scholarly journals Multiple-Capillary Measurement of RBC Speed, Flux, and Density with Optical Coherence Tomography

2013 ◽  
Vol 33 (11) ◽  
pp. 1707-1710 ◽  
Author(s):  
Jonghwan Lee ◽  
Weicheng Wu ◽  
Frederic Lesage ◽  
David A Boas
Keyword(s):  
Optical Coherence Tomography ◽  
Blood Cell ◽  
Red Blood Cell ◽  
Linear Density ◽  
Flow Dynamics ◽  
Optical Coherence ◽  
Microvascular Flow ◽  
Different Depths

As capillaries exhibit heterogeneous and fluctuating dynamics even during baseline, a technique measuring red blood cell (RBC) speed and flux over many capillaries at the same time is needed. Here, we report that optical coherence tomography can capture individual RBC passage simultaneously over many capillaries located at different depths. Further, we demonstrate the ability to quantify RBC speed, flux, and linear density. This technique will provide a means to monitor microvascular flow dynamics over many capillaries at different depths at the same time.

scholarly journals Characterizing thrombus with multiple red blood cell compositions by optical coherence tomography attenuation coefficient

2020 ◽  
Author(s):  
Hsiao‐Chuan Liu ◽  
Mehdi Abbasi ◽  
Yong Hong Ding ◽  
Eric C. Polley ◽  
Seán Fitzgerald ◽  
...  
Keyword(s):  
Optical Coherence Tomography ◽  
Blood Cell ◽  
Attenuation Coefficient ◽  
Red Blood Cell ◽  
Optical Coherence

scholarly journals Capillary red blood cell velocimetry by phase-resolved optical coherence tomography

2017 ◽  
Vol 42 (19) ◽  
pp. 3976 ◽  
Author(s):  
Jianbo Tang ◽  
Sefik Evren Erdener ◽  
Buyin Fu ◽  
David A. Boas
Keyword(s):  
Optical Coherence Tomography ◽  
Blood Cell ◽  
Red Blood Cell ◽  
Optical Coherence

In vivo microvascular structural and functional consequences of muscle length changes

1997 ◽  
Vol 272 (5) ◽  
pp. H2107-H2114 ◽  
Author(s):  
D. C. Poole ◽  
T. I. Musch ◽  
C. A. Kindig
Keyword(s):  
Blood Flow ◽  
Blood Cell ◽  
Red Blood Cell ◽  
Oxygen Delivery ◽  
Sarcomere Length ◽  
Flow Dynamics ◽  
Capillary Diameter ◽  
Luminal Diameter ◽  
Length Changes

As muscles are stretched, blood flow and oxygen delivery are compromised, and consequently muscle function is impaired. We tested the hypothesis that the structural microvascular sequellae associated with muscle extension in vivo would impair capillary red blood cell hemodynamics. We developed an intravital spinotrapezius preparation that facilitated direct on-line measurement and alteration of sarcomere length simultaneously with determination of capillary geometry and red blood cell flow dynamics. The range of spinotrapezius sarcomere lengths achievable in vivo was 2.17 +/- 0.05 to 3.13 +/- 0.11 microns. Capillary tortuosity decreased systematically with increases of sarcomere length up to 2.6 microns, at which point most capillaries appeared to be highly oriented along the fiber longitudinal axis. Further increases in sarcomere length above this value reduced mean capillary diameter from 5.61 +/- 0.03 microns at 2.4-2.6 microns sarcomere length to 4.12 +/- 0.05 microns at 3.2-3.4 microns sarcomere length. Over the range of physiological sarcomere lengths, bulk blood flow (radioactive microspheres) decreased approximately 40% from 24.3 +/- 7.5 to 14.5 +/- 4.6 ml.100 g-1.min-1. The proportion of continuously perfused capillaries, i.e., those with continuous flow throughout the 60-s observation period, decreased from 95.9 +/- 0.6% at the shortest sarcomere lengths to 56.5 +/- 0.7% at the longest sarcomere lengths and was correlated significantly with the reduced capillary diameter (r = 0.711, P < 0.01; n = 18). We conclude that alterations in capillary geometry and luminal diameter consequent to increased muscle sarcomere length are associated with a reduction in mean capillary red blood cell velocity and a greater proportion of capillaries in which red blood cell flow is stopped or intermittent. Thus not only does muscle stretching reduce bulk blood (and oxygen) delivery, it also alters capillary red blood cell flow dynamics, which may further impair blood-tissue oxygen exchange.

