The present invention provides an encapsulated gas or partial vacuum particle contrast media for use in CT imaging. In an exemplary embodiment the invention provides an enteric contrast medium formulation. An exemplary formulation comprises (a) an enteric contrast medium comprising a encapsulated gas or partial vacuum particle suspended in water. Exemplary encapsulated gas or partial vacuum particle has a specific gravity between 0.2 and 1.5. In various embodiments the encapsulated gas or partial vacuum particle is suspended in aqueous media by an agent compatible with enteric administration of the formulation to a subject in need of such administration. In an exemplary embodiment the contrast material is incorporated into a pharmaceutically acceptable carrier in which the material is suspended homogeneously. In an exemplary embodiment the encapsulated gas or partial vacuum particle comprises 5% or more of the weight of the contrast material formulation.
