What is the safest gadolinium-based contrast medium?

Mastering the art of balancing risks and benefits, according to Matthew Davenport, MD, from the University of Michigan, is what medicine is all about. When anecdotes about gadolinium-based contrast media agents allegedly poisoning patients became increasingly mainstream, its use in imaging procedures like MRIs has been questioned by the medical community.  

In a recent editorial in Radiology, Davenport discussed why so many agencies, such as the U.S. Food and Drug Administration and European Medicines Agency (EMA), differ in regulating the use of gadolinium-based contrast media.  

Over 70 percent of MRI examinations use a contrast material agent. Davenport believes that agencies differ in their regulation guidelines because of differing opinions about how to "regulate uncertainty" and "balance competing risks and benefits."

The risks of using gadolinium-based contrast agents outweigh the benefits, according to a table Davenport presents in his editorial. Six risks associated with using gadolinium-based contrast agents include "allergic like reaction, nephrogenic systemic fibrosis, gadolinium retention, cost, perception," and "historical inertia".  Benefits, on the other, hand include "relaxivity" and pharmacologic properties", according to Davenport. 

Throughout his editorial, Davenport refences a recent study by Ashkan Heshmatzadeh Behzadi, MD, (also published in Radiology) regarding whether agents differ in their risk for allergic-like reactions. This is another reason why Davenport believes that choosing the safest gadolinium-based contrast medium is "not so simple.” He claimed, unlike gadolinium retention, allergic reactions to the medium are more harmful.

According to the study by Behzadi, 3,000 to 4,000 more people may experience a life-threatening severe allergic-like reaction "in the hypothetical scenario of 100 percent macrocyclic use when compared with the hypothetical scenario of 100 percent gadodiamide use.”

"While Behzadi et al. have gone a long way in informing us how the risk and severity of allergic-like reactions can vary according to agent and agent type, we remain in a state of ignorance with respect to gadolinium retention and clinical harm," Davenport said. "Clarifying the risk of gadolinium retention in patients with normal or near-normal renal function is an urgent priority that must be pursued to better inform the decision-making process."