Automatic Plaque Segmentation in Coronary Optical Coherence Tomography Images

2019 ◽  
Vol 33 (14) ◽  
pp. 1954035 ◽  
Author(s):  
Huaqi Zhang ◽  
Guanglei Wang ◽  
Yan Li ◽  
Feng Lin ◽  
Yechen Han ◽  
...  
Keyword(s):  
Optical Coherence Tomography ◽  
Coronary Artery Stenosis ◽  
Ground Truth ◽  
High Accuracy ◽  
Similarity Coefficient ◽  
Optical Coherence ◽  
Jaccard Similarity ◽  
Plaque Area ◽  
Adaptive Weight ◽  
Different Depths

Coronary optical coherence tomography (OCT) is a new high-resolution intravascular imaging technology that clearly depicts coronary artery stenosis and plaque information. Study of coronary OCT images is of significance in the diagnosis of coronary atherosclerotic heart disease (CAD). We introduce a new method based on the convolutional neural network (CNN) and an improved random walk (RW) algorithm for the recognition and segmentation of calcified, lipid and fibrotic plaque in coronary OCT images. First, we design CNN with three different depths (2, 4 or 6 convolutional layers) to perform the automatic recognition and select the optimal CNN model. Then, we device an improved RW algorithm. According to the gray-level distribution characteristics of coronary OCT images, the weights of intensity and texture term in the weight function of RW algorithm are adjusted by an adaptive weight. Finally, we apply mathematical morphology in combination with two RWs to accurately segment the plaque area. Compared with the ground truth of clinical segmentation results, the Jaccard similarity coefficient (JSC) of calcified and lipid plaque segmentation results is 0.864, the average symmetric contour distance (ASCD) is 0.375[Formula: see text]mm, the JSC and ASCD reliabilities are 88.33% and 92.50% respectively. The JSC of fibrotic plaque is 0.876, the ASCD is 0.349[Formula: see text]mm, the JSC and ASCD reliabilities are 90.83% and 95.83% respectively. In addition, the average segmentation time (AST) does not exceed 5 s. Reliable and significantly improved results have been achieved in this study. Compared with the CNN, traditional RW algorithm and other methods. The proposed method has the advantages of fast segmentation, high accuracy and reliability, and holds promise as an aid to doctors in the diagnosis of CAD.

scholarly journals Validation of red blood cell flux and velocity estimations based on optical coherence tomography intensity fluctuations

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Paul J. Marchand ◽  
Xuecong Lu ◽  
Cong Zhang ◽  
Frédéric Lesage
Keyword(s):  
Optical Coherence Tomography ◽  
Fluorescence Microscopy ◽  
Blood Cell ◽  
Red Blood Cell ◽  
Focal Volume ◽  
Two Photon ◽  
Photon Excitation ◽  
Speed Range ◽  
Flux Estimation ◽  
Increase In Accuracy

Abstract We present a validation of red blood cell flux and speed measurements based on the passage of erythrocytes through the OCT’s focal volume. We compare the performance of the so-called RBC-passage OCT technique to co-localized and simultaneously acquired two-photon excitation fluorescence microscopy (TPEF) measurements. Using concurrent multi-modal imaging, we show that fluctuations in the OCT signal display highly similar features to TPEF time traces. Furthermore, we demonstrate an overall difference in RBC flux and speed of 2.5 ± 3.27 RBC/s and 0.12 ± 0.67 mm/s (mean ± S.D.), compared to TPEF. The analysis also revealed that the OCT RBC flux estimation is most accurate between 20 RBC/s to 60 RBC/s, and is severely underestimated at fluxes beyond 80 RBC/s. Lastly, our analysis shows that the RBC speed estimations increase in accuracy as the speed decreases, reaching a difference of 0.16 ± 0.25 mm/s within the 0–0.5 mm/s speed range.

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