Magnetic resonance imaging with fluorocarbons encapsulated in a cross-linked polymeric shell

In accordance with the present invention, compositions comprising fluorine-containing magnetic resonance imaging agent(s) contained within polymeric shells are provided. Invention compositions are useful, for example, as contrast agents for magnetic resonance imaging (MRI). Fluorinated compounds in general are hydrophobic and as such have limited water solubility; thus the invention method permits preparation of such compounds in a biocompatible form suitable for ready delivery. The shell diameter is typically approximately 2 microns in diameter. Consequently, these materials have organ specificity due to rapid scavenging by the reticuloendothial system (RES) or the mononuclear phagocyte (MNP) system upon intravenous injection. Furthermore, fluorocarbon filled polymeric shells of the invention can be used to measure and monitor local oxygen and temperature.