Generic name: Liposomes, central moiety: different, contrast effect: paramagnetic, distribution: different
Liposomes are lipid containing nanoparticles, or fat molecules, surrounding a water core. Liposomes were the first type of nanoparticles created to be used as carriers for lipophilic MRI contrast agents with novel characteristics.
Liposomes loaded with gadolinium-containing chelates have potential as blood pool agents, caused by modifications of the surface (e.g., with polyethylene glycol) leading to longer blood retention times.
The incorporation of contrast agents into either the the bilayer membrane or the aqueous inner cavity is possible. These MRI contrast agents has been used to image the lymph nodes using liposomes containing Gd-DTPA as well as dextran coated iron oxide particles.
To image the liver or the hepatobiliary system, liposomes containing Gd-HPDO3A, or MnDPDP, have been tested.
Liposomes containing gadolinium were conjugated to antibodies and targeted to a specific organ system.
A method of targeting tumors with ultrasound that also uses MRI to watch the cell destroying, uses liposomes loaded with cytotoxic drugs and also with gadolinium to make them show up in MRI. As well as used as an imaging technique, ultrasound can also be used to destroy cancer cells. Once the drugs have been administered, focusing the ultrasound on the target area makes blood vessels permeable. The liposomes leak out of the blood vessel into the target area, watched by MRI, where the cytotoxic drug can then go to work.

See also Memosomes, Superparamagnetic Iron Oxide, Classifications, Characteristics, etc. and Mangafodipir Trisodium.