Study Highlights Important Safety Issue with Widely Used MRI Contrast Agents

In a study recently published in the journal Investigative Radiology, a major safety concern was highlighted regarding a class of MRI contrast agents used in millions of patients each year. The study adds to concerns that repeated use of specific “linear-type” gadolinium-based contrast agents (GBCAs) leads to deposits of the heavy metal element in the brain. During the study, researchers designed experiments in rats to assess the effects of repeated injections of GBCAs. Over the course of five weeks, one group of rats received a series of 20 injections with gadodiamide, one of a class of agents known as “linear” GBCAs. Another group of animals were injected with a different type of GBCA, the “macrocyclic” agent gadoterate meglumine. A third group of rats received an inactive saline solution. Over time, “significant and persistent” MRI abnormalities (called T1-weighted signal hyperintensities) developed in the brains of rats receiving the linear GBCA, gadodiamide. However, no MRI abnormalities appears in the brains of rats injected with the other agents. The increases in signal hyperintensity persisted even after the injections stopped. In subsequent examinations, high total gadolinium concentrations were measured in the cerebellum of gadodiamide-treated rats, corresponding to the area of the MRI abnormalities. The findings from this study are consistent with other studies reporting T1 hyperintensities in human patients receiving multiple injections of linear GBCAs for MRI scans. In addition to the effects on patient care, this study may have a major impact on the $300 million per year U.S. contrast-agent industry. To read more about this study, click here.