Macromolecular Gd labeled albumins are a new class of contrast agents with a wide range of use e.g., MR angiography, breast MRI, perfusion MRI, Lung perfusion, etc.
Marketed gadolinium-based albumin-bound contrast media are e.g., MultiHance®, and Vasovist™; other prototypes are in development. Malignant tumors often show an increased uptake and metabolism of plasma proteins, especially albumin. Contrast agents with large molecules are delivered to all tissues, but only accumulate in those with leaky vessels by tumor capillaries (tumor neovessels). MRI tumor perfusion studies with Gd labeled albumin can show the success of tumor therapy by quantitative decrease in MR signal of the malignant tissue after therapy compared to before. In addition, the study of tumor sensitivity to a therapy with drug-labeled albumins seems possible.
After renal transplantation, MRI may diagnose albuminuria caused by glomerular disease with an albumin-bound blood pool contrast agent

See also Blood Pool Agents, Intravascular Contrast Agents, Contrast Enhanced MRI.

See Blood Pool Agents.

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.

MS-325 is the formerly code name of gadofosveset trisodium (new trade name Vasovist). MS-325 belongs to a new class of blood pool agents for magnetic resonance angiography (MRA) to diagnose vascular disease. Gadofosveset trisodium has ten times the signal-enhancing power of existing contrast agents as well as prolonged retention in the blood. This enables the rapid acquisition of high resolution MRA's using standard MRI machines.
Gadofosveset trisodium, which is gadolinium-based, stays in the blood stream as a result of transient binding to albumin. Albumin binding offers an additional benefit beyond localization in the blood pool. The contrast agent begins to spin much more slowly, at the rate albumin spins, causing a relaxivity gain that produces a substantially brighter signal than would be possible with freely circulating gadolinium. MS-325 is an intravascular contrast agent intended for use in MRI as an aid in diagnosing aortoiliac occlusive disease in patients with known or suspected peripheral vascular disease (PVD) or abdominal aortic aneurysm (AAA).
Currently clinical trials completed for peripheral vascular disease and coronary artery disease. Additional trials are also being conducted to evaluate MS-325 as an aid in diagnosing breast cancer and suggested that it might be feasible to combine the use of MS-325, injected during peak stress, with delayed high-resolution imaging to identify myocardial perfusion defects.
Vasovist (MS-325) would compete with the contrast agents Ferumoxytol (Code 7228) from AMAG Pharmaceuticals, Inc. and NC100150 Injection from Nycomed Amersham, but their further development is uncertain.
Partners in development: EPIX Pharmaceuticals, Inc., Mallinckrodt Inc., and Bayer Schering Pharma AG. Bayer Schering Pharma has the worldwide marketing rights for the product.
Formerly known under the Mallinckrodt trademark name, AngioMARK®.

See also Classifications, Characteristics, etc.

Short name: P717, generic name: Gd-DOTA-dextran, central moiety: Gd
A Gd-DOTA-dextran derivative slow-clearance blood pool agent (MRI contrast agent) under development (preclin., Guerbet SA).