Magnetic resonance imaging, or MRI, is a method of scanning the human body that provides clear, detailed pictures of organs and soft tissue. A contrast dye is sometimes used to enhance the quality of the scans, although most scans do not need it. The contrast makes it easier to see a tissue that is hard to detect. Common reasons for the use of these agents include a history of tumors, cancer, surgery, search for an inflammation or infection, and evaluation of blood vessels.
Common Side Effects
The most common, so called normal, side effects of MRI contrast agent are mild and temporary in nature. They include pain or burning at the injection site, low blood pressure, minor skin rash, mild headaches, changes in blood clotting, lightheadedness and nausea. Typically these side effects do not require any treatments. A study by the Mayo Clinic on contrast injections reported that 0.04 percent of the 450,000 patients who participated in the study reported side effects after being administered with a contrast agent for an MRI scan. The most frequently reported side effects were hives and nausea. Of the 450,000 patients that participated in the study, 19 had severe side effects requiring treatment and one person died.
Allergic reactions with contrast agents are not common. Dr. Jonathan R. Dillman and colleagues from the University of Michigan studied 78,353 patients who had gone through MRI scans with contrast agent and reported that only 54 of them had had acute allergic reactions. This study was published in the "American Journal of Roentgenology" in December 2008. Patients who are allergic to other contrast dyes, iodine or shellfish might develop such reactions. Usually allergic reactions develop soon after the contrast has been injected. The most common allergic reaction symptoms to MRI contrast agents include hives, swelling of the face, rashes, itching, sweating, watery or itchy eyes, and shortness of breath. Frequently, the reactions are mild and can be controlled with medication, says Radiology Info. If left untreated, however, allergic reaction can become serious and even life threatening. The patient is advised to contact the doctor as soon as the allergic reactions appear.
Nephrogenic Systemic Fibrosis
The most serious side effect caused by MRI contrasts are attributed to gadolinium. The FDA reports that patients with renal failure and kidney diseases cannot filter the chemical dye quickly enough and it stays in the body. There it causes a serious medical condition called nephrogenic systemic fibrosis, or NSF, according to a study conducted by Dr. Thomas Grobner that was published in "Nephrology Dialysis Transplantation" in January, 2006. NSF symptoms include hardened skin with red patches and are most commonly found in the limbs. Other frequent symptoms include muscle tightening, joint pain, yellow spots on the eyes, and internal organ dysfunction. This rare illness has no cure, but only affects patients with existing kidney problems injected with gadolinium. Patients who received other contrast dyes or those who do not suffer from kidney related problems did not get NSF. Four of the five approved gadolinium contrast agents linked to NSF include Omniscan, Multihance, Magnevist and OptiMARK, says the FDA.