1
|
Muleki-Seya P, O'Brien WD. Evaluation of Scatterer Parameters From Ultrasound Scattering Models Taking Into Account Scattering From Nuclei and Cells of Cell-Pellet Biophantoms and Ex Vivo Tumors. ULTRASONIC IMAGING 2024:1617346241256120. [PMID: 38873927 DOI: 10.1177/01617346241256120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2024]
Abstract
The Quantitative Ultrasound backscatter coefficient provides the capability to evaluate tissue microstructure parameters. Tissue-based scatterer parameters are extracted using ultrasound scattering models. It is challenging to correlate ultrasound scatterer parameters of tissue structures from optical-measured histology, possibly because of inappropriate scattering models or the presence of multiple scatterers. The objective of this study is to pursue the quantification of pertinent scatterer parameters with scattering models that consider ultrasound scattering from nuclei and cells. The concentric sphere model (CSM) and the structure factor model adapted for two types of scatterers (SFM2) are evaluated for cell-pellet biophantoms and ex vivo tumors of four cell lines: 4T1, JC, LMTK, and MAT. The structure factor model (SFM) was used for comparison. CSM and SFM2 provided scatterer parameters closer to histology (lower relative errors) for nucleus and cell radii and volume fractions than SFM but were not always accompanied by lower dispersion of the scatterer distribution (lower coefficient of variation). CSM and SFM2 quantified cell and nucleus radius and volume fraction parameters with lower relative error compared to SFM. For tumors, CSM provided better results than SFM2.
Collapse
Affiliation(s)
- Pauline Muleki-Seya
- Univ Lyon, INSA-Lyon, Université Claude Bernard Lyon 1, UJM-Saint Etienne, CNRS, Inserm, CREATIS UMR 5220, Villeurbanne, France
| | - William D O'Brien
- Bioacoustics Research Laboratory, Department of Electrical and Computer Engineering, University of Illinois Urbana-Champaign, Urbana, IL, USA
| |
Collapse
|
2
|
Omura M, Yagi K, Nagaoka R, Hasegawa H. Contrast analysis in ultrafast ultrasound blood flow imaging of jugular vein. J Med Ultrason (2001) 2023; 50:131-141. [PMID: 36757634 PMCID: PMC10955029 DOI: 10.1007/s10396-023-01289-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Accepted: 12/25/2022] [Indexed: 02/10/2023]
Abstract
PURPOSE The contrasts of flowing blood in in vitro experiments using porcine blood and in vivo measurements of human jugular veins were analyzed to demonstrate that the hemorheological property was dependent on the shear rate. METHODS Blood samples (45% hematocrit) suspended in saline or plasma were compared with examine the difference in viscoelasticity. Ultrafast plane-wave imaging at an ultrasonic center frequency of 7.5 MHz was performed on different steady flows in a graphite-agar phantom. Also, in vivo measurement was performed in young, healthy subjects and patients with diabetes. A spatiotemporal matrix of beamformed radio-frequency data was used for the singular value decomposition (SVD) clutter filter. The clutter-filtered B-mode image was calculated as the amplitude envelope normalized at the first frame in the diastolic phase to evaluate contrast. The shear rate was estimated as the velocity gradient perpendicular to the lateral axis. RESULTS Although nonaggregated erythrocytes at a high shear rate exhibited a low echogenicity, the echogenicity in the plasma sample overall increased due to erythrocyte aggregation at a low shear rate. In addition, the frequency of detection of specular components, defined as components beyond twice the standard deviation of a contrast map obtained from a clutter-filtered B-mode image, increased in the porcine blood at a high shear rate and the venous blood in healthy subjects versus patients with diabetes. CONCLUSION The possibility of characterizing hemorheological properties dependent on the shear rate and diabetes condition was indicated using ultrafast plane-wave imaging with an SVD-based clutter filter.
Collapse
Affiliation(s)
- Masaaki Omura
- Faculty of Engineering, University of Toyama, 3190 Gofuku, Toyama, 93008555, Japan.
| | - Kunimasa Yagi
- School of Medicine, Kanazawa Medical University, 1-1 Daigaku, Uchinada, Kahoku, Ishikawa, 9200293, Japan
| | - Ryo Nagaoka
- Faculty of Engineering, University of Toyama, 3190 Gofuku, Toyama, 93008555, Japan
| | - Hideyuki Hasegawa
- Faculty of Engineering, University of Toyama, 3190 Gofuku, Toyama, 93008555, Japan.
| |
Collapse
|
3
|
Omura M, Yagi K, Nagaoka R, Yoshida K, Yamaguchi T, Hasegawa H. Effect of Clutter Filter in High-Frame-Rate Ultrasonic Backscatter Coefficient Analysis. SENSORS (BASEL, SWITZERLAND) 2023; 23:2639. [PMID: 36904843 PMCID: PMC10007061 DOI: 10.3390/s23052639] [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: 01/20/2023] [Revised: 02/15/2023] [Accepted: 02/25/2023] [Indexed: 06/18/2023]
Abstract
High-frame-rate imaging with a clutter filter can clearly visualize blood flow signals and provide more efficient discrimination with tissue signals. In vitro studies using clutter-less phantom and high-frequency ultrasound suggested a possibility of evaluating the red blood cell (RBC) aggregation by analyzing the frequency dependence of the backscatter coefficient (BSC). However, in in vivo applications, clutter filtering is required to visualize echoes from the RBC. This study initially evaluated the effect of the clutter filter for ultrasonic BSC analysis for in vitro and preliminary in vivo data to characterize hemorheology. Coherently compounded plane wave imaging at a frame rate of 2 kHz was carried out in high-frame-rate imaging. Two samples of RBCs suspended by saline and autologous plasma for in vitro data were circulated in two types of flow phantoms without or with clutter signals. The singular value decomposition was applied to suppress the clutter signal in the flow phantom. The BSC was calculated using the reference phantom method, and it was parametrized by spectral slope and mid-band fit (MBF) between 4-12 MHz. The velocity distribution was estimated by the block matching method, and the shear rate was estimated by the least squares approximation of the slope near the wall. Consequently, the spectral slope of the saline sample was always around four (Rayleigh scattering), independently of the shear rate, because the RBCs did not aggregate in the solution. Conversely, the spectral slope of the plasma sample was lower than four at low shear rates but approached four by increasing the shear rate, because the aggregations were presumably dissolved by the high shear rate. Moreover, the MBF of the plasma sample decreased from -36 to -49 dB in both flow phantoms with increasing shear rates, from approximately 10 to 100 s-1. The variation in the spectral slope and MBF in the saline sample was comparable to the results of in vivo cases in healthy human jugular veins when the tissue and blood flow signals could be separated.
Collapse
Affiliation(s)
- Masaaki Omura
- Faculty of Engineering, University of Toyama, Toyama 930-8555, Japan
| | - Kunimasa Yagi
- School of Medicine, Kanazawa Medical University, Kanazawa 920-0293, Japan
| | - Ryo Nagaoka
- Faculty of Engineering, University of Toyama, Toyama 930-8555, Japan
| | - Kenji Yoshida
- Center for Frontier Medical Engineering, Chiba University, Chiba 263-8522, Japan
| | - Tadashi Yamaguchi
- Center for Frontier Medical Engineering, Chiba University, Chiba 263-8522, Japan
| | - Hideyuki Hasegawa
- Faculty of Engineering, University of Toyama, Toyama 930-8555, Japan
| |
Collapse
|
4
|
Leth-Olsen M, Døhlen G, Torp H, Nyrnes SA. Detection of Cerebral High-Intensity Transient Signals by NeoDoppler during Cardiac Catheterization and Cardiac Surgery in Infants. ULTRASOUND IN MEDICINE & BIOLOGY 2022; 48:1256-1267. [PMID: 35410742 DOI: 10.1016/j.ultrasmedbio.2022.02.021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Revised: 02/17/2022] [Accepted: 02/23/2022] [Indexed: 06/14/2023]
Abstract
There is a risk of gaseous and solid micro-embolus formation during transcatheter cardiac interventions and surgery in children with congenital heart disease (CHD). Our aim was to study the burden of high-intensity transient signals (HITS) during these procedures in infants. We used a novel color M-mode Doppler (CMD) technique by NeoDoppler, a non-invasive ultrasound system based on plane wave transmissions for transfontanellar continuous monitoring of cerebral blood flow in infants. The system displays CMD with 24 sample volumes and a Doppler spectrogram. Infants with CHD undergoing transcatheter interventions (n = 15) and surgery (n = 13) were included. HITS were manually detected based on an "embolic signature" in the CMD with corresponding intensity increase in the Doppler spectrogram. Embolus-to-blood ratio (EBR) defined HITS size. A total of 1169 HITS with a median EBR of 9.74 dB (interquartile range [IQR]: 5.10-15.80 dB) were detected. The median number of HITS in the surgery group was 45 (IQR: 11-150), while in the transcatheter group the median number was 12 (IQR: 7-24). During cardiac surgery, the highest number of HITS per hour was seen from initiation of cardiopulmonary bypass to aortic X-clamp. In this study we detected frequent HITS and determined the feasibility of using NeoDoppler monitoring for HITS detection.
Collapse
Affiliation(s)
- Martin Leth-Olsen
- Department of Circulation and Medical Imaging (ISB), Faculty of Medicine and Health Sciences, Norwegian University of Science and Technology, Trondheim, Norway; Children's Clinic, St. Olav's University Hospital, Trondheim, Norway.
| | - Gaute Døhlen
- Department of Pediatric Cardiology, Oslo University Hospital, Oslo, Norway
| | - Hans Torp
- Department of Circulation and Medical Imaging (ISB), Faculty of Medicine and Health Sciences, Norwegian University of Science and Technology, Trondheim, Norway
| | - Siri Ann Nyrnes
- Department of Circulation and Medical Imaging (ISB), Faculty of Medicine and Health Sciences, Norwegian University of Science and Technology, Trondheim, Norway; Children's Clinic, St. Olav's University Hospital, Trondheim, Norway
| |
Collapse
|
5
|
Cloutier G, Destrempes F, Yu F, Tang A. Quantitative ultrasound imaging of soft biological tissues: a primer for radiologists and medical physicists. Insights Imaging 2021; 12:127. [PMID: 34499249 PMCID: PMC8429541 DOI: 10.1186/s13244-021-01071-w] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Accepted: 08/07/2021] [Indexed: 12/26/2022] Open
Abstract
Quantitative ultrasound (QUS) aims at quantifying interactions between ultrasound and biological tissues. QUS techniques extract fundamental physical properties of tissues based on interactions between ultrasound waves and tissue microstructure. These techniques provide quantitative information on sub-resolution properties that are not visible on grayscale (B-mode) imaging. Quantitative data may be represented either as a global measurement or as parametric maps overlaid on B-mode images. Recently, major ultrasound manufacturers have released speed of sound, attenuation, and backscatter packages for tissue characterization and imaging. Established and emerging clinical applications are currently limited and include liver fibrosis staging, liver steatosis grading, and breast cancer characterization. On the other hand, most biological tissues have been studied using experimental QUS methods, and quantitative datasets are available in the literature. This educational review addresses the general topic of biological soft tissue characterization using QUS, with a focus on disseminating technical concepts for clinicians and specialized QUS materials for medical physicists. Advanced but simplified technical descriptions are also provided in separate subsections identified as such. To understand QUS methods, this article reviews types of ultrasound waves, basic concepts of ultrasound wave propagation, ultrasound image formation, point spread function, constructive and destructive wave interferences, radiofrequency data processing, and a summary of different imaging modes. For each major QUS technique, topics include: concept, illustrations, clinical examples, pitfalls, and future directions.
