:896060. [PMID: 36110932 PMCID: PMC9468861 DOI: 10.3389/fonc.2022.896060] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Accepted: 07/21/2022] [Indexed: 11/14/2022] Open
Abstract
The discrimination of tumor-infiltrated tissue from non-tumorous brain tissue during neurosurgical tumor excision is a major challenge in neurosurgery. It is critical to achieve full tumor removal since it directly correlates with the survival rate of the patient. Optical coherence tomography (OCT) might be an additional imaging method in the field of neurosurgery that enables the classification of different levels of tumor infiltration and non-tumorous tissue. This work investigated two OCT systems with different imaging wavelengths (930 nm/1310 nm) and different resolutions (axial (air): 4.9 μm/16 μm, lateral: 5.2 μm/22 μm) in their ability to identify different levels of tumor infiltration based on freshly excised ex vivo brain samples. A convolutional neural network was used for the classification. For both systems, the neural network could achieve classification accuracies above 91% for discriminating between healthy white matter and highly tumor infiltrated white matter (tumor infiltration >60%) .This work shows that both OCT systems with different optical properties achieve similar results regarding the identification of different stages of brain tumor infiltration.
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Affiliation(s)
- Paul Strenge
- Medical Laser Center Luebeck, Luebeck, Germany
- *Correspondence: Paul Strenge,
| | | | | | - Christin Grill
- Institute of Biomedical Optics, University of Luebeck, Luebeck, Germany
| | | | | | - Christian Hagel
- Institute for Neuropathology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Sonja Spahr-Hess
- Department of Neurosurgery, University Medical Center Schleswig-Holstein, Luebeck, Germany
| | - Matteo M. Bonsanto
- Department of Neurosurgery, University Medical Center Schleswig-Holstein, Luebeck, Germany
| | - Heinz Handels
- Institute of Medical Informatics, University of Luebeck, Luebeck, Germany
- German Research Center for Artificial Intelligence, Luebeck, Germany
| | - Robert Huber
- Institute of Biomedical Optics, University of Luebeck, Luebeck, Germany
| | - Ralf Brinkmann
- Medical Laser Center Luebeck, Luebeck, Germany
- Institute of Biomedical Optics, University of Luebeck, Luebeck, Germany
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20
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Xue W, Ogien J, Bulkin P, Coutrot AL, Dubois A. Mirau-based line-field confocal optical coherence tomography for three-dimensional high-resolution skin imaging. JOURNAL OF BIOMEDICAL OPTICS 2022; 27:JBO-220012GR. [PMID: 35962466 PMCID: PMC9374567 DOI: 10.1117/1.jbo.27.8.086002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Accepted: 07/29/2022] [Indexed: 06/15/2023]
Abstract
SIGNIFICANCE Line-field confocal optical coherence tomography (LC-OCT) is a recently introduced high-resolution imaging modality based on a combination of low-coherence optical interferometry and reflectance confocal optical microscopy with line illumination and line detection. Capable of producing three-dimensional (3D) images of the skin with cellular resolution, in vivo, LC-OCT has been mainly applied in dermatology and dermo-cosmetology. The LC-OCT devices capable of acquiring 3D images reported so far are based on a Linnik interferometer using two identical microscope objectives. In this configuration, LC-OCT cannot be designed to be a very compact and light device, and the image acquisition speed is limited. AIM The objective of this work was to develop a more compact and lighter LC-OCT device that is capable of acquiring images faster without significant degradation of the resolution and with optimized detection sensitivity. APPROACH We developed an LC-OCT device based on a Mirau interferometer using a single objective. Dynamic adjustment of the camera frequency during the depth scan is implemented, using a faster camera and a more powerful light source. The reflectivity of the beam-splitter in the Mirau interferometer was optimized to maximize the detection sensitivity. A galvanometer scanner was incorporated into the device for scanning the illumination line laterally. A stack of adjacent B-scans, constituting a 3D image, can thus be acquired. RESULTS The device is able to acquire and display B-scans at 17 fps. 3D images with a quasi-isotropic resolution of ∼1.5 μm (1.3, 1.9, and 1.1 μm in the x , y, and z directions, respectively) over a field of 940 μm × 600 μm × 350 μm (x × y × z) can be obtained. 3D imaging of human skin at cellular resolution, in vivo, is reported. CONCLUSIONS The acquisition rate of the B-scans, at 17 fps, is unprecedented in LC-OCT. Compared with the conventional LC-OCT devices based on a Linnik interferometer, the reported Mirau-based LC-OCT device can acquire B-scans ∼2 times faster. With potential advantages in terms of compactness and weight, a Mirau-based device could easily be integrated into a smaller and lighter handheld probe for use by dermatologists in their daily medical practice.
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Affiliation(s)
- Weikai Xue
- Université Paris-Saclay, Institut d’Optique Graduate School, CNRS, Laboratoire Charles Fabry, Palaiseau, France
| | | | - Pavel Bulkin
- LPICM, CNRS, Ecole Polytechnique, Institut Polytechnique de Paris, Palaiseau, France
| | - Anne-Lise Coutrot
- Université Paris-Saclay, Institut d’Optique Graduate School, CNRS, Laboratoire Charles Fabry, Palaiseau, France
| | - Arnaud Dubois
- Université Paris-Saclay, Institut d’Optique Graduate School, CNRS, Laboratoire Charles Fabry, Palaiseau, France
- DAMAE Medical, Paris, France
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21
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Meleppat RK, Fortenbach CR, Jian Y, Martinez ES, Wagner K, Modjtahedi BS, Motta MJ, Ramamurthy DL, Schwab IR, Zawadzki RJ. In Vivo Imaging of Retinal and Choroidal Morphology and Vascular Plexuses of Vertebrates Using Swept-Source Optical Coherence Tomography. Transl Vis Sci Technol 2022; 11:11. [PMID: 35972433 PMCID: PMC9396679 DOI: 10.1167/tvst.11.8.11] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose To perform in vivo evaluation of the structural morphology and vascular plexuses of the neurosensory retina and choroid across vertebrate species using swept-source optical coherence tomography (SS-OCT) and SS-OCT angiography (SS-OCTA) imaging. Methods A custom-built SS-OCT system with an incorporated flexible imaging arm was used to acquire the three-dimensional (3D) retinal OCT and vascular OCTA data of five different vertebrates: a mouse (C57BL/6J), a rat (Long Evans), a gray short-tailed opossum (Monodelphis domestica), a white sturgeon (Acipenser transmontanus), and a great horned owl (Bubo virginianus). Results In vivo structural morphology of the retina and choroid, as well as en face OCTA images of retinal and choroidal vasculature of all species were generated. The retinal morphology and vascular plexuses were similar between rat and mouse, whereas distinct choroidal and paired superficial vessels were observed in the opossum retina. The retinal and vascular structure of the sturgeon, as well as the pecten oculi and overlying the avascular and choroidal vasculature in the owl retina are reported in vivo. Conclusions A high-quality two-dimensional and 3D in vivo visualization of the retinal structures and en face visualization of the retina and choroidal vascular plexus of vertebrates was possible. Our studies affirm that SS-OCT and SS-OCTA are viable methods for evaluating the in vivo retinal and choroidal structure across terrestrial, aquatic, and aerial vertebrates. Translational Relevance In vivo characterization of retinal morphology and vasculature plexus of multiple species using SS-OCT and SS-OCTA imaging can increase the pool of species available as models of human retinal diseases.
