Subharmonic analysis using singular-value decomposition of ultrasound contrast agents
AUTOR(ES)
Mamou, Jonathan
FONTE
Acoustical Society of America
RESUMO
Ultrasound contrast agents (UCAs) are designed to be used below 10 MHz, but interest is growing in studying the response of agents to high-frequency ultrasound. In this study, the subharmonic response of polymer-shelled UCAs with a mean diameter of 1.1 μm excited with 40-MHz tone-bursts of 1–20 cycles was analyzed. UCAs were diluted in water and streamed through a flow phantom that permitted single-bubble backscatter events to be acquired at peak-negative pressures from 0.75 to 5.0 MPa. At each exposure condition, 1000 single-bubble-backscatter events were digitized. Subharmonic content at 20 MHz was screened using a conventional and a singular-value-decomposition (SVD) method. The conventional method evaluated each event spectrum individually while the SVD method treated the 1000-event data set at one time. A subharmonic score (SHS) indicative of how much subharmonic content a 1000-event data set contained was computed for both methods. Empirical-simulation results indicated that SHSs obtained from the two methods were linearly related. Also, experimental data with both methods indicated that subharmonic likelihood increased with pulse duration and peaked near 2 MPa. The SVD method also yielded quantitative information about subharmonic events not available with the conventional method.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=2719484Documentos Relacionados
- Robust singular value decomposition analysis of microarray data
- Reverse engineering gene networks using singular value decomposition and robust regression
- Normalization of peak intensities in bottom-up MS-based proteomics using singular value decomposition
- Singular value decomposition with self-modeling applied to determine bacteriorhodopsin intermediate spectra: Analysis of simulated data
- Cardiovascular therapeutic uses of targeted ultrasound contrast agents