Q: Is it safe to order an MRI on a patient with renal disease?
Posted on: 09/01/2008
Q: Is it safe to order an MRI on a patient with renal disease?
A: Recently, there has been growing awareness — and anxiety — regarding nephrogenic systemic fibrosis (NSF). A relatively recent disease first reported in 1997, NSF can develop over days or weeks. Skin lesions and skin thickening, develops and can lead to joint contractures and immobility. Other organs can be affected, including the lungs, liver, heart and muscles. NSF has become relevant to the field of radiology, as there is growing evidence of a relationship between NSF and gadolinium-based contrast agents, which are the agents used for MRI studies.
The patients most at risk for NSF are those on dialysis or those with very compromised renal function. Any radiology facility providing an MRI has to consider this risk before administering the contrast. The first step is to consider the necessity of contrast for the exam. Many MRI studies are preferable with contrast, but can provide sufficient and worthwhile information without contrast administration. It is also worthwhile to consider an appropriate alternative imaging study. There are no known cases of NSF in patients with normal renal function.
In an at-risk patient with renal artery stenosis, instead of performing a contrast-enhanced MR angiogram, the work-up could start with a doppler exam or non-enhanced MRA, either of which may be able to exclude renal artery stenosis. Another patient with lower extremity ischemia may be on hemodialysis and, therefore, not a good candidate for contrast-enhanced MRA. However, since there is no concern about contrast-induced nephropathy in a patient already on dialysis, CT angiography is a good alternative.
We’ve started asking additional screening questions whenever an MRI with contrast is ordered to identify patients with risk factors, such as hypertension or diabetes. If risk factors are present, or if the patient is over 60, we like to have an estimated GFR, as determined from a serum creatinine level. The vast majority of patients with documented NSF had severe or end-stage renal failure, so a GFR of 30 mL/min or less warrants a re-evaluation of the exam necessity and consideration of alternatives. If your patient has a history of renal disease, ordering a serum creatine prior to their MRI exam is recommended.
Most of the reported cases of NSF (over 90 percent) have been associated with one specific brand of gadolinium-based MRI contrast (Omniscan). At Kansas City Imaging Center, we use Opti-MARK for contrast, which seems to have an extremely low association with NSF.
If you have a question about a patient who is or may be at risk, please call us to discuss the options: 913-667-5600.
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