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Affiliation(s)
- Ratheesh K Meleppat
- UC Davis Eyepod Imaging Laboratory, University of California Davis, Davis, CA, USA.,Department of Ophthalmology & Vision Science, University of California Davis, Sacramento, CA, USA
| | - Christopher R Fortenbach
- Center for Neuroscience, University of California, Davis, Davis, CA, USA.,Department of Ophthalmology and Visual Sciences, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Yifan Jian
- Casey Eye Institute, Oregon Health & Science University, Portland, OR, USA
| | - Esteban Soto Martinez
- Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California Davis, Davis, CA, USA
| | - Karen Wagner
- Department of Entomology and UC Davis Comprehensive Cancer Center, University of California Davis, Sacramento, CA, USA
| | - Bobeck S Modjtahedi
- Department of Research and Evaluation, Southern California Permanente Medical Group, Pasadena, CA, USA.,Department of Clinical Science, Kaiser Permanente Bernard J. Tyson School of Medicine, Pasadena, CA, USA
| | - Monica J Motta
- Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California, Davis, CA, USA
| | - Deepa L Ramamurthy
- Center for Neuroscience, University of California, Davis, Davis, CA, USA
| | - Ivan R Schwab
- Department of Ophthalmology & Vision Science, University of California Davis, Sacramento, CA, USA
| | - Robert J Zawadzki
- UC Davis Eyepod Imaging Laboratory, University of California Davis, Davis, CA, USA.,Department of Ophthalmology & Vision Science, University of California Davis, Sacramento, CA, USA
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22
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Hao H, Xu C, Zhang D, Yan Q, Zhang J, Liu Y, Zhao Y. Sparse-based Domain Adaptation Network for OCTA Image Super-Resolution Reconstruction. IEEE J Biomed Health Inform 2022; 26:4402-4413. [PMID: 35895639 DOI: 10.1109/jbhi.2022.3194025] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Retinal Optical Coherence Tomography Angiography (OCTA) with high-resolution is important for the quantification and analysis of retinal vasculature. However, the resolution of OCTA images is inversely proportional to the field of view at the same sampling frequency, which is not conducive to clinicians for analyzing larger vascular areas. In this paper, we propose a novel Sparse-based domain Adaptation Super-Resolution network (SASR) for the reconstruction of realistic [Formula: see text]/low-resolution (LR) OCTA images to high-resolution (HR) representations. To be more specific, we first perform a simple degradation of the [Formula: see text]/high-resolution (HR) image to obtain the synthetic LR image. An efficient registration method is then employed to register the synthetic LR with its corresponding [Formula: see text] image region within the [Formula: see text] image to obtain the cropped realistic LR image. We then propose a multi-level super-resolution model for the fully-supervised reconstruction of the synthetic data, guiding the reconstruction of the realistic LR images through a generative-adversarial strategy that allows the synthetic and realistic LR images to be unified in the feature domain. Finally, a novel sparse edge-aware loss is designed to dynamically optimize the vessel edge structure. Extensive experiments on two OCTA sets have shown that our method performs better than state-of-the-art super-resolution reconstruction methods. In addition, we have investigated the performance of the reconstruction results on retina structure segmentations, which further validate the effectiveness of our approach.
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23
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Strenge P, Lange B, Grill C, Draxinger W, Danicke V, Theisen-Kunde D, Hagel C, Spahr-Hess S, Bonsanto MM, Huber R, Handels H, Brinkmann R. Registration of histological brain images onto optical coherence tomography images based on shape information. Phys Med Biol 2022; 67. [PMID: 35523170 DOI: 10.1088/1361-6560/ac6d9d] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Accepted: 05/06/2022] [Indexed: 11/12/2022]
Abstract
Identifying tumour infiltration zones during tumour resection in order to excise as much tumour tissue as possible without damaging healthy brain tissue is still a major challenge in neurosurgery. The detection of tumour infiltrated regions so far requires histological analysis of biopsies taken from at expected tumour boundaries. The gold standard for histological analysis is the staining of thin cut specimen and the evaluation by a neuropathologist. This work presents a way to transfer the histological evaluation of a neuropathologist onto optical coherence tomography (OCT) images. OCT is a method suitable for real timein vivoimaging during neurosurgery however the images require processing for the tumour detection. The method demonstrated here enables the creation of a dataset which will be used for supervised learning in order to provide a better visualization of tumour infiltrated areas for the neurosurgeon. The created dataset contains labelled OCT images from two different OCT-systems (wavelength of 930 nm and 1300 nm). OCT images corresponding to the stained histological images were determined by shaping the sample, a controlled cutting process and a rigid transformation process between the OCT volumes based on their topological information. The histological labels were transferred onto the corresponding OCT images through a non-rigid transformation based on shape context features retrieved from the sample outline in the histological image and the OCT image. The accuracy of the registration was determined to be 200 ± 120μm. The resulting dataset consists of 1248 labelled OCT images for each of the two OCT systems.
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Affiliation(s)
| | | | - Christin Grill
- Institute of Biomedical Optics, University of Luebeck, Luebeck, Germany
| | | | | | | | - Christian Hagel
- Institute for Neuropathology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Sonja Spahr-Hess
- Department of Neurosurgery, University Medical Center Schleswig-Holstein, Luebeck, Germany
| | - Matteo M Bonsanto
- Department of Neurosurgery, University Medical Center Schleswig-Holstein, Luebeck, Germany
| | - Robert Huber
- Institute of Biomedical Optics, University of Luebeck, Luebeck, Germany
| | - Heinz Handels
- Institute of Medical Informatics, University of Luebeck, Luebeck, Germany
| | - Ralf Brinkmann
- Medical Laser Center Luebeck, Luebeck, Germany.,Institute of Biomedical Optics, University of Luebeck, Luebeck, Germany
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24
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Gong Z, Shi Y, Wang RK. De-aliased depth-range-extended optical coherence tomography based on dual under-sampling. OPTICS LETTERS 2022; 47:2642-2645. [PMID: 35648894 DOI: 10.1364/ol.459414] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Accepted: 05/01/2022] [Indexed: 06/15/2023]
Abstract
We demonstrate a dual under-sampling (DUS) method to achieve de-aliased and depth-range-extended optical coherence tomography (OCT) imaging. The spectral under-sampling can significantly reduce the data size but causes well-known aliasing artifacts. A change in the sampling frequency used to acquire the interference spectrum alters the aliasing period within the output window except for the true image; this feature is utilized to distinguish the true image from the aliasing artifacts. We demonstrate that with DUS, the data size is reduced to 37% at an extended depth range of 24 mm, over which the true depth can be precisely measured without ambiguity. This reduction in data size and precise measuring capability would be beneficial for reducing the acquisition time for OCT imaging in various biomedical and industrial applications.
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25
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Lin YC, Yang TI, Huang SL. Ultra-broadband wavelength-swept Ti:sapphire crystal fiber laser. OPTICS LETTERS 2022; 47:2778-2781. [PMID: 35648928 DOI: 10.1364/ol.459072] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Accepted: 05/06/2022] [Indexed: 06/15/2023]
Abstract
An ultra-broadband wavelength-swept laser (WSL) was generated using glass-clad Ti:sapphire crystal fiber as the gain media. Due to the low signal propagation loss of the crystal fiber, the swept laser has a tuning bandwidth of 250 nm (i.e., 683 nm to 933 nm) at a repetition rate of 1200 Hz. The steady-state and pulsed dynamics of the WSL were analyzed. The 0.018-nm instantaneous linewidth corresponds to a 3-dB coherence roll-off of 7 mm. When using the laser for swept-source optical coherence tomography, an estimated axial resolution of 1.8 µm can be achieved.
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26
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Reich S, Göbel A, Goesmann M, Heunoske D, Schäffer S, Lueck M, Wickert M, Osterholz J. 2D and 3D Triangulation Are Suitable In Situ Measurement Tools for High-Power Large Spot Laser Penetration Processes to Visualize Depressions and Protrusions before Perforating. MATERIALS 2022; 15:ma15113743. [PMID: 35683042 PMCID: PMC9181421 DOI: 10.3390/ma15113743] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Revised: 05/18/2022] [Accepted: 05/20/2022] [Indexed: 12/10/2022]
Abstract
During laser penetration, the irradiated samples form a melt pool before perforation. Knowledge of the dynamics of this melt pool is of interest for the correct physical description of the process and leads to improved simulations. However, a direct investigation, especially at the location of high-power laser interaction with large spot diameters in the centimeter range is missing until now. Here, the applicability of 2D triangulation for surface topology observations is demonstrated. With the designed bidirectional 2D triangulation setup, the material cross-section is measured by profile detection at the front and back side. This allows a comprehensive description of the penetration process to be established, which is important for a detailed explanation of the process. Specific steps such as surface melting, indentations, protrusions during melt pool development and their dynamics, and the perforation are visualized, which were unknown until now. Furthermore, a scanning 3D triangulation setup is developed to obtain more information about the entire melt pool at the front side, and not just a single intersection line. The measurements exhibit a mirror-symmetric melt pool and the possibility to extrapolate from the central profile to the outer regions in most cases.
