Ultrasonic contrast agent shell rupture detected by inertial cavitation and rebound signals.
IEEE Trans Ultrason Ferroelectr Freq Control
; 53(1): 126-36, 2006 Jan.
Article
in En
| MEDLINE
| ID: mdl-16471439
ABSTRACT
Determining the rupture pressure threshold of ultrasound contrast agent microbubbles has significant applications for contrast imaging, development of therapeutic agents, and evaluation of potential bioeffects. Using a passive cavitation detector, this work evaluates rupture based on acoustic emissions from single, encapsulated, gas-filled microbubbles. Sinusoidal ultrasound pulses were transmitted into weak solutions of Optison at different center frequencies (0.9, 2.8, and 4.6 MHz), pulse durations (three, five, and seven cycles of the center frequencies), and peak rarefactional pressures (0.07 to 5.39 MPa). Pulse repetition frequency was 10 Hz. Signals detected with a 13-MHz, center-frequency transducer revealed postexcitation acoustic emissions (between 1 and 5 micros after excitation) with broadband spectral content. The observed acoustic emissions were consistent with the acoustic signature that would be anticipated from inertial collapse followed by "rebounds" when a microbubble ruptures and thus generates daughter/free bubbles that grow and collapse. The peak rarefactional pressure threshold for detection of these emissions increased with frequency (e.g., 0.53, 0.87, and 0.99 MPa for 0.9, 2.8, and 4.6 MHz, respectively; five-cycle pulse duration) and decreased with pulse duration. The emissions identified in this work were separated from the excitation in time and spectral content, and provide a novel determination of microbubble shell rupture.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Sonication
/
Image Interpretation, Computer-Assisted
/
Ultrasonography
/
Contrast Media
/
Microbubbles
/
Albumins
/
Fluorocarbons
Type of study:
Diagnostic_studies
/
Evaluation_studies
Language:
En
Journal:
IEEE Trans Ultrason Ferroelectr Freq Control
Journal subject:
MEDICINA NUCLEAR
Year:
2006
Type:
Article
Affiliation country:
France