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Simulation of Ultrasound RF Signals Backscattered from a 3D Model of Pulsating Artery Surrounded by Tissue. Diagnostics (Basel) 2022; 12:diagnostics12020232. [PMID: 35204323 PMCID: PMC8871234 DOI: 10.3390/diagnostics12020232] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Revised: 01/08/2022] [Accepted: 01/13/2022] [Indexed: 02/05/2023] Open
Abstract
Arterial stiffness is an independent predictor of cardiovascular events. The motion of arterial tissues during the cardiac cycle is important as a mechanical deformation representing vessel elasticity and is related to arterial stiffness. In addition, arterial pulsation is the main source of endogenous tissue micro-motions currently being studied for tissue elastography. Methods based on artery motion detection are not applied in clinical practice these days, because they must be carefully investigated in silico and in vitro before wide usage in vivo. The purpose of this paper is to propose a dynamic 3D artery model capable of reproducing the biomechanical behavior of human blood vessels surrounded by elastic tissue for endogenous deformation elastography developments and feasibility studies. The framework is based on a 3D model of a pulsating artery surrounded by tissue and simulation of linear scanning by Field II software to generate realistic dynamic RF signals and B-mode ultrasound image sequential data. The model is defined by a spatial distribution of motions, having patient-specific slopes of radial and longitudinal motion components of the artery wall and surrounding tissues. It allows for simulating the quantified mechanical micro-motions in the volume of the model. Acceptable simulation errors calculated between modeled motion patterns and those estimated from simulated RF signals and B-scan images show that this approach is suitable for the development and validation of elastography algorithms based on motion detection.
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Gao J, Lee J, Phan A, Fowlkes JB. Velocity Vector Imaging to Assess Longitudinal Wall Motion of Adult Carotid Arteries. JOURNAL OF ULTRASOUND IN MEDICINE : OFFICIAL JOURNAL OF THE AMERICAN INSTITUTE OF ULTRASOUND IN MEDICINE 2021; 40:1195-1207. [PMID: 32914417 DOI: 10.1002/jum.15501] [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: 02/22/2020] [Revised: 08/08/2020] [Accepted: 08/15/2020] [Indexed: 06/11/2023]
Abstract
OBJECTIVE We aimed to assess longitudinal wall motion of the common carotid artery (CCA) using velocity vector imaging (VVI). METHODS From October 2018 to July 2019, we prospectively performed VVI of 204 CCAs (102 adult volunteers, 57 men, 45 women) in young (n = 40, 20-44 y), mid-age (n = 30, 45-64 y), and senior (n = 32, ≥65 y) groups. VVI parameters of CCA included longitudinal motion pattern, motion parameters (strain, strain rate, displacement), and time-to-peak motion parameters (time-to-peak strain, time-to-peak strain rate, time-to-peak displacement). Statistical analyses included one-way ANOVA post-hoc testing to examine the difference in VVI parameters among the 3 age groups and in paired groups; unpaired t tests to examine the difference in VVI parameters between CCAs with and without atherosclerotic plaque, between hypertensive and normotensive subjects without atherosclerotic plaque; linear regression to analyze correlations of VVI parameters to age, carotid intima-media thickness; and intraclass correlation coefficient to test inter- and intra-observer reliability in performing VVI of the CCA. RESULTS Differences in VVI parameters and patterns among the 3 age groups, between hypertensive and normotensive, and CCAs with and without plaque were significant (p < .01). CCA motion- and time-to-peak motion parameters were correlated to age (R2 = 0.63-0.56) and carotid intima-media thickness (R2 = 0.29-0.22). CCA wall motion dyssynchrony was remarkable in seniors. The repeatability and reproducibility for performing carotid artery VVI were good (intraclass correlation coefficient > 0.85). CONCLUSIONS VVI is feasible to assess changes in longitudinal CCA wall mechanical properties and synchrony with aging, atherosclerosis, and hypertension.
