Is Iodine Safer than Gadolinium in the Renal Impaired Patient?

Posted 12:20 PM, March 7, 2007, by jaruiz

By Bob Herfkens, MD

Why nephrogenic systemic fibrosis (NSF) occurs in some patients who receive gadolinium-based contrast agents for MR imaging is still a mystery. First recognized in 1997, NSF is a rare disease occurring in renal insufficiency that causes a thickening of the skin as well as the muscles and vital organs. In the summer of 2006, NSF was linked to the administration of a high dose of gadolinium in patients with renal failure. Recently, the FDA announced an advisory, cautioning the use of gadolinium chelates in patients with moderate renal failure (gfr<60) and recommending discontinuing the use of it in patients with severe renal failure (gfr<15), unless prompt dialysis is arranged.

So, is gadolinium safe to use for our MR imaging studies? Our current MRI screening form contains a question about the presence of kidney (renal) disease. If this is checked "yes," indicating that the patient does have a history of kidney disease, the technologist must notify the radiologist before the MRI scan is initiated. The radiologist must determine if the MRI scan should be performed and if performed, if the scan should be with or without contrast agents.

In all patients with any history of renal disease, the use of gadolinium compounds should be minimized. Specifically, the use of Omniscan must be avoided. Patients with normal renal function and/or patients with no known history of renal failure who are receiving gadolinium contrast agents should voluntarily hydrate themselves after their studies.

Clearly, a whole generation of radiologists has grown up relying on the use of gadolinium. However, it is widely overlooked that most diagnoses can be made with non-contrast exams. We are too reliant on contrast enhanced exams. Time to dust off those old protocols! Because NSF has only been associated with renal failure patients, the wholesale use of iodinated contrast enhanced CT in this group should be weighed against the risk of iodinated contrast induced nephropathy. More news on this topic is forthcoming.

For more information, please visit the following links:

www.fda.gov/cder/drug/infopage/gcca/default.htm

RSNA NEWS includes a comprehensive feature article on this topic at http://www.rsna.org/Publications/rsnanews/feb07/upload/RSNANews_Feb07
_Gadolinium.pdf.

ACR MR Safe Practice Guidelines for 2007 will soon be available online on the American College of Radiology website (www.acr.org).

"Nephrogenic Systemic Fibrosis: Risk Factors and Incidence Estimation," by Elizabeth A. Sadowski, MD, and colleagues will appear in the April print issue of Radiology and is now available online at http://radiology.rsnajnls.org/cgi/content/full/2431062144v1.

"Gadolinium-based MR Contrast Agents and Nephrogenic Systemic Fibrosis," by Phillip H. Kuo, MD, PhD, and colleagues is available in the March print issue of Radiology or online at http://radiology.rsnajnls.org/cgi/content/full/2423061640v1.

GFR estimation sites:
www.globalrph.com/cgi-bin/crcl.cgi

www.nephron.com

nephron.com/cgi-bin/CGSI.cgi (includes body mass in the calculation)