MRI

Left in the Brain: Potentially Toxic Residue from MRI Drugs by Jeff Gerth

With a family history of breast cancer, Marcie Jacobs decided in June 2001 that an MRI screening was her best preventive option.

As is common with MRIs, Jacobs was injected beforehand with a contrast agent, a drug that helps sharpen the resulting images. But after a few of these treatments, she began noticing some strange cognitive effects. Jacobs began missing meetings. Over the next several years she had additional MRIs. The math skills that were crucial to her job as finance manager started deteriorating, she said.

Jacobs eventually wound up on disability. She stopped worrying about cancer – and started worrying about imaging drugs.

This month, two prominent experts in the radiology community joined in the concern, calling for more research [3] into the possible health risks after three recent studies found that gadolinium, a potentially toxic metal, wound up in the brain tissue of MRI patients who used two different contrast agents.

Editorializing in the journal “Radiology,” Dr. Emanuel Kanal at the University of Pittsburgh Medical Center, and Michael Tweedle at Ohio State University, said the studies “called into question” the “safety of at least some” of these agents. The two urged radiologists to change their prescribing habits, although not to stop using the drugs because of their proven benefits to patients. (Related video [4].)

Nine gadolinium-based contrast agents are sold in the United States. The two in question, Omniscan, made by GE Healthcare, and Magnevist, manufactured by Bayer HealthCare, once dominated the contrast agent market. Both GE and Bayer, in statements, said they were monitoring the issue and noted the new studies had not found any clinical impact, such as brain injury.

As ProPublica has reported [5], contrast agents like Omniscan had been on the market for years when, in 2006, they were linked to a crippling, sometimes fatal condition called nephrogenic systemic fibrosis, or NSF. The Food and Drug Administration put a “black box” warning on the drugs the following year, saying patients with kidney impairment may be at risk of NSF because they were unable to excrete the gadolinium.

ProPublica first disclosed in 2009 that the agency ignored two of its own medical reviewers who wanted to ban Omniscan for patients with severe kidney disease. In 2010, the FDA did act, [6] recommending that GE’s drug and two other agents shouldn’t be used in patients with impaired kidneys. The other drugs were Magnevist and Optimark, sold by Mallinckrodt Pharmaceuticals.

The new studies cited by Kanal and Tweedle have set off alarms because they show that even patients with healthy kidneys are retaining gadolinium from Omniscan and Magnevist. Estimates are that about one-third of the 20 million MRIs in the United States each year use one of the nine contrast agents.

Read more