Wednesday, September 29, 2010

Your MRI - A Hidden Danger

The FDA recently announced that it was requiring new warnings about the use of gadolinium contrast agents (dyes) used in MRI scans. Gadolinium has been conclusively connected with a rare, potentially fatal kidney condition called NSF (Nephrogenic Systemic Fibrosis). The named contrast agents most often linked to NSF are: Magnevist, Omniscan, and Optimark.

NSF is a progressive thickening of the skin's connective tissue: it can eventually affect the joints, eyes, and, most seriously, the internal organs. Patients experience tightening and hardening of the skin, with dark or reddened patches. The disease can lead to joint contracture, preventing normal movement; if it affects the internal organs, it can be fatal.

Breast cancer patients routinely undergo yearly breast MRIs in addition to our regular screening mammograms. The MRI visualizes the breast tissue without using radiation, and it can detect abnormalities which a mammography cannot. Using both of these methods provides a more comprehensive evaluation.

The MRI consists of 2 phases: a non-contrast phase, which happens first; then, the contrast phase, where an IV of saline mixed with gadolinium is administered; this provides an enhanced level of imaging.

Following the MRI, patients are advised to drink a large amount of water in order to flush the gadolinium out of their body. The added fluid lessens the chemical's impact on the kidneys, as gadolinium is a toxic substance.

Patients who have kidney disease or who are at risk for reduced kidney function should have only a non-contrast MRI, or have their physician explore non-contrast-based imaging options, due to their high risk of developing NSF.

Any patient who is experiencing a lessened ability to eliminate drugs from their system should have their kidney function evaluated prior to having a MRI using contrast.

Most patients needing a contrast MRI will have the capacity to eliminate the gadolinium from their system rapidly by drinking more water for a day or so. But, if there is any question of impaired kidney function, patients should consult with their physician before undergoing this type of imaging.

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