Methods for imaging a target
cell, tissue, or organ in a subject. In some embodiments, the methods include the steps of (a) administering to the subject a contrast agent that includes a paramagnetic or superparagmanetic material and a targeting
moiety that targets the contrast agent to the
cell, tissue, or organ; (b) introducing into the target
cell, tissue, or organ, or into the vicinity thereof, a hyperpolarized gas; and (c) imaging the target cell, tissue, or organ by detecting the presence of the contrast agent in, on, or near the target cell, tissue, or organ. Also provided are methods for screening for
metastasis of a tumor and / or a
cancer to the
lung of a subject, methods for imaging a cavity in a subject, methods for imaging a target cell, tissue, or organ in a cavity, compositions for performing the disclosed methods, and systems and kits that include the disclosed compositions and / or reagents for performing the disclosed methods.