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Gong Z, Johnstone MA, Wang RK. iStent insertion orientation and impact on trabecular meshwork motion resolved by optical coherence tomography imaging. JOURNAL OF BIOMEDICAL OPTICS 2024; 29:076008. [PMID: 39070082 PMCID: PMC11283271 DOI: 10.1117/1.jbo.29.7.076008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/29/2024] [Revised: 07/02/2024] [Accepted: 07/03/2024] [Indexed: 07/30/2024]
Abstract
Significance The iStent is a popular device designed for glaucoma treatment, functioning by creating an artificial fluid pathway in the trabecular meshwork (TM) to drain aqueous humor. The assessment of iStent implantation surgery is clinically important. However, current tools offer limited information. Aim We aim to develop innovative assessment strategies for iStent implantation using optical coherence tomography (OCT) to evaluate the position and orientation of the iStent and its biomechanical impact on outflow system dynamics. Approach We examined four iStents in the two eyes of a glaucoma patient. Three-dimensional (3D) OCT structural imaging was conducted for each iStent, and a semi-automated algorithm was developed for iStent segmentation and visualization, allowing precise measurement of position and orientation. In addition, phase-sensitive OCT (PhS-OCT) imaging was introduced to measure the biomechanical impact of the iStent on the outflow system quantified by cumulative displacement (CDisp) of pulse-dependent trabecular TM motion. Results The 3D structural image processed by our algorithm definitively resolved the position and orientation of the iStent in the anterior segment, revealing substantial variations in relevant parameters. PhS-OCT imaging demonstrated significantly higher CDisp in the regions between two iStents compared to locations distant from the iStents in both OD ( p = 0.0075 ) and OS ( p = 0.0437 ). Conclusions Our proposed structural imaging technique improved the characterization of the iStent's placement. The imaging results revealed inherent challenges in achieving precise control of iStent insertion. Furthermore, PhS-OCT imaging unveiled potential biomechanical alterations induced by the iStent. This unique methodology shows potential as a valuable clinical tool for evaluating iStent implantation.
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Affiliation(s)
- Zhaoyu Gong
- University of Washington, Department of Bioengineering, Seattle, Washington, United States
| | - Murray A. Johnstone
- University of Washington, Department of Ophthalmology, Seattle, Washington, United States
| | - Ruikang K. Wang
- University of Washington, Department of Bioengineering, Seattle, Washington, United States
- University of Washington, Department of Ophthalmology, Seattle, Washington, United States
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2
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Shi Y, Liu J, Gong Z, Burger C, Jayaraman V, Wang RK. Multi-channel delay sampling to extend imaging depth in high-speed swept-source OCT systems. OPTICS LETTERS 2024; 49:2217-2220. [PMID: 38691683 PMCID: PMC11275917 DOI: 10.1364/ol.517493] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2024] [Accepted: 03/19/2024] [Indexed: 05/03/2024]
Abstract
We present a multi-channel delay sampling method to extend imaging depth in high-speed swept-source optical coherence tomography (SS-OCT). A balanced detector captures interference signals, converting them into electrical signals, which are then split into N channels, each with fixed time delays determined by the length of electrical cables. Then, they are digitized by an N-channel acquisition card. A calibration procedure is utilized to compensate for non-uniform phase shifts resulting from fixed time delays. The N-channel signals are merged in k-space and resampled to obtain a linearized spectrum, which increases the sampling rate by a factor of N, thereby extending the ranging distance by N times, all without altering k-clock triggering or sacrificing other imaging performance. The signal-to-noise ratio and sensitivity within the original depth range also have been enhanced. This advancement contributes to the improvement of the overall performance of SS-OCT systems.
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Affiliation(s)
- Yaping Shi
- Department of Bioengineering, University of Washington, Seattle, Washington 98105, USA
| | - Jian Liu
- Department of Bioengineering, University of Washington, Seattle, Washington 98105, USA
| | - Zhaoyu Gong
- Department of Bioengineering, University of Washington, Seattle, Washington 98105, USA
| | | | | | - Ruikang K. Wang
- Department of Bioengineering, University of Washington, Seattle, Washington 98105, USA
- Department of Ophthalmology, University of Washington, Seattle, Washington 98109, USA
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3
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Xu J, Yuan X, Huang Y, Qin J, Lan G, Qiu H, Yu B, Jia H, Tan H, Zhao S, Feng Z, An L, Wei X. Deep-learning visualization enhancement method for optical coherence tomography angiography in dermatology. JOURNAL OF BIOPHOTONICS 2023; 16:e202200366. [PMID: 37289020 DOI: 10.1002/jbio.202200366] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2022] [Revised: 05/20/2023] [Accepted: 05/21/2023] [Indexed: 06/09/2023]
Abstract
Optical coherence tomography angiography (OCTA) in dermatology usually suffers from low image quality due to the highly scattering property of the skin, the complexity of cutaneous vasculature, and limited acquisition time. Deep-learning methods have achieved great success in many applications. However, the deep learning approach to improve dermatological OCTA images has not been investigated due to the requirement of high-performance OCTA systems and difficulty of obtaining high-quality images as ground truth. This study aims to generate proper datasets and develop a robust deep learning method to enhance the skin OCTA images. A swept-source skin OCTA system was employed to create low-quality and high-quality OCTA images with different scanning protocols. We propose a model named vascular visualization enhancement generative adversarial network and adopt an optimized data augmentation strategy and perceptual content loss function to achieve better image enhancement effect with small amount of training data. We demonstrate the superiority of the proposed method in skin OCTA image enhancement by quantitative and qualitative comparisons.
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Affiliation(s)
- Jingjiang Xu
- Guangdong-Hong Kong-Macao Joint Laboratory for Intelligent Micro-Nano Optoelectronic Technology, School of Physics and Optoelectronic Engineering, Foshan University, Foshan, China
- Innovation and Entrepreneurship Teams Project of Guangdong Provincial Pearl River Talents Program, Guangdong Weiren Meditech Co. Ltd, Foshan, Guangdong, China
| | - Xing Yuan
- School of Mechatronic Engineering and Automation, Foshan University, Foshan, Guangdong, China
| | - Yanping Huang
- Guangdong-Hong Kong-Macao Joint Laboratory for Intelligent Micro-Nano Optoelectronic Technology, School of Physics and Optoelectronic Engineering, Foshan University, Foshan, China
- Innovation and Entrepreneurship Teams Project of Guangdong Provincial Pearl River Talents Program, Guangdong Weiren Meditech Co. Ltd, Foshan, Guangdong, China
| | - Jia Qin
- Innovation and Entrepreneurship Teams Project of Guangdong Provincial Pearl River Talents Program, Guangdong Weiren Meditech Co. Ltd, Foshan, Guangdong, China
- Department of Ophthalmology, Clinical Medical Institute, Affiliated Hospital, Weifang Medical University, Weifang, Shandong, China
| | - Gongpu Lan
- Guangdong-Hong Kong-Macao Joint Laboratory for Intelligent Micro-Nano Optoelectronic Technology, School of Physics and Optoelectronic Engineering, Foshan University, Foshan, China
- Innovation and Entrepreneurship Teams Project of Guangdong Provincial Pearl River Talents Program, Guangdong Weiren Meditech Co. Ltd, Foshan, Guangdong, China
| | - Haixia Qiu
- Department of Laser Medicine, The First Medical Centre, Chinese PLA General Hospital, Beijing, China
| | - Bo Yu
- Department of Cardiovascular Medicine, The Second Affiliated Hospital of Harbin Medical University, Harbin, Heilongjiang, China
| | - Haibo Jia
- Department of Cardiovascular Medicine, The Second Affiliated Hospital of Harbin Medical University, Harbin, Heilongjiang, China
| | - Haishu Tan
- Guangdong-Hong Kong-Macao Joint Laboratory for Intelligent Micro-Nano Optoelectronic Technology, School of Physics and Optoelectronic Engineering, Foshan University, Foshan, China
| | - Shiyong Zhao
- Tianjin Hengyu Medical Technology Co., Ltd., Tianjin, China
| | - Zhongwu Feng
- School of Mechatronic Engineering and Automation, Foshan University, Foshan, Guangdong, China
| | - Lin An
- Innovation and Entrepreneurship Teams Project of Guangdong Provincial Pearl River Talents Program, Guangdong Weiren Meditech Co. Ltd, Foshan, Guangdong, China
- Department of Ophthalmology, Clinical Medical Institute, Affiliated Hospital, Weifang Medical University, Weifang, Shandong, China
| | - Xunbin Wei
- Biomedical Engineering Department, Peking University, Beijing, China
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4
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He Q, Wang RK. Imaging-photoplethysmography-guided optical microangiography. OPTICS LETTERS 2022; 47:2302-2305. [PMID: 35486784 DOI: 10.1364/ol.452326] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/28/2021] [Accepted: 04/04/2022] [Indexed: 06/14/2023]
Abstract
We report a method to image facial cutaneous microvascular perfusion using wide-field imaging photoplethysmography (iPPG) and handheld swept-source optical coherence tomography (OCT). The iPPG system employs a 16-bit-depth camera to provide a 2D wide-field blood pulsation map that is then used as a positioning guidance for OCT imaging of cutaneous microvasculature. We show the results from iPPG and OCT to demonstrate the ability of guided imaging of cutaneous microvasculature, which is potentially useful for the assessment of skin conditions in dermatology and cosmetology.
