Journal of Ultrasound in Medicine, Vol 14, Issue 12 949-957, Copyright © 1995 by American Institute of Ultrasound in Medicine
Parenchymal enhancement and tumor visualization using a new sonographic contrast agent
F. Forsberg, J. B. Liu, D. A. Merton, N. M. Rawool and B. B. Goldberg
Department of Radiology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA.
The purpose of this study was to assess the ability of a sonographic
contrast agent to increase parenchymal echogenicity and improve tumor
visibility. The agent is an emulsion that changes at body temperature from
nonechogenic submicrometer liquid droplets to echogenic 1 to 5 microns
microbubbles, capable of transversing the pulmonary and capillary
circulations. Peripheral venous injections (dosages of 0.05 to 0.8 ml/kg)
were administered to five woodchucks (three with multiple hepatomas), 12
rabbits (with renal VX-2 tumors), and four dogs. Ultrasonograms were
acquired from kidney, liver, tumors (including tumor vessels) and normal
vessels. Uptake and washout curves were generated via videodensitometry.
Finally, Doppler shifts from a cuff transducer around the celiac trunk were
analyzed to provide an in vivo dose-response curve. Vascular enhancement,
including hepatoma and VX-2 tumor vessels, was seen for 2 to 3 min. Maximum
enhancement was 18.7 dB for a 0.6 ml/kg dose. Enhancement of normal liver
and kidney parenchyma was observed in all three species for up to 20 min.
Small hepatomas became more echogenic centrally, but larger tumors showed
no increase in central echogenicity. In conclusion, improved tumor
visibility and parenchymal enhancement was demonstrated in animals.
