Compositions and methods for multimodal imaging

A composition for imaging of a biological tissue, said composition comprising:

• a) two or more signal modifying agents, each of said agents being specific for at least one imaging modality and each of said agents being specific for a different imaging modality;
• and
• b) a colloidal carrier comprising said two or more signal modifying agents wherein said carrier retains a sufficient amount of said agents for a time sufficient to acquire in vivo imaging data from each of the two or more signal modifying agents using said composition, and wherein said composition is specific for two or more imaging modalities selected from magnetic resonance imaging (MRI), X-ray, positron emission tomography (PET), computed tomography (CT), autoradiography, single-photon emission computed tomography (SPECT), fluoroscopy, optical imaging, fluorescence imaging, bioluminescence imaging and combinations thereof.