MRI Health Risks May Extend Beyond MRI Contrast Agent

Halifax, NSThere is no question that Magnetic Resonance Imaging (MRI) is safer from a radiation standpoint than CT scan. In fact, MRI uses no radiation at all but rather a magnetic field to produce an image. The danger for some patients lies in the MRI contrast agent, which contains gadolinium, and which patients with kidney disease are unable to efficiently expel from their bodies. For these patients, MRI dialysis is vital.

Yet there are other MRI health risks. Witness the template for a consent form posted on the website of the Neuroethics New Emerging Team, a Canadian entity founded in 2003 that researches "different aspects of the legal and ethical issues raised by the paediatric use of Magnetic Resonance Imaging (MRI)."

Titled "Template Text for Potential Harms Section of MRI Research Consent Form," the document—which is effectively a screening form for potential study participants—outlines in specific detail what MRI is, together with the risks involved.

The risks primarily center on the magnetic field and what happens if there is any metal object in the scanning room within close proximity to the MRI machine, contained on the person being scanned, or imbedded in the patient internally.

External objects such as hair barrettes, rings and pendants are an obvious danger, and are easily removed prior to scanning. However, imbedded and implanted objects can also prove a hazard.

"The magnet may cause metal or implants inside your body (e.g. embedded metal filings, aneurysm clips) to heat up or move leading to potentially serious injury or death," the document says. "The magnet may also affect some electronic or magnetic devices (e.g., cardiac pacemakers). In some cases, having a particular device or implant means you should not have a MRI scan."

The document goes on to state that that there are no known long-term health risks from magnetic fields or radio waves from the MRI scanner. As for MRI contrast agent, the consent form notes that allergic reactions are rare but potentially life-threatening.

And under the heading "Pregnancy," the document states: "There is no evidence of injury or harm from MRI scans to the fetus. However, there may be risks to the fetus associated with MRI scanning during pregnancy that are unknown at this time."