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27
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Qian R, Zhou KC, Zhang J, Viehland C, Dhalla AH, Izatt JA. Video-rate high-precision time-frequency multiplexed 3D coherent ranging. Nat Commun 2022; 13:1476. [PMID: 35351891 PMCID: PMC8964719 DOI: 10.1038/s41467-022-29177-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Accepted: 02/25/2022] [Indexed: 01/02/2023] Open
Abstract
Frequency-modulated continuous wave (FMCW) light detection and ranging (LiDAR) is an emerging 3D ranging technology that offers high sensitivity and ranging precision. Due to the limited bandwidth of digitizers and the speed limitations of beam steering using mechanical scanners, meter-scale FMCW LiDAR systems typically suffer from a low 3D frame rate, which greatly restricts their applications in real-time imaging of dynamic scenes. In this work, we report a high-speed FMCW based 3D imaging system, combining a grating for beam steering with a compressed time-frequency analysis approach for depth retrieval. We thoroughly investigate the localization accuracy and precision of our system both theoretically and experimentally. Finally, we demonstrate 3D imaging results of multiple static and moving objects, including a flexing human hand. The demonstrated technique achieves submillimeter localization accuracy over a tens-of-centimeter imaging range with an overall depth voxel acquisition rate of 7.6 MHz, enabling densely sampled 3D imaging at video rate.
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Affiliation(s)
- Ruobing Qian
- Department of Biomedical Engineering, Duke University, Durham, NC, 27708, USA
| | - Kevin C Zhou
- Department of Biomedical Engineering, Duke University, Durham, NC, 27708, USA
| | - Jingkai Zhang
- Department of Biomedical Engineering, Duke University, Durham, NC, 27708, USA
| | - Christian Viehland
- Department of Biomedical Engineering, Duke University, Durham, NC, 27708, USA
| | - Al-Hafeez Dhalla
- Department of Biomedical Engineering, Duke University, Durham, NC, 27708, USA
| | - Joseph A Izatt
- Department of Biomedical Engineering, Duke University, Durham, NC, 27708, USA.
- Department of Ophthalmology, Duke University Medical Center, Durham, NC, 27710, USA.
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28
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Wang A, Qi W, Gao T, Tang X. Molecular Contrast Optical Coherence Tomography and Its Applications in Medicine. Int J Mol Sci 2022; 23:ijms23063038. [PMID: 35328454 PMCID: PMC8949853 DOI: 10.3390/ijms23063038] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Revised: 03/05/2022] [Accepted: 03/08/2022] [Indexed: 12/28/2022] Open
Abstract
The growing need to understand the molecular mechanisms of diseases has prompted the revolution in molecular imaging techniques along with nanomedicine development. Conventional optical coherence tomography (OCT) is a low-cost in vivo imaging modality that provides unique high spatial and temporal resolution anatomic images but little molecular information. However, given the widespread adoption of OCT in research and clinical practice, its robust molecular imaging extensions are strongly desired to combine with anatomical images. A range of relevant approaches has been reported already. In this article, we review the recent advances of molecular contrast OCT imaging techniques, the corresponding contrast agents, especially the nanoparticle-based ones, and their applications. We also summarize the properties, design criteria, merit, and demerit of those contrast agents. In the end, the prospects and challenges for further research and development in this field are outlined.
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29
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Tang EM, El-Haddad MT, Patel SN, Tao YK. Automated instrument-tracking for 4D video-rate imaging of ophthalmic surgical maneuvers. BIOMEDICAL OPTICS EXPRESS 2022; 13:1471-1484. [PMID: 35414968 PMCID: PMC8973184 DOI: 10.1364/boe.450814] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Revised: 02/07/2022] [Accepted: 02/09/2022] [Indexed: 05/11/2023]
Abstract
Intraoperative image-guidance provides enhanced feedback that facilitates surgical decision-making in a wide variety of medical fields and is especially useful when haptic feedback is limited. In these cases, automated instrument-tracking and localization are essential to guide surgical maneuvers and prevent damage to underlying tissue. However, instrument-tracking is challenging and often confounded by variations in the surgical environment, resulting in a trade-off between accuracy and speed. Ophthalmic microsurgery presents additional challenges due to the nonrigid relationship between instrument motion and instrument deformation inside the eye, image field distortion, image artifacts, and bulk motion due to patient movement and physiological tremor. We present an automated instrument-tracking method by leveraging multimodal imaging and deep-learning to dynamically detect surgical instrument positions and re-center imaging fields for 4D video-rate visualization of ophthalmic surgical maneuvers. We are able to achieve resolution-limited tracking accuracy at varying instrument orientations as well as at extreme instrument speeds and image defocus beyond typical use cases. As proof-of-concept, we perform automated instrument-tracking and 4D imaging of a mock surgical task. Here, we apply our methods for specific applications in ophthalmic microsurgery, but the proposed technologies are broadly applicable for intraoperative image-guidance with high speed and accuracy.
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Affiliation(s)
- Eric M. Tang
- Vanderbilt University, Department of Biomedical Engineering, Nashville, TN 37232, USA
| | - Mohamed T. El-Haddad
- Vanderbilt University, Department of Biomedical Engineering, Nashville, TN 37232, USA
| | - Shriji N. Patel
- Vanderbilt Eye Institute, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Yuankai K. Tao
- Vanderbilt University, Department of Biomedical Engineering, Nashville, TN 37232, USA
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30
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Göb M, Pfeiffer T, Draxinger W, Lotz S, Kolb JP, Huber R. Continuous spectral zooming for in vivo live 4D-OCT with MHz A-scan rates and long coherence. BIOMEDICAL OPTICS EXPRESS 2022; 13:713-727. [PMID: 35284187 PMCID: PMC8884208 DOI: 10.1364/boe.448353] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Revised: 12/20/2021] [Accepted: 12/27/2021] [Indexed: 06/14/2023]
Abstract
We present continuous three-dimensional spectral zooming in live 4D-OCT using a home-built FDML based OCT system with 3.28 MHz A-scan rate. Improved coherence characteristics of the FDML laser allow for imaging ranges up to 10 cm. For the axial spectral zoom feature, we switch between high resolution and long imaging range by adjusting the sweep range of our laser. We present a new imaging setup allowing for synchronized adjustments of the imaging range and lateral field of view during live OCT imaging. For this, a novel inline recalibration algorithm was implemented that enables numerical k-linearization of the raw OCT fringes for every frame instead of every volume. This is realized by acquiring recalibration data within the dead time of the raster scan at the turning points of the fast axis scanner. We demonstrate in vivo OCT images of fingers and hands at different resolution modes and show real three-dimensional zooming during live 4D-OCT. A three-dimensional spectral zooming feature for live 4D-OCT is expected to be a useful tool for a wide range of biomedical, scientific and research applications, especially in OCT guided surgery.
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Affiliation(s)
- Madita Göb
- Institut für Biomedizinische Optik, Universität zu Lübeck, Peter-Monnik-Weg 4, 23562 Lübeck, Germany
| | - Tom Pfeiffer
- Institut für Biomedizinische Optik, Universität zu Lübeck, Peter-Monnik-Weg 4, 23562 Lübeck, Germany
- Optores GmbH, Gollierstr. 70, 80339 Munich, Germany
| | - Wolfgang Draxinger
- Institut für Biomedizinische Optik, Universität zu Lübeck, Peter-Monnik-Weg 4, 23562 Lübeck, Germany
| | - Simon Lotz
- Institut für Biomedizinische Optik, Universität zu Lübeck, Peter-Monnik-Weg 4, 23562 Lübeck, Germany
| | - Jan Philip Kolb
- Institut für Biomedizinische Optik, Universität zu Lübeck, Peter-Monnik-Weg 4, 23562 Lübeck, Germany
| | - Robert Huber
- Institut für Biomedizinische Optik, Universität zu Lübeck, Peter-Monnik-Weg 4, 23562 Lübeck, Germany
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31
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OCT-Guided Surgery for Gliomas: Current Concept and Future Perspectives. Diagnostics (Basel) 2022; 12:diagnostics12020335. [PMID: 35204427 PMCID: PMC8871129 DOI: 10.3390/diagnostics12020335] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Revised: 01/19/2022] [Accepted: 01/26/2022] [Indexed: 02/01/2023] Open
Abstract
Optical coherence tomography (OCT) has been recently suggested as a promising method to obtain in vivo and real-time high-resolution images of tissue structure in brain tumor surgery. This review focuses on the basics of OCT imaging, types of OCT images and currently suggested OCT scanner devices and the results of their application in neurosurgery. OCT can assist in achieving intraoperative precision identification of tumor infiltration within surrounding brain parenchyma by using qualitative or quantitative OCT image analysis of scanned tissue. OCT is able to identify tumorous tissue and blood vessels detection during stereotactic biopsy procedures. The combination of OCT with traditional imaging such as MRI, ultrasound and 5-ALA fluorescence has the potential to increase the safety and accuracy of the resection. OCT can improve the extent of resection by offering the direct visualization of tumor with cellular resolution when using microscopic OCT contact probes. The theranostic implementation of OCT as a part of intelligent optical diagnosis and automated lesion localization and ablation could achieve high precision, automation and intelligence in brain tumor surgery. We present this review for the increase of knowledge and formation of critical opinion in the field of OCT implementation in brain tumor surgery.