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Affiliation(s)
- Jing Gao
- Rocky Vista University, Ivins, Utah
- Weill Cornell Medicine, Cornell University, New York, New York
| | | | | | - J Brian Fowlkes
- Department of Radiology, University of Michigan, Ann Arbor, Michigan
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Marais L, Pernot M, Khettab H, Tanter M, Messas E, Zidi M, Laurent S, Boutouyrie P. Arterial Stiffness Assessment by Shear Wave Elastography and Ultrafast Pulse Wave Imaging: Comparison with Reference Techniques in Normotensives and Hypertensives. ULTRASOUND IN MEDICINE & BIOLOGY 2019; 45:758-772. [PMID: 30642659 DOI: 10.1016/j.ultrasmedbio.2018.10.032] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Revised: 10/31/2018] [Accepted: 10/31/2018] [Indexed: 06/09/2023]
Abstract
Shear wave elastography and ultrafast imaging of the carotid artery pulse wave were performed in 27 normotensive participants and 29 age- and sex-matched patients with essential hypertension, and compared with reference techniques: carotid-femoral pulse wave velocity (cfPWV) determined via arterial tonometry and carotid stiffness (carPWV) determined via echotracking. Shear wave speed in the carotid anterior (a-SWS) and posterior (p-SWS) walls were assessed throughout the cardiac cycle. Ultrafast PWV was measured in early systole (ufPWV-FW) and in end-systole (dicrotic notch, ufPWV-DN). Shear wave speed in the carotid anterior appeared to be the best candidate to evaluate arterial stiffness from ultrafast imaging. In univariate analysis, a-SWS was associated with carPWV (r = 0.56, p = 0.003) and carotid-to-femoral PWV (r = 0.66, p < 0.001). In multivariate analysis, a-SWS was independently associated with age (R² = 0.14, p = 0.02) and blood pressure (R² = 0.21, p = 0.004). Moreover, a-SWS increased with blood pressure throughout the cardiac cycle and did not differ between normotensive participants and patients with essential hypertension when compared at similar blood pressures.
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Affiliation(s)
- Louise Marais
- Inserm U970, Paris Cardiovascular Research Center (PARCC), Georges Pompidou European Hospital, Paris, France; Bioengineering, Tissue and Neuroplasticity, EA 7377, Paris-Est Créteil University, Faculty of Medicine, Surgical Research Center, 94010 Créteil, France.
| | - Mathieu Pernot
- Institut Langevin, ESPCI-ParisTech, PSL Research University, CNRS UMR 7587, Inserm U979, Paris, France
| | - Hakim Khettab
- Inserm U970, Paris Cardiovascular Research Center (PARCC), Georges Pompidou European Hospital, Paris, France
| | - Mickael Tanter
- Institut Langevin, ESPCI-ParisTech, PSL Research University, CNRS UMR 7587, Inserm U979, Paris, France
| | - Emmanuel Messas
- Inserm U970, Paris Cardiovascular Research Center (PARCC), Georges Pompidou European Hospital, Paris, France
| | - Mustapha Zidi
- Bioengineering, Tissue and Neuroplasticity, EA 7377, Paris-Est Créteil University, Faculty of Medicine, Surgical Research Center, 94010 Créteil, France
| | - Stéphane Laurent
- Inserm U970, Paris Cardiovascular Research Center (PARCC), Georges Pompidou European Hospital, Paris, France
| | - Pierre Boutouyrie
- Inserm U970, Paris Cardiovascular Research Center (PARCC), Georges Pompidou European Hospital, Paris, France
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Campo A, McGarry MD, Panis T, Dirckx J, Konofagou E. Effect of Local Neck Anatomy on Localized One-Dimensional Measurements of Arterial Stiffness: A Finite-Element Model Study. J Biomech Eng 2019; 141:2720656. [PMID: 30702744 DOI: 10.1115/1.4042435] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2018] [Indexed: 11/08/2022]
Abstract
Cardiovascular diseases (CVD) are the most prevalent cause of death in the Western World, and their prevalence is only expected to rise. Several screening modalities aim at detecting CVD at the early stages. A common target for early screening is common carotid artery (CCA) stiffness, as reflected in the pulse wave velocity (PWV). For assessing the CCA stiffness using ultrasound (US), one-dimensional (1D) measurements along the CCA axis are typically used, ignoring possible boundary conditions of neck anatomy and the US probe itself. In this study, the effect of stresses and deformations induced by the US probe, and the effect of anatomy surrounding CCA on a simulated 1D stiffness measurement (PWVus) is compared with the ground truth stiffness (PWVgt) in 60 finite-element models (FEM) derived from anatomical computed tomography (CT) scans of ten healthy male volunteers. Based on prior knowledge from the literature, and from results in this study, we conclude that it is safe to approximate arterial stiffness using 1D measurements of compliance or pulse wave velocity, regardless of boundary conditions emerging from the anatomy or from the measurement procedure.