Collapse
Affiliation(s)
- Guy Cloutier
- Laboratory of Biorheology and Medical Ultrasonics, Centre de recherche du Centre hospitalier de l'Université de Montréal (CRCHUM), 900 St-Denis, Montréal, Québec, H2X 0A9, Canada.
- Department of Radiology, Radio-oncology, and Nuclear Medicine, Université de Montréal, Montréal, Québec, Canada.
- Institute of Biomedical Engineering, Université de Montréal, Montréal, Québec, Canada.
| | - François Destrempes
- Laboratory of Biorheology and Medical Ultrasonics, Centre de recherche du Centre hospitalier de l'Université de Montréal (CRCHUM), 900 St-Denis, Montréal, Québec, H2X 0A9, Canada
| | - François Yu
- Department of Radiology, Radio-oncology, and Nuclear Medicine, Université de Montréal, Montréal, Québec, Canada
- Institute of Biomedical Engineering, Université de Montréal, Montréal, Québec, Canada
- Microbubble Theranostics Laboratory, CRCHUM, Montréal, Québec, Canada
| | - An Tang
- Department of Radiology, Radio-oncology, and Nuclear Medicine, Université de Montréal, Montréal, Québec, Canada
- Department of Radiology, Centre hospitalier de l'Université de Montréal (CHUM), Montréal, Québec, Canada
- Laboratory of Medical Image Analysis, Montréal, CRCHUM, Canada
| |
Collapse
|
6
|
Specification and Evaluation of Plasticizer Migration Simulants for Human Blood Products: A Delphi Study. Biomolecules 2021; 11:biom11081081. [PMID: 34439748 PMCID: PMC8392596 DOI: 10.3390/biom11081081] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Revised: 07/16/2021] [Accepted: 07/20/2021] [Indexed: 11/26/2022] Open
Abstract
Potentially toxic plasticizers are commonly added to polyvinyl chloride medical devices for transfusion in order to improve their flexibility and workability. As the plasticizers are not chemically bonded to the PVC, they can be released into labile blood products (LBPs) during storage. Ideally, LBPs would be used in laboratory studies of plasticizer migration from the medical device. However, short supply (i.e., limited stocks of human blood in collection centres) has prompted the development of specific simulants for each type of LBP in the evaluation of new transfusion devices. We performed a Delphi study with a multidisciplinary panel of 24 experts. In the first (qualitative) phase, the panel developed consensus definitions of the specification criteria to be met by each migration simulant. Next, we reviewed the literature on techniques for simulating the migration of plasticizers into LBPs. A questionnaire was elaborated and sent out to the experts, and the replies were synthesized in order to obtain a consensus. The qualitative study established specifications for each biological matrix (whole blood, red blood cell concentrate, plasma, and platelet concentrate) and defined the criteria required for a suitable LBP simulant. Ten criteria were suggested: physical and chemical characteristics, opacity, form, stability, composition, ability to mimic a particular clinical situation, ease and safety of use, a simulant–plastic interaction correlated with blood, and compatibility with analytical methods. The questionnaire data revealed a consensus on the use of natural products (such as pig’s blood) to mimic the four LBPs. Opinions diverged with regard to synthetic products. However, an isotonic solution and a rheological property modifier were considered to be of value in the design of synthetic simulants. Consensus reached by the Delphi group could be used as a database for the development of simulants used to assess the migration of plasticizers from PVC bags into LBPs.
Collapse
|
7
|
Iori G, Du J, Hackenbeck J, Kilappa V, Raum K. Estimation of Cortical Bone Microstructure From Ultrasound Backscatter. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2021; 68:1081-1095. [PMID: 33104498 DOI: 10.1109/tuffc.2020.3033050] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Multichannel pulse-echo ultrasound using linear arrays and single-channel data acquisition systems opens new perspectives for the evaluation of cortical bone. In combination with spectral backscatter analysis, it can provide quantitative information about cortical microstructural properties. We present a numerical study, based on the finite-difference time-domain method, to estimate the backscatter cross section of randomly distributed circular pores in a bone matrix. A model that predicts the backscatter coefficient using arbitrary pore diameter distributions was derived. In an ex vivo study on 19 human tibia bones (six males, 13 females, 83.7 ± 8.4 years), multidirectional ultrasound backscatter measurements were performed using an ultrasound scanner equipped with a 6-MHz 128-element linear array with sweep motor control. A normalized depth-dependent spectral analysis was performed to derive backscatter and attenuation coefficients. Site-matched reference values of tissue acoustic impedance Z , cortical thickness (Ct.Th), pore density (Ct.Po.Dn), porosity (Ct.Po), and characteristic parameters of the pore diameter (Ct.Po.Dm) distribution were obtained from 100-MHz scanning-acoustic microscopy images. Proximal femur areal bone mineral density (aBMD), stiffness S , and ultimate force Fu from the same donors were available from a previous study. All pore structure and material properties could be predicted using linear combinations of backscatter parameters with a median to high accuracy (0.28 ≤ adjusted R2 ≤ 0.59). The combination of cortical thickness and backscatter parameter provided similar or better prediction accuracies than aBMD. For the first time, a method for the noninvasive assessment of the pore diameter distribution in cortical bone by ultrasound is proposed. The combined assessment of cortical thickness, sound velocity, and pore size distribution in a mobile, nonionizing measurement system could have a major impact on preventing osteoporotic fractures.
Collapse
|
8
|
Altun B, Demirkan I, Isik EO, Kocaturk O, Unlu MB, Garipcan B. Acoustic impedance measurement of tissue mimicking materials by using scanning acoustic microscopy. ULTRASONICS 2021; 110:106274. [PMID: 33130362 DOI: 10.1016/j.ultras.2020.106274] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2020] [Revised: 10/02/2020] [Accepted: 10/06/2020] [Indexed: 06/11/2023]
Abstract
Tissue-mimicking materials (TMMs) play a key role in the quality assurance of ultrasound diagnostic equipment and should have acoustic properties similar to human tissues. We propose a method to quantify the acoustic properties of TMM samples through the use of an 80 MHz Scanning Acoustic Microscopy (SAM), which provides micrometer resolution and fast data recording. We produced breast TMM samples in varying compositions that resulted in acoustic impedance values in the range of 1.373 ± 0.031 and 1.707 ± 0.036 MRayl. Additionally, liver TMM and blood mimicking fluid (BMF) samples were prepared that had acoustic impedance values of 1.693 ± 0.085 MRayl and 1.624 ± 0.006 MRayl, respectively. The characterization of the TMMs by SAM may provide reproducible and uniform acoustic reference data for tissue substitutes in a single-run microscopy experiment.
Collapse
Affiliation(s)
- Burak Altun
- Bogazici University, Institute of Biomedical Engineering, Istanbul 34684, Turkey
| | - Irem Demirkan
- Bogazici University, Department of Physics, Istanbul 34342, Turkey
| | - Esin Ozturk Isik
- Bogazici University, Institute of Biomedical Engineering, Istanbul 34684, Turkey
| | - Ozgur Kocaturk
- Bogazici University, Institute of Biomedical Engineering, Istanbul 34684, Turkey
| | - Mehmet Burcin Unlu
- Bogazici University, Department of Physics, Istanbul 34342, Turkey; Global Station for Quantum Medical Science and Engineering, Global Institution for Collaborative Research and Education (GI-CoRE), Hokkaido University, Sapporo 060- 8648, Japan
| | - Bora Garipcan
- Bogazici University, Institute of Biomedical Engineering, Istanbul 34684, Turkey.
| |
Collapse
|
9
|
Chayer B, Allard L, Qin Z, Garcia-Duitama J, Roger L, Destrempes F, Cailhier JF, Denault A, Cloutier G. Pilot clinical study of quantitative ultrasound spectroscopy measurements of erythrocyte aggregation within superficial veins. Clin Hemorheol Microcirc 2020; 74:109-126. [PMID: 31476146 PMCID: PMC7242846 DOI: 10.3233/ch-180541] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND: An enhanced inflammatory response is a trigger to the production of blood macromolecules involved in abnormally high levels of erythrocyte aggregation. OBJECTIVE: This study aimed at demonstrating for the first time the clinical feasibility of a non-invasive ultrasound-based erythrocyte aggregation quantitative measurement method for potential application in critical care medicine. METHODS: Erythrocyte aggregation was evaluated using modeling of the backscatter coefficient with the Structure Factor Size and Attenuation Estimator (SFSAE). SFSAE spectral parameters W (packing factor) and D (mean aggregate diameter) were measured within the antebrachial vein of the forearm and tibial vein of the leg in 50 healthy participants at natural flow and reduced flow controlled by a pressurized bracelet. Blood samples were also collected to measure erythrocyte aggregation ex vivo with an erythroaggregometer (parameter S10). RESULTS: W and Din vivo measurements were positively correlated with the ex vivoS10 index for both measurement sites and shear rates (correlations between 0.35–0.81, p < 0.05). Measurement at low shear rate was found to increase the sensitivity and reliability of this non-invasive measurement method. CONCLUSIONS: We behold that the SFSAE method presents systemic measures of the erythrocyte aggregation level, since results on upper and lower limbs were highly correlated.
Collapse
Affiliation(s)
- Boris Chayer
- Laboratory of Biorheology and Medical Ultrasonics, University of Montreal Hospital Research Center (CRCHUM), Montréal, QC, Canada
| | - Louise Allard
- Laboratory of Biorheology and Medical Ultrasonics, University of Montreal Hospital Research Center (CRCHUM), Montréal, QC, Canada
| | - Zhao Qin
- Laboratory of Biorheology and Medical Ultrasonics, University of Montreal Hospital Research Center (CRCHUM), Montréal, QC, Canada
| | - Julian Garcia-Duitama
- Laboratory of Biorheology and Medical Ultrasonics, University of Montreal Hospital Research Center (CRCHUM), Montréal, QC, Canada.,Institute of Biomedical Engineering, University of Montreal, Montréal, QC, Canada
| | - Laurence Roger
- Laboratory of Biorheology and Medical Ultrasonics, University of Montreal Hospital Research Center (CRCHUM), Montréal, QC, Canada
| | - François Destrempes
- Laboratory of Biorheology and Medical Ultrasonics, University of Montreal Hospital Research Center (CRCHUM), Montréal, QC, Canada
| | | | - André Denault
- Montreal Heart Institute, University of Montreal Hospital, and Department of Anesthesiology, University of Montreal, Montréal, QC, Canada
| | - Guy Cloutier
- Laboratory of Biorheology and Medical Ultrasonics, University of Montreal Hospital Research Center (CRCHUM), Montréal, QC, Canada.,Institute of Biomedical Engineering, University of Montreal, Montréal, QC, Canada.,Department of Radiology, Radio-Oncology and Nuclear Medicine, University of Montreal, Montreal, QC, Canada
| |
Collapse
|
10
|
Comparison between minimum lumen cross-sectional area and intraluminal ultrasonic intensity analysis using integrated backscatter intravascular ultrasound for prediction of functionally significant coronary artery stenosis. Heart Vessels 2018; 34:208-217. [DOI: 10.1007/s00380-018-1233-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Accepted: 07/27/2018] [Indexed: 01/10/2023]
|
11
|
Gyawali P, Ziegler D, Cailhier JF, Denault A, Cloutier G. Quantitative Measurement of Erythrocyte Aggregation as a Systemic Inflammatory Marker by Ultrasound Imaging: A Systematic Review. ULTRASOUND IN MEDICINE & BIOLOGY 2018; 44:1303-1317. [PMID: 29661483 DOI: 10.1016/j.ultrasmedbio.2018.02.020] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2017] [Revised: 02/21/2018] [Accepted: 02/28/2018] [Indexed: 06/08/2023]
Abstract
This systematic review is aimed at answering two questions: (i) Is erythrocyte aggregation a useful biomarker in assessing systemic inflammation? (ii) Does quantitative ultrasound imaging provide the non-invasive option to measure erythrocyte aggregation in real time? The search was executed through bibliographic electronic databases CINAHL, EMB Review, EMBASE, MEDLINE, PubMed and the grey literature. The majority of studies correlated elevated erythrocyte aggregation with inflammatory blood markers for several pathologic states. Some studies used "erythrocyte aggregation" as an established marker of systemic inflammation. There were limited but promising articles regarding the use of quantitative ultrasound spectroscopy to monitor erythrocyte aggregation. Similarly, there were limited studies that used other ultrasound techniques to measure systemic inflammation. The quantitative measurement of erythrocyte aggregation has the potential to be a routine clinical marker of inflammation as it can reflect the cumulative inflammatory dynamics in vivo, is relatively simple to measure, is cost-effective and has a rapid turnaround time. Technologies like quantitative ultrasound spectroscopy that can measure erythrocyte aggregation non-invasively and in real time may offer the advantage of continuous monitoring of the inflammation state and, thus, may help in rapid decision making in a critical care setup.