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32
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Lee MW, Jang N, Choi N, Yang S, Jeong J, Nam HS, Oh S, Kim K, Hwang D. In Vivo Cellular-Level 3D Imaging of Peripheral Nerves Using a Dual-Focusing Technique for Intra-Neural Interface Implantation. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2022; 9:e2102876. [PMID: 34845862 PMCID: PMC8787432 DOI: 10.1002/advs.202102876] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Revised: 11/09/2021] [Indexed: 06/13/2023]
Abstract
In vivo volumetric imaging of the microstructural changes of peripheral nerves with an inserted electrode could be key for solving the chronic implantation failure of an intra-neural interface necessary to provide amputated patients with natural motion and sensation. Thus far, no imaging devices can provide a cellular-level three-dimensional (3D) structural images of a peripheral nerve in vivo. In this study, an optical coherence tomography-based peripheral nerve imaging platform that employs a newly proposed depth of focus extension technique is reported. A point spread function with the finest transverse resolution of 1.27 µm enables the cellular-level volumetric visualization of the metal wire and microstructural changes in a rat sciatic nerve with the metal wire inserted in vivo. Further, the feasibility of applying the imaging platform to large animals for a preclinical study is confirmed through in vivo rabbit sciatic nerve imaging. It is expected that new possibilities for the successful chronic implantation of an intra-neural interface will open up by providing the 3D microstructural changes of nerves around the inserted electrode.
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Affiliation(s)
- Min Woo Lee
- Center for Intelligent and Interactive RoboticsKorea Institute of Science and TechnologySeoul02792Republic of Korea
| | - Namseon Jang
- Center for Intelligent and Interactive RoboticsKorea Institute of Science and TechnologySeoul02792Republic of Korea
| | - Nara Choi
- Center for Intelligent and Interactive RoboticsKorea Institute of Science and TechnologySeoul02792Republic of Korea
| | - Sungwook Yang
- Center for Intelligent and Interactive RoboticsKorea Institute of Science and TechnologySeoul02792Republic of Korea
| | - Jinwoo Jeong
- Center for Intelligent and Interactive RoboticsKorea Institute of Science and TechnologySeoul02792Republic of Korea
| | - Hyeong Soo Nam
- Department of Mechanical EngineeringKorea Advanced Institute of Science and TechnologyDaejeon34141Republic of Korea
| | - Sang‐Rok Oh
- Center for Intelligent and Interactive RoboticsKorea Institute of Science and TechnologySeoul02792Republic of Korea
| | - Keehoon Kim
- Department of Mechanical EngineeringPohang University of Science and TechnologyGyeongbuk37673Republic of Korea
| | - Donghyun Hwang
- Center for Intelligent and Interactive RoboticsKorea Institute of Science and TechnologySeoul02792Republic of Korea
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33
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Bouma B, de Boer J, Huang D, Jang I, Yonetsu T, Leggett C, Leitgeb R, Sampson D, Suter M, Vakoc B, Villiger M, Wojtkowski M. Optical coherence tomography. NATURE REVIEWS. METHODS PRIMERS 2022; 2:79. [PMID: 36751306 PMCID: PMC9901537 DOI: 10.1038/s43586-022-00162-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
Optical coherence tomography (OCT) is a non-contact method for imaging the topological and internal microstructure of samples in three dimensions. OCT can be configured as a conventional microscope, as an ophthalmic scanner, or using endoscopes and small diameter catheters for accessing internal biological organs. In this Primer, we describe the principles underpinning the different instrument configurations that are tailored to distinct imaging applications and explain the origin of signal, based on light scattering and propagation. Although OCT has been used for imaging inanimate objects, we focus our discussion on biological and medical imaging. We examine the signal processing methods and algorithms that make OCT exquisitely sensitive to reflections as weak as just a few photons and that reveal functional information in addition to structure. Image processing, display and interpretation, which are all critical for effective biomedical imaging, are discussed in the context of specific applications. Finally, we consider image artifacts and limitations that commonly arise and reflect on future advances and opportunities.
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Affiliation(s)
- B.E. Bouma
- Wellman Center for Photomedicine, Massachusetts General Hospital, Boston, MA, USA,Institute for Medical Engineering and Physics, Massachusetts Institute of Technology, Cambridge, MA, USA,Harvard Medical School, Boston, MA, USA,Corresponding author:
| | - J.F. de Boer
- Department of Physics and Astronomy, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - D. Huang
- Casey Eye Institute, Oregon Health and Science University, Portland, OR, USA
| | - I.K. Jang
- Harvard Medical School, Boston, MA, USA,Cardiology Division, Massachusetts General Hospital, Boston, MA, USA
| | - T. Yonetsu
- Department of Cardiovascular Medicine, Tokyo Medical and Dental University
| | - C.L. Leggett
- Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, MN, USA
| | - R. Leitgeb
- Institute of Medical Physics, University of Vienna, Wien, Austria
| | - D.D. Sampson
- School of Physics and School of Biosciences and Medicine, University of Surrey, Guildford, United Kingdom
| | - M. Suter
- Harvard Medical School, Boston, MA, USA,Division of Pulmonary and Critical Care Medicine, Massachusetts General Hospital, Boston, MA, USA
| | - B. Vakoc
- Wellman Center for Photomedicine, Massachusetts General Hospital, Boston, MA, USA,Harvard Medical School, Boston, MA, USA
| | - M. Villiger
- Wellman Center for Photomedicine, Massachusetts General Hospital, Boston, MA, USA,Harvard Medical School, Boston, MA, USA
| | - M. Wojtkowski
- Institute of Physical Chemistry and International Center for Translational Eye Research, Institute of Physical Chemistry, Polish Academy of Sciences, Warsaw, Poland,Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University, Torun, Poland
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34
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Wu M, Liu S, Leartprapun N, Adie S. Investigation of multiple scattering in space and spatial-frequency domains: with application to the analysis of aberration-diverse optical coherence tomography. BIOMEDICAL OPTICS EXPRESS 2021; 12:7478-7499. [PMID: 35003847 PMCID: PMC8713691 DOI: 10.1364/boe.439395] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Revised: 10/25/2021] [Accepted: 10/26/2021] [Indexed: 05/12/2023]
Abstract
Optical microscopy suffers from multiple scattering (MS), which limits the optical imaging depth into scattering media. We previously demonstrated aberration-diverse optical coherence tomography (AD-OCT) for MS suppression, based on the principle that for datasets acquired with different aberration states of the imaging beam, MS backgrounds become decorrelated while single scattering (SS) signals remain correlated, so that a simple coherent average can be used to enhance the SS signal over the MS background. Here, we propose a space/spatial-frequency domain analysis framework for the investigation of MS in OCT, and apply the framework to compare AD-OCT (using astigmatic beams) to standard Gaussian-beam OCT via experiments in scattering tissue phantoms. Utilizing this framework, we found that increasing the astigmatic magnitude produced a large drop in both MS background and SS signal, but the decay experienced by the MS background was larger than the SS signal. Accounting for the decay in both SS signal and MS background, the overall signal-to-background ratio (SBR) of AD-OCT was similar to the Gaussian control after about 10 coherent averages, when deeper line foci was positioned at the plane-of-interest and the line foci spacing was smaller than or equal to 80 µm. For an even larger line foci spacing of 160 µm, AD-OCT resulted in a lower SBR than the Gaussian-beam control. This work provides an analysis framework to gain deeper levels of understanding and insights for the future study of MS and MS suppression in both the space and spatial-frequency domains.
