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Pressure dependence of subharmonic signals from contrast microbubbles
W T Shi1, F Forsberg, J S Raichlen
1Jefferson Ultrasound Education and Research Institute and Department of Radiology, Thomas Jefferson University, Philadelphia, PA 19107, USA. bill@esther.rad.tju.edu
Ultrasound in Medicine & Biology
|May 13, 1999
Summary
This study shows that microbubble ultrasound contrast agents can noninvasively measure heart and vascular pressure. Changes in subharmonic signal amplitude correlate with hydrostatic pressure, enabling pressure detection.
Area of Science:
- Biomedical Engineering
- Ultrasound Imaging
- Cardiovascular Diagnostics
Background:
- Noninvasive pressure estimation is crucial for diagnosing heart and vascular diseases.
- Microbubble ultrasound contrast agents offer potential for pressure measurements due to their compressibility.
- Existing methods for pressure assessment can be invasive.
Purpose of the Study:
- To evaluate the feasibility of using microbubble ultrasound contrast agents for noninvasive pressure estimation.
- To determine the relationship between microbubble reflectivity and pressure changes in cardiovascular settings.
Main Methods:
- Utilized a galactose-based ultrasound contrast agent.
- Employed 2.0-MHz ultrasound tone bursts for signal interrogation.
- Measured subharmonic and harmonic amplitudes of scattered signals across a pressure range of 0-186 mmHg.
Main Results:
- Subharmonic signal amplitude decreased by up to 10 dB with increasing hydrostatic pressure.
- First and second harmonic amplitudes showed minimal decrease (<3 dB) under the same conditions.
- An excellent correlation was observed between subharmonic amplitude and hydrostatic pressure.
Conclusions:
- Subharmonic signal changes in microbubbles can serve as a reliable indicator of noninvasive pressure variations.
- This technique holds promise for improved cardiovascular disease assessment.
- Further research can optimize this method for clinical application.