A contrast agent adapted for magnetic resonance imaging of a sample, the contrast agent comprising a suspension in a medium acceptable for magnetic resonance imaging of (a) coated particles of a contrast agent possessing paramagnetic characteristics and (b) coated particles of a contrast agent possessing diamagnetic characteristics, each of the coatings being selected from a group of materials which [I] renders the coated particles (a) and (b) substantially comparable with and substantially biologically and substantially chemically inert to each other and the environments to which the contrast agent is exposed during magnetic resonance imaging and [II] which substantially stabilizes the suspension; the nature of each of the coatings and the relative amounts of (a) and (b) in the suspension being such that the positive magnetic susceptibility of (a) substantially offsets the negative magnetic susceptibility of (b) and the resulting suspension has substantially zero magnetic susceptibility and, when employed in magnetic resonance imaging, results in the substantial elimination of imaging artifacts. Also disclosed is a method of imaging a sample which comprises introducing into the sample the above-described contrast agent and generating an image thereof.
展开▼
