Short name: Mn-DPDP
This MRI contrast agent is a chelate complex of the paramagnetic metal ion manganese (Mn) and fodipir. Mn-DPDP (Teslascan) shortens the longitudinal relaxation time and is used for the T1 weighted enhancement of MR images. Mangafodipir trisodium accumulates after intravenous injection in the healthy tissue of the liver and improves the detection, localization, characterization, and evaluation of lesions of the liver, pancreas, but can also be used in cardiac MRI.
See also Hepatobiliary Chelates and Teslascan®.
The United States Food and Drug Administration (FDA) has granted marketing clearance 1997, to Nycomed Amersham's MRI contrast medium. Nycomed/Amersham, now GE Healthcare markets the product under the trade name Teslascan®.

(Mn-DPDP) This agent, mangafodipir trisodium, is a hepatocyte specific MRI contrast agent. Manganese is very toxic, so it has to be chelated and put in the form of a vitamin B6 analog, which is taken up by normal hepatocytes to some extent.
Teslascan® was developed in the early 1980's, went through clinical trials in the early 1990's, and was approved in 1997. One problem with assessing the efficacy of this agent is the fact that the phase III trials finished in the early 1990's, and the techniques used for MR today are very different from the techniques used almost a decade ago.
This contrast agent shortens the T1 relaxation time. On T1 weighted pictures it makes a normal liver look brighter. Since metastases, for example, do not generally take up this agent, the contrast between the enhancing liver and the non-enhancing lesions will increase on T1 weighted pictures. It does not have much effect on T2 weighted images.

Contrast agents are chemical substances introduced to the anatomical or functional region being imaged, to increase the differences between different tissues or between normal and abnormal tissue, by altering the relaxation times. MRI contrast agents are classified by the different changes in relaxation times after their injection.
The design objectives for the next generation of MR contrast agents will likely focus on prolonging intravascular retention, improving tissue targeting, and accessing new contrast mechanisms. Macromolecular paramagnetic contrast agents are being tested worldwide. Preclinical data shows that these agents demonstrate great promise for improving the quality of MR angiography, and in quantificating capillary permeability and myocardial perfusion.
Ultrasmall superparamagnetic iron oxide (USPIO) particles have been evaluated in multicenter clinical trials for lymph node MR imaging and MR angiography, with the clinical impact under discussion. In addition, a wide variety of vector and carrier molecules, including antibodies, peptides, proteins, polysaccharides, liposomes, and cells have been developed to deliver magnetic labels to specific sites. Technical advances in MR imaging will further increase the efficacy and necessity of tissue-specific MRI contrast agents.

See also Adverse Reaction and Nephrogenic Systemic Fibrosis.

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

Hepatobiliary chelates used in MRI are paramagnetic contrast agents consisting of a metal ion bound to an organic ligand. Paramagnetic metal ions such as gadolinium improve the MRI signal, but the toxicity of these uncomplexed metal ions makes the use of a chelate to bind the metal ion essential. Due to the hepatocyte uptake of this chelate complex, the different contrast between normal parenchyma and liver lesions improves the detection and characterization of specific diseases. In addition, the hepatobiliary excretion allows the assessment of the hepatobiliary system.
Chelates for hepatobiliary imaging: MultiHance® (Gadobenate Dimeglumine), Teslascan® (Mangafodipir Trisodium), Gd-HIDA, Cr-HIDA, and Fe-EHPG IronIII or other derivatives.

See also Hepatobiliary Contrast Agents, Liver Imaging.

Contrast agent with a preferential intracellular distribution.
Intracellular agents (such as manganese derivatives and ultrasmall superparamagnetic iron oxide), exhibit a flow- and metabolism-dependent uptake. These properties may allow delayed imaging, similar to isotopic methods.
Phospholipid liposomes are rapidly sequestered by the cells in the reticuloendothelial system (RES), primarily in the liver. For imaging of the liver, liposomes may be labeled with MR contrast medium, both positive (T1-shortening) paramagnetic media, and negative (T2-shortening) superparamagnetic media.
Several other nonliposome MR contrast media are also taken up by the RES, e.g.:
Other MR contrast agents accumulate selectively in the hepatocytes, e.g.: