Superparamagnetic particles as an MRI contrast agent for the gastrointestinal tract.

Non-biodegradable superparamagnetic particles containing magnetite were evaluated as a potential contrast agent for the gastrointestinal tract. The particles were administered to pigs perorally either suspended in water or mixed with food. The gastrointestinal tract structures were excellently depicted through a lowered signal intensity of their content in both T1 and T2 weighted images. Relatively large volumes with low particle concentration seemed to give a good contrast agent distribution, especially when the administration was extended over a period of time. Problems with artefacts and blurring in the images caused by a too high local concentration of the contrast agent should also be minimized by using low particle concentrations.