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Kim G, Park HS, Shin P, Eom T, Yoon JH, Jeong Y, Oh WY. Direct Blood Cell Flow Imaging in Microvascular Networks. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2023; 19:e2302244. [PMID: 37309282 DOI: 10.1002/smll.202302244] [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: 03/16/2023] [Revised: 05/19/2023] [Indexed: 06/14/2023]
Abstract
Blood flow dynamics in microvascular networks are intimately related to the health of tissues and organs. While numerous imaging modalities and techniques have been developed to assess blood flow dynamics for various applications, their utilization has been hampered by limited imaging speed and indirect quantification of blood flow dynamics. Here, direct blood cell flow imaging (DBFI) is demonstrated that provides visualization of individual motions of blood cells over a field of 0.71 mm × 1.42 mm with a time resolution of 0.69 ms (1450 frames s-1 ) without using any exogenous agents. DBFI enables precise dynamic analysis of blood cell flow velocities and fluxes in various vessels over a large field, from capillaries to arteries and veins, with unprecedented time resolution. Three exemplary applications of DBFI, quantification of blood flow dynamics of 3D vascular networks, analysis of heartbeat induced blood flow dynamics, and analysis of blood flow dynamics of neurovascular coupling, illustrate the potential of this new imaging technology.
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Affiliation(s)
- Gyounghwan Kim
- Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology, Daejeon, 34141, Republic of Korea
- KI for Health Science and Technology, Korea Advanced Institute of Science and Technology, Daejeon, 34141, Republic of Korea
| | - Hyun-Sang Park
- Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology, Daejeon, 34141, Republic of Korea
- KI for Health Science and Technology, Korea Advanced Institute of Science and Technology, Daejeon, 34141, Republic of Korea
| | - Paul Shin
- Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology, Daejeon, 34141, Republic of Korea
- KI for Health Science and Technology, Korea Advanced Institute of Science and Technology, Daejeon, 34141, Republic of Korea
| | - Taeguk Eom
- Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology, Daejeon, 34141, Republic of Korea
- KI for Health Science and Technology, Korea Advanced Institute of Science and Technology, Daejeon, 34141, Republic of Korea
| | - Jin-Hui Yoon
- KI for Health Science and Technology, Korea Advanced Institute of Science and Technology, Daejeon, 34141, Republic of Korea
- Department of Bio and Brain Engineering, Korea Advanced Institute of Science and Technology, Daejeon, 34141, Republic of Korea
| | - Yong Jeong
- KI for Health Science and Technology, Korea Advanced Institute of Science and Technology, Daejeon, 34141, Republic of Korea
- Department of Bio and Brain Engineering, Korea Advanced Institute of Science and Technology, Daejeon, 34141, Republic of Korea
| | - Wang-Yuhl Oh
- Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology, Daejeon, 34141, Republic of Korea
- KI for Health Science and Technology, Korea Advanced Institute of Science and Technology, Daejeon, 34141, Republic of Korea
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Lee B, Kang W, Oh SH, Cho S, Shin I, Oh EJ, Kim YJ, Ahn JS, Yook JM, Jung SJ, Lim JH, Kim YL, Cho JH, Oh WY. In vivo imaging of renal microvasculature in a murine ischemia-reperfusion injury model using optical coherence tomography angiography. Sci Rep 2023; 13:6396. [PMID: 37076541 PMCID: PMC10115874 DOI: 10.1038/s41598-023-33295-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Accepted: 04/11/2023] [Indexed: 04/21/2023] Open
Abstract
Optical coherence tomography angiography (OCTA) provides three-dimensional structural and semiquantitative imaging of microvasculature in vivo. We developed an OCTA imaging protocol for a murine kidney ischemia-reperfusion injury (IRI) model to investigate the correlation between renal microvascular changes and ischemic damage. Mice were divided into mild and moderate IRI groups according to the duration of ischemia (10 and 35 mins, respectively). Each animal was imaged at baseline; during ischemia; and at 1, 15, 30, 45, and 60 mins after ischemia. Amplitude decorrelation OCTA images were constructed with 1.5-, 3.0-, and 5.8-ms interscan times, to calculate the semiquantitative flow index in the superficial (50-70 μm) and the deep (220-340 μm) capillaries of the renal cortex. The mild IRI group showed no significant flow index change in both the superfial and the deep layers. The moderate IRI group showed a significantly decreased flow index from 15 and 45 mins in the superficial and deep layers, respectively. Seven weeks after IRI induction, the moderate IRI group showed lower kidney function and higher collagen deposition than the mild IRI group. OCTA imaging of the murine IRI model revealed changes in superficial blood flow after ischemic injury. A more pronounced decrease in superficial blood flow than in deep blood flow was associated with sustained dysfunction after IRI. Further investigation on post-IRI renal microvascular response using OCTA may improve our understanding of the relationship between the degree of ischemic insult and kidney function.
