Description gadodiamide is a gadolinium based contrast agent used in mr imaging procedures to assist in the visualization of blood vessels.mechanism of action based on the behavior of protons when placed in a strong magnetic field, which is interpreted and transformed into images by magnetic resonance (mr) instruments. paramagnetic agents have unpaired electrons that generate a magnetic field about 700 times larger than the proton s field, thus disturbing the proton s local magnetic field. when the local magnetic field around a proton is disturbed, its relaxation process is altered. mr images are based on proton density and proton relaxation dynamics. mr instruments can record 2 different relaxation processes, the t1 (spin-lattice or longitudinal relaxation time) and the t2 (spin-spin or transverse relaxation time).