Ferristene is a superparamagnetic agent that has been used as a magnetic iron particle solution for gastrointestinal use as a negative contrast agent with 23.4 Fe/200ml required concentration.

See also Abdoscan®, Oral Contrast Agents.

See Ferucarbotran.

A substance, such as iron, that has a large positive magnetic susceptibility.

A contrast agent, which due to their ferromagnetism produce local field inhomogeneities and hence visible image alterations in the tissues where they are present. Therefore, they can act as contrast media. Usually, particles exhibiting superparamagnetism rather than ferromagnetism are used.

See also the related poll result: 'The development of contrast agents in MRI is'

Ferromagnetism is a phenomenon by which a material can exhibit a spontaneous magnetization: a net magnetic moment in the absence of an external magnetic field. More recently: a material is ferromagnetic, only if all of its magnetic ions add a positive contribution to the net magnetization (for differentiation to ferrimagnetic and antiferromagnetic materials). If some of the magnetic ions subtract from the net magnetization (if they are partially anti-aligned), then the material is ferrimagnetic. If the ions anti-align completely so as to have zero net magnetization, despite the magnetic ordering, then it is an antiferromagnet. All of these alignment effects only occur at temperatures below a certain critical temperature, called the Curie temperature (for ferromagnets and ferrimagnets) or the Néel temperature (for antiferromagnets). Typical ferromagnetic materials are iron, cobalt, and nickel.
In MRI ferromagnetic objects, even very small ones, as implants or incorporations distort the homogeneity of the main magnetic field and cause susceptibility artifacts.