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A chemical injected before MRI scans to help create sharper images may cause some patients to experience a potentially deadly complication in rare cases, a new study suggests.
Researchers from the University of New Mexico found that gadolinium – a toxic rare earth metal used in MRI scans – could mix with oxalic acid found in many foods to precipitate tiny nanoparticles of the metal in human tissues.
The research, published in the journal Magnetic Resonance Imaging, assessed the formation of these nanoparticles associated with potentially deadly health problems in the kidneys and other organs.
Scientists say gadolinum-based contrast agents may cause nephrogenic systemic fibrosis, a rare condition leading to the thickening and hardening of the skin, heart, and lungs with painful contracture of the joints.
“People have succumbed after just a single dose,” said Brent Wagner, an author of the study from UNW.
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When injected, gadolinum tightly binds to other molecules and is excreted from the body, and most people experience no adverse effects, researchers say.
However, even in those without symptoms, the metal particles have been found in kidney and brain tissues, and has been detected in the blood and urine “years after exposure”, scientists say.
The latest study probed why some people get sick while most don’t and how gadolinium particles get pried loose from the other molecules in the contrast agent.
“This nanoparticle formation might explain a few things. It might explain why there’s such an amplification of the disease,” Dr Wagner said.
“When a cell is trying to deal with this alien metallic nanoparticle within it, it’s going to send out signals that tell the body to respond to it,” he said.
Scientists particularly probed the role of oxalic acid – found in many foods like tomatoes, spinach, nuts and berries – as the molecule binds with metal ions and is implicated in the formation of kidney stones.
Oxalic acid also forms in the body when people eat food or supplements containing vitamin C, researchers say.
They found that oxalic acid caused small amounts of gadolinium to precipitate out of the contrast agent and form nanoparticles that infiltrated the cells of various organs.
Some patients may be more susceptible to this kind of nanoparticle precipitation due to their metabolism, researchers say.
“It might be if they were in a high oxalic state or a state where molecules are more prone to linking to the gadolinium, leading to the formation of the nanoparticles,” Dr Wagner said.
“That might be why some individuals have such awful symptoms and this massive disease response, whereas other people are fine,” he explained.
Researchers suggest some ways to mitigate risks associated with MRI scans.
“I wouldn’t take vitamin C if I needed to have an MRI with contrast because of the reactivity of the metal,” Dr Wagner said.
“I’m hoping that we’re getting closer to some recommendations for helping these individuals,” he added.
