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Koo B, Liu Y, Abboud M, Qin B, Wu Y, Choi S, Kozak D, Zheng J. Characterizing how size distribution and concentration affect echogenicity of ultrasound contrast agents. ULTRASONICS 2023; 127:106827. [PMID: 36063769 DOI: 10.1016/j.ultras.2022.106827] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2021] [Revised: 04/28/2022] [Accepted: 08/13/2022] [Indexed: 06/15/2023]
Abstract
We investigated the effects of UCA gas bubble size distribution and concentration on the generated ultrasound echogenicity signal. Gas bubble size characterization using Coulter Counter and cryogenic-SEM revealed the hollow structure and rare presence of microbubbles >10 µm in a commercial UCA product, Lumason™. Volume-weighed size and concentration were observed to be more sensitive to changes in UCA bubble stability than number-weighted size and concentration. Size distribution measurements showed that the force (e.g., shaking/agitation energy) used to redisperse the sample did not affect the size distribution, concentration, or echogenicity of the UCA sample. The ultrasound backscattering coefficient (BSC) of size fractionated and serial diluted microbubbles showed that the echogenicity signal correlates most with UCA bubble concentration, especially volume-weighted concentration. Findings from this study may be used to support demonstrating the equivalence of a generic UCA product to the reference listed drug.
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Affiliation(s)
- Bonhye Koo
- Division of Therapeutic Performance, Office of Research and Standards, Office of Generic Drugs, Center for Drug Evaluation and Research, Food and Drug Administration, Silver Spring, MD 20993, United States; Division of Biology, Chemistry and Materials Science, Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, Food and Drug Administration, Silver Spring, MD 20993, United States
| | - Yunbo Liu
- Division of Applied Mechanics, Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, Food and Drug Administration, Silver Spring, MD 20993, United States
| | - Monica Abboud
- Division of Applied Mechanics, Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, Food and Drug Administration, Silver Spring, MD 20993, United States
| | - Bin Qin
- Division of Therapeutic Performance, Office of Research and Standards, Office of Generic Drugs, Center for Drug Evaluation and Research, Food and Drug Administration, Silver Spring, MD 20993, United States
| | - Yong Wu
- Division of Biology, Chemistry and Materials Science, Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, Food and Drug Administration, Silver Spring, MD 20993, United States
| | - Stephanie Choi
- Division of Therapeutic Performance, Office of Research and Standards, Office of Generic Drugs, Center for Drug Evaluation and Research, Food and Drug Administration, Silver Spring, MD 20993, United States
| | - Darby Kozak
- Division of Therapeutic Performance, Office of Research and Standards, Office of Generic Drugs, Center for Drug Evaluation and Research, Food and Drug Administration, Silver Spring, MD 20993, United States.
| | - Jiwen Zheng
- Division of Biology, Chemistry and Materials Science, Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, Food and Drug Administration, Silver Spring, MD 20993, United States.
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Harfield C, Fury CR, Memoli G, Jones P, Ovenden N, Stride E. Analysis of the Uncertainty in Microbubble Characterization. ULTRASOUND IN MEDICINE & BIOLOGY 2016; 42:1412-8. [PMID: 26993799 DOI: 10.1016/j.ultrasmedbio.2016.01.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2015] [Revised: 12/22/2015] [Accepted: 01/11/2016] [Indexed: 05/23/2023]
Abstract
There is increasing interest in the use of microbubble contrast agents for quantitative imaging applications such as perfusion and blood pressure measurement. The response of a microbubble to ultrasound excitation is, however, extremely sensitive to its size, the properties of its coating and the characteristics of the sound field and surrounding environment. Hence the results of microbubble characterization experiments can be significantly affected by experimental uncertainties, and this can limit their utility in predictive modelling. The aim of this study was to attempt to quantify these uncertainties and their influence upon measured microbubble characteristics. Estimates for the parameters characterizing the microbubble coating were obtained by fitting model data to numerical simulations of microbubble dynamics. The effect of uncertainty in different experimental parameters was gauged by modifying the relevant input values to the fitting process. The results indicate that even the minimum expected uncertainty in, for example, measurements of microbubble radius using conventional optical microscopy, leads to variations in the estimated coating parameters of ∼20%. This should be taken into account in designing microbubble characterization experiments and in the use of data obtained from them.
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Affiliation(s)
- Caroline Harfield
- Institute of Biomedical Engineering, Department of Engineering Science, Old Road Campus Research Building, University of Oxford, Oxford, UK
| | - Christopher R Fury
- Acoustics Group, National Physical Laboratory, Teddington, UK; Department of Physics and Astronomy, University College London, London, UK
| | - Gianluca Memoli
- Acoustics Group, National Physical Laboratory, Teddington, UK
| | - Philip Jones
- Department of Physics and Astronomy, University College London, London, UK
| | - Nick Ovenden
- Department of Mathematics, University College London, London, UK
| | - Eleanor Stride
- Institute of Biomedical Engineering, Department of Engineering Science, Old Road Campus Research Building, University of Oxford, Oxford, UK.
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