Collapse
Affiliation(s)
- Prajwal Gyawali
- Laboratory of Biorheology and Medical Ultrasonics, University of Montreal Hospital Research Center (CRCHUM), Montréal, Québec, Canada
| | - Daniela Ziegler
- Documentation Center, University of Montreal Hospital, Montréal, Québec, Canada
| | - Jean-François Cailhier
- University of Montreal Hospital Research Center (CRCHUM), Montréal, Québec, Canada; Department of Medicine, University of Montreal, Montréal, Québec, Canada
| | - André Denault
- University of Montreal Hospital, Montreal, Québec, Canada; Montreal Heart Institute, Montreal, Québec, Canada; Department of Anesthesiology, University of Montreal, Montréal, Québec, Canada
| | - Guy Cloutier
- Laboratory of Biorheology and Medical Ultrasonics, University of Montreal Hospital Research Center (CRCHUM), Montréal, Québec, Canada; Department of Radiology, Radio-Oncology and Nuclear Medicine, Montréal, Québec, Canada; Institute of Biomedical Engineering, University of Montreal, Montréal, Québec, Canada.
| |
Collapse
|
12
|
Oglat AA, Suardi N, Matjafri MZ, Oqlat MA, Abdelrahman MA, Oqlat AA. A Review of Suspension-Scattered Particles Used in Blood-Mimicking Fluid for Doppler Ultrasound Imaging. J Med Ultrasound 2018; 26:68-76. [PMID: 30065522 PMCID: PMC6029209 DOI: 10.4103/jmu.jmu_1_17] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2017] [Accepted: 11/13/2017] [Indexed: 11/21/2022] Open
Abstract
Doppler ultrasound imaging system description and calibration need blood-mimicking fluids (BMFs) for the test target of medical ultrasound diagnostic tools, with known interior features and acoustic and physical properties of this fluid (BMF). Physical and acoustical properties determined in the International Electrotechnical Commission (IEC) standard are specified as constant values, the materials used in the BMF preparation should have values similar to the IEC standard values. However, BMF is ready-made commercially from a field of medical usage, which may not be appropriate in the layout of ultrasound system or for an estimate of novel imaging mechanism. It is often eligible to have the capability to make sound properties and mimic blood arrangement for specific applications. In this review, sufficient BMF materials, liquids, and measures are described which have been generated by utilizing diverse operation mechanism and materials that have sculptured a range of biological systems.
Collapse
Affiliation(s)
- Ammar A. Oglat
- Department of Medical Physics and Radiation Science, School of Physics, Universiti Sains Malaysia, 11800 Penang, Malaysia
| | - Nursakinah Suardi
- Department of Medical Physics and Radiation Science, School of Physics, Universiti Sains Malaysia, 11800 Penang, Malaysia
| | - M. Z. Matjafri
- Department of Medical Physics and Radiation Science, School of Physics, Universiti Sains Malaysia, 11800 Penang, Malaysia
| | - Mohammad A. Oqlat
- Department of Biological Sciences, School of Science, Yarmouk University, Irbid, Jordan
| | | | - Ahmad A. Oqlat
- Department of Emergency, Faculty of Medicine, JUST, Irbid, Jordan
| |
Collapse
|
13
|
Garcia-Duitama J, Chayer B, Garcia D, Goussard Y, Cloutier G. Protocol for Robust In Vivo Measurements of Erythrocyte Aggregation Using Ultrasound Spectroscopy. ULTRASOUND IN MEDICINE & BIOLOGY 2017; 43:2871-2881. [PMID: 28893425 DOI: 10.1016/j.ultrasmedbio.2017.08.005] [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: 02/27/2017] [Revised: 07/19/2017] [Accepted: 08/08/2017] [Indexed: 06/07/2023]
Abstract
Erythrocyte aggregation is a non-specific marker of acute and chronic inflammation. Although it is usual to evaluate this phenomenon from blood samples analyzed in laboratory instruments, in vivo real-time assessment of aggregation is possible with spectral ultrasound techniques. However, variable blood flow can affect the interpretation of acoustic measures. Therefore, flow standardization is required. Two techniques of flow standardization were evaluated with porcine and equine blood samples in Couette flow. These techniques consisted in either stopping the flow or reducing it. Then, the sensibility and repeatability of the retained method were evaluated in 11 human volunteers. We observed that stopping the flow compromised interpretation and repeatability. Conversely, maintaining a low flow provided repeatable measures and could distinguish between normal and high extents of erythrocyte aggregation. Agreement was observed between in vivo and ex vivo measures of the phenomenon (R2 = 82.7%, p value < 0.0001). These results support the feasibility of assessing in vivo erythrocyte aggregation in humans by quantitative ultrasound means.
Collapse
Affiliation(s)
- Julian Garcia-Duitama
- Laboratory of Biorheology and Medical Ultrasonics, University of Montreal Hospital Research Center (CRCHUM), Montreal, Quebec, Canada
| | - Boris Chayer
- Laboratory of Biorheology and Medical Ultrasonics, University of Montreal Hospital Research Center (CRCHUM), Montreal, Quebec, Canada
| | - Damien Garcia
- Laboratory of Biorheology and Medical Ultrasonics, University of Montreal Hospital Research Center (CRCHUM), Montreal, Quebec, Canada; Research Unit of Biomechanics and Imaging in Cardiology, CRCHUM, Montreal, Quebec, Canada; Department of Radiology, Radio-oncology and Nuclear Medicine, University of Montreal, Montreal, Quebec, Canada; Institute of Biomedical Engineering, University of Montreal, Montreal, Quebec, Canada
| | - Yves Goussard
- Department of Electrical Engineering, École Polytechnique of Montreal, Montreal, Quebec, Canada; Institute of Biomedical Engineering, École Polytechnique of Montreal, Montreal, Quebec, Canada
| | - Guy Cloutier
- Laboratory of Biorheology and Medical Ultrasonics, University of Montreal Hospital Research Center (CRCHUM), Montreal, Quebec, Canada; Department of Radiology, Radio-oncology and Nuclear Medicine, University of Montreal, Montreal, Quebec, Canada; Institute of Biomedical Engineering, University of Montreal, Montreal, Quebec, Canada.
| |
Collapse
|
14
|
Strohm EM, Wirtzfeld LA, Czarnota GJ, Kolios MC. High frequency ultrasound imaging and simulations of sea urchin oocytes. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2017; 142:268. [PMID: 28764480 DOI: 10.1121/1.4993594] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
High frequency ultrasound backscatter signals from sea urchin oocytes were measured using a 40 MHz transducer and compared to numerical simulations. The Faran scattering model was used to calculate the ultrasound scattered from single oocytes in suspension. The urchin oocytes are non-nucleated with uniform size and biomechanical properties; the backscatter from each cell is similar and easy to simulate, unlike typical nucleated mammalian cells. The time domain signal measured from single oocytes in suspension showed two distinct peaks, and the power spectrum was periodic with minima spaced approximately 10 MHz apart. Good agreement to the Faran scattering model was observed. Measurements from tightly packed oocyte cell pellets showed similar periodic features in the power spectra, which was a result of the uniform size and consistent biomechanical properties of the cells. Numerical simulations that calculated the ultrasound scattered from individual oocytes within a three dimensional volume showed good agreement to the measured signals and B-scan images. A cepstral analysis of the signal was used to calculate the size of the cells, which was 78.7 μm (measured) and 81.4 μm (simulated). This work supports the single scattering approximation, where ultrasound is discretely scattered from single cells within a bulk homogeneous sample, and that multiple scattering has a negligible effect. This technique can be applied towards understanding the complex scattering behaviour from heterogeneous tissues.
Collapse
Affiliation(s)
- Eric M Strohm
- Department of Physics, Ryerson University, 350 Victoria Street, Toronto, Ontario M5B 2K3, Canada
| | - Lauren A Wirtzfeld
- Department of Physics, Ryerson University, 350 Victoria Street, Toronto, Ontario M5B 2K3, Canada
| | - Gregory J Czarnota
- Senior Scientist and Director, Odette Cancer Research Program, Sunnybrook Research Institute, 2075 Bayview Avenue, Toronto, Ontario M4N 3M5, Canada
| | - Michael C Kolios
- Department of Physics, Ryerson University, 350 Victoria Street, Toronto, Ontario M5B 2K3, Canada
| |
Collapse
|
15
|
Chen AI, Balter ML, Chen MI, Gross D, Alam SK, Maguire TJ, Yarmush ML. Multilayered tissue mimicking skin and vessel phantoms with tunable mechanical, optical, and acoustic properties. Med Phys 2017; 43:3117-3131. [PMID: 27277058 DOI: 10.1118/1.4951729] [Citation(s) in RCA: 70] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
PURPOSE This paper describes the design, fabrication, and characterization of multilayered tissue mimicking skin and vessel phantoms with tunable mechanical, optical, and acoustic properties. The phantoms comprise epidermis, dermis, and hypodermis skin layers, blood vessels, and blood mimicking fluid. Each tissue component may be individually tailored to a range of physiological and demographic conditions. METHODS The skin layers were constructed from varying concentrations of gelatin and agar. Synthetic melanin, India ink, absorbing dyes, and Intralipid were added to provide optical absorption and scattering in the skin layers. Bovine serum albumin was used to increase acoustic attenuation, and 40 μm diameter silica microspheres were used to induce acoustic backscatter. Phantom vessels consisting of thin-walled polydimethylsiloxane tubing were embedded at depths of 2-6 mm beneath the skin, and blood mimicking fluid was passed through the vessels. The phantoms were characterized through uniaxial compression and tension experiments, rheological frequency sweep studies, diffuse reflectance spectroscopy, and ultrasonic pulse-echo measurements. Results were then compared to in vivo and ex vivo literature data. RESULTS The elastic and dynamic shear behavior of the phantom skin layers and vessel wall closely approximated the behavior of porcine skin tissues and human vessels. Similarly, the optical properties of the phantom tissue components in the wavelength range of 400-1100 nm, as well as the acoustic properties in the frequency range of 2-9 MHz, were comparable to human tissue data. Normalized root mean square percent errors between the phantom results and the literature reference values ranged from 1.06% to 9.82%, which for many measurements were less than the sample variability. Finally, the mechanical and imaging characteristics of the phantoms were found to remain stable after 30 days of storage at 21 °C. CONCLUSIONS The phantoms described in this work simulate the mechanical, optical, and acoustic properties of human skin tissues, vessel tissue, and blood. In this way, the phantoms are uniquely suited to serve as test models for multimodal imaging techniques and image-guided interventions.
