MRI Contrast Agents: Are they Safe?

Washington, DCPatients with renal insufficiency (chronic kidney disease or acute kidney injury) have been warned of MRI Health Risks, namely nephrogenic systemic fibrosis (NSF) following exposure to gadolinium based MRI contrast agents (GBMCA). Experts have also advised physicians who order MRI scans for patients that the risk of NSF depends on the degree of renal dysfunction, dose of contrast agent, gadolinium contrast agent stability and severity of concomitant illness.

The Journal of Urology (2008 Sep;180(3):830-5) reported an investigation by the Division of Nephrology, Vanderbilt University Medical Center. "Magnetic resonance imaging using gadolinium based contrast agents must be performed judiciously in patients with renal dysfunction, carefully weighing on a case by case basis the benefits of magnetic resonance imaging and the risk of nephrogenic systemic fibrosis as well as the disadvantages of undergoing alternative or foregoing imaging studies," said writers G. Bhave, J. B. Lewis and S.S. Chang.

Their data from case series reports, nephrogenic systemic fibrosis patient databases, nephrogenic systemic fibrosis case reporting to the FDA after gadolinium contrast agent exposure and retrospective case control studies also showed that occurrence of NSF after gadolinium contrast agent exposure "may vary from negligible up to 2 percent to 5 percent in select high risk clinical situations".

This report is cause for concern for patients who have even moderate renal insufficiency (60< GFR >30). NSF symptoms are known to develop within weeks to months after exposure to GBMCA, however there can also be a latency period from 1 to 2 years. Patients with any degree of renal insufficiency who have received gadolinium in the past few years are advised to receive close follow-up. The experts concluded that "Further research needs to be directed to finding agents that will stabilize gadolinium and make MRI imaging safe even in patients with CKD" {chronic kidney disease].

Is Magnetic Resonance Imaging (MRI) Safe?

MRI or MRA procedures are safe; the risk of developing NSF is associated with exposure (injected into the bloodstream) to gadolinium, which is in the contrast agent or dye. Some contrast agents do not contain gadolinium, i.e., Feridex I.V. and Teslascan, but they are only FDA-approved to evaluate lesions of the liver. Since June 1988, the FDA approved 5 gadolinium-based contrast agents (GBCAs) in the US: Magnevist; ProHance; Omniscan; OptiMARK; and MultiHance.

MRA and Gadolinium Off-label Use

Gadolinium-based contrast agents are also used with magnetic resonance angiography (MRA), an imaging procedure used to evaluate blood vessels. However, it is only used off-label: the FDA has not approved GBCAs for use with MRA procedures. As well, up to 3 times as much contrast dye is used with MRAs compared with MRIs, which could potentially cause serious risk of NSF for patients getting an MRA.