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Affiliation(s)
- Adriaan Campo
- Ultrasound Elasticity Imaging Laboratory, Columbia University, Columbia University Medical Campus, 630 West 168th Street, Physicians & Surgeons 19-418, New York, NY 10032.,Laboratory of Biomedical Physics, Antwerp University, Campus Groenenborger, Groenenborgerlaan 171 G.U.339, Antwerp 2020, Belgium e-mail:
| | - Matthew D McGarry
- Thayer School of Engineering Dartmouth, 14 Engineering Drive, Hanover, NH 03755 e-mail:
| | - Thomas Panis
- Radiology Department, University Hospital of Brussels, UZ Brussel, Campus Jette, Laarbeeklaan 101, Brussels B-1090, Belgium e-mail:
| | - Joris Dirckx
- Laboratory of Biomedical Physics, Antwerp University, Campus Groenenborger, Groenenborgerlaan 171 G.U.342, Antwerp 2020, Belgium e-mail:
| | - Elisa Konofagou
- Ultrasound Elasticity Imaging Laboratory, Columbia University, Columbia University Medical Campus, 630 West 168th Street, Physicians & Surgeons 19-418, New York, NY 10032 e-mail:
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Podgórski M, Winnicka M, Polguj M, Grzelak P, Łukaszewski M, Stefańczyk L. Does the internal jugular vein affect the elasticity of the common carotid artery? Cardiovasc Ultrasound 2016; 14:40. [PMID: 27639559 PMCID: PMC5027086 DOI: 10.1186/s12947-016-0084-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/12/2016] [Accepted: 09/09/2016] [Indexed: 01/22/2023] Open
Abstract
Background Arterial stiffness is an early marker of atherosclerosis. The carotid arteries are easily accessible by ultrasound and are commonly used for the evaluation of atherosclerosis development. However, this stiffness assessment is based on the elastic properties of the artery, which may be influenced by the adjacent internal jugular vein (IJV). The aim of the present study is to evaluate the influence of internal jugular vein morphology on the stiffness of the common carotid artery. Methods Bilateral carotid ultrasound was performed in 248 individuals. When no carotid plaque was detected (90.9 % cases), the distensibility coefficient and β - stiffness index were calculated. The global and segmental circumferential strain parameters of the carotid wall were evaluated with 2D-Speckle Tracking. The cross-sectional area of the IJV and degree of its adherence to the carotid wall (angle of adherence) were measured. Results The morphology of the IJV did not influence the standard stiffness parameters nor the global circumferential strain. However, segmental analysis found the sector adjacent to the IJV to have significantly higher strain parameters than its opposite counterpart. In addition, the strain correlated significantly and positively with IJV cross-sectional area and angle of adherence. Conclusions The movement of the carotid artery wall caused by the passage of the pulse wave is not homogeneous. The greatest strain is observed in a segment adjacent to the IJV, and the degree of wall deformation is associated with the size of the vein and the degree of its adherence.