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Affiliation(s)
- Meiqi Wu
- Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY 14853, USA
| | - Siyang Liu
- School of Electrical and Computer Engineering, Cornell University, Ithaca, NY 14853, USA
| | - Nichaluk Leartprapun
- Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY 14853, USA
| | - Steven Adie
- Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY 14853, USA
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35
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Münter M, Pieper M, Kohlfaerber T, Bodenstorfer E, Ahrens M, Winter C, Huber R, König P, Hüttmann G, Schulz-Hildebrandt H. Microscopic optical coherence tomography (mOCT) at 600 kHz for 4D volumetric imaging and dynamic contrast. BIOMEDICAL OPTICS EXPRESS 2021; 12:6024-6039. [PMID: 34745719 PMCID: PMC8547980 DOI: 10.1364/boe.425001] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Revised: 08/03/2021] [Accepted: 08/06/2021] [Indexed: 05/11/2023]
Abstract
Volumetric imaging of dynamic processes with microscopic resolution holds a huge potential in biomedical research and clinical diagnosis. Using supercontinuum light sources and high numerical aperture (NA) objectives, optical coherence tomography (OCT) achieves microscopic resolution and is well suited for imaging cellular and subcellular structures of biological tissues. Currently, the imaging speed of microscopic OCT (mOCT) is limited by the line-scan rate of the spectrometer camera and ranges from 30 to 250 kHz. This is not fast enough for volumetric imaging of dynamic processes in vivo and limits endoscopic application. Using a novel CMOS camera, we demonstrate fast 3-dimensional OCT imaging with 600,000 A-scans/s at 1.8 µm axial and 1.1 µm lateral resolution. The improved speed is used for imaging of ciliary motion and particle transport in ex vivo mouse trachea. Furthermore, we demonstrate dynamic contrast OCT by evaluating the recorded volumes rather than en face planes or B-scans. High-speed volumetric mOCT will enable the correction of global tissue motion and is a prerequisite for applying dynamic contrast mOCT in vivo. With further increase in imaging speed and integration in flexible endoscopes, volumetric mOCT may be used to complement or partly replace biopsies.
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Affiliation(s)
- Michael Münter
- University of Lübeck,
Institute of Biomedical Optics,
Peter-Monnik-Weg 4, 23562 Lübeck, Germany
- Medizinisches Laserzentrum
Lübeck GmbH, Peter-Monnik-Weg 4, 23562 Lübeck, Germany
| | - Mario Pieper
- University of
Lübeck, Institute of Anatomy, Ratzeburger Allee 160,
23562 Lübeck, Germany
- Airway Research Center North
Member of the German Center for Lung Research, DZL,
22927 Großhansdorf, Germany
| | - Tabea Kohlfaerber
- Medizinisches Laserzentrum
Lübeck GmbH, Peter-Monnik-Weg 4, 23562 Lübeck, Germany
| | - Ernst Bodenstorfer
- Austrian Institute of
Technology GmbH, Giefinggasse 4, 1210 Vienna, Austria
| | - Martin Ahrens
- University of Lübeck,
Institute of Biomedical Optics,
Peter-Monnik-Weg 4, 23562 Lübeck, Germany
- Airway Research Center North
Member of the German Center for Lung Research, DZL,
22927 Großhansdorf, Germany
| | | | - Robert Huber
- University of Lübeck,
Institute of Biomedical Optics,
Peter-Monnik-Weg 4, 23562 Lübeck, Germany
| | - Peter König
- University of
Lübeck, Institute of Anatomy, Ratzeburger Allee 160,
23562 Lübeck, Germany
- Airway Research Center North
Member of the German Center for Lung Research, DZL,
22927 Großhansdorf, Germany
| | - Gereon Hüttmann
- University of Lübeck,
Institute of Biomedical Optics,
Peter-Monnik-Weg 4, 23562 Lübeck, Germany
- Medizinisches Laserzentrum
Lübeck GmbH, Peter-Monnik-Weg 4, 23562 Lübeck, Germany
- Airway Research Center North
Member of the German Center for Lung Research, DZL,
22927 Großhansdorf, Germany
| | - Hinnerk Schulz-Hildebrandt
- University of Lübeck,
Institute of Biomedical Optics,
Peter-Monnik-Weg 4, 23562 Lübeck, Germany
- Medizinisches Laserzentrum
Lübeck GmbH, Peter-Monnik-Weg 4, 23562 Lübeck, Germany
- Airway Research Center North
Member of the German Center for Lung Research, DZL,
22927 Großhansdorf, Germany
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36
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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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37
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Abstract
Early detection and monitoring are critical to the diagnosis and management of glaucoma, a progressive optic neuropathy that causes irreversible blindness. Optical coherence tomography (OCT) has become a commonly utilized imaging modality that aids in the detection and monitoring of structural glaucomatous damage. Since its inception in 1991, OCT has progressed through multiple iterations, from time-domain OCT, to spectral-domain OCT, to swept-source OCT, all of which have progressively improved the resolution and speed of scans. Even newer technological advancements and OCT applications, such as adaptive optics, visible-light OCT, and OCT-angiography, have enriched the use of OCT in the evaluation of glaucoma. This article reviews current commercial and state-of-the-art OCT technologies and analytic techniques in the context of their utility for glaucoma diagnosis and management, as well as promising future directions.
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Affiliation(s)
- Alexi Geevarghese
- Department of Ophthalmology, NYU Langone Health, NYU Grossman School of Medicine, New York, NY 10016, USA;
| | - Gadi Wollstein
- Department of Ophthalmology, NYU Langone Health, NYU Grossman School of Medicine, New York, NY 10016, USA;
- Department of Biomedical Engineering, NYU Tandon School of Engineering, Brooklyn, New York 11201, USA
- Center for Neural Science, NYU College of Arts and Sciences, New York, NY 10003, USA
| | - Hiroshi Ishikawa
- Department of Ophthalmology, NYU Langone Health, NYU Grossman School of Medicine, New York, NY 10016, USA;
- Department of Biomedical Engineering, NYU Tandon School of Engineering, Brooklyn, New York 11201, USA
| | - Joel S Schuman
- Department of Ophthalmology, NYU Langone Health, NYU Grossman School of Medicine, New York, NY 10016, USA;
- Department of Biomedical Engineering, NYU Tandon School of Engineering, Brooklyn, New York 11201, USA
- Center for Neural Science, NYU College of Arts and Sciences, New York, NY 10003, USA
- Department of Physiology and Neuroscience, NYU Langone Health, NYU Grossman School of Medicine, New York, NY 10016, USA
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38
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Hakert H, Eibl M, Tillich M, Pries R, Hüttmann G, Brinkmann R, Wollenberg B, Bruchhage KL, Karpf S, Huber R. Time-encoded stimulated Raman scattering microscopy of tumorous human pharynx tissue in the fingerprint region from 1500-1800 cm -1. OPTICS LETTERS 2021; 46:3456-3459. [PMID: 34264237 DOI: 10.1364/ol.424726] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Accepted: 06/14/2021] [Indexed: 06/13/2023]
Abstract
Stimulated Raman scattering (SRS) microscopy for biomedical analysis can provide a molecular localization map to infer pathological tissue changes. Compared to spontaneous Raman, SRS achieves much faster imaging speeds at reduced spectral coverage. By targeting spectral features in the information dense fingerprint region, SRS allows fast and reliable imaging. We present time-encoded (TICO) SRS microscopy of unstained head-and-neck biopsies in the fingerprint region with molecular contrast. We combine a Fourier-domain mode-locked (FDML) laser with a master oscillator power amplifier (MOPA) to cover Raman transitions from 1500-1800cm-1. Both lasers are fiber-based and electronically programmable making this fingerprint TICO system robust and reliable. The results of our TICO approach were cross-checked with a spontaneous Raman micro-spectrometer and show good agreement, paving the way toward clinical applications.
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39
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Rao D S S, Jensen M, Grüner-Nielsen L, Olsen JT, Heiduschka P, Kemper B, Schnekenburger J, Glud M, Mogensen M, Israelsen NM, Bang O. Shot-noise limited, supercontinuum-based optical coherence tomography. LIGHT, SCIENCE & APPLICATIONS 2021; 10:133. [PMID: 34183643 PMCID: PMC8239030 DOI: 10.1038/s41377-021-00574-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2020] [Revised: 05/26/2021] [Accepted: 06/07/2021] [Indexed: 05/19/2023]
Abstract
We present the first demonstration of shot-noise limited supercontinuum-based spectral domain optical coherence tomography (SD-OCT) with an axial resolution of 5.9 μm at a center wavelength of 1370 nm. Current supercontinuum-based SD-OCT systems cannot be operated in the shot-noise limited detection regime because of severe pulse-to-pulse relative intensity noise of the supercontinuum source. To overcome this disadvantage, we have developed a low-noise supercontinuum source based on an all-normal dispersion (ANDi) fiber, pumped by a femtosecond laser. The noise performance of our 90 MHz ANDi fiber-based supercontinuum source is compared to that of two commercial sources operating at 80 and 320 MHz repetition rate. We show that the low-noise of the ANDi fiber-based supercontinuum source improves the OCT images significantly in terms of both higher contrast, better sensitivity, and improved penetration. From SD-OCT imaging of skin, retina, and multilayer stacks we conclude that supercontinuum-based SD-OCT can enter the domain of shot-noise limited detection.
