Gas or air filled microbubble suspensions in aqueous phases usable as imaging
contrast agents in ultrasonic echography. They contain laminarized surfactants
and, optionally, hydrophilic stabilizers. The laminarized surfactants can be in
the form of liposomes. The suspensions are obtained by exposing the laminarized
surfactants to air or a gas before or after admixing with an aqueous phase.
