Molecular imaging agents are extending the potential of noninvasive medical diagnosis from basic gross anatomical descriptions to complicated phenotypic characterizations, based upon the recognition of unique cell-surface biochemical signatures. Originally the purview of nuclear medicine, molecular imaging is now a prominent feature of most clinically relevant imaging modalities, in particular magnetic resonance imaging and ultrasound. Nanoparticulate molecular imaging agents afford the opportunity not only for targeted diagnostic studies but also for image-monitored site-specific therapeutic delivery. Combining imaging with drug delivery permits verification and quantification of treatment and offers new clinical strategies to many diseases, e.g., cardiovascular, oncologic, and rheumatologic pathology. Ligand-targeted perfluorocarbon nanoparticles represent a novel platform technology in this emerging field, providing molecular imaging for all relevant imaging modalities and vascular-targeted drug delivery across a broad disease spectrum.