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Affiliation(s)
- Michał Podgórski
- Department of Radiology and Diagnostic Imaging, Medical University of Lodz, 22, Kopcińskiego St., Barlicki Hospital, Lodz, Poland.
| | - Monika Winnicka
- Department of Angiology, Chair of Anatomy, Medical University of Lodz, 60, Narutowicza St, Lodz, Poland
| | - Michał Polguj
- Department of Angiology, Chair of Anatomy, Medical University of Lodz, 60, Narutowicza St, Lodz, Poland
| | - Piotr Grzelak
- Department of Radiology and Diagnostic Imaging, Medical University of Lodz, 22, Kopcińskiego St., Barlicki Hospital, Lodz, Poland
| | - Maciej Łukaszewski
- Department of Diagnostic Imaging, Polish Mother's Memorial Hospital Research Institute, 281/289, Rzgowska St, Lodz, Poland
| | - Ludomir Stefańczyk
- Department of Radiology and Diagnostic Imaging, Medical University of Lodz, 22, Kopcińskiego St., Barlicki Hospital, Lodz, Poland
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Asymmetric pulsation of rat carotid artery bifurcation in three-dimension observed by ultrasound imaging. Int J Cardiovasc Imaging 2016; 32:1499-508. [PMID: 27378096 DOI: 10.1007/s10554-016-0934-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Accepted: 07/01/2016] [Indexed: 02/01/2023]
Abstract
The arterial structure cyclically fluctuates in three-dimensions (3-D) caused by pulsatile blood flow. The evaluation of arterial wall motion and hemodynamics contributes to early diagnosis of carotid atherosclerosis. Ultrasound is one of the most appropriate imaging modalities to evaluate arterial wall motion in real time. Although many previous studies have discussed the mechanical properties of the carotid artery bifurcation (CAB) from the two-dimensional (2-D) view, the spatio-temporal variation of carotid artery geometry in 3-D has not yet been investigated in detail. In this study, the 3-D data set of CAB from rats was acquired using a high spatio-temporal resolution ultrasound imaging system with a 40 MHz probe using mechanical sector scanning. A total of 31 slices of cross-section images were stored and a spoke scan algorithm was implemented to radially scan the lumen area in polar coordinates based on a pre-tracked seed point. The boundary of the arterial lumen was segmented using intensity-threshold-based boundary detection and fitted by polynomial regression. Two operators, who were trained with the same protocol to minimize inter- and intra-operator variability, manually segmented the lumen boundary on systolic and diastolic phase from the gray-scale images. Finally, the 3-D lumen geometries of CAB during one cardiac cycle were constructed based on the segmented lumen boundaries. From this constructed 3-D geometry, we observed that the CAB geometry favorably expanded to the anterior/posterior direction, parallel to the sagittal plane; and the manually segmented geometry also confirmed the asymmetrical change in bifurcation geometry. This is the first study on visualization and quantification on the asymmetrical variation of the CAB geometry of a rat in 3-D during a whole cardiac cycle. This finding may be useful in understanding hemodynamic etiology of various cardiovascular diseases such as arterial stenosis and its complications, and also provides reference information for numerical simulation studies on arterial wall motion.
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Nam KH, Kim J, Ra G, Lee CH, Paeng DG. Feasibility Study of Ex Ovo Chick Chorioallantoic Artery Model for Investigating Pulsatile Variation of Arterial Geometry. PLoS One 2015; 10:e0145969. [PMID: 26717244 PMCID: PMC4696805 DOI: 10.1371/journal.pone.0145969] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2015] [Accepted: 12/10/2015] [Indexed: 11/19/2022] Open
Abstract
Despite considerable research efforts on the relationship between arterial geometry and cardiovascular pathology, information is lacking on the pulsatile geometrical variation caused by arterial distensibility and cardiomotility because of the lack of suitable in vivo experimental models and the methodological difficulties in examining the arterial dynamics. We aimed to investigate the feasibility of using a chick embryo system as an experimental model for basic research on the pulsatile variation of arterial geometry. Optical microscope video images of various arterial shapes in chick chorioallantoic circulation were recorded from different locations and different embryo samples. The high optical transparency of the chorioallantoic membrane (CAM) allowed clear observation of tiny vessels and their movements. Systolic and diastolic changes in arterial geometry were visualized by detecting the wall boundaries from binary images. Several to hundreds of microns of wall displacement variations were recognized during a pulsatile cycle. The spatial maps of the wall motion harmonics and magnitude ratio of harmonic components were obtained by analyzing the temporal brightness variation at each pixel in sequential grayscale images using spectral analysis techniques. The local variations in the spectral characteristics of the arterial wall motion were reflected well in the analysis results. In addition, mapping the phase angle of the fundamental frequency identified the regional variations in the wall motion directivity and phase shift. Regional variations in wall motion phase angle and fundamental-to-second harmonic ratio were remarkable near the bifurcation area. In summary, wall motion in various arterial geometry including straight, curved and bifurcated shapes was well observed in the CAM artery model, and their local and cyclic variations could be characterized by Fourier and wavelet transforms of the acquired video images. The CAM artery model with the spectral analysis method is a useful in vivo experimental model for studying pulsatile variation in arterial geometry.