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5
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Kirby MA, Tang P, Liou HC, Kuriakose M, Pitre JJ, Pham TN, Ettinger RE, Wang RK, O'Donnell M, Pelivanov I. Probing elastic anisotropy of human skin in vivo with light using non-contact acoustic micro-tapping OCE and polarization sensitive OCT. Sci Rep 2022; 12:3963. [PMID: 35273250 PMCID: PMC8913799 DOI: 10.1038/s41598-022-07775-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2022] [Accepted: 02/24/2022] [Indexed: 12/19/2022] Open
Abstract
Skin broadly protects the human body from undesired factors such as ultraviolet radiation and abrasion and helps conserve body temperature and hydration. Skin's elasticity and its level of anisotropy are key to its aesthetics and function. Currently, however, treatment success is often speculative and subjective, and is rarely based on skin's elastic properties because there is no fast and accurate non-contact method for imaging of skin's elasticity. Here we report on a non-contact and non-invasive method to image and characterize skin's elastic anisotropy. It combines acoustic micro-tapping optical coherence elastography (AμT-OCE) with a nearly incompressible transversely isotropic (NITI) model to quantify skin's elastic moduli. In addition, skin sites were imaged with polarization sensitive optical coherence tomography (PS-OCT) to help define fiber orientation. Forearm skin areas were investigated in five volunteers. Results clearly demonstrate elastic anisotropy of skin in all subjects. AμT-OCE has distinct advantages over competitive techniques because it provides objective, quantitative characterization of skin's elasticity without contact, which opens the door for broad translation into clinical use. Finally, we demonstrate that a combination of multiple OCT modalities (structural OCT, OCT angiography, PS-OCT and AμT-OCE) may provide rich information about skin and can be used to characterize scar.
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Affiliation(s)
- Mitchell A Kirby
- Department of Bioengineering, University of Washington, Seattle, WA, USA
| | - Peijun Tang
- Department of Bioengineering, University of Washington, Seattle, WA, USA
| | - Hong-Cin Liou
- Department of Bioengineering, University of Washington, Seattle, WA, USA
| | - Maju Kuriakose
- Department of Bioengineering, University of Washington, Seattle, WA, USA
| | - John J Pitre
- Department of Bioengineering, University of Washington, Seattle, WA, USA
| | - Tam N Pham
- Harborview Medical Center, University of Washington, Seattle, WA, USA
| | | | - Ruikang K Wang
- Department of Bioengineering, University of Washington, Seattle, WA, USA
| | - Matthew O'Donnell
- Department of Bioengineering, University of Washington, Seattle, WA, USA
| | - Ivan Pelivanov
- Department of Bioengineering, University of Washington, Seattle, WA, USA.
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6
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Ji Y, Zhou K, Ibbotson SH, Wang RK, Li C, Huang Z. A novel automatic 3D stitching algorithm for optical coherence tomography angiography and its application in dermatology. JOURNAL OF BIOPHOTONICS 2021; 14:e202100152. [PMID: 34260830 DOI: 10.1002/jbio.202100152] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Revised: 07/12/2021] [Accepted: 07/12/2021] [Indexed: 06/13/2023]
Abstract
Optical coherence tomography (OCT) and OCT angiography (OCTA) techniques offer numerous advantages in clinical skin applications but the field of view (FOV) of current commercial systems are relatively limited to cover the entire skin lesion. The typical method to expand the FOV is to apply wide field objective lens. However, lateral resolution is often sacrificed when scanning with these lenses. To overcome this drawback, we developed an automated 3D stitching method for creating high-resolution skin structure and vascular volumes with large field of view, which was realized by montaging multiple adjacent OCT and OCTA volumes. The proposed stitching method is demonstrated by montaging 3 × 3 OCT and OCTA volumes (nine OCT/OCTA volumes as one data set with each volume covers 2.5 cm × 2.5 cm area) of healthy thin and thick skin from six volunteers. The proposed stitching protocol achieves high flexibility and repeatable for all the participants. Moreover, according to evaluation of structural similarity index and feature similarity index, our proposed stitched result has a superior similarity to single scanning protocol in large-scaled. We had also verified its improved performance through assessing metrics of vessel contrast-noise-ratio (CNR) from 2.07 ± 0.44 (single large-scaled scanning protocol) to 3.05 ± 0.51 (proposed 3 × 3 sub-volume stitching method).
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Affiliation(s)
- Yubo Ji
- School of Science and Engineering, University of Dundee, Dundee, Scotland, UK
| | - Kanheng Zhou
- School of Science and Engineering, University of Dundee, Dundee, Scotland, UK
| | - Sally Helen Ibbotson
- University of Dundee, Photobiology Unit, Ninewells Hospital and Medical School, Dundee, UK
| | - Ruikang K Wang
- Department of Bioengineering, University of Washington, Seattle, Washington, USA
| | - Chunhui Li
- School of Science and Engineering, University of Dundee, Dundee, Scotland, UK
| | - Zhihong Huang
- School of Science and Engineering, University of Dundee, Dundee, Scotland, UK
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7
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Park KS, Park E, Lee H, Lee HJ, Lee SW, Eom TJ. Phase stable swept-source optical coherence tomography with active mode-locking laser for contrast enhancements of retinal angiography. Sci Rep 2021; 11:16636. [PMID: 34404853 PMCID: PMC8371173 DOI: 10.1038/s41598-021-95982-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Accepted: 07/30/2021] [Indexed: 11/23/2022] Open
Abstract
Swept-source optical coherence tomography (SS-OCT) is an attractive high-speed imaging technique for retinal angiography. However, conventional swept lasers vary the cavity length of the laser mechanically to tune the output wavelength. This causes sweep-timing jitter and hence low phase stability in OCT angiography. Here, we improve an earlier phase-stabilized, akinetic, SS-OCT angiography (OCTA) method by introducing coherent averaging. We develop an active mode-locking (AML) laser as a high phase-stable akinetic swept source for the OCTA system. The phase stability of the improved system was analyzed, and the effects of coherent averaging were validated using a retina phantom. The effectiveness of the coherent averaging method was further confirmed by comparing coherently and conventionally averaged en face images of human retinal vasculature for their contrast-to-noise ratio, signal-to-noise ratio, and vasculature connectivity. The contrast-to-noise ratio was approximately 1.3 times larger when applying the coherent averaging method in the human retinal experiment. Our coherent averaging method with the high phase-stability AML laser source for OCTA provides a valuable tool for studying healthy and diseased retinas.
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Affiliation(s)
- Kwan Seob Park
- Advanced Photonics Research Institute, Gwangju Institute of Science and Technology, 123 Cheomdan-gwagiro, Buk-gu, Gwangju, 61005, South Korea
| | - Eunwoo Park
- Advanced Photonics Research Institute, Gwangju Institute of Science and Technology, 123 Cheomdan-gwagiro, Buk-gu, Gwangju, 61005, South Korea
| | - Hwidon Lee
- Harvard Medical School, Boston, MA, 02115, USA.,Wellman Center for Photomedicine, Harvard Medical School and Massachusetts General Hospital, 40 Blossom Street, Boston, MA, 02114, USA
| | - Hyun-Ji Lee
- Safety Measurement Institute, Korea Research Institute of Standards and Science, 267 Gajeong-ro, Yuseong-gu, Daejeon, 34113, South Korea.,Department of Medical Physics, University of Science and Technology, 217 Gajeong-ro, Yuseong-gu, Daejeon, 34113, South Korea
| | - Sang-Won Lee
- Safety Measurement Institute, Korea Research Institute of Standards and Science, 267 Gajeong-ro, Yuseong-gu, Daejeon, 34113, South Korea.,Department of Medical Physics, University of Science and Technology, 217 Gajeong-ro, Yuseong-gu, Daejeon, 34113, South Korea
| | - Tae Joong Eom
- Advanced Photonics Research Institute, Gwangju Institute of Science and Technology, 123 Cheomdan-gwagiro, Buk-gu, Gwangju, 61005, South Korea.
