What brain MRI scans tell us about gadolinium-based contrast agents

When researchers compared brain MRI scans of patients who had previously received gadobutrol, a common gadolinium-based contrast agent (GBCA), with patients not exposed to gadobutrol, they did not observe any visual signal intensity changes. The team noted, however, that patients who received gadobutrol had shorter T1 relaxation times of the globus pallidus.

Author Marc Saake, MD, of the Institute of Radiology at University Hospital Erlangen in Germany, and colleagues published their findings Jan. 1 in Radiology. The researchers started with 160 patients who had received gadobutrol, separating them into two groups: patients who had received at least five contrast-enhanced examinations and had normal kidney function (group 1) and patients who had received at least one contrast-enhanced examination and had impaired kidney function. Unenhanced brain MRI was then performed on each patient and another 60 participants who served as the control group. Some participants from the control group had normal kidney function (group 3) while some had impaired kidney function (group 4).

Overall, “neither visual signal alternations nor differences in signal intensity ratio or T2 mapping were found” in the patients in groups 1 and 2. However, those patients did exhibit shorter T1 relaxation times, and “an inverse correlation” between T1 times and the overall number of gadobutrol doses was observed in patients from group 1. No such correlations were noted for patients from group 2.

So, what does this mean in regards to the impact GBCAs have on patients?

“It is currently unclear whether the observed T1 relaxation time changes are an indicator for small amounts of gadolinium in the globus pallidus,” the authors wrote. But they did indicate that patients should be informed about “the possibility of subclinical gadobutrol brain retention” before undergoing such exams going forward.