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Pressure-dependent attenuation and scattering of phospholipid-coated microbubbles at low acoustic pressures.
- Source :
-
Ultrasound in medicine & biology [Ultrasound Med Biol] 2009 Jan; Vol. 35 (1), pp. 102-11. Date of Electronic Publication: 2008 Oct 02. - Publication Year :
- 2009
-
Abstract
- Previous optical studies have shown threshold behavior of single-contrast agent microbubbles. Below the acoustic pressure threshold, phospholipid-coated microbubbles with sizes <5.0 mum in diameter oscillate significantly less than above the threshold pressure. Previous studies also revealed an acoustic pressure-dependent attenuation of ultrasound by microbubble contrast agents. In this study, we investigated whether pressure-dependent acoustic behavior may be explained by threshold behavior. For this purpose, pressure-dependent attenuation and scattering of a phospholipid-coated contrast agent were measured. Transmit frequencies between 1.5 and 6.0 MHz and acoustic pressures between 5 and 200 kPa were applied. Unlike the galactose-based contrast agent Levovist, the phospholipid-coated contrast agent BR14 showed a pressure-dependent attenuation. In addition, it was found that filtered suspensions with only microbubbles <3.0 mum in diameter show more pressure-dependent attenuation behavior than native suspensions of phospholipid-coated microbubbles. For the scattering measurements conducted at 3.0 MHz, the native suspension did not show any pressure-dependent behavior. However, the filtered suspension responded highly nonlinearly. Between 30 and 150 kPa, 16 dB additional scattered power was obtained. We concluded that threshold behavior of phospholipid-coated microbubbles results in pressure-dependent attenuation and scattering.
Details
- Language :
- English
- ISSN :
- 1879-291X
- Volume :
- 35
- Issue :
- 1
- Database :
- MEDLINE
- Journal :
- Ultrasound in medicine & biology
- Publication Type :
- Academic Journal
- Accession number :
- 18829153
- Full Text :
- https://doi.org/10.1016/j.ultrasmedbio.2008.07.005