Gadolinium for MRI

Breast MRI Contrast Agent: Gadolinium
Malignant breast tumors begin to grow their own blood supply network once they reach a certain size; this is the only way the cancer can continue to grow. In a breast MRI scan, a contrast agent injected into the bloodstream can provide information about blood supply to the breast tissues; the agent "lights up" a tumor by highlighting its blood vessel network. Usually, several scans are taken: one before the contrast agent is injected and at least one after. The pre-contrast and post-contrast images are compared and areas of difference are highlighted. It is important to note that if the patient moves even slightly between the two scans, the shape or size of the image may be distorted--a big loss of information.
What is Gadolinium?
This is an FDA approved contrast agent for MRI. Gadolinium, or gadodiamide, provides greater contrast between normal tissue and abnormal tissue in the brain and body. Gadolinium looks clear like water and is non-radioactive. After it is injected into a vein, Gadolinium accumulates in the abnormal tissue that may be affecting the body or head. Gadolinium causes these abnormal areas to become very bright (enhanced) on the MRI. This makes it very easy to see. Gadolinium is then rapidly cleared from the body by the kidneys.
Does Gadolinium go by other names?
Gadolinium, gadolinium-DPTA, gadodiamide. It also goes by various brand names, depending on the pharmaceutical company that makes it:
Magnevist (Berlex Laboratories, Inc.)
Omniscan (Nycomed Amersham plc)
ProHance (Bracco Diagnostics, Inc.)
What does Gadolinium do?
Gadolinium allows the MRI to define abnormal tissue with greater clarity than ever before. Tumors enhance after Gadolinium is given. The exact size of the tumor and location are very important in treatment planning and follow up. Gadolinium is also helpful in finding small tumors by making them bright and easy to see.
Is Gadolinium safe?
Gadolinium has been used for years in adults and children in the United States, Europe and Japan, without any serious complications in thousands of patients. The FDA declared Gadolinium safe for use in MRI in 1988. A few side effects, such as mild headache, nausea and local burning can occur. Very rarely (less than one in a thousand), patients are allergic to Gadolinium. If you have kidney problems, it must be used with caution. Gadolinium should be used in pregnant patients or nursing mothers only when the benefits outweigh the risk. Gadolinium used in MRI is many times safer than the iodine type contrast used in CT scans. There is more information at the International MR Safety Central Web Site.
What are the side effects?
Side effects of the contrast agent injection include mild headache, nausea and local pain. Rarely (less than 1% of the time) low blood pressure and lightheadedness occurs. This can be treated immediately with intravenous fluids. Very rarely (less than one in one thousand), patients are allergic to the contrast agent. These effects are most commonly hives and itchy eyes, but more severe reactions have been seen which result in shortness of breath.
What about breast feeding?
According to Dr. Emanual Kanal of the International MR Safety Central Web Site: "More data are available for Magnevist than for the other agents. Magnevist is excreted in very low concentrations (i.e., 0.011% of the total dose) in human breast milk over approximately 33 hours. The concentration of this contrast agent in breast milk peaks at approximately 4.75 hours and decreases to less than a fifth of this level (to less than 1 micromol/L) 22 hours after injection. For this reason, and as an extra precaution, it is recommended that nursing mothers express their breasts and not breastfeed for 36 to 48 hours after administration of an MR imaging contrast agent, to ensure that the nursing child does not receive the drug in any appreciable quantity."
What about new contrast agents?
New contrast agents to improve breast MRI are currently being developed and studied in safety and efficacy clinical trials.