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8
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Wei S, Kang JU. Stabilizing the phase of swept-source optical coherence tomography by a wrapped Gaussian mixture model. OPTICS LETTERS 2021; 46:2932-2935. [PMID: 34129577 PMCID: PMC9808914 DOI: 10.1364/ol.420898] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Accepted: 05/20/2021] [Indexed: 06/12/2023]
Abstract
The phase of an optical coherence tomography (OCT) signal carries critical information about particle micro-displacements. However, swept-source OCT (SSOCT) suffers from phase instability problems due to trigger jitters from the swept source. In this Letter, a wrapped Gaussian mixture model (WGMM) is proposed to stabilize the phase of SSOCT systems. A closed-form iteration solution of the WGMM is derived using the expectation-maximization algorithm. Necessary approximations are made for real-time graphic processing unit implementation. The performance of the proposed method is demonstrated through ex vivo, in vivo, and flow phantom experiments. The results show the robustness of the method in different application scenarios.
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9
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Liu X, Jiang L, Ke M, Schmetterer L, Barathi VA. Using image data to numerically correct the jitter in polarization depth encoding PS-OCT. OPTICS LETTERS 2021; 46:1692-1695. [PMID: 33793520 DOI: 10.1364/ol.420029] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Accepted: 03/06/2021] [Indexed: 06/12/2023]
Abstract
In swept source polarization depth encoding polarization sensitive optical coherence tomography (PS-OCT), the laser jitter induces additional noise to the polarization sensitive measurement. In this Letter, we developed a numerical algorithm to correct the jitter phases based on the image data using the Mueller matrix calculus. The algorithm was demonstrated on in vivo retina imaging of a guinea pig with a custom-built PS-OCT system. The performance of the proposed algorithm was almost comparable to the conventional method of using a physical calibration signal. By not requiring a hardware generated calibration signal and k-clock, the proposed algorithm is useful to reduce the complexity and the cost of a polarization depth encoding PS-OCT system.
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10
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Wei X, Hormel TT, Jia Y. Phase-stabilized complex-decorrelation angiography. BIOMEDICAL OPTICS EXPRESS 2021; 12:2419-2431. [PMID: 33996238 PMCID: PMC8086438 DOI: 10.1364/boe.420503] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Revised: 03/20/2021] [Accepted: 03/23/2021] [Indexed: 06/12/2023]
Abstract
In this study, we developed a novel phase-stabilized complex-decorrelation (PSCD) optical coherence tomography (OCT) angiography (OCTA) method that can generate high quality OCTA images. This method has been validated using three different types of OCT systems and compared with conventional complex- and amplitude-based OCTA algorithms. Our results suggest that in combination with a pre-processing phase stabilization method, the PSCD method is insensitive to bulk motion phase shifts, less dependent on OCT reflectance than conventional complex methods and demonstrates extended dynamic range of flow signal, in contrast to other two methods.
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Affiliation(s)
- Xiang Wei
- Casey Eye Institute, Oregon Health and Science University, Portland, Oregon 97239, USA
- Department of Biomedical Engineer, Oregon Health and Science University, Portland, Oregon 97239, USA
| | - Tristan T. Hormel
- Casey Eye Institute, Oregon Health and Science University, Portland, Oregon 97239, USA
| | - Yali Jia
- Casey Eye Institute, Oregon Health and Science University, Portland, Oregon 97239, USA
- Department of Biomedical Engineer, Oregon Health and Science University, Portland, Oregon 97239, USA
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11
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Yang Z, Shang J, Liu C, Zhang J, Liang Y. Classification of Salivary Gland Tumors Based on Quantitative Optical Coherence Tomography. Lasers Surg Med 2021; 53:830-837. [PMID: 33442913 DOI: 10.1002/lsm.23370] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Revised: 11/30/2020] [Accepted: 12/11/2020] [Indexed: 12/13/2022]
Abstract
BACKGROUND AND OBJECTIVES Visual inspection is the primary diagnostic method for oral diseases, and its accuracy of diagnosis mainly depends on surgeons' experience. Histological examination is still the golden standard, but it is invasive and time-consuming. In order to address these issues, as a noninvasive imaging technique, optical coherence tomography (OCT) can differentiate oral tissue with advantages of real-time, in situ, and high resolution. The aim of this study is to explore optimal quantitative parameters in OCT images to distinguish different salivary gland tumors. STUDY DESIGN/MATERIALS AND METHODS OCT images of four salivary gland tumors were obtained from 14 patients, including mucoepidermoid carcinoma (MC), adenoid cystic carcinoma (ACC), basal cell adenoma (BCA), and pleomorphic adenoma (PA). Two parameters of optical attenuation coefficient (OAC) and standard deviation (SD) along the depth of OCT signal were combined to create a computational model of classification, and sensitivity/specificity of classification was calculated statistically to evaluate their results. RESULTS A total of 5,919 two-dimensional (2D) OCT images were used for quantitative analysis. The classification sensitivities of 89.6%, 95.0%, 89.5%, 97.8%, and specificities of 97.6%, 99.0%, 98.0%, 98.2%, respectively, were obtained for MC, ACC, BCA, and PA, with the thresholds of 3.6 mm-1 based on OAC and 0.22/0.18 based on SD. CONCLUSION It was demonstrated that OAC and SD could be considered as important parameters in quantitative analysis of OCT images for salivary gland tissue characterization and intraoperative diagnosis. It is of great potential value in promoting the application of this method based on OCT in clinical practice. Lasers Surg. © 2020 Wiley Periodicals LLC.
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Affiliation(s)
- Zihan Yang
- Institute of Modern Optics, Nankai University, Tianjin Key Laboratory of Optoelectronic Sensor and Sensing Network Technology, Tianjin Key Laboratory of Micro-scale Optical Information Science and Technology, Tianjin, 300350, China
| | - Jianwei Shang
- Department of Oral Pathology, Tianjin Stomatological Hospital, Hospital of Stomatology, Nankai University, Tianjin, 300041, China
| | - Chenlu Liu
- Department of Oral Medicine, Tianjin Stomatological Hospital, Hospital of Stomatology, Nankai University, Tianjin, 300041, China
| | - Jun Zhang
- Department of Oral-Maxillofacial Surgery, Tianjin Stomatological Hospital; Hospital of Stomatology, Nankai University, Tianjin, 300041, China
| | - Yanmei Liang
- Institute of Modern Optics, Nankai University, Tianjin Key Laboratory of Optoelectronic Sensor and Sensing Network Technology, Tianjin Key Laboratory of Micro-scale Optical Information Science and Technology, Tianjin, 300350, China
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12
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Imaging Motion: A Comprehensive Review of Optical Coherence Tomography Angiography. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2021; 1310:343-365. [PMID: 33834441 DOI: 10.1007/978-981-33-6064-8_12] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Optical coherence tomography (OCT) is a three-dimensional (3-D) optical imaging technology that provides noninvasive, micrometer resolution images of structural interiors within biological samples with an approximately 1 ~ 2 mm penetration depth. Over the last decades, advances in OCT have revolutionized biomedical imaging by demonstrating a potential of optical biopsy in preclinical and clinical settings. Recently, functional OCT imaging has shown a promise as angiography to visualize cell-perfused vasculatures in the tissue bed in vivo without requiring any exogenous contrast agents. This new technology termed OCT angiography (OCTA) possesses a unique imaging capability of delineating tissue morphology and blood or lymphatic vessels down to capillaries at real-time acquisition rates. For the past 10 years since 2007, OCTA has been proven to be a useful tool to identify disorder or dysfunction in tissue microcirculation from both experimental animal studies and clinical studies in ophthalmology and dermatology. In this section, we overview about OCTA including a basic principle of OCTA explained with simple optical physics, and its scan protocols and post-processing algorithms for acquisition of angiography. Then, potential and challenge of OCTA for clinical settings are shown with outcomes of human studies.
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13
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He Q, Liu T, Wang RK. Handheld swept-source optical coherence tomography guided by smartphone-enabled wide-field autofluorescence photography for imaging facial sebaceous glands. OPTICS LETTERS 2020; 45:5704-5707. [PMID: 33057264 DOI: 10.1364/ol.405765] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Accepted: 09/08/2020] [Indexed: 05/28/2023]
Abstract
We report a method to image facial sebaceous glands (SGs) using smartphone-enabled wide-field autofluorescence photography (AFP) and handheld swept-source optical coherence tomography (SS-OCT). Smartphone-enabled AFP provides a 2D wide-field fluorescence image that is used both as a functional mapping of the sebum and a positioning guidance for OCT imaging of the SG. Following the guidance, handheld SS-OCT conducts the volume scan to investigate depth-resolved conditions of the SG in the selected regions of interest. We show the results from smartphone-enabled AFP and handheld SS-OCT to demonstrate the ability of our method to image facial SGs, potentially useful for the assessment of skin conditions in dermatology and cosmetology.