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Affiliation(s)
- ByungKun Lee
- Department of Mechanical Engineering, KAIST, Daejeon, Republic of Korea
- KI for Health Science and Technology, KAIST, Daejeon, Republic of Korea
| | - Woojae Kang
- Department of Mechanical Engineering, KAIST, Daejeon, Republic of Korea
- KI for Health Science and Technology, KAIST, Daejeon, Republic of Korea
| | - Se-Hyun Oh
- Division of Nephrology, Department of Internal Medicine, Kyungpook National University Hospital, Daegu, Republic of Korea
- Cell and Matrix Research Institute, Kyungpook National University, Daegu, Republic of Korea
| | - Seungwan Cho
- Department of Mechanical Engineering, KAIST, Daejeon, Republic of Korea
- KI for Health Science and Technology, KAIST, Daejeon, Republic of Korea
| | - Inho Shin
- Department of Mechanical Engineering, KAIST, Daejeon, Republic of Korea
- KI for Health Science and Technology, KAIST, Daejeon, Republic of Korea
| | - Eun-Joo Oh
- Division of Nephrology, Department of Internal Medicine, Kyungpook National University Hospital, Daegu, Republic of Korea
| | - You-Jin Kim
- Division of Nephrology, Department of Internal Medicine, Kyungpook National University Hospital, Daegu, Republic of Korea
- Cell and Matrix Research Institute, Kyungpook National University, Daegu, Republic of Korea
| | - Ji-Sun Ahn
- Division of Nephrology, Department of Internal Medicine, Kyungpook National University Hospital, Daegu, Republic of Korea
| | - Ju-Min Yook
- Division of Nephrology, Department of Internal Medicine, Kyungpook National University Hospital, Daegu, Republic of Korea
| | - Soo-Jung Jung
- Division of Nephrology, Department of Internal Medicine, Kyungpook National University Hospital, Daegu, Republic of Korea
- Cell and Matrix Research Institute, Kyungpook National University, Daegu, Republic of Korea
| | - Jeong-Hoon Lim
- Division of Nephrology, Department of Internal Medicine, Kyungpook National University Hospital, Daegu, Republic of Korea
- Cell and Matrix Research Institute, Kyungpook National University, Daegu, Republic of Korea
| | - Yong-Lim Kim
- Division of Nephrology, Department of Internal Medicine, Kyungpook National University Hospital, Daegu, Republic of Korea
- Cell and Matrix Research Institute, Kyungpook National University, Daegu, Republic of Korea
| | - Jang-Hee Cho
- Division of Nephrology, Department of Internal Medicine, Kyungpook National University Hospital, Daegu, Republic of Korea.
- Cell and Matrix Research Institute, Kyungpook National University, Daegu, Republic of Korea.
| | - Wang-Yuhl Oh
- Department of Mechanical Engineering, KAIST, Daejeon, Republic of Korea.
- KI for Health Science and Technology, KAIST, Daejeon, Republic of Korea.
