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.