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14
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Tan B, Sim R, Chua J, Wong DWK, Yao X, Garhöfer G, Schmidl D, Werkmeister RM, Schmetterer L. Approaches to quantify optical coherence tomography angiography metrics. ANNALS OF TRANSLATIONAL MEDICINE 2020; 8:1205. [PMID: 33241054 PMCID: PMC7576021 DOI: 10.21037/atm-20-3246] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Optical coherence tomography (OCT) has revolutionized the field of ophthalmology in the last three decades. As an OCT extension, OCT angiography (OCTA) utilizes a fast OCT system to detect motion contrast in ocular tissue and provides a three-dimensional representation of the ocular vasculature in a non-invasive, dye-free manner. The first OCT machine equipped with OCTA function was approved by U.S. Food and Drug Administration in 2016 and now it is widely applied in clinics. To date, numerous methods have been developed to aid OCTA interpretation and quantification. In this review, we focused on the workflow of OCTA-based interpretation, beginning from the generation of the OCTA images using signal decorrelation, which we divided into intensity-based, phase-based and phasor-based methods. We further discussed methods used to address image artifacts that are commonly observed in clinical settings, to the algorithms for image enhancement, binarization, and OCTA metrics extraction. We believe a better grasp of these technical aspects of OCTA will enhance the understanding of the technology and its potential application in disease diagnosis and management. Moreover, future studies will also explore the use of ocular OCTA as a window to link ocular vasculature to the function of other organs such as the kidney and brain.
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Affiliation(s)
- Bingyao Tan
- Institute for Health Technologies, Nanyang Technological University, Singapore, Singapore.,Singapore Eye Research Institute, Singapore National Eye Centre, Singapore, Singapore.,SERI-NTU Advanced Ocular Engineering (STANCE) Program, Nanyang Technological University, Singapore, Singapore
| | - Ralene Sim
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore, Singapore
| | - Jacqueline Chua
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore, Singapore.,Academic Clinical Program, Duke-NUS Medical School, Singapore, Singapore
| | - Damon W K Wong
- Institute for Health Technologies, Nanyang Technological University, Singapore, Singapore.,Singapore Eye Research Institute, Singapore National Eye Centre, Singapore, Singapore.,SERI-NTU Advanced Ocular Engineering (STANCE) Program, Nanyang Technological University, Singapore, Singapore
| | - Xinwen Yao
- Institute for Health Technologies, Nanyang Technological University, Singapore, Singapore.,Singapore Eye Research Institute, Singapore National Eye Centre, Singapore, Singapore.,SERI-NTU Advanced Ocular Engineering (STANCE) Program, Nanyang Technological University, Singapore, Singapore
| | - Gerhard Garhöfer
- Department of Clinical Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Doreen Schmidl
- Department of Clinical Pharmacology, Medical University of Vienna, Vienna, Austria
| | - René M Werkmeister
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | - Leopold Schmetterer
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore, Singapore.,SERI-NTU Advanced Ocular Engineering (STANCE) Program, Nanyang Technological University, Singapore, Singapore.,Academic Clinical Program, Duke-NUS Medical School, Singapore, Singapore.,Department of Clinical Pharmacology, Medical University of Vienna, Vienna, Austria.,Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria.,Yong Loo Lin School of Medicine, National University of Singapore and National University Health System, Singapore, Singapore.,Department of Ophthalmology, Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore.,Institute of Molecular and Clinical Ophthalmology, Basel, Switzerland
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15
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Le N, Subhash HM, Kilpatrick-Liverman L, Wang RK. Noninvasive multimodal imaging by integrating optical coherence tomography with autofluorescence imaging for dental applications. JOURNAL OF BIOPHOTONICS 2020; 13:e202000026. [PMID: 32191393 DOI: 10.1002/jbio.202000026] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Revised: 03/09/2020] [Accepted: 03/16/2020] [Indexed: 05/25/2023]
Abstract
We report the development of an integrated multifunctional imaging system capable of providing anatomical (optical coherence tomography, OCT), functional (OCT angiography, OCTA) and molecular imaging (light-induced autofluorescence, LIAF) for in vivo dental applications. Blue excitation light (405 nm) was used for LIAF imaging, while the OCT was powered by a 1310 nm swept laser source. A red-green-blue digital camera, with a 450 nm cut-on broadband optical filter, was used for LIAF detection. The exciting light source and camera were integrated directly with the OCT scanning probe. The integrated system used two noninvasive imaging modalities to improve the speed of in vivo OCT data collection and to better target the regions of interest. The newly designed system maintained the ability to detect differences between healthy and hypomineralized teeth, identify dental biofilm and visualize the microvasculature of gingival tissue. The development of the integrated OCT-LIAF system provides an opportunity to conduct clinical studies more efficiently, examining changes in oral conditions over time.
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Affiliation(s)
- Nhan Le
- Department of Bioengineering, University of Washington, Seattle, WA, USA
| | - Hrebesh M Subhash
- Clinical Method Development - Oral Care, Colgate-Palmolive Company, Piscataway, NJ, USA
| | | | - Ruikang K Wang
- Department of Bioengineering, University of Washington, Seattle, WA, USA
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16
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Xie Z, Wang G, Cheng Y, Zhang Q, Le MN, Wang RK. Optical coherence tomography angiography measures blood pulsatile waveforms at variable tissue depths. Quant Imaging Med Surg 2020; 11:907-917. [PMID: 33654664 DOI: 10.21037/qims-20-778] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Background Photoplethysmography (PPG) is routinely used to detect the blood pulse signal from skin tissue beds in clinics. However, the origin of the PPG signal remains controversial. The purpose of this study is to explore optical coherence tomography angiography (OCTA) to indicate pulsatile waveforms in the papillary plexus and dermal plexus separately under different hand elevations. Method Optical microangiography (OMAG) algorithm was used to obtain a 3D OCTA signals, from which the depth-resolved pulsatile blood flow signals were extracted from different skin vascular plexus. The systolic amplitude, crest time, and delta T were measured from the OCTA pulsatile signals when the hand was placed at the positions of 50 cm below, 0 cm, and 50 cm above the heart level. Results The pulse signal integrated from all the depths has a similar waveform to that of the PPG and showed the same morphological change at different hand elevations. The pulsatile patterns from the papillary plexus and dermal plexus showed distinct morphological changes at different local blood pressure. Less amplitude difference was found from papillary plexus comparing to that of the dermal plexus. Crest time was found in an increasing trend in the OCTA pulsatile waveform from both plexuses when the arm was raised from the position below to above the heart level. In contrast, a decreasing trend of Delta T was detected in the dermal pulsatile but was not observed from that of the papillary plexus, indicating that vascular resistance associated with the arm elevations does not necessarily have the same effect on the two plexuses. Conclusions OCTA can provide depth-resolved pulsatile waveforms within different microvascular plexus within tissue skin beds. This technique could open doors to understanding the mechanisms of how blood flow changes at different skin circulatory plexus.