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Affiliation(s)
- Shreesha Rao D S
- DTU Fotonik, Dept. of Photonics Engineering, Technical University of Denmark, Ørsteds Plads, 2800, Kongens Lyngby, Denmark
| | - Mikkel Jensen
- DTU Fotonik, Dept. of Photonics Engineering, Technical University of Denmark, Ørsteds Plads, 2800, Kongens Lyngby, Denmark
| | - Lars Grüner-Nielsen
- DTU Fotonik, Dept. of Photonics Engineering, Technical University of Denmark, Ørsteds Plads, 2800, Kongens Lyngby, Denmark
| | | | - Peter Heiduschka
- Department of Ophthalmology, University of Münster Medical Centre, Domagkstr. 15, D-48149, Münster, Germany
| | - Björn Kemper
- Biomedical Technology Center of the Medical Faculty, University of Münster, Mendelstr. 17, D-48149, Münster, Germany
| | - Jürgen Schnekenburger
- Biomedical Technology Center of the Medical Faculty, University of Münster, Mendelstr. 17, D-48149, Münster, Germany
| | - Martin Glud
- Department of Dermatology, Bisbebjerg Hospital, University of Copenhagen, Bispebjerg Bakke 23, 2400, Copenhagen NV, Denmark
| | - Mette Mogensen
- Department of Dermatology, Bisbebjerg Hospital, University of Copenhagen, Bispebjerg Bakke 23, 2400, Copenhagen NV, Denmark
| | - Niels Møller Israelsen
- DTU Fotonik, Dept. of Photonics Engineering, Technical University of Denmark, Ørsteds Plads, 2800, Kongens Lyngby, Denmark
| | - Ole Bang
- DTU Fotonik, Dept. of Photonics Engineering, Technical University of Denmark, Ørsteds Plads, 2800, Kongens Lyngby, Denmark.
- NKT Photonics A/S, Blokken 84, 3460, Birkerød, Denmark.
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40
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Choi S, Ota T, Nin F, Shioda T, Suzuki T, Hibino H. Rapid optical tomographic vibrometry using a swept multi-gigahertz comb. OPTICS EXPRESS 2021; 29:16749-16768. [PMID: 34154231 DOI: 10.1364/oe.425972] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Accepted: 05/10/2021] [Indexed: 06/13/2023]
Abstract
We propose a rapid tomographic vibrometer technique using an optical comb to measure internal vibrations, transient phenomena, and tomographic distributions in biological tissue and microelectromechanical system devices at high frequencies. This method allows phase-sensitive tomographic measurement in the depth direction at a multi-MHz scan rate using a frequency-modulated broadband electrooptic multi-GHz supercontinuum comb. The frequency spacing was swept instantaneously in time and axisymmetrically about the center wavelength via a dual-drive Mach-Zehnder modulator driven by a variable radio frequency signal. This unique sweeping method permits direct measurement of fringe-free interferometric amplitude and phase with arbitrarily changeable measurement range and scan rate. Therefore, a compressive measurement can be made in only the depth region where the vibration exists, reducing the number of measurement points. In a proof-of-principle experiment, the interferometric amplitude and phase were investigated for in-phase and quadrature phase-shifted interferograms obtained by a polarization demodulator. Tomographic transient displacement measurements were performed using a 0.12 mm thick glass film and piezo-electric transducer oscillating at 10-100 kHz with scan rates in the range 1-20 MHz. The depth resolution and precision of the vibrometer were estimated to be approximately 25 µm and 1.0 nm, respectively.
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41
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Lotz S, Grill C, Göb M, Draxinger W, Kolb JP, Huber R. Cavity length control for Fourier domain mode locked (FDML) lasers with µm precision. BIOMEDICAL OPTICS EXPRESS 2021; 12:2604-2616. [PMID: 34123491 PMCID: PMC8176810 DOI: 10.1364/boe.422898] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Revised: 03/19/2021] [Accepted: 03/19/2021] [Indexed: 06/12/2023]
Abstract
In highly dispersion compensated Fourier domain mode locked (FDML) lasers, an ultra-low noise operation can only be achieved by extremely precise and stable matching of the filter tuning period and light circulation time in the cavity. We present a robust and high precision closed-loop control algorithm and an actively cavity length controlled FDML laser. The cavity length control achieves a stability of ∼0.18 mHz at a sweep repetition rate of ∼418 kHz which corresponds to a ratio of 4×10-10. Furthermore, we prove that the rapid change of the cavity length has no negative impact on the quality of optical coherence tomography using the FDML laser as light source.
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Affiliation(s)
- Simon Lotz
- Institut für Biomedizinische Optik, Universität zu Lübeck, Peter-Monnik-Weg 4, 23562 Lübeck, Germany
- Medizinisches Laserzentrum Lübeck GmbH, Peter-Monnik-Weg 4, 23562 Lübeck, Germany
| | - Christin Grill
- Institut für Biomedizinische Optik, Universität zu Lübeck, Peter-Monnik-Weg 4, 23562 Lübeck, Germany
| | - Madita Göb
- Institut für Biomedizinische Optik, Universität zu Lübeck, Peter-Monnik-Weg 4, 23562 Lübeck, Germany
| | - Wolfgang Draxinger
- Institut für Biomedizinische Optik, Universität zu Lübeck, Peter-Monnik-Weg 4, 23562 Lübeck, Germany
| | - Jan Philip Kolb
- Institut für Biomedizinische Optik, Universität zu Lübeck, Peter-Monnik-Weg 4, 23562 Lübeck, Germany
| | - Robert Huber
- Institut für Biomedizinische Optik, Universität zu Lübeck, Peter-Monnik-Weg 4, 23562 Lübeck, Germany
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42
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Hohmann M, Hecht D, Lengenfelder B, Späth M, Klämpfl F, Schmidt M. Proof of Principle for Direct Reconstruction of Qualitative Depth Information from Turbid Media by a Single Hyper Spectral Image. SENSORS 2021; 21:s21082860. [PMID: 33921629 PMCID: PMC8073672 DOI: 10.3390/s21082860] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Revised: 04/12/2021] [Accepted: 04/14/2021] [Indexed: 01/14/2023]
Abstract
In medical applications, hyper-spectral imaging is becoming more and more common. It has been shown to be more effective for classification and segmentation than normal RGB imaging because narrower wavelength bands are used, providing a higher contrast. However, until now, the fact that hyper-spectral images also contain information about the three-dimensional structure of turbid media has been neglected. In this study, it is shown that it is possible to derive information about the depth of inclusions in turbid phantoms from a single hyper-spectral image. Here, the depth information is encoded by a combination of scattering and absorption within the phantom. Although scatter-dominated regions increase the backscattering for deep vessels, absorption has the opposite effect. With this argumentation, it makes sense to assume that, under certain conditions, a wavelength is not influenced by the depth of the inclusion and acts as an iso-point. This iso-point could be used to easily derive information about the depth of an inclusion. In this study, it is shown that the iso-point exists in some cases. Moreover, it is shown that the iso-point can be used to obtain precise depth information.
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Affiliation(s)
- Martin Hohmann
- Institute of Photonic Technologies (LPT), Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Konrad-Zuse-Strasse 3/5, 91052 Erlangen, Germany; (D.H.); (B.L.); (M.S.); (F.K.); (M.S.)
- Erlangen Graduate School in Advanced Optical Technologies (SAOT), Paul-Gordon-Strasse 6, 91052 Erlangen, Germany
- Correspondence:
| | - Damaris Hecht
- Institute of Photonic Technologies (LPT), Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Konrad-Zuse-Strasse 3/5, 91052 Erlangen, Germany; (D.H.); (B.L.); (M.S.); (F.K.); (M.S.)
| | - Benjamin Lengenfelder
- Institute of Photonic Technologies (LPT), Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Konrad-Zuse-Strasse 3/5, 91052 Erlangen, Germany; (D.H.); (B.L.); (M.S.); (F.K.); (M.S.)
