The ability of magnetic compounds to increase the relaxation rates of the surrounding water proton spins.
Relaxivity is used to improve the contrast of the image, and to study tissue specific areas where the contrast agent better diffuses or to perform functional magnetic resonance imaging.
The relaxivity of MRI contrast agents depends on the molecular structure and kinetic of the complex. To increase the number of water molecules that are in the inner sphere of the complex, or to slow down the molecular rotational correlation time, are possibilities to improve the water relaxivity.
Relaxivity units (r1, r2) are mM-1 * sec-1 (at varying temperatures).

Resovist® is an organ-specific MRI contrast agent, used for the detection and characterization of especially small focal liver lesions.
Resovist® consists of superparamagnetic iron oxide (SPIO) nanoparticles coated with carboxydextran, which are accumulated by phagocytosis in cells of the reticuloendothelial system (RES) of the liver. The uptake of Resovist® Injection in the reticuloendothelial cells results in a decrease of the signal intensity of normal liver parenchyma on both T2- and T1 weighted images.
Most malignant liver tumors do not contain RES cells and therefore do not uptake the iron particles. The resulting imaging effect is an improved contrast between the tumor (bright) and the surrounding tissue (dark).
Resovist® can be injected as an intravenous bolus, which allows immediate imaging of the liver and reduces the overall examination time. A dynamic imaging strategy after bolus injection supports to characterize lesions. In comprehensive clinical trials, it demonstrated an excellent safety profile.
In 2001, Resovist® was approved for the European market.

See also Superparamagnetic Iron Oxide.

Resovist® competed with Primovist™, the other liver imaging agent of Bayer Schering Pharma AG. Due to this reason, the production of Resovist® has been abandoned in 2009.

From GE Healthcare;
three dedicated MRI systems - a neuro imager, a cardiovascular system, and a whole body scanner - all in one system.

From GE Healthcare;
'EXCITE technology has the potential to open the door to new imaging techniques and clinical applications, leaping beyond conventional two and three-dimensional MRI to true 4D imaging that will improve the diagnosis of disease throughout the human body from head to foot.' Robert R. Edelman, M.D., Professor of Radiology at Northwestern University Medical School and Chairman, Department of Radiology, at Evanston Northwestern Healthcare.

From GE Healthcare;
a friendly and less confining appearance targets the 7% of individuals who refuse to have an MRI because of claustrophobia. This open MRI system is also up to three times faster than other scanners, therefore the Signa OpenSpeedâ„¢ reducing exam time and scheduling issues. In addition, a swing table provides better access and supports up to 500 pounds.