alk about a study in contrasts.
On Tuesday, the Food and Drug Administration issued a warning about contrast agents used in MRI scans, over concerns they contain a potentially toxic metal that can be left in the brain tissue. But regulators elsewhere have been far tougher on the issue: Last week, the U.K. National Health Service suspended two agents over the same concerns. The European Medicines Agency, meanwhile, has suspended use of three agents. Last month, Japan also restricted usage of some agents.