- Erlangen Graduate School in Advanced Optical Technologies (SAOT), Paul-Gordon-Strasse 6, 91052 Erlangen, Germany
| | - Moritz Späth
- Institute of Photonic Technologies (LPT), Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Konrad-Zuse-Strasse 3/5, 91052 Erlangen, Germany; (D.H.); (B.L.); (M.S.); (F.K.); (M.S.)
- Erlangen Graduate School in Advanced Optical Technologies (SAOT), Paul-Gordon-Strasse 6, 91052 Erlangen, Germany
| | - Florian Klämpfl
- Institute of Photonic Technologies (LPT), Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Konrad-Zuse-Strasse 3/5, 91052 Erlangen, Germany; (D.H.); (B.L.); (M.S.); (F.K.); (M.S.)
- Erlangen Graduate School in Advanced Optical Technologies (SAOT), Paul-Gordon-Strasse 6, 91052 Erlangen, Germany
| | - Michael Schmidt
- Institute of Photonic Technologies (LPT), Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Konrad-Zuse-Strasse 3/5, 91052 Erlangen, Germany; (D.H.); (B.L.); (M.S.); (F.K.); (M.S.)
- Erlangen Graduate School in Advanced Optical Technologies (SAOT), Paul-Gordon-Strasse 6, 91052 Erlangen, Germany
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43
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Zhang J, Nguyen T, Potsaid B, Jayaraman V, Burgner C, Chen S, Li J, Liang K, Cable A, Traverso G, Mashimo H, Fujimoto JG. Multi-MHz MEMS-VCSEL swept-source optical coherence tomography for endoscopic structural and angiographic imaging with miniaturized brushless motor probes. BIOMEDICAL OPTICS EXPRESS 2021; 12:2384-2403. [PMID: 33996236 PMCID: PMC8086463 DOI: 10.1364/boe.420394] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Revised: 03/10/2021] [Accepted: 03/18/2021] [Indexed: 05/02/2023]
Abstract
Swept source optical coherence tomography (SS-OCT) enables volumetric imaging of subsurface structure. However, applications requiring wide fields of view (FOV), rapid imaging, and higher resolutions have been challenging because multi-MHz axial scan (A-scan) rates are needed. We describe a microelectromechanical systems vertical cavity surface-emitting laser (MEMS-VCSEL) SS-OCT technology for A-scan rates of 2.4 and 3.0 MHz. Sweep to sweep calibration and resampling are performed using dual channel acquisition of the OCT signal and a Mach Zehnder interferometer signal, overcoming inherent optical clock limitations and enabling higher performance. We demonstrate ultrahigh speed structural SS-OCT and OCT angiography (OCTA) imaging of the swine gastrointestinal tract using a suite of miniaturized brushless motor probes, including a 3.2 mm diameter micromotor OCT catheter, a 12 mm diameter tethered OCT capsule, and a 12 mm diameter widefield OCTA probe. MEMS-VCSELs promise to enable ultrahigh speed SS-OCT with a scalable, low cost, and manufacturable technology, suitable for a diverse range of imaging applications.
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Affiliation(s)
- Jason Zhang
- Department of Electrical Engineering and Computer Science, Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
- These authors contributed equally to this work
| | - Tan Nguyen
- Department of Electrical Engineering and Computer Science, Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
- These authors contributed equally to this work
| | - Benjamin Potsaid
- Department of Electrical Engineering and Computer Science, Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
- Advanced Imaging Group, Thorlabs Inc., Newton, NJ 07860, USA
| | | | | | - Siyu Chen
- Department of Electrical Engineering and Computer Science, Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Jinxi Li
- Department of Electrical Engineering and Computer Science, Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Kaicheng Liang
- Department of Electrical Engineering and Computer Science, Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Alex Cable
- Advanced Imaging Group, Thorlabs Inc., Newton, NJ 07860, USA
| | - Giovanni Traverso
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
- Division of Gastroenterology, Massachusetts General Hospital, Boston, MA 02114, USA
- Division of Gastroenterology, Brigham and Women’s Hospital, Boston, MA 02115, USA
- Harvard Medical School, Boston, MA 02115, USA
| | - Hiroshi Mashimo
- Harvard Medical School, Boston, MA 02115, USA
- Veterans Affairs Boston Healthcare System, Boston, MA 02132, USA
| | - James G. Fujimoto
- Department of Electrical Engineering and Computer Science, Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
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44
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Kim Y, Lippok N, Vakoc BJ. Multi-beam OCT imaging based on an integrated, free-space interferometer. BIOMEDICAL OPTICS EXPRESS 2021; 12:100-109. [PMID: 33520379 PMCID: PMC7818951 DOI: 10.1364/boe.408703] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Revised: 10/27/2020] [Accepted: 10/28/2020] [Indexed: 06/12/2023]
Abstract
While it is a common practice to increase the speed of swept-source optical coherence tomography (OCT) systems by using a high-speed source, this approach may not always be optimal. Parallelization in the form of multiple imaging beams is an alternative approach, but scalable and low-loss multi-beam OCT architectures are needed to capitalize on its advantages. In this study, we demonstrate an eight-beam OCT system using an interferometer architecture comprising planar lightwave circuits (PLC) splitters, V-groove assemblies (VGA), and optical ribbon fibers. We achieved an excess loss and heterodyne efficiency on each channel that was close to that of single-beam systems. In vivo structural imaging of a human finger and OCT angiography imaging of a mouse ear was performed to demonstrate the imaging performance of the system. This work provides further evidence supporting multi-beam architectures as a viable strategy for increasing OCT imaging speed.
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Affiliation(s)
- Yongjoo Kim
- Wellman Center for Photomedicine, Massachusetts General Hospital, 40 Blossom St., Boston, MA 02114, USA
- Harvard Medical School, 25 Shattuck Street, Boston, MA 02115, USA
| | - Norman Lippok
- Wellman Center for Photomedicine, Massachusetts General Hospital, 40 Blossom St., Boston, MA 02114, USA
- Harvard Medical School, 25 Shattuck Street, Boston, MA 02115, USA
| | - Benjamin J. Vakoc
- Wellman Center for Photomedicine, Massachusetts General Hospital, 40 Blossom St., Boston, MA 02114, USA
- Harvard Medical School, 25 Shattuck Street, Boston, MA 02115, USA
- Harvard-MIT Division of Health Sciences and Technology, Cambridge, MA 02139, USA
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45
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Qin J, An L. Optical Coherence Tomography for Ophthalmology Imaging. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2021; 3233:197-216. [PMID: 34053029 DOI: 10.1007/978-981-15-7627-0_10] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Optical coherence tomography (OCT) is a depth-resolved imaging modality, which is able to achieve micrometer-scale resolution within biological tissue noninvasively. In the past 30 years, researchers all around the world had made several essential efforts on techniques relevant to OCT. OCT has become a routine process for eye diseases with different types. In this chapter, the three important stages in the development of OCT are briefly illustrated, including the time domain OCT (TD-OCT), the frequency domain OCT (FD-OCT) and the optical coherence tomography angiography (OCTA). Each of the technique has made great progress for use on living human eye imaging in clinical applications. TD-OCT was first proposed and commercialized, which is able to achieve acceptable 2D depth-resolved cross-sectional images of human retina in vivo. FD-OCT was the upgraded OCT technique compared with TD-OCT. By capturing the coherent signal within the Fourier space, the FD-OCT could improve the image sensitivity compared with TD-OCT, and achieve dozens of kilo hertz imaging speed. OCTA is the newest developments of OCT technique, which is able to visualize the micro vasculature networks of human retina in vivo. With OCTA technique, the newest ophthalmologic OCT system is able to achieve detailed diagnosis for both micro-structure and vasculature abnormalities for clinical applications. The further development of OCT technique on imaging speed, contrast, resolution, field of view, and so on will make OCT to be a more powerful tool for clinical usages.
