Ultrasonic Backscatter from Contrast Producing Collagen Microspheres

Abstract

Measurements of ultrasonic backscatter from solid collagen microspheres in suspension and from a standard erythrocyte suspension were performed. When normalized to a standard particle size and concentration, the back-scatter from the collagen was 29.6 dB above that of the erythrocytes. An in vivo canine experiment using commercial diagnostic equipment demonstrated enhanced backscatter from the liver after intravenous injection of the microspheres. Calculations show that the in vivo enhancement cannot be explained from the earlier studies. Possible mechanisms responsible for this effect are proposed.