Document Detail

Influence of shell properties on high-frequency ultrasound imaging and drug delivery using polymer-shelled microbubbles.
MedLine Citation:
PMID:  23287913     Owner:  NLM     Status:  MEDLINE    
This two-part study investigated shell rupture of ultrasound contrast agents (UCAs) under static overpressure conditions and the subharmonic component from UCAs subjected to 20-MHz tonebursts. Five different polylactide-shelled UCAs with shell-thickness-to-radius ratios (STRRs) of 7.5, 30, 40, 65, and 100 nm/¿m were subjected to static overpressure in a glycerol-filled test chamber. A video microscope imaged the UCAs as pressure varied from 2 to 330 kPa over 90 min. Images were postprocessed to obtain the pressure threshold for rupture and the diameter of individual microbubbles. Backscatter from individual UCAs was investigated by flowing a dilute UCA solution through a wall-less flow phantom placed at the geometric focus of a 20-MHz transducer. UCAs were subjected to 10- and 20-cycle tonebursts of acoustic pressures ranging from 0.3 to 2.3 MPa. A method based on singular-value decomposition (SVD) was employed to obtain a cumulative subharmonic score (SHS). Different UCA types exhibited distinctly different rupture thresholds that were linearly related to their STRR, but uncorrelated with UCA size. The rupture threshold for the UCAs with an STRR = 100 nm/μm was more than 4 times greater than the UCAs with an STRR = 7.5 nm/μm. The polymer-shelled UCAs produced substantial subharmonic response but the subharmonic response to 20- MHz excitation did not correlate with STRRs or UCA-rupture pressures. The 20-cycle excitation resulted in an SHS that was 2 to 3 times that of UCAs excited with 10-cycle tonebursts.
Parag V Chitnis; Sujeethraj Koppolu; Jonathan Mamou; Ceciel Chlon; Jeffrey A Ketterling
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Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural    
Journal Detail:
Title:  IEEE transactions on ultrasonics, ferroelectrics, and frequency control     Volume:  60     ISSN:  1525-8955     ISO Abbreviation:  IEEE Trans Ultrason Ferroelectr Freq Control     Publication Date:  2013 Jan 
Date Detail:
Created Date:  2013-01-04     Completed Date:  2013-06-10     Revised Date:  2013-07-17    
Medline Journal Info:
Nlm Unique ID:  9882735     Medline TA:  IEEE Trans Ultrason Ferroelectr Freq Control     Country:  United States    
Other Details:
Languages:  eng     Pagination:  53-64     Citation Subset:  IM    
The F. L . Lizzi Center for Biomedical Engineering, Riverside Research, New York, NY, USA.
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MeSH Terms
Contrast Media / chemistry*
Drug Delivery Systems / instrumentation,  methods*
Elastic Modulus
Microscopy, Video
Phantoms, Imaging
Polymers / chemistry*
Ultrasonography / instrumentation,  methods*
Grant Support
Reg. No./Substance:
0/Contrast Media; 0/Polymers

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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