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Visualization of three-dimensional microcirculation of rodents' retina and choroid for studies of critical illness using optical coherence tomography angiography. Sci Rep 2021; 11:14302. [PMID: 34253747 PMCID: PMC8275781 DOI: 10.1038/s41598-021-93631-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Accepted: 06/08/2021] [Indexed: 02/06/2023] Open
Abstract
We developed a method to measure the relative blood flow speed using optical coherence tomography angiography (OCTA) in retina and choroid, and investigated the feasibility of this method for assessing microcirculatory function in rat models of sepsis and hemorrhagic shock. Two sepsis models, 6-h severe sepsis without treatment and 30-h moderate sepsis maintaining mean arterial pressure, and volume controlled hemorrhagic shock and fluid resuscitation model were used to see the change of microcirculation. The blood flow index (BFI), which was calculated from the OCTA images to represent the average relative blood flow, was decreasing during the 6-h severe sepsis model. Its change is in parallel with the mean arterial blood pressure (MAP) and blood lactate levels. In the 30-h moderate sepsis model, the BFI was decreased while maintaining MAP, and lactate was increased. In the hemorrhagic shock model, the change of BFI is in line with MAP and lactate levels. In all models, BFI change is more sensitive in choroid than in retina. This study presents the OCTA-based retinal and choroidal microcirculatory blood flow monitoring method and shows its utility for assessment of critical illness.
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Shin I, Oh WY. Visualization of two-dimensional transverse blood flow direction using optical coherence tomography angiography. JOURNAL OF BIOMEDICAL OPTICS 2020; 25:JBO-200253R. [PMID: 33331149 PMCID: PMC7739998 DOI: 10.1117/1.jbo.25.12.126003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Accepted: 11/24/2020] [Indexed: 05/02/2023]
Abstract
SIGNIFICANCE Evaluation of vessel patency and blood flow direction is important in various medical situations, including diagnosis and monitoring of ischemic diseases, and image-guided vascular surgeries. While optical coherence tomography angiography (OCTA) is the most widely used functional extension of optical coherence tomography that visualizes three-dimensional vasculature, inability to provide information of blood flow direction is one of its limitations. AIM We demonstrate two-dimensional (2D) transverse blood flow direction imaging in en face OCTA. APPROACH A series of triangular beam scans for the fast axis was implemented in the horizontal direction for the first volume scan and in the vertical direction for the following volume scan, and the inter A-line OCTA was performed for the blood flow direction imaging while the stepwise pattern was used for each slow axis scan. The decorrelation differences between the forward and the backward inter A-line OCTA were calculated for the horizontal and the vertical fast axis scans, and the ratio of the horizontal and the vertical decorrelation differences was utilized to show the 2D transverse flow direction information. RESULTS OCTA flow direction imaging was verified using flow phantoms with various flow orientations and speeds, and we identified the flow speed range relative to the scan speed for reliable flow direction measurement. We demonstrated the visualization of 2D transverse blood flow orientations in mouse brain vascular networks in vivo. CONCLUSIONS The proposed OCTA imaging technique that provides information of 2D transverse flow direction can be utilized in various clinical applications and preclinical studies.
