“The worst disease caused by MRI contrast agents is nephrogenic systemic fibrosis,” said Dr. Brent Wagner, a professor in the Department of Internal Medicine at the University of New Mexico. This rare debilitating disease, with symptoms including swollen skin and stiffened, painful organs and joint contractures, has had fatal outcomes following administration of only a single dose of gadolinium-based contrast agents (GBCAs). Wagner’s blunt commentary highlights the significance of new findings that may challenge our assumptions about the safety of MRIs.
Rare earth metal gadolinium plays a key part of the success in diagnostic MRI scans. Its magnetic properties enable radiologists to create clear, nuanced images of internal structures. Due to its intrinsic toxicity, gadolinium is covalently conjugated to chelating molecules to be safely eliminated from the body. But accumulating evidence indicates that gadolinium particles remain in human tissues, including the brain, kidneys and bones, for years after exposure. This has prompted important questions surrounding why certain people experience stronger health effects than others.
Dr. Wagner and his colleagues are focusing on oxalic acid, a compound that occurs in some plant-based foods, including spinach, rhubarb, nuts and chocolate, that may trigger the formation of gadolinium nanoparticles. Their study in the journal Magnetic Resonance Imaging showed that oxalic acid can bind with gadolinium, that causes it to precipitate into nanoparticles. Those nanoparticles go on to penetrate cells in multiple organs, triggering inflammatory responses that can exacerbate disease symptoms.
The implications of this finding are enormous. In laboratory experiments, oxalic acid was found to yank gadolinium away from its chelating molecules, setting off the formation of these toxic nanoparticles. Wagner proposes that variations in individual metabolism may be a key factor influencing susceptibility. And “Some people might form these things, while others do not, and it may be their metabolic milieu,” Wagner said. Waste products lead to growth of particles, which due to food habits, genetic predisposition and existing medical conditions can continue to form and favor the growth of the nanoparticles.
This metabolic heterogeneity may also explains why almost half of nephrogenic systemic fibrosis patients had had only 1 exposure to gadolinium contrast agents. Wagner said, “Almost half of the patients had been exposed only a single time, which means that there’s something that is amplifying the disease signal.” The nanoparticles, he theorizes, could be signaling the body to sound alarms, provoking an overblown immune response.
The findings also point to potential preventive strategies. Wagner also recommends abstaining from vitamin C before MRI contrast, as it may react with gadolinium and accelerate nanoparticle formation. Wagner said: “I wouldn’t take vitamin C if I needed to have an MRI with contrast because of the reactivity of the metal,” This recommendation is simple but can go a long way in mitigating risks to patients who are undergoing MRI procedures.
The research team is now working to identify people at the highest risk. They are creating an international registry of patients to gather biological samples blood, urine, fingernails and hair to monitor gadolinium accumulation and its health effects. The registry seeks to determine the factors that predispose some patients to severe symptoms while others stay asymptomatic by studying medical histories, medication use and eating patterns.
These findings have important ramifications that go beyond personal health. Those words now confront the medical community to rethink the use of gadolinium-based contrast agents and consider safer alternatives. Although most people can tolerate gadolinium including the majority he sees, Wagner believes it’s imperative to understand why some do not.
With research ongoing, one can hope that improvements in this domain will result in technical standards surrounding journalists that lead to clinical guidelines prioritizing patient health and technological infrastructure maintaining patient safety. The many interactions like those covered between therapy agents and food compounds and oxalic acid show how one myth leads to the other. It also reinforces the need for ongoing best evidence to understand the long-term effects of medical procedures on health.
The results from the University of New Mexico are a significant step in cracking the code of gadolinium toxicity. They invite not just healthcare professionals and researchers, but also those concerned about their health, to rethink not just the benefits of MRI scans, but the risks that an innocent looking dietary choice may pose. The challenge to understand and address these risks will continue, providing safe, effective diagnostic tests for all.
