Particles having an average diameter of less than about 12 microns comprising fatty acid cores encapsulated with human serum albumin and methods for their preparation are disclosed. These materials are useful as contrast agents in ultrasonic imaging, having scattering intensities that are equivalent to or greater than those obtained from dispersed microbubbles but being much more stable, both in storage and when used in vivo, than are contrast agents based on dispersed microbubbles.
展开▼