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Affiliation(s)
- Zhiying Xie
- Department of Bioengineering, University of Washington, Seattle, WA, USA
| | - Geng Wang
- Department of Bioengineering, University of Washington, Seattle, WA, USA
| | - Yuxuan Cheng
- Department of Bioengineering, University of Washington, Seattle, WA, USA
| | - Qinqin Zhang
- Department of Bioengineering, University of Washington, Seattle, WA, USA
| | - Minh Nhan Le
- Department of Bioengineering, University of Washington, Seattle, WA, USA
| | - Ruikang K Wang
- Department of Bioengineering, University of Washington, Seattle, WA, USA
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17
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Brady EL, Kirby MA, Olszewski E, Grosjean P, Johansson F, Davis J, Wang RK, Stevens KR. Guided vascularization in the rat heart leads to transient vessel patterning. APL Bioeng 2020; 4:016105. [PMID: 32161835 PMCID: PMC7058427 DOI: 10.1063/1.5122804] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Accepted: 02/10/2020] [Indexed: 12/29/2022] Open
Abstract
Recent progress in the production and maturation of iPSC-cardiomyocytes has facilitated major advances in building bioartificial heart tissue with functional cardiomyocytes. Despite this progress, vascularizing these constructs continues to be a barrier to clinical application. One emerging strategy for vascularization uses aligned "cords" of endothelial cells in tissue grafts to guide assembly of chimeric microvessels upon graft implantation. Here, we test whether this approach can guide vascularization of a bioartificial tissue implanted on the rat heart. We find that patterned cords of human endothelial cells anastomose and become perfused with host blood by 3 days post-implantation. Immunohistochemical staining confirmed that graft-derived micro-vessels persist in the patch for 7 days. Furthermore, we noted a shift in distribution of vessels in the patch from patterned cord-associated clustering at 3 days to a more diffuse distribution pattern at 7 days. This loss of patterning corresponded to an infiltration of CD68+ cells and an increase in collagen within the patch. Upon further engraftment of patches containing both cords and human cardiomyocytes, we identified human cardiomyocytes and graft derived vasculature at the time of explant. Our findings show that patterned endothelial cords guide transient vessel patterning on the rat heart. Our results also suggest that future work should be directed at further adapting vascularization strategies to the epicardial environment and add to an important emerging dialog in cardiac cell therapy that points to the need to characterize host response prior to or in parallel with efficacy studies.
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Affiliation(s)
| | - Mitchell A. Kirby
- Department of Bioengineering, University of Washington, Seattle, Washington 98195, USA
| | | | - Parker Grosjean
- Department of Bioengineering, University of Washington, Seattle, Washington 98195, USA
| | - Fredrik Johansson
- Department of Bioengineering, University of Washington, Seattle, Washington 98195, USA
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18
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Meiburger KM, Chen Z, Sinz C, Hoover E, Minneman M, Ensher J, Kittler H, Leitgeb RA, Drexler W, Liu M. Automatic skin lesion area determination of basal cell carcinoma using optical coherence tomography angiography and a skeletonization approach: Preliminary results. JOURNAL OF BIOPHOTONICS 2019; 12:e201900131. [PMID: 31100191 PMCID: PMC7065618 DOI: 10.1002/jbio.201900131] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Revised: 05/15/2019] [Accepted: 05/16/2019] [Indexed: 05/05/2023]
Abstract
Cutaneous blood flow plays a key role in numerous physiological and pathological processes and has significant potential to be used as a biomarker to diagnose skin diseases such as basal cell carcinoma (BCC). The determination of the lesion area and vascular parameters within it, such as vessel density, is essential for diagnosis, surgical treatment and follow-up procedures. Here, an automatic skin lesion area determination algorithm based on optical coherence tomography angiography (OCTA) images is presented for the first time. The blood vessels are segmented within the OCTA images and then skeletonized. Subsequently, the skeleton is searched over the volume and numerous quantitative vascular parameters are calculated. The vascular density is then used to segment the lesion area. The algorithm is tested on both nodular and superficial BCC, and comparing with dermatological and histological results, the proposed method provides an accurate, non-invasive, quantitative and automatic tool for BCC lesion area determination.
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Affiliation(s)
- Kristen M. Meiburger
- Biolab, Department of Electronics and TelecommunicationsPolitecnico di TorinoTorinoItaly
| | - Zhe Chen
- Center for Medical Physics and Biomedical EngineeringMedical University of ViennaViennaAustria
| | - Christoph Sinz
- Department of DermatologyMedical University of ViennaViennaAustria
| | | | | | | | - Harald Kittler
- Department of DermatologyMedical University of ViennaViennaAustria
| | - Rainer A. Leitgeb
- Center for Medical Physics and Biomedical EngineeringMedical University of ViennaViennaAustria
| | - Wolfgang Drexler
- Center for Medical Physics and Biomedical EngineeringMedical University of ViennaViennaAustria
| | - Mengyang Liu
- Center for Medical Physics and Biomedical EngineeringMedical University of ViennaViennaAustria
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19
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An amplitude variation Field subtraction technique for visualization of vasculature of the human eye. Biomed Signal Process Control 2019. [DOI: 10.1016/j.bspc.2019.101573] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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20
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Optical coherence tomography angiography in preclinical neuroimaging. Biomed Eng Lett 2019; 9:311-325. [PMID: 31456891 DOI: 10.1007/s13534-019-00118-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2019] [Revised: 04/29/2019] [Accepted: 06/27/2019] [Indexed: 01/22/2023] Open
Abstract
Preclinical neuroimaging allows for the assessment of brain anatomy, connectivity, and function in laboratory animals, such as mice and this imaging field has been a rapidly growing aimed at bridging the translation gap between animal and human research. The progress in the animal research could be accelerated by high-resolution in vivo optical imaging technologies. Optical coherence tomography-based angiography (OCTA) estimates the scattering from moving red blood cells, providing the visualization of functional micro-vessel networks within tissue beds in vivo without a need for exogenous contrast agents. Recent advancement of OCTA methods have expanded its application to neuroimaging of small animal models of brain disorders. In this paper, we overview the recent development of OCTA techniques for blood flow imaging and its preclinical applications in neuroimaging. In specific, a summary of preclinical OCTA studies for traumatic brain injury, cerebral stroke, and aging brain on mice is reviewed.
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21
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Burwood GWS, Fridberger A, Wang RK, Nuttall AL. Revealing the morphology and function of the cochlea and middle ear with optical coherence tomography. Quant Imaging Med Surg 2019; 9:858-881. [PMID: 31281781 PMCID: PMC6571188 DOI: 10.21037/qims.2019.05.10] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2019] [Accepted: 05/09/2019] [Indexed: 01/17/2023]
Abstract
Optical coherence tomography (OCT) has revolutionized physiological studies of the hearing organ, the vibration and morphology of which can now be measured without opening the surrounding bone. In this review, we provide an overview of OCT as used in the otological research, describing advances and different techniques in vibrometry, angiography, and structural imaging.
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Affiliation(s)
- George W. S. Burwood
- Department of Otolaryngology, Oregon Hearing Research Center/HNS, Oregon Health & Science University, Portland, OR, USA
| | - Anders Fridberger
- Department of Otolaryngology, Oregon Hearing Research Center/HNS, Oregon Health & Science University, Portland, OR, USA
- Department of Clinical and Experimental Medicine, Section for Neurobiology, Linköping University, Linköping, Sweden
| | - Ruikang K. Wang
- Department of Bioengineering and Department of Ophthalmology, University of Washington, Seattle, WA, USA
| | - Alfred L. Nuttall
- Department of Otolaryngology, Oregon Hearing Research Center/HNS, Oregon Health & Science University, Portland, OR, USA
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22
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Yamanari M, Uematsu S, Ishihara K, Ikuno Y. Parallel detection of Jones-matrix elements in polarization-sensitive optical coherence tomography. BIOMEDICAL OPTICS EXPRESS 2019; 10:2318-2336. [PMID: 31149375 PMCID: PMC6524579 DOI: 10.1364/boe.10.002318] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Revised: 03/16/2019] [Accepted: 03/18/2019] [Indexed: 06/09/2023]
Abstract
The polarization properties of a sample can be characterized using a Jones matrix. To measure the Jones matrix without assumptions of the sample, two different incident states of polarization are usually used. This requirement often causes certain drawbacks in polarization-sensitive optical coherence tomography (PS-OCT), e.g., a decrease in the effective A-scan rate or axial depth range, if a multiplexing scheme is used. Because both the A-scan rate and axial depth range are important for clinical applications, including the imaging of an anterior eye segment, a new PS-OCT method that does not have these drawbacks is desired. Here, we present a parallel-detection approach that maintains the same A-scan rate and axial measurement range as conventional OCT. The interferometer consists of fiber-optic components, most of which are polarization-maintaining components with fast-axis blocking free from polarization management. When a parallel detection is implemented using swept-source OCT (SS-OCT), synchronization between the A-scans and synchronization between the detection channels have critical effects on the Jones-matrix measurement. Because it is difficult to achieve perfect synchronization using only hardware, we developed a solution using a numerical correction with signals from a static mirror. Using the developed system, we demonstrate the imaging of an anterior eye segment from the cornea to the back surface of the crystalline lens.
