Researchers at the University of Buffalo have shown that gadolinium MRI contrast dyes can accumulate in the brain when administered to patients in the early stages of multiple sclerosis, or MS.
While the gadolinium deposits did not appear to correlate with any discernable clinical impact, the findings suggested the most frequently exposed patients experienced more severe disease progression.
Gadolinium MRI contrast dyes are used to enhance the appearance of tissue, blood vessels, organs, and other images that appear on a scan.
For years, gadolinium agents have been contraindicated for patients with impaired kidney function, as their inability to eliminate the toxic heavy metal can cause a potentially deadly disease called Nephrogenic Systemic Fibrosis, or NSF. Until recently, however, gadolinium retention was not considered a concern for patients with healthy kidneys.
In December 2017, the U.S. Food & Drug Administration (FDA) warned of mounting scientific evidence suggesting that gadolinium deposits can remain in the brain, tissue, organs, and skin, for months or years after an MRI, even in the absence of kidney problems. 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).
Pathological skin changes and adverse events involving multiple organ systems have also been reported in patients with normal renal function following the administration of gadolinium contrast dyes. While the FDA hasn’t concluded that a direct link exists between gadolinium deposits and the reported complications, the agency did order contrast dye manufacturers to conduct post-market studies to better evaluate the products’ safety and effectiveness.
Because of blood-brain barrier disruption that can be characteristic of the disease, it’s possible that MS patients may be more vulnerable to gadolinium retention.
This latest study followed 203 patients from the time of their MS diagnosis for an average of five years. Each received identical doses of Ominiscan at the same MRI machine at Buffalo General Medical Center. Their scans were then compared to those obtained from 262 health controls.
The results showed similar gadolinium deposits in MS patients who had between five and eight doses, while patients with fewer than five doses behaved similarly to healthy controls. At the same time, nearly 9% of MS patients who received fewer than 5 doses did have hyperintensity in the dentate nucleus, a part of the brain involved in voluntary motor function and cognition that’s often affected by MS. This was not observed in any of the healthy controls.
According to the study authors, there was no correlation between gadolinium deposits and clinical or MRI outcomes, such as an accumulation of lesions, brain atrophy, or MS severity, at least in the first five years of the disease. However, patients who received more than 8 gadolinium doses did have more brain lesions and more advanced atrophy of grey compared to those who received fewer doses.
For that reason, they could not completely rule out the possibility that gadolinium deposits might impact MS disease progression or severity.