The growing availability of new technology could allow doctors to monitor disease progression in Multiple Sclerosis (MS) patients without using gadolinium-based MRI contrast agents.
People with relapsing MS generally undergo MRI brain scans with gadolinium-based agents every six months to two years. But enhanced MRIs take longer and cost more, while repeated exposure to the toxic metal may increase the likelihood that a patient will retain gadolinium in their brain, tissue, and other organs.
Advances in non-contrast MRI image acquisition and post-processing technology, along with the increasing availability of powerful 3T MRI machines, recently raised the possibility that gadolinium-free MRIs could have a role in MS follow-up imaging.
To test this thesis, scientists at the Technische Universität München in Germany used a 3T MRI scanner to assess new or enlarged brain lesions in 359 MS patients. Both 3D MRI and subtraction maps were used to significantly improve the visualization achieved on the unenhanced scans.
Out of 507 follow-up images, 264 showed evidence of disease progression. A total of 1,992 new or enlarged lesions were also detected. According to the study authors, the gadolinium-free MRIs identified all cases of MS progression and missed just four of the lesions.
“Several vendors have made tools for generating subtraction images commercially available,” senior author Benedikt Wiestler, M.D., said in a statement announcing the study’s findings. “Implementing such tools into the routine clinical work flow will help to make the use of contrast agent dispensable in routine follow-up imaging of MS patients.”
The U.S. Food & Drug Administration (FDA) has approved eight gadolinium-based MRI agents for use in the United States:
In 2007, the agency warned that gadolinium-contrast dyes could cause debilitating disease called nephrogenic systemic fibrosis in people with pre-existing kidney disease. The agents have been contraindicated for this patient population ever since.
The FDA issued a new warning in December 2018, after several studies found that gadolinium could be retained in the body for months or years after an MRI, even in patients with normal kidney function.
Among other things, the agency noted that linear agents (Eovist, Magnevist, MultiHance, Ominiscan, and OptiMark) appeared to be associated with higher rates of gadolinium retention compared to their macrocylic counterparts (Dotarem, Gadavist, and Prohance). Doctors were subsequently advised to consider retention characteristics when choosing an MRI contrast dye for patients who may be at higher risk, including:
While the FDA has received reports of adverse events involving multiple organ systems in patients with normal renal function, it has yet to conclude that gadolinium retention caused any of the reported complications.
Nevertheless, a growing number of plaintiffs claim gadolinium-based MRIs did harm patients with healthy kidneys. According to their lawsuits, these individuals allegedly suffer from Gadolinium Deposition Disease, a debilitating disorder characterized by one or more of the following symptoms:
Plaintiffs further assert that the drugs’ manufacturers were aware for years that gadolinium deposits could remain in the body long after an MRI, but failed to warn doctors and patients about the risks potentially associated with their products.