Collapse
Affiliation(s)
- Alvin I Chen
- Department of Biomedical Engineering, Rutgers University, Piscataway, New Jersey 08854
| | - Max L Balter
- Department of Biomedical Engineering, Rutgers University, Piscataway, New Jersey 08854
| | - Melanie I Chen
- Ernest Mario School of Pharmacy, Rutgers University, Piscataway, New Jersey 08854
| | - Daniel Gross
- Riverside Research Institute, Piscataway, New York, New York 10038
| | - Sheikh K Alam
- Center for Computational Biomedicine Imaging and Modeling, Rutgers University, Piscataway, New Jersey 08854
| | | | - Martin L Yarmush
- Department of Biomedical Engineering, Rutgers University, Piscataway, New Jersey 08854
| |
Collapse
|
16
|
Quantitative Assessment of First Annular Pulley and Adjacent Tissues Using High-Frequency Ultrasound. SENSORS 2017; 17:s17010107. [PMID: 28067854 PMCID: PMC5298680 DOI: 10.3390/s17010107] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/10/2016] [Revised: 01/03/2017] [Accepted: 01/05/2017] [Indexed: 11/17/2022]
Abstract
Due to a lack of appropriate image resolution, most ultrasound scanners are unable to sensitively discern the pulley tissues. To extensively investigate the properties of the A1 pulley system and the surrounding tissues for assessing trigger finger, a 30 MHz ultrasound system was implemented to perform in vitro experiments using the hypodermis, A1 pulley, and superficial digital flexor tendon (SDFT) dissected from cadavers. Ultrasound signals were acquired from both the transverse and sagittal planes of each tissue sample. The quantitative ultrasonic parameters, including sound speed, attenuation coefficient, integrated backscatter (IB) and Nakagami parameter (m), were subsequently estimated to characterize the tissue properties. The results demonstrated that the acquired ultrasound images have high resolution and are able to sufficiently differentiate the variations of tissue textures. Moreover, the attenuation slope of the hypodermis is larger than those of the A1 pulley and SDFT. The IB of A1 pulley is about the same as that of the hypodermis, and is very different from SDFT. The m parameter of the A1 pulley is also very different from those of hypodermis and SDFT. This study demonstrated that high-frequency ultrasound images in conjunction with ultrasonic parameters are capable of characterizing the A1 pulley system and surrounding tissues.
Collapse
|
17
|
Muleki-Seya P, Guillermin R, Guglielmi J, Chen J, Pourcher T, Konofagou E, Franceschini E. High-Frequency Quantitative Ultrasound Spectroscopy of Excised Canine Livers and Mouse Tumors Using the Structure Factor Model. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2016; 63:1335-1350. [PMID: 27164586 DOI: 10.1109/tuffc.2016.2563169] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Three scattering models were examined for characterizing ex vivo canine livers and HT29 mouse tumors in the 10-38- and the 15-42-MHz frequency bandwidth, respectively. The spherical Gaussian model (SGM) and the fluid sphere model (FSM) that were examined are suitable for dealing with sparse media, whereas the structure factor model (SFM) is adapted for characterizing concentrated media. For the canine livers, the scatterer radius and the acoustic concentration estimated with the three models were similar and matched well the nuclear structures obtained from histological analysis (with relative errors less than 7%). These results show that the livers could be considered as a diluted medium and that the nuclei in liver could be a dominant source of scattering. For the homogeneous mouse tumors, containing mostly viable HT29 cells, scatterer radius and volume fraction estimated with the SFM showed good agreement with the whole cell structures obtained from histological analysis (with relative errors less than 15%), whereas the sparse models (the SGM and the FSM) gave no consistent quantitative ultrasound parameters. This suggests that the viable HT29 cell areas have densely packed cellular content and that the whole HT29 cell could be responsible for scattering. For the heterogeneous tumors, the hyperechogenic zones observed in the B-mode images were linked to the presence of small necrotic areas surrounded by viable HT29 cells. Comparison between sparse and concentrated models shows that these hyperechogenic zones could be considered as a concentrated medium.
Collapse
|
18
|
Swillens A, Shcherbakova D, Trachet B, Segers P. Pitfalls of Doppler Measurements for Arterial Blood Flow Quantification in Small Animal Research: A Study Based on Virtual Ultrasound Imaging. ULTRASOUND IN MEDICINE & BIOLOGY 2016; 42:1399-1411. [PMID: 27004960 DOI: 10.1016/j.ultrasmedbio.2016.01.010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2015] [Revised: 01/14/2016] [Accepted: 01/19/2016] [Indexed: 06/05/2023]
Abstract
High-resolution Doppler is a popular tool for evaluating cardiovascular physiology in mutant mice, though its 1-D nature and spectral broadening processes complicate interpretation of the measurement. Hence, it is crucial for pre-clinical researchers to know how error sources in Doppler assessments reveal themselves in the murine arterial system. Therefore, we performed virtual Doppler experiments in a computer model of an aneurysmatic murine aorta with full control of the imaging and insonified fluid dynamics. We observed significant variability in Doppler performance and derived vascular indices depending on the interrogated flow, operator settings and signal processing. In particular, we found that (i) Doppler spectra in the upper aortic branches and celiac artery exhibited more broadening because of complex out-of-beam flow paths; (ii) mean frequency tracking outperforms tracking of the outer envelope, but is sensitive to errors in angle correction; and (iii) imaging depths deviating much from the elevation focus suffer from decreased spectral quality.
Collapse
Affiliation(s)
- Abigail Swillens
- IbiTech-bioMMeda, Department of Electronics and Information Systems, Ghent University, Ghent, Belgium.
| | - Darya Shcherbakova
- IbiTech-bioMMeda, Department of Electronics and Information Systems, Ghent University, Ghent, Belgium
| | - Bram Trachet
- IbiTech-bioMMeda, Department of Electronics and Information Systems, Ghent University, Ghent, Belgium; Institute of Bioengineering, Ecole Polytechnique Federale de Lausanne, Lausanne, Switzerland
| | - Patrick Segers
- IbiTech-bioMMeda, Department of Electronics and Information Systems, Ghent University, Ghent, Belgium
| |
Collapse
|
19
|
Vestito D, Desantis D, Colonna P. Three-dimensional Transesophageal Echocardiography Demonstration of Left Atrial Appendage Echocontrast Regression after 6 Months Therapy with Dabigatran and not with Warfarin. J Cardiovasc Echogr 2016; 26:52-55. [PMID: 28465961 PMCID: PMC5224660 DOI: 10.4103/2211-4122.183751] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
While warfarin therapy is efficacious in treating left atrial (LA) thrombus formation in patients with nonvalvular atrial fibrillation (AF), it does not affect red cell aggregation in vitro or LA spontaneous echo-contrast in patients. In this patient with left ventricular (LV) dysfunction secondary to AF, we observed the disappearance of dense echo-contrast in the atrial appendage after therapy with dabigatran and not with well-controlled warfarin. This allowed us to analyze accurately the appendage with three-dimensional (3D) transesophageal echocardiography (TEE) excluding thrombi and to perform electrical cardioversion to obtain a significant improvement of LV function. This case demonstrates the capability of dabigatran and not of warfarin in reducing the intense spontaneous echocontrast in atrial appendage and the ability of 3D TEE in analyzing accurately the appendage, excluding thrombi to safely perform cardioversion.
Collapse
Affiliation(s)
| | - Delia Desantis
- Department of Cardiology, Hospital Policlinico, Bari, Italy
| | - Paolo Colonna
- Department of Cardiology, Hospital Policlinico, Bari, Italy
| |
Collapse
|
20
|
Garcia-Duitama J, Chayer B, Han A, Garcia D, Oelze ML, Cloutier G. Experimental application of ultrafast imaging to spectral tissue characterization. ULTRASOUND IN MEDICINE & BIOLOGY 2015; 41:2506-2519. [PMID: 26119459 DOI: 10.1016/j.ultrasmedbio.2015.04.017] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2014] [Revised: 04/22/2015] [Accepted: 04/26/2015] [Indexed: 06/04/2023]
Abstract
Ultrasound ultrafast imaging (UI) allows acquisition of thousands of frames per second with a sustained image quality at any depth in the field of view. Therefore, it would be ideally suited to obtain good statistical sampling of fast-moving tissues using spectral-based techniques to derive the backscatter coefficient (BSC) and associated quantitative parameters. In UI, an image is formed by insonifying the medium with plane waves steered at different angles, beamforming them and compounding the resulting radiofrequency images. We aimed at validating, experimentally, the effect of these beamforming protocols on the BSC, under both isotropic and anisotropic conditions. Using UI techniques with a linear array transducer (5-14 MHz), we estimated the BSCs of tissue-mimicking phantoms and flowing porcine blood at depths up to 35 mm with a frame rate reaching 514 Hz. UI-based data were compared with those obtained using single-element transducers and conventional focusing imaging. Results revealed that UI compounded images can produce valid estimates of BSCs and effective scatterer size (errors less than 2.2 ± 0.8 and 0.26 ± 0.2 dB for blood and phantom experiments, respectively). This work also describes the use of pre-compounded UI images (i.e., steered images) to assess the angular dependency of circulating red blood cells. We have concluded that UI data sets can be used for BSC spectral tissue analysis and anisotropy characterization.
Collapse
Affiliation(s)
- Julian Garcia-Duitama
- Laboratory of Biorheology and Medical Ultrasonics, University of Montreal Hospital Research Center (CRCHUM), Montreal, Quebec, Canada; Bioacoustics Research Laboratory, Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Boris Chayer
- Laboratory of Biorheology and Medical Ultrasonics, University of Montreal Hospital Research Center (CRCHUM), Montreal, Quebec, Canada
| | - Aiguo Han
- Bioacoustics Research Laboratory, Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Damien Garcia
- Laboratory of Biorheology and Medical Ultrasonics, University of Montreal Hospital Research Center (CRCHUM), Montreal, Quebec, Canada; Research Unit of Biomechanics and Imaging in Cardiology, CRCHUM, Montreal, Quebec, Canada; Department of Radiology, Radio-Oncology and Nuclear Medicine and Institute of Biomedical Engineering, University of Montreal, Montreal, Quebec, Canada
| | - Michael L Oelze
- Bioacoustics Research Laboratory, Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Guy Cloutier
- Laboratory of Biorheology and Medical Ultrasonics, University of Montreal Hospital Research Center (CRCHUM), Montreal, Quebec, Canada; Department of Radiology, Radio-Oncology and Nuclear Medicine and Institute of Biomedical Engineering, University of Montreal, Montreal, Quebec, Canada.
| |
Collapse
|
21
|
Yeom E, Lee SJ. Microfluidic-based speckle analysis for sensitive measurement of erythrocyte aggregation: A comparison of four methods for detection of elevated erythrocyte aggregation in diabetic rat blood. BIOMICROFLUIDICS 2015; 9:024110. [PMID: 25945136 PMCID: PMC4385097 DOI: 10.1063/1.4917023] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2015] [Accepted: 03/26/2015] [Indexed: 05/15/2023]
Abstract
Biochemical alterations in the plasma and red blood cell (RBC) membrane of diabetic blood lead to excessive erythrocyte aggregation (EA). EA would significantly impede the blood flow and increase the vascular flow resistance contributing to peripheral vascular diseases. In this study, a simple microfluidic-based method is proposed to achieve sensitive detection of hyperaggregation. When a blood sample is delivered into the device, images of blood flows are obtained with a short exposure time for a relatively long measuring time. A micro-particle image velocimetry technique was employed to monitor variation of the flow rate of blood as a function of time. Given that EA formation in the channel creates clear speckle patterns, the EA extent can be estimated by calculating a speckle area (ASpeckle) through a normalized autocovariance function. The hematocrit effect is assessed by comparing optical images transmitted through blood samples. EA variations caused by dextran treatment are quantitatively evaluated using characteristic time (λSpeckle) obtained by fitting the variations of ASpeckle. Other indices including number of RBCs in an aggregate (NRBC), characteristic time of erythrocyte sedimentation rate (λESR), and aggregation index estimated from ultrasound signals (AIEcho) are determined under different EA conditions using conventional techniques. The four different methods are applied to diabetic blood samples to compare their indices under hyperaggregation conditions. It is found that the proposed method can detect variation of EA reasonably, compared with conventional measurement techniques. These experimental demonstrations support the notion that the proposed method is capable of effectively monitoring the biophysical properties of diabetic blood.