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Affiliation(s)
- Masahiro Yamanari
- Engineering Department, Tomey Corporation, 2-11-33 Noritakeshinmachi, Nishiku, Nagoya, Aichi, 451-0051, Japan
| | - Sato Uematsu
- Department of Ophthalmology, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Kenji Ishihara
- Engineering Department, Tomey Corporation, 2-11-33 Noritakeshinmachi, Nishiku, Nagoya, Aichi, 451-0051, Japan
| | - Yasushi Ikuno
- Ikuno Eye Center, 2-9-10 3F Juso-Higashi, Yodogawaku, Osaka, Osaka, 532-0023, Japan
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23
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Song S, Zhou K, Xu JJ, Zhang Q, Lyu S, Wang R. Development of a clinical prototype of a miniature hand-held optical coherence tomography probe for prematurity and pediatric ophthalmic imaging. BIOMEDICAL OPTICS EXPRESS 2019; 10:2383-2398. [PMID: 31143494 DOI: 10.1364/boe.10.002383] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Revised: 04/06/2019] [Accepted: 04/08/2019] [Indexed: 02/05/2023]
Abstract
We report a novel design and operation of a highly integrated miniature handheld OCT probe, with high-speed angiography function that can be used in clinical settings for young children and infants, providing rapid, non-invasive structural and angiographic imaging of the retina and choroid. The imaging system is operated at 200 kHz, with 3D OCT and OCTA scan time of 0.8 and 3.2 seconds, respectively, and the scanning angle on the pupil is ± 36°, covering the full perifoveal region. Operator assisting features of the direct-view iris camera and on-probe display are integrated into the hand-held probe, and the fixation target can display animations to attract the attention of young subjects. Compared to conventional OCT systems, the high-speed hand-held OCT system significantly improves the operator's experience and scanning efficiency, which is important for imaging infants. Imaging results indicate a significant reduction in total time consumption in pediatric ophthalmic imaging sessions, as well as the image quality of OCT angiography.
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Affiliation(s)
- Shaozhen Song
- Department of Bioengineering, University of Washington, Seattle, Washington, USA
| | - Kanheng Zhou
- Department of Bioengineering, University of Washington, Seattle, Washington, USA.,School of Science and Engineering, University of Dundee, Dundee, Scotland, United Kingdom
| | - Jing Jiang Xu
- Department of Bioengineering, University of Washington, Seattle, Washington, USA
| | - Qinqin Zhang
- Department of Bioengineering, University of Washington, Seattle, Washington, USA
| | - Shuyuan Lyu
- Department of Bioengineering, University of Washington, Seattle, Washington, USA.,Department of Ophthalmology, West China Hospital, Sichuan University, Chengdu, China
| | - Ruikang Wang
- Department of Bioengineering, University of Washington, Seattle, Washington, USA.,Department of Ophthalmology, University of Washington, Seattle, Washington, USA
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24
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Le NM, Song S, Zhou H, Xu J, Li Y, Sung CE, Sadr A, Chung KH, Subhash HM, Kilpatrick L, Wang RK. A noninvasive imaging and measurement using optical coherence tomography angiography for the assessment of gingiva: An in vivo study. JOURNAL OF BIOPHOTONICS 2018; 11:e201800242. [PMID: 30112807 DOI: 10.1002/jbio.201800242] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Accepted: 08/13/2018] [Indexed: 05/20/2023]
Abstract
Gingiva is the soft tissue that surrounds and protects the teeth. Healthy gingiva provides an effective barrier to periodontal insults to deeper tissue, thus is an important indicator to a patient's periodontal health. Current methods in assessing gingival tissue health, including visual observation and physical examination with probing on the gingiva, are qualitative and subjective. They may become cumbersome when more complex cases are involved, such as variations in gingival biotypes where feature and thickness of the gingiva are considered. A noninvasive imaging technique providing depth-resolved structural and vascular information is necessary for an improved assessment of gingival tissue and more accurate diagnosis of periodontal status. We propose a three-dimensional (3D) imaging technique, optical coherence tomography (OCT), to perform in situ imaging on human gingiva. Ten volunteers (five male, five female, age 25-35) were recruited; and the labial gingival tissues of upper incisors were scanned using the combined use of state-of-the-art swept-source OCT and OCT angiography (OCTA). Information was collected describing the 3D tissue microstructure and capillary vasculature of the gingiva within a penetration depth of up to 2 mm. Results indicate significant structural and vascular differences between the two extreme gingival biotypes (ie, thick and thin gingiva), and demonstrate special features of vascular arrangement and characteristics in gingival inflammation. Within the limit of this study, the OCT/OCTA technique is feasible in quantifying different attributes of gingival biotypes and the severity of gingival inflammation.
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Affiliation(s)
- Nhan M Le
- Department of Bioengineering, University of Washington, Seattle, Washington
| | - Shaozhen Song
- Department of Bioengineering, University of Washington, Seattle, Washington
| | - Hao Zhou
- Department of Bioengineering, University of Washington, Seattle, Washington
| | - Jingjiang Xu
- Department of Bioengineering, University of Washington, Seattle, Washington
| | - Yuandong Li
- Department of Bioengineering, University of Washington, Seattle, Washington
| | - Cheng-En Sung
- Department of Periodontology, School of Dentistry, Tri-Service General Hospital and National Defense Medical Center, Taipei, Taiwan
- Department of Restorative Dentistry, University of Washington, Seattle, Washington
| | - Alireza Sadr
- Department of Restorative Dentistry, University of Washington, Seattle, Washington
| | - Kwok-Hung Chung
- Department of Restorative Dentistry, University of Washington, Seattle, Washington
| | - Hrebesh M Subhash
- Clinical Method Development - Oral Care, Colgate-Palmolive Company, Piscataway, New Jersey
| | - Latonya Kilpatrick
- Clinical Method Development - Oral Care, Colgate-Palmolive Company, Piscataway, New Jersey
| | - Ruikang K Wang
- Department of Bioengineering, University of Washington, Seattle, Washington
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25
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Moon S, Chen Z. Phase-stability optimization of swept-source optical coherence tomography. BIOMEDICAL OPTICS EXPRESS 2018; 9:5280-5295. [PMID: 30460128 PMCID: PMC6238911 DOI: 10.1364/boe.9.005280] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2018] [Revised: 09/21/2018] [Accepted: 09/25/2018] [Indexed: 05/18/2023]
Abstract
Phase-resolved imaging of swept-source optical coherence tomography (SS-OCT) is subject to phase measurement instabilities involved with the sweep variation of a frequency-swept source. In general, optically generated timing references are utilized to track the variations imposed on OCT signals. But they might not be accurately synchronized due to relative time delays. In this research, we investigated the impact of the signal delays on the timing instabilities and the consequent deviations of the measured phases. We considered two types of timing signals utilized in a popular digitizer operation mode: a sweep trigger from a fiber Bragg grating (FBG) that initiates a series of signal sampling actions clocked by an auxiliary Mach-Zehnder interferometer (MZI) signal. We found that significant instabilities were brought by the relative delays through incoherent timing corrections and timing collisions between the timing references. The best-to-worst ratio of the measured phase errors was higher than 200 while only the signal delays varied. Noise-limited phase stability was achieved with a wide dynamic range of OCT signals above 50 dB in optimized delays. This demonstrated that delay optimization is very effective in phase stabilization of SS-OCT.
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Affiliation(s)
- Sucbei Moon
- Beckman Laser Institute, University of California, Irvine, Irvine, CA 92617, USA
- Department of Physics, Kookmin University, Seoul 02707, South Korea
| | - Zhongping Chen
- Beckman Laser Institute, University of California, Irvine, Irvine, CA 92617, USA
- Department of Biomedical Engineering, University of California, Irvine, Irvine, CA 92697, USA
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26
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Lal C, Subhash HM, Alexandrov S, Leahy MJ. Feasibility of correlation mapping optical coherence tomography angiographic technique using a 200 kHz vertical-cavity surface-emitting laser source for in vivo microcirculation imaging applications. APPLIED OPTICS 2018; 57:E224-E231. [PMID: 30117906 DOI: 10.1364/ao.57.00e224] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Accepted: 07/04/2018] [Indexed: 05/19/2023]
Abstract
Optical coherence tomography (OCT) angiography is a well-established in vivo imaging technique to assess the overall vascular morphology of tissues and is an emerging field of research for the assessment of blood flow dynamics and functional parameters such as oxygen saturation. In this study, we present a modified scanning-based correlation mapping OCT using a 200 kHz high-speed swept-source OCT system operating at 1300 nm and demonstrate its wide field-imaging capability in ocular angiographic studies.
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27
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Chen W, Du C, Pan Y. Cerebral capillary flow imaging by wavelength-division-multiplexing swept-source optical Doppler tomography. JOURNAL OF BIOPHOTONICS 2018; 11:e201800004. [PMID: 29603668 DOI: 10.1002/jbio.201800004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2018] [Revised: 02/27/2018] [Accepted: 03/13/2018] [Indexed: 05/09/2023]
Abstract
Swept-source-based optical coherence tomography (SS-OCT) has demonstrated the unique advantages for fast imaging rate and long imaging distance; however, limited axial resolution and complex phase noises restrict swept-source optical Doppler tomography (SS-ODT) for quantitative capillary blood flow imaging in the deep cortices. Here, the wavelength-dividing-multiplexing optical Doppler tomography (WDM-ODT) method that divides a single interferogram into multiple phase-correlated interferograms is proposed to effectively enhance the sensitivity for cerebral capillary flow imaging. Both flow phantom and in vivo mouse brain imaging studies show that WDM-ODT is able to significantly suppress background phase noise and image cerebral capillary flow down to the vessel size of 5.6 μm. Comparison between the wavelength-division-multiplexing SS-ODT and the spectral-domain ultrahigh-resolution ODT (uODT) reveals that SS-ODT outpaces uODT by extending the capillary flow imaging depth to 1.6 mm in mouse cortex. Thus, for the first time, quantitative capillary flow imaging is demonstrated using SS-ODT in the deep cortex.
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Affiliation(s)
- Wei Chen
- Biomedical Engineering, Stony Brook University, Stony Brook, New York
| | - Congwu Du
- Biomedical Engineering, Stony Brook University, Stony Brook, New York
| | - Yingtian Pan
- Biomedical Engineering, Stony Brook University, Stony Brook, New York
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28
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Men S, Wong JM, Welch EJ, Xu J, Song S, Deegan AJ, Ravichander A, Casavant B, Berthier E, Wang RK. OCT-based angiography of human dermal microvascular reactions to local stimuli: Implications for increasing capillary blood collection volumes. Lasers Surg Med 2018; 50:908-916. [PMID: 29799134 DOI: 10.1002/lsm.22944] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/09/2018] [Indexed: 12/22/2022]
Abstract
OBJECTIVES To measure and compare microvascular responses within the skin of the upper arm to local stimuli, such as heating or rubbing, through the use of optical coherence tomography angiography (OCTA), and to investigate its impact on blood volume collection. MATERIALS AND METHODS With the use of heat packs or rubbing, local stimulation was applied to the skin of either the left or right upper arm. Data from the stimulated sites were obtained using OCTA comparing pre- and post-stimulation microvascular parameters, such as vessel density, mean vessel diameter, and mean avascular pore size. Additionally, blood was collected using a newly designed collection device and volume was recorded to evaluate the effect of the skin stimulation. RESULTS Nineteen subjects were recruited for local stimulation study (including rubbing and heating) and 21 subjects for blood drawn study. Of these subjects, 14 agreed to participate in both studies. OCTA was successful in monitoring and measuring minute changes in the microvasculature of the stimulated skin. Compared to baseline, significant changes after local heating and rubbing were respectively found in vessel density (16% [P = 0.0004] and 33% [P < 0.0001] increase), mean vessel diameter (14% and 11% increase) and mean avascular pore size (5% [P = 0.0068] and 8% [P = 0.0005] decrease) after stimulations. A gradual recovery was recorded for each parameter, with no difference being measured after 30 minutes. Blood collection volumes significantly increased after stimulations of heating (48% increase; P = 0.049) and rubbing (78% increase; P = 0.048). Significant correlations were found between blood volume and microvascular parameters except mean avascular pore size under the heating condition. CONCLUSIONS OCTA can provide important information regarding microvascular adaptations to local stimuli. With that, both heating and rubbing of the skin have positive effects on blood collection capacity, with rubbing having the most significant effect. Lasers Surg. Med. 50:908-916, 2018. © 2018 Wiley Periodicals, Inc.
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Affiliation(s)
- Shaojie Men
- Department of Bioengineering, University of Washington, 3720 15th Ave. NE., Seattle 98195, Washington
| | - Jennifer Manyu Wong
- Department of Bioengineering, University of Washington, 3720 15th Ave. NE., Seattle 98195, Washington
| | - Emily J Welch
- Tasso, Inc., 1631 15th Ave. W., Suite 105, Seattle 98119, Washington
| | - Jingjiang Xu
- Department of Bioengineering, University of Washington, 3720 15th Ave. NE., Seattle 98195, Washington
| | - Shaozhen Song
- Department of Bioengineering, University of Washington, 3720 15th Ave. NE., Seattle 98195, Washington
| | - Anthony J Deegan
- Department of Bioengineering, University of Washington, 3720 15th Ave. NE., Seattle 98195, Washington
| | | | - Benjamin Casavant
- Tasso, Inc., 1631 15th Ave. W., Suite 105, Seattle 98119, Washington
| | - Erwin Berthier
- Tasso, Inc., 1631 15th Ave. W., Suite 105, Seattle 98119, Washington
| | - Ruikang K Wang
- Department of Bioengineering, University of Washington, 3720 15th Ave. NE., Seattle 98195, Washington
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Ju MJ, Heisler M, Athwal A, Sarunic MV, Jian Y. Effective bidirectional scanning pattern for optical coherence tomography angiography. BIOMEDICAL OPTICS EXPRESS 2018; 9:2336-2350. [PMID: 29760992 PMCID: PMC5946793 DOI: 10.1364/boe.9.002336] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2018] [Revised: 04/17/2018] [Accepted: 04/17/2018] [Indexed: 05/18/2023]
Abstract
We demonstrate the utility of a novel scanning method for optical coherence tomography angiography (OCTA). Although raster scanning is commonly used for OCTA imaging, a bidirectional approach would lessen the distortion caused by galvanometer-based scanners as sources continue to increase sweep rates. As shown, a unidirectional raster scan approach has a lower effective scanning time than bidirectional approaches; however, a strictly bidirectional approach causes contrast variation along the B-scan direction due to the non-uniform time interval between B-scans. Therefore, a stepped bidirectional approach is introduced and successfully applied to retinal imaging in normal controls and in a pathological subject with diabetic retinopathy.
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Deegan AJ, Wang W, Men S, Li Y, Song S, Xu J, Wang RK. Optical coherence tomography angiography monitors human cutaneous wound healing over time. Quant Imaging Med Surg 2018; 8:135-150. [PMID: 29675355 DOI: 10.21037/qims.2018.02.07] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Background In vivo imaging of the complex cascade of events known to be pivotal elements in the healing of cutaneous wounds is a difficult but essential task. Current techniques are highly invasive, or lack the level of vascular and structural detail required for accurate evaluation, monitoring and treatment. We aimed to use an advanced optical coherence tomography (OCT)-based angiography (OCTA) technique for the non-invasive, high resolution imaging of cutaneous wound healing. Methods We used a clinical prototype OCTA to image, identify and track key vascular and structural adaptations known to occur throughout the healing process. Specific vascular parameters, such as diameter and density, were measured to aid our interpretations under a spatiotemporal framework. Results We identified multiple distinct, yet overlapping stages, hemostasis, inflammation, proliferation, and remodeling, and demonstrated the detailed vascularization and anatomical attributes underlying the multifactorial processes of dermatologic wound healing. Conclusions OCTA provides an opportunity to both qualitatively and quantitatively assess the vascular response to acute cutaneous damage and in the future, may help to ascertain wound severity and possible healing outcomes; thus, enabling more effective treatment options.
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Affiliation(s)
- Anthony J Deegan
- Department of Bioengineering, University of Washington, Seattle, Washington, USA
| | - Wendy Wang
- Department of Bioengineering, University of Washington, Seattle, Washington, USA
| | - Shaojie Men
- Department of Bioengineering, University of Washington, Seattle, Washington, USA
| | - Yuandong Li
- Department of Bioengineering, University of Washington, Seattle, Washington, USA
| | - Shaozhen Song
- Department of Bioengineering, University of Washington, Seattle, Washington, USA
| | - Jingjiang Xu
- Department of Bioengineering, University of Washington, Seattle, Washington, USA
| | - Ruikang K Wang
- Department of Bioengineering, University of Washington, Seattle, Washington, USA.,Department of Ophthalmology, University of Washington, Seattle, Washington, USA
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Song S, Xu J, Wang R. Flexible wide-field optical micro-angiography based on Fourier-domain multiplexed dual-beam swept source optical coherence tomography. JOURNAL OF BIOPHOTONICS 2018; 11:10.1002/jbio.201700203. [PMID: 28941235 PMCID: PMC5839934 DOI: 10.1002/jbio.201700203] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Revised: 09/13/2017] [Accepted: 09/14/2017] [Indexed: 05/19/2023]
Abstract
Wide-field optical coherence tomography angiography (OCTA) is gaining interest in clinical imaging applications. In this pursuit, it is challenging to maintain the imaging resolution and sensitivity throughout the wide field of view (FoV). Here, we propose a novel method/system of dual-beam arrangement and Fourier-domain multiplexing to achieve wide-field OCTA when imaging the uneven surface samples. The proposed system provides 2 separate FoVs, with flexibility that the imaging area, focus of the imaging beam and imaging depth range can be individually adjusted for each FoV, leading to either (1) increased system imaging FoV or (2) capability of targeting 2 regions of interests that locate at depths with large difference between each other. We demonstrate this novel method by employing 100 kHz laser source in a swept source OCTA to achieve an effective 200 kHz sweeping rate, covering a 22 × 22 mm FoV. The results are verified by a SS-OCTA system employing a 200 kHz laser source, together with the experimental demonstrations when imaging whole brain vasculature in rodent models and skin blood perfusion in human fingers, show-casing the capability of proposed system to image live large samples with complex surface topography.
