There are some cases during an MRI that require the injection of a contrast agent into the patient. An MRI contrast agent (or dye) is a substance that is more susceptible to magnetic fields that occur during scanning and therefore produces a better image. Of the different contrast dyes, gadolinium is the best known.
Gadolinium is a metal with very strong paramagnetic properties. In other words, it lines up very easily with an external magnetic field, allowing the MRI to scan your body much more efficiently. Gadolinium can be very lethal to humans as an ion, so for its use to be safe it must go through chelation, a process that will bind gadolinium to other molecular compounds. There are currently five FDA-approved gadolinium contrast agents:
– Magnevista
– Omniscan
– OptiMARK
– MultiHance
– ProHance
Fortunately, under most circumstances, there is no potential danger from having gadolinium injected. The concentrations are kept low to avoid side effects and the kidneys will be able to remove the dye in time.
The real problem is for people who do not have properly functioning kidneys. There is evidence linking gadolinium contrast agents to the cause of NSF or nephrogenic systemic fibrosis. NSF is a life-threatening disease that causes fibrous tissue to overgrow. Consequently, your skin can become very tight and painful and your joint mobility can become extremely limited. If your kidneys cannot purge the dye from your body, you are at great risk for NSF.