Collapse
Affiliation(s)
- Eunseop Yeom
- Department of Mechanical Engineering, Pohang University of Science and Technology (POSTECH) , Pohang, South Korea
| | - Sang Joon Lee
- Department of Mechanical Engineering, Pohang University of Science and Technology (POSTECH) , Pohang, South Korea
| |
Collapse
|
22
|
Huang CC, Chou HL, Chen PY. Measurement of the Doppler power of flowing blood using ultrasound Doppler devices. ULTRASOUND IN MEDICINE & BIOLOGY 2015; 41:565-573. [PMID: 25542489 DOI: 10.1016/j.ultrasmedbio.2014.09.032] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2014] [Revised: 09/22/2014] [Accepted: 09/30/2014] [Indexed: 06/04/2023]
Abstract
Measurement of the Doppler power of signals backscattered from flowing blood (henceforth referred to as the Doppler power of flowing blood) and the echogenicity of flowing blood have been used widely to assess the degree of red blood cell (RBC) aggregation for more than 20 y. Many studies have used Doppler flowmeters based on an analogue circuit design to obtain the Doppler shifts in the signals backscattered from flowing blood; however, some recent studies have mentioned that the analogue Doppler flowmeter exhibits a frequency-response problem whereby the backscattered energy is lost at higher Doppler shift frequencies. Therefore, the measured Doppler power of flowing blood and evaluations of RBC aggregation obtained using an analogue Doppler device may be inaccurate. To overcome this problem, the present study implemented a field-programmable gate array-based digital pulsed-wave Doppler flowmeter to measure the Doppler power of flowing blood, in the aim of providing more accurate assessments of RBC aggregation. A clinical duplex ultrasound imaging system that can acquire pulsed-wave Doppler spectrograms is now available, but its usefulness for estimating the ultrasound scattering properties of blood is still in doubt. Therefore, the echogenicity and Doppler power of flowing blood under the same flow conditions were measured using a laboratory pulser-receiver system and a clinical ultrasound system, respectively, for comparisons. The experiments were carried out using porcine blood under steady laminar flow with both RBC suspensions and whole blood. The experimental results indicated that a clinical ultrasound system used to measure the Doppler spectrograms is not suitable for quantifying Doppler power. However, the Doppler power measured using a digital Doppler flowmeter can reveal the relationship between backscattering signals and the properties of blood cells because the effects of frequency response are eliminated. The measurements of the Doppler power and echogenicity of flowing blood were compared with those obtained in several previous studies.
Collapse
Affiliation(s)
- Chih-Chung Huang
- Department of Biomedical Engineering, National Cheng Kung University, Tainan, Taiwan.
| | - Hung-Lung Chou
- Department of Electrical Engineering, Fu Jen Catholic University, New Taipei City, Taiwan
| | - Pay-Yu Chen
- Department of Biomedical Engineering, National Cheng Kung University, Tainan, Taiwan
| |
Collapse
|
23
|
Yeom E, Nam KH, Paeng DG, Lee SJ. Effects of red blood cell aggregates dissociation on the estimation of ultrasound speckle image velocimetry. ULTRASONICS 2014; 54:1480-7. [PMID: 24794508 DOI: 10.1016/j.ultras.2014.04.017] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2013] [Revised: 02/24/2014] [Accepted: 04/13/2014] [Indexed: 05/11/2023]
Abstract
Ultrasound speckle image of blood is mainly attributed by red blood cells (RBCs) which tend to form RBC aggregates. RBC aggregates are separated into individual cells when the shear force is over a certain value. The dissociation of RBC aggregates has an influence on the performance of ultrasound speckle image velocimetry (SIV) technique in which a cross-correlation algorithm is applied to the speckle images to get the velocity field information. The present study aims to investigate the effect of the dissociation of RBC aggregates on the estimation quality of SIV technique. Ultrasound B-mode images were captured from the porcine blood circulating in a mock-up flow loop with varying flow rate. To verify the measurement performance of SIV technique, the centerline velocity measured by the SIV technique was compared with that measured by Doppler spectrograms. The dissociation of RBC aggregates was estimated by using decorrelation of speckle patterns in which the subsequent window was shifted as much as the speckle displacement to compensate decorrelation caused by in-plane loss of speckle patterns. The decorrelation of speckles is considerably increased according to shear rate. Its variations are different along the radial direction. Because the dissociation of RBC aggregates changes ultrasound speckles, the estimation quality of SIV technique is significantly correlated with the decorrelation of speckles. This degradation of measurement quality may be improved by increasing the data acquisition rate. This study would be useful for simultaneous measurement of hemodynamic and hemorheological information of blood flows using only speckle images.
Collapse
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
| | - 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.
| |
Collapse
|
24
|
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.
Collapse
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.
| |
Collapse
|
25
|
Wallace S, Logallo N, Faiz KW, Lund C, Brucher R, Russell D. Relative blood flow changes measured using calibrated frequency-weighted Doppler power at different hematocrit levels. ULTRASOUND IN MEDICINE & BIOLOGY 2014; 40:828-836. [PMID: 24462159 DOI: 10.1016/j.ultrasmedbio.2013.04.016] [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: 10/10/2012] [Revised: 04/14/2013] [Accepted: 04/21/2013] [Indexed: 06/03/2023]
Abstract
In theory, the power of a trans-cranial Doppler signal may be used to measure changes in blood flow and vessel diameter in addition to velocity. In this study, a flow index (FI) of relative changes in blood flow was derived from frequency-weighted Doppler power signals. The FI, plotted against velocity, was calibrated to the zero intercept with absent flow to reduce the effects of non-uniform vessel insonation. An area index was also calculated. FIs were compared with actual flow in four silicone tubes of different diameter at increasing flow rates and increasing hematocrit (Hct) in a closed-loop phantom model. FI values were strongly correlated with actual flow, at constant Hct, but varied substantially with changes in Hct. Percentage changes in area indexes, relative to the 4-mm tube, were strongly correlated with tube cross-sectional area. The implications of these results for in vivo use are discussed.
Collapse
Affiliation(s)
- Sean Wallace
- Department of Neurology, Oslo University Hospital, Rikshospitalet, Oslo, Norway.
| | - Nicola Logallo
- Department of Neurology, Haukeland University Hospital, Bergen, Norway
| | - Kashif W Faiz
- Department of Neurology, Akershus University Hospital, Oslo, Norway
| | - Christian Lund
- Department of Neurology, Oslo University Hospital, Rikshospitalet, Oslo, Norway
| | - Rainer Brucher
- Department of Medical Engineering, University of Applied Sciences, Ulm, Germany
| | - David Russell
- Department of Neurology, Oslo University Hospital, Rikshospitalet, Oslo, Norway
| |
Collapse
|
26
|
Nam KH, Bok TH, Kong Q, Paeng DG. High spatial and temporal resolution observations of pulsatile changes in blood echogenicity in the common carotid artery of rats. ULTRASOUND IN MEDICINE & BIOLOGY 2013; 39:1665-71. [PMID: 23830099 DOI: 10.1016/j.ultrasmedbio.2013.03.032] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2012] [Revised: 03/25/2013] [Accepted: 03/30/2013] [Indexed: 05/24/2023]
Abstract
Previous studies have found that ultrasound backscatter from blood in vascular flow systems varies under pulsatile flow, with the maximum values occurring during the systolic period. This phenomenon is of particular interest in hemorheology because it is contrary to the well-known fact that red blood cell (RBC) aggregation, which determines the intensity of ultrasound backscatter from blood, decreases at a high systolic shear rate. In the present study, a rat model was used to provide basic information on the characteristics of blood echogenicity in arterial blood flow to investigate the phenomenon of RBC aggregation under pulsatile flow. Blood echogenicity in the common carotid arteries of rats was measured using a high-frequency ultrasound imaging system with a 40-MHz probe. The electrocardiography-based kilohertz visualization reconstruction technique was employed to obtain high-temporal-resolution and high-spatial-resolution time-course B-mode cross-sectional and longitudinal images of the vessel. The experimental results indicate that blood echogenicity in rat carotid arteries varies during a cardiac cycle. Blood echogenicity tends to decrease during early systole and reaches its peak during late systole, followed by a slow decline thereafter. The time delay of the echogenicity peak from peak systole in the present results is the main difference from previous in vitro and in vivo observations of backscattering peaks during early systole, which may be caused by the very rapid heart rates and low RBC aggregation tendency of rats compared with humans and other mammalian species. The present study may provide useful information elucidating the characteristics of RBC aggregation in arterial blood flow.
Collapse
Affiliation(s)
- Kweon-Ho Nam
- Department of Ocean System Engineering, Jeju National University, Jeju, South Korea
| | | | | | | |
Collapse
|
27
|
Li Y, Jensen JA. Synthetic aperture flow imaging using dual stage beamforming: simulations and experiments. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2013; 133:2014-2024. [PMID: 23556572 DOI: 10.1121/1.4794396] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
A method for synthetic aperture flow imaging using dual stage beamforming has been developed. The main motivation is to increase the frame rate and still maintain a beamforming quality sufficient for flow estimation that is possible to implement in a commercial scanner. This method can generate continuous high frame rate flow images with lower calculation demands than the full synthetic aperture flow imaging. The performance of the approach was investigated using Field II simulations and measurements with the experimental scanner SARUS. A laminar flow with a parabolic profile was generated by a flow rig system. The flow data were acquired by a commercial 7 MHz linear array transducer. Four emissions were transmitted sequentially and repeated 12 times corresponding to 48 emissions. Flow with a peak velocity of 0.12 m/s was measured, the relative standard deviation was 6.4%, and the bias was 7.6% (2.1% and 3.2% for the simulations). A parameter study revealed that emission spacing, number of cross-correlation functions used for averaging, and the length of the velocity searching range influence the performance. Compared to the full synthetic aperture flow imaging the total number of beamformed samples are reduced by a factor of 64 times, and the frame rate is much higher than the conventional method for the same velocity estimation accuracy.
Collapse
Affiliation(s)
- Ye Li
- Department of Electrical Engineering, Technical University of Denmark, Center for Fast Ultrasound Imaging, Building 349, DK-2800 Kgs. Lyngby, Denmark
| | | |
Collapse
|
28
|
Huang CC, Liao CC, Lee PY, Shih CC. The effect of flow acceleration on the cyclic variation of blood echogenicity under pulsatile flow. ULTRASOUND IN MEDICINE & BIOLOGY 2013; 39:670-80. [PMID: 23384462 DOI: 10.1016/j.ultrasmedbio.2012.10.018] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2012] [Revised: 09/22/2012] [Accepted: 10/28/2012] [Indexed: 05/24/2023]
Abstract
It has been shown that the echogenicity of blood varies during a flow cycle under pulsatile flow both in vitro and in vivo. In general, the echogenicity of flowing whole blood increases during the early systole phase and then reduces to a minimum at late diastole. While it has been postulated that this cyclic variation is associated with the dynamics of erythrocyte aggregation, the mechanisms underlying this increasing echogenicity with flow velocity remain uncertain. The effect of flow acceleration has also been proposed as an explanation for this phenomenon, but no specific experiments have been conducted to test this hypothesis. In addition, the influence of ultrasonic attenuation on the cyclic variation of echogenicity requires clarification. In the present study, a Couette flow system was designed to simulate blood flowing with different acceleration patterns, and the flow velocity, attenuation, and backscattering coefficient were measured synchronously from 20%- and 40%-hematocrit porcine whole blood and erythrocyte suspensions using 35-MHz ultrasound transducers. The results showed ultrasonic attenuation exerted only minor effects on the echogenicity of blood under pulsatile flow conditions. Cyclic variations of echogenicity were clearly observed for whole blood with a hematocrit of 40%, but no variations were apparent for erythrocyte suspensions. The echogenicity did not appear to be enhanced when instantaneous acceleration was applied to flowing blood in any case. These findings show that flow acceleration does not promote erythrocyte aggregation, even when a higher peak velocity is applied to the blood. Comparison of the results obtained with different accelerations revealed that the cyclic variation in echogenicity observed during pulsatile blood flow may be jointly attributable to the effect of shear rate and the distribution of erythrocyte on aggregation.
