Short name: PEG-APD (MnHA/PEG-APD), generic name: Manganese substituted hydroxylapatite, central moiety: Mn2+, relaxivity: r1=21.7, r2=26.9, B0=1.0 T
An intravascular MRI contrast agent under development (preclin.) for MR angiography.

The paramagnetic water-soluble metallofullerenes (Gd-fullerenols), which have strong T1 shortening effect, can be used as a novel core material of MRI contrast agents. Gadolinium endohedral metallofullerenes have been synthesized as polyhydroxyl forms (Gd@C82(OH)n, Gd-fullerenes) with the evaluation of their paramagnetic properties. The modification to the water-soluble forms is essential for the biomedical application of the metallofullerenes. The in vitro water proton relaxivity, R1 (the effect on 1/T1), of Gd-fullerenes is significantly higher (20-folds) than that of commercial MRI contrast agents - e.g. Gd-DTPA.

Short name: Mn(III)TPPS4, chemical compound: manganese(III) tetra-[4- sulfanatophenyl] porphyrin, central moiety: Mn2+, relaxivity: r1=7.5, r2=8.6
Manganese(III) TPPS4 is an agent under development (preclin. for MRI contrast medium) with tumor selective uptake for tumor detection and control.

See also Metalloporphyrins.

Short name: MION, central moiety: Fe3+/Fe2+, relaxivity: r1=3.7, r2=6.5, B0=0.47T
MIONs are under development (preclin.) as contrast agents (taken up by the RES) for MR angiography, MR lymphography, tumor detection and detection of infarctioned tissue. Also called monodisperse iron oxide nanoparticles or nanocompounds.

Omniscan® is a nonionic chelate complex with low osmolality used as a paramagnetic MRI contrast agent. The efficacy of Omniscan® is similar to that of Gd-DTPA. Omniscan® is given intravenously to enhance images of intracranial and spinal lesions where there is abnormal vascularity or an abnormal blood brain barrier. The complex does not cross an intact blood brain barrier so Omniscan® only accumulates in lesions such as neoplasm's and abscesses.

WARNING: NEPHROGENIC SYSTEMIC FIBROSIS Gadolinium-based contrast agents increase the risk for nephrogenic systemic fibrosis (NSF) in patients with acute or chronic severe renal insufficiency (glomerular filtration rate less than 30 mL/min/1.73m²), or acute renal insufficiency of any severity due to the hepato-renal syndrome or in the perioperative liver transplantation period.

See also Gadodiamide, and Classifications, Characteristics, etc.