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Affiliation(s)
- Inho Shin
- Korea Advanced Institute of Science and Technology, Department of Mechanical Engineering, Daejeon, Republic of Korea
- Korea Advanced Institute of Science and Technology, KI for Health Science and Technology, Daejeon, Republic of Korea
| | - Wang-Yuhl Oh
- Korea Advanced Institute of Science and Technology, Department of Mechanical Engineering, Daejeon, Republic of Korea
- Korea Advanced Institute of Science and Technology, KI for Health Science and Technology, Daejeon, Republic of Korea
- Address all correspondence to Wang-Yuhl Oh,
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Kim TS, Joo J, Shin I, Shin P, Kang WJ, Vakoc BJ, Oh WY. 9.4 MHz A-line rate optical coherence tomography at 1300 nm using a wavelength-swept laser based on stretched-pulse active mode-locking. Sci Rep 2020; 10:9328. [PMID: 32518256 PMCID: PMC7283258 DOI: 10.1038/s41598-020-66322-0] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2019] [Accepted: 05/08/2020] [Indexed: 01/07/2023] Open
Abstract
In optical coherence tomography (OCT), high-speed systems based at 1300 nm are among the most broadly used. Here, we present 9.4 MHz A-line rate OCT system at 1300 nm. A wavelength-swept laser based on stretched-pulse active mode locking (SPML) provides a continuous and linear-in-wavenumber sweep from 1240 nm to 1340 nm, and the OCT system using this light source provides a sensitivity of 98 dB and a single-sided 6-dB roll-off depth of 2.5 mm. We present new capabilities of the 9.4 MHz SPML-OCT system in three microscopy applications. First, we demonstrate high quality OCTA imaging at a rate of 1.3 volumes/s. Second, by utilizing its inherent phase stable characteristics, we present wide dynamic range en face Doppler OCT imaging with multiple time intervals ranging from 0.25 ms to 2.0 ms at a rate of 0.53 volumes/s. Third, we demonstrate video-rate 4D microscopic imaging of a beating Xenopus embryo heart at a rate of 30 volumes/s. This high-speed and high-performance OCT system centered at 1300 nm suggests that it can be one of the most promising high-speed OCT platforms enabling a wide range of new scientific research, industrial, and clinical applications at speeds of 10 MHz.
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Affiliation(s)
- Tae Shik Kim
- Department of Mechanical Engineering, KAIST, Daejeon, Republic of Korea.,KI for Health Science and Technology, KAIST, Daejeon, Republic of Korea
| | - JongYoon Joo
- Department of Mechanical Engineering, KAIST, Daejeon, Republic of Korea.,KI for Health Science and Technology, KAIST, Daejeon, Republic of Korea
| | - Inho Shin
- Department of Mechanical Engineering, KAIST, Daejeon, Republic of Korea.,KI for Health Science and Technology, KAIST, Daejeon, Republic of Korea
| | - Paul Shin
- Department of Mechanical Engineering, KAIST, Daejeon, Republic of Korea.,KI for Health Science and Technology, KAIST, Daejeon, Republic of Korea
| | - Woo Jae Kang
- Department of Mechanical Engineering, KAIST, Daejeon, Republic of Korea.,KI for Health Science and Technology, KAIST, Daejeon, Republic of Korea
| | - Benjamin J Vakoc
- Wellman Center for Photomedicine, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA.
| | - Wang-Yuhl Oh
- Department of Mechanical Engineering, KAIST, Daejeon, Republic of Korea. .,KI for Health Science and Technology, KAIST, Daejeon, Republic of Korea.
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Gräfe MGO, Nadiarnykh O, De Boer JF. Optical coherence tomography velocimetry based on decorrelation estimation of phasor pair ratios (DEPPAIR). BIOMEDICAL OPTICS EXPRESS 2019; 10:5470-5485. [PMID: 31799025 PMCID: PMC6865093 DOI: 10.1364/boe.10.005470] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2019] [Revised: 09/17/2019] [Accepted: 09/20/2019] [Indexed: 05/13/2023]
Abstract
Quantitative velocity estimations in optical coherence tomography requires the estimation of the axial and lateral flow components. Optical coherence tomography measures the depth resolved complex field reflected from a sample. While the axial velocity component can be determined from the Doppler shift or phase shift between a pair of consecutive measurements at the same location, the estimation of the lateral component for in vivo applications is still challenging. One approach to determine lateral velocity is multiple simultaneous measurements at different angles. In another approach the lateral component can be retrieved through repeated measurements at (nearly) the same location by an analysis of the decorrelation over time. In this paper we follow the latter approach. We describe a model for the complex field changes between consecutive measurements and use it to predict the uncertainties for amplitude-based, phase-based and complex algorithms. The uncertainty of the flow estimations follows from a statistical analysis and is determined by the number of available measurements and the applied analysis method. The model is verified in phantom measurements and the dynamic range of velocity estimations is investigated. We demonstrate that phase-based and complex (phasor) based lateral flow estimation methods are superior to amplitude-based algorithms.
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