Collapse
Affiliation(s)
- Chih-Chung Huang
- Department of Electrical Engineering, Fu Jen Catholic University, New Taipei City, Taiwan.
| | | | | | | |
Collapse
|
29
|
Chih-Chung Huang. Detecting Spatial Variations of Erythrocytes by Ultrasound Backscattering Statistical Parameters Under Pulsatile Flow. IEEE Trans Biomed Eng 2011; 58:1163-71. [DOI: 10.1109/tbme.2010.2096537] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
|
30
|
Li Y, Bok TH, Yang JH, Choi MJ, Paeng DG. The acute effects of smoking on the cyclic variations in blood echogenicity of carotid artery. ULTRASOUND IN MEDICINE & BIOLOGY 2011; 37:513-21. [PMID: 21420578 DOI: 10.1016/j.ultrasmedbio.2010.12.014] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2010] [Revised: 11/22/2010] [Accepted: 12/28/2010] [Indexed: 05/24/2023]
Abstract
The objective of this research is to study the cyclic variations in echogenicity (CVE) as an acute response to smoking. CVEs, caused by the aggregation of red blood cells (RBC) were measured from the cross-sectional images of the common carotid artery using coded harmonic imaging of a commercial ultrasound system. The amplitude of the CVE (A(cve)) was analyzed among 28 smokers before and after smoking. A(cve) was increased in 22 smokers and decreased in six smokers after 1-2 cigarettes were smoked. Heart rate (HR) was also estimated from the ultrasonic images before and after smoking. The smokers were optimally divided into two clusters with respect to the change in A(cve) and the intrinsic characteristics of smokers (i.e., daily consumed cigarettes and smoking years) through a two-step cluster analysis (TSCA). The increase in A(cve) after smoking was significantly higher in the heavy smoker cluster compared with the light smoker cluster. The results suggest that the acute changes in A(cve) in response to smoking are different between heavy smokers and light smokers. This preliminary study demonstrates the potential application of coded harmonic ultrasound imaging to detect or characterize RBC aggregation. In addition, the results may be useful for understanding the acute physiologic changes caused by smoking.
Collapse
Affiliation(s)
- Ying Li
- Department of Ocean System Engineering, Jeju National University, Jeju Special Self Governing Province, Korea
| | | | | | | | | |
Collapse
|
31
|
Huang CC, Chang YC. Ultrasonic attenuation and backscatter from flowing whole blood are dependent on shear rate and hematocrit between 10 and 50 MHz. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2011; 58:357-368. [PMID: 21342821 DOI: 10.1109/tuffc.2011.1813] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Ultrasonic backscatter has recently been used extensively to investigate erythrocyte aggregation, which is an inherent hematological phenomenon in the blood circulation system. The size of rouleaux can be estimated by measuring certain parameters of signals backscattered from flowing blood. However, most measurements of backscatter from blood use a constant value for the attenuation coefficient to compensate for the loss of ultrasound energy. This correction may be inaccurate because the attenuation varies with the blood properties, which prompted us to explore the effects of hemodynamic properties on ultrasonic attenuation and backscatter to better understand the blood rheological behaviors. Experiments were performed on porcine whole blood in a Couette flow apparatus. Ultrasonic attenuation and the backscattering coefficient of blood were measured at various frequencies (from 10 to 50 MHz), hematocrits (from 0 to 60%), and shear rates (from 0.1 to 200 s⁻¹). The results indicated that the attenuation and backscattering coefficients of blood are highly variable, depending in a complex manner on shear rate, hematocrit, and the measurement ultrasound frequency. The attenuation of blood decreased rapidly with increasing shear rates, eventually reaching a steady state asymptotically, and increased linearly with the hematocrit from 10 to 50 MHz at various shear rates, and also with the ultrasound frequency. The effect of erythrocyte aggregation means that the change in ultrasonic attenuation in blood with shear rate may be attributed to the absorption mechanism, which is enhanced by the increased blood viscosity at lower shear rates. Compensating the measured backscattering coefficients of blood for the shear-rate-dependent attenuation coefficient increased the accuracy of erythrocyte aggregation assessments. Together, the experimental results suggest that the shear-rate-dependent attenuation coefficient should be considered in future developments of ultrasonic technologies for characterizing blood rheology when the ultrasound frequency is higher than 20 MHz.
Collapse
Affiliation(s)
- Chih-Chung Huang
- Department of Electrical Engineering, Fu Jen Catholic University, Taipei, Taiwan.
| | | |
Collapse
|
32
|
Huang CC. High-frequency attenuation and backscatter measurements of rat blood between 30 and 60 MHz. Phys Med Biol 2010; 55:5801-15. [PMID: 20844333 DOI: 10.1088/0031-9155/55/19/012] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
There has recently been a great deal of interest in noninvasive high-frequency ultrasound imaging of small animals such as rats due to their being the preferred animal model for gene therapy and cancer research. Improving the interpretation of the obtained images and furthering the development of the imaging devices require a detailed knowledge of the ultrasound attenuation and backscattering of biological tissue (e.g. blood) at high frequencies. In the present study, the attenuation and backscattering coefficients of the rat red blood cell (RBC) suspensions and whole blood with hematocrits ranging from 6% to 40% were measured between 30 and 60 MHz using a modified substitution approach. The acoustic parameters of porcine blood under the same conditions were also measured in order to compare differences in the blood properties between these two animals. For porcine blood, both whole blood and RBC suspension were stirred at a rotation speed of 200 rpm. Three different rotation speeds of 100, 200 and 300 rpm were carried out for rat blood experiments. The attenuation coefficients of both rat and porcine blood were found to increase linearly with frequency and hematocrit (the values of coefficients of determination (r(2)) are around 0.82-0.97 for all cases). The average attenuation coefficient of rat whole blood with a hematocrit of 40% increased from 0.26 Nepers mm(-1) at 30 MHz to 0.47 Nepers mm(-1) at 60 MHz. The maximum backscattering coefficients of both rat and porcine RBC suspensions were between 10% and 15% hematocrits at all frequencies. The fourth-power dependence of backscatter on frequency was approximately valid for rat RBC suspensions with hematocrits between 6% and 40%. However, the frequency dependence of the backscatter estimate deviates from a fourth-power law for porcine RBC suspension with hematocrit higher than 20%. The backscattering coefficient plateaued for hematocrits higher than 15% in porcine blood, but for rat blood it was maximal around a hematocrit of 20% at the same rotation speed, and shifted to a hematocrit of 10% at a higher speed. The backscattering properties of rat RBCs in plasma are similar to those of RBCs in saline at a higher rotation speed. The differences in attenuation and backscattering between rat and porcine blood may be attributed to RBCs' being smaller and the RBC aggregation level being lower for rat blood than for porcine blood.
Collapse
Affiliation(s)
- Chih-Chung Huang
- Department of Electrical Engineering, Fu Jen Catholic University, Taipei, Taiwan, Republic of China.
| |
Collapse
|
33
|
Paeng DG, Nam KH. Ultrasonic visualization of dynamic behavior of red blood cells in flowing blood. J Vis (Tokyo) 2009. [DOI: 10.1007/bf03181874] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
|
34
|
Huang CC. Cyclic variations of high-frequency ultrasonic backscattering from blood under pulsatile flow. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2009; 56:1677-88. [PMID: 19686983 DOI: 10.1109/tuffc.2009.1232] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
It was shown previously that ultrasonic scattering from whole blood varies during the flow cycle under pulsatile flow both in vitro and in vivo. It has been postulated that the cyclic variations of the backscattering signal are associated with red blood cell (RBC) aggregation in flowing whole blood. To obtain a better understanding of the relationship between blood backscattering and RBC aggregation behavior for pulsatile flowing blood, the present study used high-frequency ultrasound to characterize blood properties. The backscattering signals from both whole blood and an RBC suspension at different peak flow velocities (from 10 to 30 cm/s) and hematocrits (20% and 40%) under pulsatile flow (stroke rate of 20 beats/min) were measured with 3 single-element transducers at frequencies of 10, 35, and 50 MHz in a mock flow loop. To avoid the frequency response problem of a Doppler flowmeter, the integrated backscatter (IB) and flow velocity as functions of time were calculated directly using RF signals from flowing blood. The experimental results showed that cyclic variations of the IB curve were clearly observed at a low flow velocity and a hematocrit of 40% when using 50 MHz ultrasound, and that these variations became weaker as the peak flow velocity increased. However, these cyclic variations were detected only at 10 cm/s when using 10 MHz ultrasound. These results demonstrate that a high flow velocity can stop the formation of rouleaux and that a high hematocrit can promote RBC aggregation to produce cyclic variations of the backscattering signal under pulsatile flow. In addition, slight cyclic variations of the IB curve for an RBC suspension were observed at 35 and 50 MHz. Furthermore, the peak of the IB curve from whole blood led the peak of the velocity waveform when using high-frequency ultrasound, which could be explained by the assumption that a rapid flow can promote RBC aggregation under pulsatile flow. Together, the experimental results showed that the sensitivity and resolution of detecting blood properties are higher for 50 MHz ultrasound than for 10 MHz ultrasound.
Collapse
Affiliation(s)
- Chih-Chung Huang
- Department of Electronic Engineering, Fu Jen Catholic University, Taipei, Taiwan.
| |
Collapse
|
35
|
Paeng DG, Nam KH, Choi MJ, Shung KK. Three-dimensional reconstruction of the "bright ring" echogenicity from porcine blood upstream in a stenosed tube. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2009; 56:880-885. [PMID: 19406719 DOI: 10.1109/tuffc.2009.1113] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
To investigate the echogenicity variation due to blood flow disturbance near a stenosis under pulsatile flow, a series of in vitro experiments were performed in a rigid tube with an eccentric stenosis of 70% area reduction in a mock flow loop. An ultrasonic B-mode with a Doppler spectrogram was used to correlate echogenicity with flow speed and stroke rate. This paper reports echogenicity variation upstream of a stenosis under pulsatile flow. The experimental results showed that blood flow disturbed by the stenosis affects echogenicity and red blood cell rouleaux upstream. A hypoechoic "black hole" was shown at the center of the stream at systole. During diastole, the "bright ring" in cross-sectional images was observed as eddy-like or parabolic profiles in longitudinal images. These images could be reconstructed into a 3-dimensional animation, providing a better understanding of dynamic changes of the rouleaux distribution upstream of a stenosis under pulsatile flow.
