Authors: Martha Powell
Researchers from Charité–Universitätsmedizin Berlin (Germany) and the Max Delbrück Center for Molecular Medicine (Berlin, Germany) have examined the use of linear and macrocyclic MRI contrast agents in multiple sclerosis (MS) patients. The team demonstrated that deposits caused by repeated use of linear contrast agents could be reduced by utilizing alternative macrocyclic agents and have suggested that this discovery could improve future clinical practice.
The study, published recently in the Multiple Sclerosis Journal, examined contrast agents based on the rare earth element gadolinium. It has been reported in other patient groups that use of gadolinium-based MRI agents can lead to permanent deposits in the dentate nucleus. Although there is currently no evidence to suggest the accumulations pose a health risk, concern has built in light of recent findings.
The researchers examined a cohort of 97 MS patients who received MRI scans at pre-defined intervals independent of disease activity. Individuals suffering from MS have previously been excluded from studies investigating gadolinium-based contrast agents. However, as MS symptoms often present in young adulthood, consequently patients will undergo relatively large numbers of contrast-enhanced MRI scans in their lifetimes.
The participants were administered either gadopentetate dimeglumine, which is linear in structure, or gadobutrol, which is macrocyclic. The team observed that brain deposits in the dentate nucleus were associated with repeated use of the linear agent; however, there was no evidence of increased deposits with administration of the marcrocyclic agent.
Author Michael Scheel, from the Charité- Universitätsmedizin Berlin, commented: “Patients who received a different type of MRI contrast agent – one that is referred to as a macrocyclic contrast agent – showed no evidence of gadolinium brain deposition.
“Available data currently suggest that the risk of deposits is considerably higher with contrast agents that have a linear molecular structure. This effect appears to be absent, or much reduced, when using contrast agents with a ring-shaped, macrocyclic structure.”
This study is the first to examine the effects of MRI contrast agents in MS patients and to demonstrate that risk of gadolinium deposits is reduced with macrocyclic agents. The researchers suggest that neurologists and radiologists should take these findings into account in order to improve future clinical practice.
Sources: Schlemm L, Chien C, Bellmann-Strobl J et al. Gadopentetate but not gadobutrol accumulates in the dentate nucleus of multiple sclerosis patients. Mult Scler. doi:10.1177/1352458516670738 (2016) (Epub ahead of print); www.charite.de/en/service/press_reports/artikel/detail/multiple_sklerose_weniger_kontrastmittel_ablagerungen_im_gehirn/