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Affiliation(s)
- Kweon-Ho Nam
- Interdisciplinary Postgraduate Program in Biomedical Engineering, Jeju National University, Jeju, South Korea
- Department of Ocean System Engineering, Jeju National University, Jeju, South Korea
| | - Juho Kim
- Department of Ocean System Engineering, Jeju National University, Jeju, South Korea
| | - Gicheol Ra
- Department of Ocean System Engineering, Jeju National University, Jeju, South Korea
| | - Chong Hyun Lee
- Department of Ocean System Engineering, Jeju National University, Jeju, South Korea
| | - Dong-Guk Paeng
- Interdisciplinary Postgraduate Program in Biomedical Engineering, Jeju National University, Jeju, South Korea
- Department of Ocean System Engineering, Jeju National University, Jeju, South Korea
- * E-mail:
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Kenwright DA, Laverick N, Anderson T, Moran CM, Hoskins PR. Wall-less flow phantom for high-frequency ultrasound applications. ULTRASOUND IN MEDICINE & BIOLOGY 2015; 41:890-7. [PMID: 25542496 PMCID: PMC4342409 DOI: 10.1016/j.ultrasmedbio.2014.09.018] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2014] [Revised: 09/10/2014] [Accepted: 09/11/2014] [Indexed: 05/23/2023]
Abstract
There are currently very few test objects suitable for high-frequency ultrasound scanners that can be rapidly manufactured, have appropriate acoustic characteristics and are suitably robust. Here we describe techniques for the creation of a wall-less flow phantom using a physically robust konjac and carrageenan-based tissue-mimicking material. Vessel dimensions equivalent to those of mouse and rat arteries were achieved with steady flow, with the vessel at a depth of 1.0 mm. We then employed the phantom to briefly investigate velocity errors using pulsed wave Doppler with a commercial preclinical ultrasound system. This phantom will provide a useful tool for testing preclinical ultrasound imaging systems.
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Affiliation(s)
- David A Kenwright
- Centre for Cardiovascular Science, University of Edinburgh, Edinburgh, United Kingdom.
| | - Nicola Laverick
- Centre for Cardiovascular Science, University of Edinburgh, Edinburgh, United Kingdom
| | - Tom Anderson
- Centre for Cardiovascular Science, University of Edinburgh, Edinburgh, United Kingdom
| | - Carmel M Moran
- Centre for Cardiovascular Science, University of Edinburgh, Edinburgh, United Kingdom
| | - Peter R Hoskins
- Centre for Cardiovascular Science, University of Edinburgh, Edinburgh, United Kingdom
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Yeom E, Nam KH, Jin C, Paeng DG, Lee SJ. 3D reconstruction of a carotid bifurcation from 2D transversal ultrasound images. ULTRASONICS 2014; 54:2184-2192. [PMID: 24965564 DOI: 10.1016/j.ultras.2014.06.002] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2014] [Revised: 05/12/2014] [Accepted: 06/01/2014] [Indexed: 06/03/2023]
Abstract
Visualizing and analyzing the morphological structure of carotid bifurcations are important for understanding the etiology of carotid atherosclerosis, which is a major cause of stroke and transient ischemic attack. For delineation of vasculatures in the carotid artery, ultrasound examinations have been widely employed because of a noninvasive procedure without ionizing radiation. However, conventional 2D ultrasound imaging has technical limitations in observing the complicated 3D shapes and asymmetric vasodilation of bifurcations. This study aims to propose image-processing techniques for better 3D reconstruction of a carotid bifurcation in a rat by using 2D cross-sectional ultrasound images. A high-resolution ultrasound imaging system with a probe centered at 40MHz was employed to obtain 2D transversal images. The lumen boundaries in each transverse ultrasound image were detected by using three different techniques; an ellipse-fitting, a correlation mapping to visualize the decorrelation of blood flow, and the ellipse-fitting on the correlation map. When the results are compared, the third technique provides relatively good boundary extraction. The incomplete boundaries of arterial lumen caused by acoustic artifacts are somewhat resolved by adopting the correlation mapping and the distortion in the boundary detection near the bifurcation apex was largely reduced by using the ellipse-fitting technique. The 3D lumen geometry of a carotid artery was obtained by volumetric rendering of several 2D slices. For the 3D vasodilatation of the carotid bifurcation, lumen geometries at the contraction and expansion states were simultaneously depicted at various view angles. The present 3D reconstruction methods would be useful for efficient extraction and construction of the 3D lumen geometries of carotid bifurcations from 2D ultrasound images.