Collapse
|
36
|
Xu X, Yu L, Chen Z. Effect of erythrocyte aggregation on hematocrit measurement using spectral-domain optical coherence tomography. IEEE Trans Biomed Eng 2009; 55:2753-8. [PMID: 19126454 DOI: 10.1109/tbme.2008.2002134] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Optical coherence tomography (OCT) has the potential to be a noninvasive method for hematocrit (HCT) measurement. This study shows the effect of erythrocyte aggregation at the level seen in healthy humans and pathological states on HCT measurement based on monitoring the slope changes in OCT depth reflectivity profile using spectral-domain optical coherence tomography (SDOCT). Our measurement indicates that the HCT estimated by SDOCT depends on the erythrocyte aggregation state and the flow rate. Measured HCT in blood samples with 0.6% and 2% dextran 500 is underestimated by 4.5%-10.5% and 17.1%-19.5% for HCT from 35%-55% at a flow rate of 4.7 mm/s. Underestimation is smaller at a high flow rate as compared to a low flow rate, indicating erythrocyte aggregation is an important factor that will affect accurate HCT measurement using SDOCT.
Collapse
Affiliation(s)
- Xiangqun Xu
- School of Science, Zhejiang Sci-Tech University, Hangzhou 310018, China.
| | | | | |
Collapse
|
37
|
Nam KH, Paeng DG, Choi MJ. Ultrasonic backscatter from rat blood in aggregating media under in vitro rotational flow. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2009; 56:270-279. [PMID: 19251514 DOI: 10.1109/tuffc.2009.1036] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Ultrasonic backscatter from flowing and static rat red blood cells (RBCs) in autologous plasma and in 360 kDa polyvinylpyrrolidone (PVP 360) solution was measured as a function of hematocrit. The flow speed was varied by a stirring magnet in a cylindrical chamber. The radio-frequency (RF) signals backscattered by RBC samples were measured over 5 min in a pulse-echo setup with a 5 MHz focused transducer. Although the intact rat blood has poor RBC aggregability, RBC aggregation of rat blood was enhanced by replacing its plasma with a higher molecular weight polymer solution. The experimental results showed that the nonlinear relationship between hematocrit and ultrasonic backscatter from rat RBCs in plasma and aggregating media is affected by flow speed, which may provide a unified insight into hematocrit dependence of RBC aggregation under flowing and static conditions.
Collapse
Affiliation(s)
- Kweon-Ho Nam
- Department of Bioengineering, University of Utah, Salt Lake City, UT, USA
| | | | | |
Collapse
|
38
|
Saha RK, Cloutier G. Monte Carlo study on ultrasound backscattering by three-dimensional distributions of red blood cells. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2008; 78:061919. [PMID: 19256880 DOI: 10.1103/physreve.78.061919] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2008] [Revised: 09/17/2008] [Indexed: 05/24/2023]
Abstract
A Monte Carlo study on ultrasound backscattering by red blood cells (RBCs) is presented for three-dimensional (3D) distributions of particles. The cells were treated as classical spherical particles and accordingly, the Boltzmann distribution was considered to describe probability distribution of energy states of a system composed of such particles. The well-known Metropolis algorithm can generate configurations according to that probability distribution and therefore, was employed in this study to simulate some realizations of both nonaggregating and aggregating RBCs. The study of nonaggregating particles was motivated to compare simulations with existing experimental results and consequently, to validate the model. In the case of aggregating RBCs, the interaction potential between cells was modeled with the Morse potential and the frequency-dependent backscattering coefficient (BSC) was investigated at different hematocrits (H, particle volume fractions). The impact of aggregation potential on the spectral slope (SS) was also evaluated. It is shown that BSC increased as the magnitude of aggregating potential was raised and the effect was more pronounced at higher hematocrits. Moreover, spectral slopes at nonaggregating and low aggregating conditions were found to be around 4, which is consistent with the Rayleigh scattering theory. However, it had diminished significantly, particularly at higher hematocrits as the magnitude of the attractive potential energy was raised. For instance, at H=40% SS dropped from 4.04 for nonaggregating particles to 3.62 at the highest aggregating potential considered in this study. Our results suggest that this 3D model is capable of reflecting the effects of RBC aggregation on BSC and SS.
Collapse
Affiliation(s)
- Ratan K Saha
- Laboratory of Biorheology and Medical Ultrasonics, University of Montréal Hospital Research Centre (CRCHUM), 2099 Alexandre de Sève (Room Y-1619), Montréal, Québec H2L 2W5, Canada.
| | | |
Collapse
|
39
|
Libgot-Callé R, Ossant F, Gruel Y, Lermusiaux P, Patat F. High frequency ultrasound device to investigate the acoustic properties of whole blood during coagulation. ULTRASOUND IN MEDICINE & BIOLOGY 2008; 34:252-264. [PMID: 18077082 DOI: 10.1016/j.ultrasmedbio.2007.06.018] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2006] [Revised: 06/08/2007] [Accepted: 06/20/2007] [Indexed: 05/25/2023]
Abstract
This study was designed to investigate the changes in acoustic properties of whole blood during the coagulation process. High frequency (from 20 to 40 MHz) ultrasound parameters were measured both in double transmission (DT) and backscattering (BS) mode to assess sound velocity and backscatter coefficient, respectively. The integrated backscatter coefficient (IBC) and the effective scatterer size (ESS) were deducted from the backscatter coefficient. Measurements were performed on whole blood samples collected from 12 healthy volunteers. During the blood clotting process (2 h observation), acoustic parameters were measured with 15 s time resolution for the transmission parameter and 5 s (for the 5 first min) and 30 s (for the end of the observation time) for the backscattering parameters. The results obtained clearly showed that simultaneous measurements of parameters in DT and BS modes are able to identify several stages during the in vitro blood clotting process. In particular, red blood cell (RBC) aggregation can be described from the backscattering parameters and liquid-gel transition phase of blood from the sound velocity. Intra- and inter-individual dispersion of these parameters were also measured and discussed.
Collapse
Affiliation(s)
- Rachel Libgot-Callé
- Université François Rabelais Tours, Laboratoire Ultrasons Signaux Instrumentation, CNRS FRE 2448, Tours, France.
| | | | | | | | | |
Collapse
|
40
|
Huang CC, Wang SH. Assessment of blood coagulation under various flow conditions with ultrasound backscattering. IEEE Trans Biomed Eng 2008; 54:2223-30. [PMID: 18075038 DOI: 10.1109/tbme.2007.908334] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Several in vitro studies have employed ultrasonic techniques to detect varying properties of coagulating blood under static or stirred conditions. Most of those studies mainly addressed on the development and feasibility of modalities and however were not fully considering the effect of blood flow. To better elucidate this issue, ultrasonic backscattering were measured from the coagulating porcine blood circulated in a mock flow loop with various steady laminar flows at mean shear rates from 10 to 100 s(-1). A 3 ml of 0.5 M CaCl2 solution for inducing blood coagulation was added to that of 30 ml blood circulated in the conduit. For each measurement carried out with a 10-MHz transducer, backscattered signals digitized at 100-MHz sampling frequency were acquired for a total of 20 min at temporal resolution of 50 A-lines per s. The integrated backscatter (IB) was calculated for assessing backscattering properties of coagulating blood. The results show that blood coagulation tended to be increased corresponding to the addition of CaCl2 solution: the IB was increased approximately 6.1 +/- 0.6 (mean +/- standard deviation), 5.4 +/- 0.9, and 4.5 +/- 1.2 dB at 310 +/- 62, 420 +/- 88, and 610 +/- 102 s associated with mean shear rates of 10, 40, and 100 s(-1), respectively. The rate of increasing IB for evaluating the growth of clot was estimated to be 0.075 +/- 0.017, 0.052 +/- 0.027, and 0.038 +/- 0.012 delta dB delta s(-1) corresponding to the increase of mean shear rates. These results consistently demonstrate that higher shear rate tends to prolong the duration for the flowing blood to be coagulated and to decrease the rate of IB. Moreover, the laminar flow was changed to turbulent flow during that the blood was clotting discerned by spatial variations of ultrasound backscattering in the conduit. All these results validate that ultrasound backscattering is feasible to be utilized for detecting and assessing blood coagulation under dynamic conditions.
Collapse
Affiliation(s)
- Chih-Chung Huang
- Department of Biomedical Engineering, Chung Yuan Christian University, Chung Li 32023, Taiwan, ROC
| | | |
Collapse
|
41
|
Nam KH, Paeng DG, Choi MJ, Shung KK. Ultrasonic observation of blood disturbance in a stenosed tube: effects of flow acceleration and turbulence downstream. ULTRASOUND IN MEDICINE & BIOLOGY 2008; 34:114-22. [PMID: 17900794 DOI: 10.1016/j.ultrasmedbio.2007.07.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2006] [Revised: 06/30/2007] [Accepted: 07/16/2007] [Indexed: 05/17/2023]
Abstract
Red blood cell (RBC) aggregation is known to be highly dependent on hemodynamic parameters such as shear rate, flow turbulence and flow acceleration under pulsatile flow. The effects of all three hemodynamic parameters on RBC aggregation and echogenicity of porcine whole blood were investigated downstream of an eccentric stenosis in a mock flow loop using B-mode images with Doppler spectrograms of a commercial ultrasonic system. A hyperechoic parabolic profile appeared downstream during flow acceleration, yielding another piece of evidence suggesting that the enhancement of rouleaux formation may be caused by flow acceleration. It was also found that echogenicity increased locally at a distance of three tube diameters downstream from the stenosis. The local increase of echogenicity is thought to be mainly due to flow turbulence. The hypoechoic "black hole" was also seen at the center of the tube downstream of the stenosis where blood flow was disturbed, and this may be caused by the compound effect of flow turbulence and shear rate.
Collapse
Affiliation(s)
- Kweon-Ho Nam
- Interdisciplinary Postgraduate Program in Biomedical Engineering, Cheju National University, Jeju, Korea
| | | | | | | |
Collapse
|
42
|
Huang CC, Wang SH. Statistical variations of ultrasound signals backscattered from flowing blood. ULTRASOUND IN MEDICINE & BIOLOGY 2007; 33:1943-54. [PMID: 17673357 DOI: 10.1016/j.ultrasmedbio.2007.06.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2007] [Revised: 05/25/2007] [Accepted: 06/01/2007] [Indexed: 05/16/2023]
Abstract
The statistical distributions of ultrasonic signals backscattered from blood have recently been used to characterize hemodynamic properties, such as red blood cell (RBC) aggregation and blood coagulation. However, a thorough understanding of the relationship between blood properties and the statistical behavior of signals backscattered from flowing blood is still lacking. This prompted us to use the statistical parameter to characterize signals backscattered from both whole blood and RBC suspensions at different flow velocities (from 10 to 60 cm/s) and hematocrits (from 20% to 50%) under a steady laminar flow condition. The Nakagami parameter, scaling parameter, backscatter amplitude profile and flow velocity profile across a flow tube were acquired using a 10 MHz focused ultrasonic transducer. The backscattered signal peaked approximately at the centerline of the flow tube due to the effects of RBC aggregation, with the peak value increasing as the flow velocity of whole blood decreased. The Nakagami parameter increased from 0.45 to 0.78 as the flow velocity increased from 10 to 60 cm/s. The probability density function (PDF) of signals backscattered from flowing whole blood conformed with a pre-Rayleigh distribution. The Nakagami parameter was close to 1 for signals backscattered from RBC suspensions at all the flow velocities and hematocrits tested, for which the PDF was Rayleigh distributed. These differences in the statistical distributions of backscattered signals between whole blood and RBC suspensions suggest that variations in the size of dynamic scatterers in the flow affect the shape of the backscattered signal envelope, which should be considered in future statistical models used to characterize blood properties.
