| In vitro contrast-enhanced ultrasound measurements of capillary microcirculation: comparison between polymer- and phospholipid-shelled microbubbles. | |
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MedLine Citation:
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PMID: 20542310 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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The focus of contrast-enhanced ultrasound research has developed beyond visualizing the blood pool and its flow to new areas such as perfusion imaging, drug and gene therapy, and targeted imaging. In this work comparison between the application of polymer- and phospholipid-shelled ultrasound contrast agents (UCAs) for characterization of the capillary microcirculation is reported. All experiments are carried out using a microtube as a vessel phantom. The first set of experiments evaluates the optimal concentration level where backscattered signal from microbubbles depends on concentration linearly. For the polymer-shelled UCAs the optimal concentration level is reached at a value of about 2×10(4)MB/ml, whereas for the phospholipid-shelled UCAs the optimal level is found at about 1×10(5)MB/ml. Despite the fact that the polymer shell occupies 30% of the radius of microbubble, compared to 0.2% of the phospholipid-shelled bubble, approximately 5-fold lower concentration of the polymer UCA is needed for investigation compared to phospholipid-shelled analogues. In the second set of experiments, destruction/replenishment method with varied time intervals ranging from 2ms to 3s between destructive and monitoring pulses is employed. The dependence of the peak-to-peak amplitude of backscattered wave versus pulse interval is fitted with an exponential function of the time γ=A(1-exp(-βt)) where A represents capillary volume and the time constant β represents velocity of the flow. Taking into account that backscattered signal is linearly proportional to the microbubble concentration, for both types of the UCAs it is observed that capillary volume is linearly proportional to the concentration of the microbubbles, but the estimation of the flow velocity is not affected by the change of the concentration. Using the single capillary model, for the phospholipid-shelled UCA a delay of about 0.2-0.3s in evaluation of the perfusion characteristics is found while polymer-shelled UCA provide response immediately. The latter at the concentration lower than 3.6×10(5)MB/ml have no statistically significant delay (p<0.01), do not cause any attenuation of the backscattered signal or saturation of the receiving part of the system. In conclusion, these results suggest that the novel polymer-shelled microbubbles have a potential to be used for perfusion evaluation. |
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Authors:
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Dmitry Grishenkov; Leif Kari; Lars-Ke Brodin; Torkel B Brismar; Gaio Paradossi |
Publication Detail:
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Type: Comparative Study; In Vitro; Journal Article; Research Support, Non-U.S. Gov't Date: 2010-05-24 |
Journal Detail:
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Title: Ultrasonics Volume: 51 ISSN: 1874-9968 ISO Abbreviation: Ultrasonics Publication Date: 2011 Jan |
Date Detail:
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Created Date: 2010-10-18 Completed Date: 2010-12-02 Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 0050452 Medline TA: Ultrasonics Country: Netherlands |
Other Details:
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Languages: eng Pagination: 40-8 Citation Subset: IM |
Copyright Information:
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Copyright © 2010 Elsevier B.V. All rights reserved. |
Affiliation:
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School of Engineering Sciences, Royal Institute of Technology, Stockholm, Sweden. dmitryg@kth.se |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Albumins
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chemistry*,
pharmacokinetics* Capillaries / ultrasonography* Contrast Media / chemistry*, pharmacokinetics* Fluorocarbons / chemistry*, pharmacokinetics* Humans Microbubbles Microcirculation* Phantoms, Imaging Phospholipids / chemistry*, pharmacokinetics* Polymers / chemistry Sulfur Hexafluoride / chemistry*, pharmacokinetics* Transducers |
| Chemical | |
Reg. No./Substance:
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0/Albumins; 0/Contrast Media; 0/FS 069; 0/Fluorocarbons; 0/Phospholipids; 0/Polymers; 0/contrast agent BR1; 2551-62-4/Sulfur Hexafluoride |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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