As NSF Incidence Drops, Other Concerns Remain for Gadolinium-based MRI Contrast
Wednesday, Dec. 02, 2015
Even though the risk of nephrogenic systemic fibrosis (NSF) from gadolinium-based contrast agents (GBCA) used in MRI has largely been mitigated, radiologists still need to be aware of other potential issues with these commonly used agents, according to experts who spoke at a Tuesday Controversy Session.
NSF, a disease that involves progressive, severe fibrosis of the skin and other organs, was first linked to GBCA in 2006. Since then, various measures like lower doses of GBCA and pre-screening for kidney function have virtually eliminated the disease, said presenter Martin R. Prince, M.D., Ph.D., professor of radiology at Weill Cornell Medical College and Columbia University.
"The number of new cases has almost completely disappeared," he said. This change should not cause radiologists to become complacent about GBCA administration, according to Richard H. Cohan, M.D., from the University of Michigan Health System. Dr. Cohan discussed acute adverse reactions, a rare but potentially serious issue associated with GBCA that can include rashes, hives and nausea. For reasons unknown, some of the agents more likely to be associated with NSF are less likely to be associated with acute reactions, and GBCA package inserts are "confusing at best," Dr. Cohan said.
"We shouldn't forget that acute reactions occur and if they occur we have to be able to treat them," Dr. Cohan said.
Dr. Cohan recommended that radiologists review treatment algorithms for acute reactions at least once every six to nine months. Steroid pre-medication can reduce the likelihood of a reaction, he said, and may be useful in some patients with a history of reactions to GBCA.
The long-term effects of GBCA are under scrutiny in the wake of research from Japan earlier this year that found post-mortem evidence of gadolinium in the brains of people who had received multiple GBCA administrations.
"We've also found gadolinium in the bone and in skin samples," said presenter Emanuel Kanal, M.D., from the University of Pittsburgh Medical Center. "There are a bunch of studies going on in different countries on the clinical significance of this, and we should know more in the future."
While NSF only occurs in patients with impaired kidney function, gadolinium deposition has been found in people with normally functioning kidneys—a much larger group, considering the number of GBCA administrations worldwide every year.
"Now instead of a few hundred people we're talking about dozens of millions," Dr. Kanal said.
Dr. Kanal pointed out that the risk of gadolinium retention varies among the nine U.S. Food and Drug Administration-approved GBCAs. Radiologists should be aware of the differences and use the low-risk agents whenever possible—especially in pediatric patients.
NSF Draws Parallels with Contrast-induced Nephropathy
The evolution in understanding the risk of gadolinium-related NSF is similar to that of contrast-induced nephropathy (CIN), or decline in kidney function, in patients who receive iodinated contrast media for CT imaging, said presenter Matthew S. Davenport, M.D., from the University of Michigan Health System.
Dr. Davenport discussed how fears of CIN were initially overstated because a good working definition of the disorder was lacking. A renaissance in understanding took place through several large studies in the past 10 years.
"These studies showed that CIN is much less common than once believed," he said. "The vast majority of patients have little or no risk."
In cases where contrast is deemed necessary in patients with significantly impaired kidney function and MRI and CT are considered diagnostically equivalent, Dr. Davenport recommended CT for patients receiving chronic dialysis and a single dose of low-risk GBCA for those not on chronic dialysis.
"Consider informed consent if the patient is not on chronic dialysis, regardless of contrast type," Dr. Davenport said.