An MRI, or a magnetic resonance imaging scan, is a medical diagnostic tool used by doctors to image the internal organs and tissues of a patient. Unlike an X-ray, which can only image bones and other very dense tissues, an MRI can give doctors a detailed image of organs and other soft tissues. Doctors typically use MRI scans to diagnose a patient when other diagnostic techniques are not enough to come to a conclusion.
To get an image of tissues with an MRI machine, a patient must be given what is called a contrast agent, like Omniscan or Magnevist. This is a chemical that gives improves the visibility of organs and gives a clearer, more detailed picture. While these agents can help doctors make a better diagnosis, they can also cause side effects. More seriously, recent studies have shown that these agents may even leave a toxic residue in the brain and cause significant cognitive side effects.
What is an MRI?
An MRI scan is an image created using a large machine. MRI stands for magnetic resonance imaging and this imaging technique uses a large magnet and radio waves to create the image of the inside of the body. An MRI machine is a large, circular magnet. To be imaged, you must lie inside that magnet where a magnetic field is then applied along with radio waves to alter the positions of hydrogen atoms in the body. This movement gives off signals that can be used to create an image. Images from an MRI scan are produced in slices.
The Role of Contrast Agents
Not all MRI scans require a contrast agent, but many do. The agent is injected into the bloodstream of the patient through an intravenous line. The agent alters the signals that are produced in the body during the scan and provide better contrast and clearer images for the doctor to see. With a clearer picture, a doctor can see more details and may be able to make a better diagnosis.
Gadolinium-Based Contrast Agents (GBCAs)
The most commonly used contrast agents in MRI scanning are those that contain the element gadolinium. Gadolinium is a heavy metal and is known to be toxic. The risks of its toxicity have been balanced against the benefits of being able to see more detail in an MRI scan when it is used as a contrast agent.
The smaller the structures that need to be imaged, like tiny blood vessels, the more of the contrast agent must be injected prior to the scan. GBCAs are commonly used to scan blood vessels in an imaging technique called magnetic resonance angiography, or MRA. The U.S. Food and Drug Administration (FDA) approved GBCAs, like Omniscan and Magnevist, for MRIs, but not for MRAs. Doctors use them off-label for MRAs.
Two of the commonly used GBCAs, both of which are approved by the FDA, are gadiodiamide (Omniscan) and gadiopentate (Magnevist). Omniscan is made by General Electric’s GE Health care and Magnevist is made by Bayer. Magnevist is the earliest GBCA, first approved in 1987, and is still in use.
Not everyone will experience adverse reactions to GBCAs, but they are possible. Side effects of using Omniscan can include blurry vision, chest pains, confusion, bloody stools, dizziness, a changed heartbeat, fatigue, difficulty breathing, a cough, headaches, sweating, shivering, seizures, trembling, vomiting, and changes in skin color.
Magnevist may cause wheezing, sweating, cold- or flu-like symptoms, fatigue, swelling, irritated eyes, itchy skin, nervousness, nausea, seizures, chills, blurred vision, hives, trouble breathing, confusion, jaw, back, or arm pain, chest pains, headaches, loss of bladder control, and an irregular heartbeat.
Nephrogenic Systemic Fibrosis
In addition to the many possible side effects, GBCAs have been found to cause other, more serious conditions. The FDA issued a warning in 2007 that there is evidence GBCAs may cause nephrogenic systemic fibrosis (NSF). The risk is serious enough that the FDA has required that manufacturers include a boxed warning on the labels of their GBCAs.
NSF is a condition that causes fibrosis, or excessive formation of connective tissue, in the skin, eyes, joints, and internal organs. This condition is rare and was only first described in 1997 and is not well understood. It seems to be related to the kidneys, kidney damage, and dialysis. The FDA warns that those most at risk for NSF when using GBCAs are those with kidney disease or damage.
Gadolinium in the Brain
A major new concern with GBCAs, including Omniscan and Magnevist, is the possibility that gadolinium is getting into the brain, accumulating there, and causing damage. The FDA announced in 2015 that the agency would be investigating reports that GBCAs have caused neurological damage and symptoms. These include confusion, changes in mood, speech disorders, seizures, and even coma.
The FDA began investigating this because several studies reported in journals found that patients receiving four or more MRIs with GBCAs were found to have deposits of gadolinium in the brain. Currently the FDA is not requiring manufacturers to change their labels in any way, but the ongoing study may find that these accumulations of toxic metal are causing damage and harm. The continuing research will look into how gadolinium is escaping the GBCA and getting to the brain and how it could be better contained.
Lawsuits against manufacturers of GBCAs, like Omniscan and Magnevist, have been filed by patients who developed NSF after MRI scans. Some have been settled, but others are still pending. What may become even more common in the years to follow are lawsuits regarding the damage that these agents have done to the brains of patients receiving multiple MRI scans.
The type of brain damage that gadolinium may be causing in patients because of GBCAs can cause life-altering consequences. No one yet knows just how damaging this toxic metal could be, but time will tell. If you have been harmed by the use of GBCAs in MRI scans, you too could file a lawsuit against GE Healthcare, Bayer, or others. Let a lawyer guide you and help you determine your options.