MICROPARTICLES, MEDIA CONTAINING THE LATTER FOR ULTRASONIC DIAGNOSIS AS WELL AS PROCESS FOR THE PRODUCTION OF THE PARTICLES AND MEDIA

摘要

The invention concerns gas-containing microparticles for use in ultrasound diagnostics. The wall material of the microparticles is made either from block copolymers of .alpha.-, .beta.-, or .gamma.-hydroxycarboxylic acid polyesters with linear or stellate polyethylene glycols and, optionally, liquid crystals, or from .alpha.-, .beta.-, or .gamma.-hydroxycarboxylic acid polyesters with liquid crystals. The invention also concerns agents containing these particles for use in ultrasound diagnostics and processes for producing the said agents and particles.