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Affiliation(s)
- Jia Qin
- Innovation and Entrepreneurship Teams Project of Guangdong Pearl River Talents Program, Guangdong Weiren Meditech Co., Ltd, Foshan, Guangdong, People's Republic of China
| | - Lin An
- Innovation and Entrepreneurship Teams Project of Guangdong Pearl River Talents Program, Guangdong Weiren Meditech Co., Ltd, Foshan, Guangdong, People's Republic of China
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46
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Butler SM, Singaravelu PKJ, O'Faolain L, Hegarty SP. Long cavity photonic crystal laser in FDML operation using an akinetic reflective filter. OPTICS EXPRESS 2020; 28:38813-38821. [PMID: 33379441 DOI: 10.1364/oe.410525] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Accepted: 11/04/2020] [Indexed: 06/12/2023]
Abstract
A novel configuration of a Fourier domain mode locked (FDML) laser based on silicon photonics platform is presented in this work that exploits the narrowband reflection spectrum of a photonic crystal (PhC) cavity resonator. Configured as a linear Fabry-Perot laser, forward biasing of a p-n junction on the PhC cavity allowed for thermal tuning of the spectrum. The modulation frequency applied to the reflector equalled the inverse roundtrip time of the long cavity resulting in stable FDML operation over the swept wavelength range. An interferometric phase measurement measured the sweeping instantaneous frequency of the laser. The silicon photonics platform has potential for very compact implementation, and the electro-optic modulation method opens the possibility of modulation speeds far beyond those of mechanical filters.
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47
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Huang D, Li F, He Z, Cheng Z, Shang C, Wai PKA. 400 MHz ultrafast optical coherence tomography. OPTICS LETTERS 2020; 45:6675-6678. [PMID: 33325868 DOI: 10.1364/ol.409607] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Accepted: 11/06/2020] [Indexed: 05/18/2023]
Abstract
An ultrafast time-stretched swept source with a sweep rate of 400 MHz is demonstrated based on the buffering of a 100 MHz femtosecond laser pulse train. To the best of our knowledge, this is the highest sweep rate of swept sources for optical coherence tomography (OCT) that has been reported. With a 10 dB sweep range of ∼100nm, an axial resolution of 19 µm is obtained in the OCT. OCT imaging of high-speed rotating disks is demonstrated. A composite complex apodization method is proposed and demonstrated to enhance the signal to noise ratio in the OCT imaging.
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48
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Pfeiffer T, Göb M, Draxinger W, Karpf S, Kolb JP, Huber R. Flexible A-scan rate MHz-OCT: efficient computational downscaling by coherent averaging. BIOMEDICAL OPTICS EXPRESS 2020; 11:6799-6811. [PMID: 33282524 PMCID: PMC7687947 DOI: 10.1364/boe.402477] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Revised: 09/18/2020] [Accepted: 09/28/2020] [Indexed: 05/29/2023]
Abstract
In order to realize adjustable A-scan rates of fast optical coherence tomography (OCT) systems, we investigate averaging of OCT image data acquired with a MHz-OCT system based on a Fourier Domain Mode Locked (FDML) laser. Increased system sensitivity and image quality can be achieved with the same system at the cost of lower imaging speed. Effectively, the A-scan rate can be reduced in software by a freely selectable factor. We demonstrate a detailed technical layout of the strategies necessary to achieve efficient coherent averaging. Since there are many new challenges specific to coherent averaging in swept source MHz-OCT, we analyze them point by point and describe the appropriate solutions. We prove that coherent averaging is possible at MHz OCT-speed without special interferometer designs or digital phase stabilization. We find, that in our system up to ∼100x coherent averaging is possible while achieving a sensitivity increase close to the ideal values. This corresponds to a speed reduction from 3.3 MHz to 33 kHz and a sensitivity gain of 20 dB. We show an imaging comparison between coherent and magnitude averaging of a human finger knuckle joint in vivo with 121 dB sensitivity for the coherent case. Further, the benefits of computational downscaling in low sensitivity MHz-OCT systems are analyzed.
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Affiliation(s)
- Tom Pfeiffer
- Institut für Biomedizinische Optik, Universität zu Lübeck, Peter-Monnik-Weg 4, 23562 Lübeck, Germany
- Optores GmbH, Gollierstr. 70, 80339 Munich, Germany
| | - Madita Göb
- Institut für Biomedizinische Optik, Universität zu Lübeck, Peter-Monnik-Weg 4, 23562 Lübeck, Germany
| | - Wolfgang Draxinger
- Institut für Biomedizinische Optik, Universität zu Lübeck, Peter-Monnik-Weg 4, 23562 Lübeck, Germany
| | - Sebastian Karpf
- Institut für Biomedizinische Optik, Universität zu Lübeck, Peter-Monnik-Weg 4, 23562 Lübeck, Germany
| | - Jan Philip Kolb
- Institut für Biomedizinische Optik, Universität zu Lübeck, Peter-Monnik-Weg 4, 23562 Lübeck, Germany
- Medizinisches Laserzentrum Lübeck GmbH, Peter-Monnik-Weg 4, 23562 Lübeck, Germany
| | - Robert Huber
- Institut für Biomedizinische Optik, Universität zu Lübeck, Peter-Monnik-Weg 4, 23562 Lübeck, Germany
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49
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Iyer RR, Žurauskas M, Cui Q, Gao L, Theodore Smith R, Boppart SA. Full-field spectral-domain optical interferometry for snapshot three-dimensional microscopy. BIOMEDICAL OPTICS EXPRESS 2020; 11:5903-5919. [PMID: 33149995 PMCID: PMC7587259 DOI: 10.1364/boe.402796] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Revised: 09/16/2020] [Accepted: 09/16/2020] [Indexed: 05/08/2023]
Abstract
Prevalent techniques in label-free linear optical microscopy are either confined to imaging in two dimensions or rely on scanning, both of which restrict their applications in imaging subtle biological dynamics. In this paper, we present the theoretical basis along with demonstrations supporting that full-field spectral-domain interferometry can be used for imaging samples in 3D with no moving parts in a single shot. Consequently, we propose a novel optical imaging modality that combines low-coherence interferometry with hyperspectral imaging using a light-emitting diode and an image mapping spectrometer, called Snapshot optical coherence microscopy (OCM). Having first proved the feasibility of Snapshot OCM through theoretical modeling and a comprehensive simulation, we demonstrate an implementation of the technique using off-the-shelf components capable of capturing an entire volume in 5 ms. The performance of Snapshot OCM, when imaging optical targets, shows its capability to axially localize and section images over an axial range of ±10 µm, while maintaining a transverse resolution of 0.8 µm, an axial resolution of 1.4 µm, and a sensitivity of up to 80 dB. Additionally, its performance in imaging weakly scattering live cells shows its capability to not only localize the cells in a densely populated culture but also to generate detailed phase profiles of the structures at each depth for long durations. Consolidating the advantages of several widespread optical microscopy modalities, Snapshot OCM has the potential to be a versatile imaging technique for a broad range of applications.
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Affiliation(s)
- Rishyashring R. Iyer
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
- Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Mantas Žurauskas
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Qi Cui
- Department of Bioengineering, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Liang Gao
- Department of Bioengineering, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - R. Theodore Smith
- Department of Ophthalmology, New York Eye and Ear Infirmary of Mount Sinai, New York, NY 10003, USA
| | - Stephen A. Boppart
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
- Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
- Department of Bioengineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
- Carle Illinois College of Medicine, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
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50
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Münter M, Vom Endt M, Pieper M, Casper M, Ahrens M, Kohlfaerber T, Rahmanzadeh R, König P, Hüttmann G, Schulz-Hildebrandt H. Dynamic contrast in scanning microscopic OCT. OPTICS LETTERS 2020; 45:4766-4769. [PMID: 32870852 DOI: 10.1364/ol.396134] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Accepted: 07/07/2020] [Indexed: 05/18/2023]
Abstract
While optical coherence tomography (OCT) provides a resolution down to 1 µm, it has difficulties in visualizing cellular structures due to a lack of scattering contrast. By evaluating signal fluctuations, a significant contrast enhancement was demonstrated using time-domain full-field OCT (FF-OCT), which makes cellular and subcellular structures visible. The putative cause of the dynamic OCT signal is the site-dependent active motion of cellular structures in a sub-micrometer range, which provides histology-like contrast. Here we demonstrate dynamic contrast with a scanning frequency-domain OCT (FD-OCT), which we believe has crucial advantages. Given the inherent sectional imaging geometry, scanning FD-OCT provides depth-resolved images across tissue layers, a perspective known from histopathology, much faster and more efficiently than FF-OCT. Both shorter acquisition times and tomographic depth-sectioning reduce the sensitivity of dynamic contrast for bulk tissue motion artifacts and simplify their correction in post-processing. Dynamic contrast makes microscopic FD-OCT a promising tool for the histological analysis of unstained tissues.
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