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Affiliation(s)
- Shaozhen Song
- Department of Bioengineering, University of Washington, Seattle, Washington 98195, USA
| | - Jingjiang Xu
- Department of Bioengineering, University of Washington, Seattle, Washington 98195, USA
| | - Ruikang Wang
- Department of Bioengineering, University of Washington, Seattle, Washington 98195, USA
- Department of Ophthalmology, University of Washington, Seattle, Washington 98195, USA
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Deegan AJ, Talebi-Liasi F, Song S, Li Y, Xu J, Men S, Shinohara MM, Flowers ME, Lee SJ, Wang RK. Optical coherence tomography angiography of normal skin and inflammatory dermatologic conditions. Lasers Surg Med 2018; 50:183-193. [PMID: 29356051 DOI: 10.1002/lsm.22788] [Citation(s) in RCA: 62] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/16/2017] [Indexed: 11/09/2022]
Abstract
BACKGROUND In clinical dermatology, the identification of subsurface vascular and structural features known to be associated with numerous cutaneous pathologies remains challenging without the use of invasive diagnostic tools. OBJECTIVE To present an advanced optical coherence tomography angiography (OCTA) method to directly visualize capillary-level vascular and structural features within skin in vivo. METHODS An advanced OCTA system with a 1310 nm wavelength was used to image the microvascular and structural features of various skin conditions. Subjects were enrolled and OCTA imaging was performed with a field of view of approximately 10 × 10 mm. Skin blood flow was identified using an optical microangiography (OMAG) algorithm. Depth-resolved microvascular networks and structural features were derived from segmented volume scans, representing tissue slabs of 0-132, 132-330, and 330-924 μm, measured from the surface of the skin. RESULTS Subjects with both healthy and pathological conditions, such as benign skin lesions, psoriasis, chronic graft-versus-host-disease (cGvHD), and scleroderma, were OCTA scanned. Our OCTA results detailed variations in vascularization and local anatomical characteristics, for example, depth-dependent vascular, and structural alterations in psoriatic skin, alongside their resolve over time; vascular density changes and distribution irregularities, together with corresponding structural depositions in the skin of cGvHD patients; and vascular abnormalities in the nail folds of a patient with scleroderma. CONCLUSION OCTA can image capillary blood flow and structural features within skin in vivo, which has the potential to provide new insights into the pathophysiology, as well as dynamic changes of skin diseases, valuable for diagnoses, and non-invasive monitoring of disease progression and treatment. Lasers Surg. Med. 50:183-193, 2018. © 2018 Wiley Periodicals, Inc.
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Affiliation(s)
- Anthony J Deegan
- Department of Bioengineering, University of Washington, 3720 15th Ave. N.E., Seattle, Washington 98195
| | - Faezeh Talebi-Liasi
- School of Medicine, University of Washington, 1959 N.E. Pacific St., Seattle, Washington 98195
| | - Shaozhen Song
- Department of Bioengineering, University of Washington, 3720 15th Ave. N.E., Seattle, Washington 98195
| | - Yuandong Li
- Department of Bioengineering, University of Washington, 3720 15th Ave. N.E., Seattle, Washington 98195
| | - Jingjiang Xu
- Department of Bioengineering, University of Washington, 3720 15th Ave. N.E., Seattle, Washington 98195
| | - Shaojie Men
- Department of Bioengineering, University of Washington, 3720 15th Ave. N.E., Seattle, Washington 98195
| | - Michi M Shinohara
- Division of Dermatology and Dermatopathology, University of Washington, 1959 N.E. Pacific St., Seattle, Washington 98195
| | - Mary E Flowers
- Clinical Research Division, Fred Hutchinson Cancer Research Center, 1100 Fairview Ave. N., Seattle, Washington 98109
| | - Stephanie J Lee
- Clinical Research Division, Fred Hutchinson Cancer Research Center, 1100 Fairview Ave. N., Seattle, Washington 98109
| | - Ruikang K Wang
- Department of Bioengineering, University of Washington, 3720 15th Ave. N.E., Seattle, Washington 98195
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Xu J, Song S, Li Y, Wang RK. Complex-based OCT angiography algorithm recovers microvascular information better than amplitude- or phase-based algorithms in phase-stable systems. Phys Med Biol 2017; 63:015023. [PMID: 29049034 DOI: 10.1088/1361-6560/aa94bc] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Optical coherence tomography angiography (OCTA) is increasingly becoming a popular inspection tool for biomedical imaging applications. By exploring the amplitude, phase and complex information available in OCT signals, numerous algorithms have been proposed that contrast functional vessel networks within microcirculatory tissue beds. However, it is not clear which algorithm delivers optimal imaging performance. Here, we investigate systematically how amplitude and phase information have an impact on the OCTA imaging performance, to establish the relationship of amplitude and phase stability with OCT signal-to-noise ratio (SNR), time interval and particle dynamics. With either repeated A-scan or repeated B-scan imaging protocols, the amplitude noise increases with the increase of OCT SNR; however, the phase noise does the opposite, i.e. it increases with the decrease of OCT SNR. Coupled with experimental measurements, we utilize a simple Monte Carlo (MC) model to simulate the performance of amplitude-, phase- and complex-based algorithms for OCTA imaging, the results of which suggest that complex-based algorithms deliver the best performance when the phase noise is < ~40 mrad. We also conduct a series of in vivo vascular imaging in animal models and human retina to verify the findings from the MC model through assessing the OCTA performance metrics of vessel connectivity, image SNR and contrast-to-noise ratio. We show that for all the metrics assessed, the complex-based algorithm delivers better performance than either the amplitude- or phase-based algorithms for both the repeated A-scan and the B-scan imaging protocols, which agrees well with the conclusion drawn from the MC simulations.
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Affiliation(s)
- Jingjiang Xu
- Department of Bioengineering, University of Washington, Seattle, WA 98195, United States of America
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Xu J, Song S, Men S, Wang RK. Long ranging swept-source optical coherence tomography-based angiography outperforms its spectral-domain counterpart in imaging human skin microcirculations. JOURNAL OF BIOMEDICAL OPTICS 2017; 22:1-11. [PMID: 29185292 PMCID: PMC5712670 DOI: 10.1117/1.jbo.22.11.116007] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2017] [Accepted: 11/08/2017] [Indexed: 05/07/2023]
Abstract
There is an increasing demand for imaging tools in clinical dermatology that can perform in vivo wide-field morphological and functional examination from surface to deep tissue regions at various skin sites of the human body. The conventional spectral-domain optical coherence tomography-based angiography (SD-OCTA) system is difficult to meet these requirements due to its fundamental limitations of the sensitivity roll-off, imaging range as well as imaging speed. To mitigate these issues, we demonstrate a swept-source OCTA (SS-OCTA) system by employing a swept source based on a vertical cavity surface-emitting laser. A series of comparisons between SS-OCTA and SD-OCTA are conducted. Benefiting from the high system sensitivity, long imaging range, and superior roll-off performance, the SS-OCTA system is demonstrated with better performance in imaging human skin than the SD-OCTA system. We show that the SS-OCTA permits remarkable deep visualization of both structure and vasculature (up to ∼2 mm penetration) with wide field of view capability (up to 18×18 mm2), enabling a more comprehensive assessment of the morphological features as well as functional blood vessel networks from the superficial epidermal to deep dermal layers. It is expected that the advantages of the SS-OCTA system will provide a ground for clinical translation, benefiting the existing dermatological practice.
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Affiliation(s)
- Jingjiang Xu
- University of Washington, Department of Bioengineering, Seattle, Washington, United States
| | - Shaozhen Song
- University of Washington, Department of Bioengineering, Seattle, Washington, United States
| | - Shaojie Men
- University of Washington, Department of Bioengineering, Seattle, Washington, United States
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