In the June issue of the American Journal of Kidney Diseases, gadolinium-based contrasting agents used in MRIs was reported to increase the risk for Nephrogenic Systemic Fibrosis. It has been known for some months that there was a link between gadolinium exposure and NSF presenting itself in those with kidney failure. In fact, the U.S. Food and Drug Administration late 2007 issued a “black box”, the most severe warning, for any MRI contrasting products containing the agent. Dr. Alexander J. Kallen from the Centers for Disease Control and Prevention, Atlanta, and colleagues conducted a case-control study of 19 patients with NSF treated at a St. Louis hospital dialysis unit and 57 matched controls from the same unit. The authors reported that 14 patients with NSF had undergone an MRI with a gadolinium injection in the previous year that showed a median interval of 123 days from the gadolinium use in the MRI and the time the disease was detected. Four of the remaining five patients had gadolinium exposure between 16 and 68 months before diagnosis. The risk for NSF increased in steps from one MRI, two to three MRIs, or four or more MRIs, compared with controls. “Providers should carefully weigh both the benefits and potential harms of contrast MRI in their clinical decision making and avoid the use of gadolinium contrast agents if possible in patients with renal failure,” the authors concluded. “If gadolinium contrast is needed, clinicians should use the lowest possible dose and limit the number of future contrast administrations. The mechanism by which gadolinium contrast might cause NSF is unknown,” the researchers add.