In this paper, the application and effectivity of two procedures, electron paramagnetic resonance imaging (EPRI) and proton-electron double-resonance imaging (PEDRI), that have the capacity to depict distribution of exogenous, free radical based contrast agents in vivo. Both techniques employ electron paramagnetic resonance (EPR) to determine and render imaging of the free radical occurrence being studied. Currently, EPRI is confined to small animal studies. PEDRI utilizes conventional MRI methods and proffers excellent spatial resolution to EPRI. However, PEDRI needs high power EPR irradiation. PEDRI is being considered for imaging free radicals in humans.