Journal of Ultrasound in Medicine, Vol 5, Issue 9 493-498, Copyright © 1986 by American Institute of Ultrasound in Medicine
Automated production and analysis of echo contrast agents
M. W. Keller, S. B. Feinstein, R. A. Briller and S. M. Powsner
To develop and standardize contrast agents for use in contrast
echocardiographic imaging, microbubble size, concentration, decay, and
ultrasound backscatter must be known. These parameters were assessed with a
scanning laser particle counter, a commercial ultrasound unit, and various
sonicated intravenous solutions. The scanning laser particle counter proved
to be a fast and effective means of evaluating microbubble size,
concentration, and stability. In addition, sonication was found to be a
reliable and reproducible technique for preparing standardized echo
contrast agent solutions containing uniformly small microbubbles. The
bubbles generated ranged in size from 1 to 15 micron in diameter. All
solutions had mean bubble diameters less than 6 micron. The half life of
solutions ranged from 44 +/- 12 seconds for Hypaque 50%, to 253 +/- 73
seconds for Iopamidol. Addition of the surfactant to dextrose 70% prolonged
bubble half life from 58 +/- 12 seconds to 1018 +/- 276 seconds. Phased
array two-dimensional echocardiography of sonicated microbubble solutions,
and subsequent videodensitometric analysis, revealed that bubble
concentration was directly proportional to echo-reflective properties, and
that the solutions have significant ultrasound reflective properties in
vitro at concentrations of less than 1500 bubbles/ml.
