Gadolinium based contrast agents, and magnetic imaging

What is a Gadolinium Based Contrast Agent?

Gadolinium is a silvery white rare earth metal of atomic weight 64. It has a metallic luster, and it is strongly magnetic. Unlike other rare earth elements, gadolinium is relatively stable in dry air. Gadolinium compounds and gadolinium-organic complexes in water solutions are used in MRI's and MRA's. Swallowed or injected intravenously, the Gadolinium Based Contrast Agents selectively absorbed by certain tissues, causing the tissues to show very brightly in magnetic resonance imaging. The use of gadolinium contrast agents enables radiologists to view organs and structures more clearly, and make more precise diagnoses.

Names of Gadolinium Based Contrast Agents and their manufacturers

Casey Gerry pharmaceutical lawyers have identified four pharmaceutical manufacturers who market Gadolinium Based Contrast Agents in the United States. The products and the companies are:

How Gadolinium Based Contrast Agents are used in Magnetic Resonance Imaging, MRI, and Magnetic Resonance Angiography, MRA

Contrast agents are used in many magnetic resonance imaging, MRI, studies in order to get the clearest possible image. Tissues and fluids that have absorbed a gadolinium contrast agent appear very bright on MRI images. This brighter image enables the radiologist to study the area of interest, and detect tumors, narrowing of arteries and other abnormalities. The first GBCA, Magnevist, sold by Bayer HealthCare Pharmaceuticals Inc, was approved for use in contrast MRI's by the Food and Drug Administration in 1988.

Magnetic resonance angiography, MRA, is the use of magnetic resonance technology to examine the interior of arteries. MRA studies allow the radiologist look for abnormalities such as aneurysms, weaknesses or thinning of the artery wall which creates the risk of the artery rupturing, or stenosis, a pathological narrowing of the vessel. In a MRA, a gadolinium based contrast agent is injected into the arteries to be examined. The blood absorbs the gadolinium, and appears very bright on the MRA image, so that stenoses, aneurysms and other abnormalities in the arterial walls are clearly seen.

Magnetic Resonance Angiography procedures require a far higher dose of gadolinium contrast agent than MRI's do. In its Public Alert in May 2007, the FDA noted that in magnetic resonance angiography, MRA, the administered dose of the GBCA may be up to three times higher than the approved dose for MRI.

None of the gadolinium based contrast agents used in MRI's are approved by the FDA for use in Magnetic Resonance Angiography. Despite the fact that they are not approved for this use, gadolinium based contrast agents are frequently used in MRA's, exposing patients to a significantly greater dose of gadolinium than the FDA has judged to be safe.

The FDA permits such "off-label" use of drugs by physicians when in the physician's clinical judgment the use is warranted. Federal law prohibits drug companies from promoting off-label uses of drugs. If the manufacturers of Gadolinium Based Contrast Agents or their agents have encouraged the use of their products for MRA's, this could be a violation of federal law.