Researchers have confirmed that there is an association between a common MRI contrast agent and abnormalities found on brain MRI scans, according to a study published online in the journal Radiology.
The use of a gadolinium-based contrast medium (Gd-CM) is quite common because gadolinium's paramagnetic properties make it useful for MRI. However, the toxicity of the gadolinium ion means that it has to be chemically bonded with non-metal ions to make sure it can be carried through the kidneys and out of the body before the toxic ion is released in tissue.
Researchers led by Tomonori Kanda, M.D., Ph.D., from Teikyo University School of Medicine and the Hyogo Cancer Center I Akashi, Japan, saw evidence in patients who have undergone multiple administrations of Gd-CM of hyperintensity in two regions of the brain--the dentate nucleus (DN) and the globus pallidus (GP). Hyperintensity in the DN has been associated with multiple sclerosis, while in the GP it is associated with hypatic disfunctions.
In their study, the researchers compared 19 patients who had undergone six or more contrast-enhanced brain scans with 16 who had received six or more unenhanced brain scans. They found that the hyperintensity of both the DN and GP regions correlated with the number of GD-CM administrations.
"Hyperintensity in the DN and GP on unenhanced MRI may be a consequence of the number of previous Gd-CM administrations," Kanda said in an announcement. "Because gadolinium has a high signal intensity in the body, our data may suggest that the toxic gadolinium component remains in the body even in patients with normal renal function."
Kanda emphasized there is no proof that gadolinium is responsible for the hyperintensity seen on brain MRI, and said that further research based on autopsy specimens and animal studies will be needed to clarify the relationship between gadolinium and these brain abnormalities.