Collapse
Affiliation(s)
- Chih-Chung Huang
- Department of Biomedical Engineering and R & D Center for Membrane Technology, Chung Yuan Christian University, Chung Li, Taiwan.
| | | |
Collapse
|
43
|
Hoskins PR. Physical properties of tissues relevant to arterial ultrasound imaging and blood velocity measurement. ULTRASOUND IN MEDICINE & BIOLOGY 2007; 33:1527-39. [PMID: 17601650 DOI: 10.1016/j.ultrasmedbio.2007.04.020] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2007] [Revised: 04/23/2007] [Accepted: 04/30/2007] [Indexed: 05/16/2023]
Abstract
A review was undertaken of physical phenomena and the values of associated physical quantities relevant to arterial ultrasound imaging and measurement. Arteries are multilayered anisotropic structures. However, the requirement to obtain elasticity measurements from the data available using ultrasound imaging necessitates the use of highly simplified constitutive models involving Young's modulus, E. Values of E are reported for healthy arteries and for the constituents of diseased arteries. It is widely assumed that arterial blood flow is Newtonian. However, recent studies suggest that non-Newtonian behavior has a strong influence on arterial flow, and the balance of published evidence suggests that non-Newtonian behavior is associated primarily with red cell deformation rather than with aggregation. Hence, modeling studies should account for red cell deformation and the shear thinning effect that this produces. Published literature in healthy adults gives an average hematocrit and high-shear viscosity of 0.44 +/- 0.03 and 3.9 +/- 0.6 mPa.s, respectively. Published data on the acoustic properties of arteries and blood is sufficiently consistent between papers to allow compilation and derivation of best-fit equations summarizing the behavior across a wide frequency range, which then may be used in future modeling studies. Best-fit equations were derived for the attenuation coefficient vs. frequency in whole arteries (R(2) = 0.995), plasma (R(2) = 0.963) and blood with hematocrit near 45% (R(2) = 0.999), and for the backscatter coefficient vs. frequency from blood with hematocrit near 45% (R(2) = 0.958).
Collapse
Affiliation(s)
- Peter R Hoskins
- Medical Physics Section, University of Edinburgh, Edinburgh, UK.
| |
Collapse
|
44
|
Yu FTH, Cloutier G. Experimental ultrasound characterization of red blood cell aggregation using the structure factor size estimator. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2007; 122:645-56. [PMID: 17614521 DOI: 10.1121/1.2735805] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
The frequency dependence of the ultrasonic backscattering coefficient (BSC) was studied to assess the level of red blood cell (RBC) aggregation. Three monoelement focused wideband transducers were used to insonify porcine blood sheared in a Couette flow from 9 to 30 MHz. A high shear rate was first applied to promote disaggregation. Different residual shear rates were then used to promote formation of RBC aggregates. The structure factor size estimator (SFSE), a second-order data reduction model based on the structure factor, was applied to the frequency-dependent BSC. Two parameters were extracted from the model to describe the level of aggregation at 6% and 40% hematocrits: W, the packing factor, and D the aggregate diameter, expressed in number of RBCs. Both parameters closely matched theoretical values for nonaggregated RBCs. W and D increased during aggregation with stabilized values modulated by the applied residual shear rate. Furthermore, parameter D during the kinetics of aggregation at 6% hematocrit under static conditions correlated with an optical RBC aggregate size estimation from microscopic images (r(2)=0.76). To conclude, the SFSE presents an interesting framework for tissue characterization of partially correlated dense tissues such as aggregated RBCs.
Collapse
Affiliation(s)
- François T H Yu
- Laboratory of Biorheology and Medical Ultrasonics, University of Montreal Hospital Research Center, Pavilion J.A. de Sève, 2099 Alexandre de Sève, Montréal, Québec, Canada.
| | | |
Collapse
|
45
|
Rouffiac V, Lavisse S, Bidault F, Paci A, Péronneau P, Roche A, Lassau N. [Validation of a new methodology for characterizing ultrasound contrast agents (UCA)]. ACTA ACUST UNITED AC 2005; 86:325-34. [PMID: 15908873 DOI: 10.1016/s0221-0363(05)81362-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
PURPOSE Validation of an experimental ultrasound system on erythrocyte suspensions with variable levels of aggregation and application to the echogenicity quantification of UCA under quasi-physiologic flow conditions. MATERIALS AND METHODS. The system is constituted with a Couette cell with variable applied shear rates, an ultrasound emitter/receiver and a digital scope for radio-frequency signal acquisition. Ultrasound indices (UI) were defined for the two experimental established protocols based on the gold standard laser methodology. Washed red cells with or without variable Dextran 70 kD concentrations were used to simulate a wide particle size range. A preliminary application to UCA was conducted with Levovist for calibration of the system. RESULTS For each protocol, applied ten times on identical whole blood samples, a student t-test revealed no significant variation for all UI. Results on washed red cells were in good agreement with Rayleigh's theory of ultrasound backscattering. Significant correlations were obtained between laser and UI for washed red cells with different Dextran concentrations. An elevation of 12.13 dB in backscattered intensity was obtained after addition of Levovist. CONCLUSION The constituted Couette system allowed reproducible and accurate echogenicity quantification of small scatterers such as UCA in quasi-physiologic blood flow conditions.
Collapse
Affiliation(s)
- V Rouffiac
- Laboratoire d'Imagerie du Petit Animal, Institut Gustave Roussy.
| | | | | | | | | | | | | |
Collapse
|
46
|
Hughes MS, Marsh JN, Hall CS, Fuhrhop RW, Lacy EK, Lanza GM, Wickline SA. Acoustic characterization in whole blood and plasma of site-targeted nanoparticle ultrasound contrast agent for molecular imaging. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2005; 117:964-72. [PMID: 15759715 DOI: 10.1121/1.1810251] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
The ability to enhance specific molecular markers of pathology with ultrasound has been previously demonstrated by our group employing a nanoparticle contrast agent [Lanza et al., Invest. Radiol. 35, 227-234 (2000); Ultrasound Med. Biol. 23, 863-870 (1997)]. One of the advantages of this agent is very low echogenicity in the blood pool that allows increased contrast between the blood pool and the bound, site-targeted agent. We measured acoustic backscatter and attenuation coefficient as a function of the contrast agent concentration, ambient pressure, peak acoustic pressure, and as an effect of duty cycle and wave form shape. Measurements were performed while the nanoparticles were suspended in either whole porcine blood or plasma. The nanoparticles were only detectable when insonified within plasma devoid of red blood cells and were shown to exhibit backscatter levels more than 30 dB below the backscatter from whole blood. Attenuation of nanoparticles in whole porcine blood was not measurably different from that of whole blood alone over a range of concentrations up to eight times the maximum in vivo dose. The resulting data provide upper bounds on blood pool attenuation coefficient and backscatter and will be needed to more precisely define levels of molecular contrast enhancement that may be obtained in vivo.
Collapse
Affiliation(s)
- Michael S Hughes
- Washington University School of Medicine, Cardiovascular Division, St Louis, Missouri 63110, USA.
| | | | | | | | | | | | | |
Collapse
|
47
|
Paeng DG, Joo Choi M, Kirk Shung K. Investigation of blood under pulsatile flow using ultrasound imaging. ACTA ACUST UNITED AC 2004. [DOI: 10.1016/j.ics.2004.07.035] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
48
|
Le Floc'h J, Chérin E, Zhang MY, Akirav C, Adamson SL, Vray D, Foster FS. Developmental changes in integrated ultrasound backscatter from embryonic blood in vivo in mice at high US frequency. ULTRASOUND IN MEDICINE & BIOLOGY 2004; 30:1307-1319. [PMID: 15582230 DOI: 10.1016/j.ultrasmedbio.2004.07.018] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2003] [Revised: 07/13/2004] [Accepted: 07/29/2004] [Indexed: 05/24/2023]
Abstract
Mouse blood imaged using high-frequency ultrasound (US) is more echogenic in embryos than in adults. Studying changes in blood echogenicity in embryos may be of fundamental interest in studies on the genetic regulation of normal and abnormal blood development in mutant mice. Embryonic red blood cells (RBCs) are large and nucleated in midgestation but decrease in size and become enucleated as they mature. We therefore hypothesised that these structural alterations are responsible for variations in echogenicity of embryonic blood with gestational age and development. The objective of the current study was to quantify these structural changes in echogenicity (echo brightness) and apparent integrated backscatter (AIB) from embryonic blood at high US frequencies in vivo in mice. Results from anaesthetised pregnant mice studied using transcutaneous US showed that echogenicity of embryonic blood in the heart, aorta and umbilical cord and AIB within the heart chambers peaked at embryonic day (ED) 13.5 and then decreased progressively toward term. Between EDs 13.5 and 17.5 (near term), RBC mean cell volume decreased from 133 to 109 fL, haematocrit increased from 12 to 34%, and the percentage of nucleated RBCs decreased from 59 to 2%. Relative to younger ages, RBC nuclei at ED 13.5 were small and dense (pyknotic) which may have contributed to the peak in echogenicity and AIB at this age. To calculate the AIB, radiofrequency (RF) signals with centre frequencies of 28 MHz and 35 MHz were integrated over the 16- to 35-MHz and 21- to 42-MHz frequency range, respectively. At 28 MHz, mean apparent integrated backscatter of blood in the embryonic heart increased significantly from 0.0023 +/- 0.0004 Sr.cm(-1) (mean +/- SEM) at ED 12.5 to peak at 0.0037 +/- 0.0005 Sr.cm(-1) at ED 13.5. The mean AIB then decreased progressively with advancing gestation to 0.0002 +/- 0.0001 Sr.cm(-1) at ED 17.5. At 35 MHz, the mean AIB changed similarly with gestational age, except that values were lower than at 28 MHz at all ages. Higher attenuation of US at 35 MHz than at 28 MHz in tissue likely accounted for the lower AIB of blood insonified at 35 MHz. We speculate that developmental changes in red cell morphology are responsible for the observed changes in echogenicity and AIB of embryonic blood with gestational age in mice.
Collapse
Affiliation(s)
- Johann Le Floc'h
- Department of Medical Biophysics, Sunnybrook and Women's College Health Sciences Centre, Toronto, ONT, Canada.
| | | | | | | | | | | | | |
Collapse
|
49
|
|
50
|
Paeng DG, Chiao RY, Shung KK. Echogenicity variations from porcine blood II: the "bright ring" under oscillatory flow. ULTRASOUND IN MEDICINE & BIOLOGY 2004; 30:815-825. [PMID: 15219961 DOI: 10.1016/j.ultrasmedbio.2004.03.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2003] [Revised: 02/11/2004] [Accepted: 02/26/2004] [Indexed: 05/24/2023]
Abstract
Echogenicity variations from porcine blood were observed in a mock flow loop under pulsatile flow in a series of experiments (Paeng et al. 2004). In this paper, oscillatory flow was generated to further investigate the cyclic and radial variation of blood echogenicity and its origin and mechanisms by several parameters, including stroke volume, stroke rate, mean steady flow and transducer angle, using a GE LOGIQ 700 Expert system. The echogenicity at the center of the tube was enhanced during acceleration and lower during deceleration, and the expansion and collapse of the "bright ring" was observed twice per cycle. The "black hole," a central echo-poor zone surrounded by a hyperechoic zone, was barely observable under oscillatory flow, and these patterns differed from those under pulsatile flow. The cyclic and radial variation of echogenicity under oscillatory flow was affected by such hemodynamic parameters as stroke volume, stroke rate and mean steady flow. It was suggested that rouleaux might be aligned at an angle of about 25 degrees relative to the tube axis during the acceleration phase, based on the experimental results reaching a maximum of the echogenicity variation at a transducer angle of 25 degrees. Radial distribution of rouleaux alignments was proposed to be another important factor to blood echogenicity variation, in addition to combined effects of shear rate and flow acceleration on erythrocyte aggregation and blood echogenicity. The weak cyclic variation of echogenicity was also observed from the porcine erythrocyte suspensions under pure oscillatory flow, but not under pulsatile flow. It is postulated that the echogenicity variations from erythrocyte suspensions are from red cell deformation.
Collapse
Affiliation(s)
- Dong-Guk Paeng
- Marine Industrial Engineering, Cheju National University, Jeju, South Korea.
| | | | | |
Collapse
|