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Affiliation(s)
- Eunseop Yeom
- Department of Mechanical Engineering, Pohang University of Science and Technology, Pohang, South Korea
| | - Kweon-Ho Nam
- Department of Ocean System Engineering, Interdisciplinary Postgraduate Program in Biomedical Engineering, Jeju National University, Jeju, South Korea
| | - Changzhu Jin
- Department of Ocean System Engineering, Interdisciplinary Postgraduate Program in Biomedical Engineering, Jeju National University, Jeju, South Korea
| | - Dong-Guk Paeng
- Department of Ocean System Engineering, Interdisciplinary Postgraduate Program in Biomedical Engineering, Jeju National University, Jeju, South Korea.
| | - Sang-Joon Lee
- Department of Mechanical Engineering, Pohang University of Science and Technology, Pohang, South Korea.
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Nam KH, Paeng DG. In vivo observation of the hypo-echoic "black hole" phenomenon in rat arterial bloodstream: a preliminary Study. ULTRASOUND IN MEDICINE & BIOLOGY 2014; 40:1619-1628. [PMID: 24785440 DOI: 10.1016/j.ultrasmedbio.2014.01.023] [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: 10/14/2013] [Revised: 12/26/2013] [Accepted: 01/27/2014] [Indexed: 06/03/2023]
Abstract
The "black hole," a hypo-echoic hole at the center of the bloodstream surrounded by a hyper-echoic zone in cross-sectional views, has been observed in ultrasound backscattering measurements of blood with red blood cell aggregation in in vitro studies. We investigated whether the phenomenon occurs in the in vivo arterial bloodstream of rats using a high-frequency ultrasound imaging system. Longitudinal and cross-sectional ultrasound images of the rat common carotid artery (CCA) and abdominal aorta were obtained using a 40-MHz ultrasound system. A high-frame-rate retrospective imaging mode was employed to precisely examine the dynamic changes in blood echogenicity in the arteries. When the imaging was performed with non-invasive scanning, blood echogenicity was very low in the CCA as compared with the surrounding tissues, exhibiting no hypo-echoic zone at the center of the vessel. Invasive imaging of the CCA by incising the skin and subcutaneous tissues at the imaging area provided clearer and brighter blood echo images, showing the "black hole" phenomenon near the center of the vessel in longitudinal view. The "black hole" was also observed in the abdominal aorta under direct imaging after laparotomy. The aortic "black hole" was clearly observed in both longitudinal and cross-sectional views. Although the "black hole" was always observed near the center of the arteries during the diastolic phase, it dissipated or was off-center along with the asymmetric arterial wall dilation at systole. In conclusion, we report the first in vivo observation of the hypo-echoic "black hole" caused by the radial variation of red blood cell aggregation in arterial bloodstream.
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Affiliation(s)
- Kweon-Ho Nam
- Department of Ocean System Engineering, Jeju National University, Jeju, South Korea
| | - Dong-Guk Paeng
- Department of Ocean System Engineering, Jeju National University, Jeju, South Korea; Interdisciplinary Postgraduate Program in Biomedical Engineering, Jeju National University, Jeju, South Korea.
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