MRI contrast agents may accumulate in the brains of multiple sclerosis patients

Over the last few years, studies have shown that gadolinium-based contrast agents (GBCA), which are used routinely to enhance the contrast in magnetic resonance imaging, accumulate in specific regions of the human brain. Although there is currently no evidence of clinical adverse effects associated with this observation, doctors and patients are increasingly concerned about the long-term safety of GBCAs. Gadolinium deposition in the brain may be of  particularly  high  relevance  to  multiple sclerosis (MS)  patients: they are mostly young at the age of diagnosis with  a  long  life  expectancy  and  usually  receive  a  high  number  of  contrast-enhanced  scans  over  the  years. Despite these unique clinical characteristics, MS patients were excluded from most studies examining gadolinium deposition in the brain.

Scientists from Charité – Universitätsmedizin Berlin, the NeuroCure Clinical Research Center, and the Max Delbrueck Center for Molecular Medicine have now jointly investigated to what extent signs of gadolinium deposition can be found in the brains of MS patients after repeated GBCA administrations. The researchers studied two commonly used contrast agents with different molecular structures (one linear, one macrocyclic). In agreement with previous studies, they could demonstrate that patients with MS who received repeated administrations of the linear GBCA showed signs of gadolinium deposition in a specific nucleus of the cerebellum (dentate nucleus) similar to other patient groups. In patients who had received the macrocyclic contrast agent, on the other hand, they found no evidence of gadolinium deposition.

The authors draw the conclusion that the repeated use of GBCAs during contrast-enhanced MRI scans can lead to gadolinium deposition in the brains of MS patients. Considering the currently available scientific evidence and the results of the current study, contrast agents with linear molecular structure seem to be affected most. Contrast agents with a macrocyclic structure have been associated with cerebral gadolinium deposition to a much lesser extent. The scientists recommend that neurologists and radiologists involved in the care of MS patients take into account the results of the current study when deciding to use gadolinium-based contrast agents.

Link: https://www.ncbi.nlm.nih.gov/pubmed/27679460