The Risks of MRI Contrast in Patients with Kidney Disease: Gadolinium and Nephrogenic Systemic Fibrosis (NSF)
First, some background. Patients with kidney disease very frequently have narrowing of the blood vessels due to atherosclerosis. This narrowing takes place in different parts of the body -- in blood vessels in the head, neck, legs, heart, and the arteries supplying the kidneys.
There are several methods of visualizing blood vessels to detect abnormal narrowings. One method is an angiogram, typically performed by cardiologists, radiologists, or vascular surgeons. This involves placing a catheter directly in the blood vessel and injecting dye (usually iodine-based). There are two disadvantages to angiograms. One, this is a relatively invasive procedure. Two, the iodine-based dye can sometime cause decreased kidney function or acute renal failure, a condition called "contrast nephropathy."
A second method is a CT scan (or CAT scan). While less invasive than an angiogram, CT scans to visualize blood vessels usually require the administration of larger amounts of iodine-based dye than angiograms. As mentioned in the last paragraph, this type of dye can lead to contrast nephropathy and acute renal failure.
A third method for visualizing blood vessels is an MRI or MRA (magnetic reasonance angiogram). In this procedure, the dye used is gadolinium. MRAs have the advantage of being less invasive than an angiogram with a catheter and the use of gadolinium avoids the use of iodine-based dyes, which can cause contrast nephropathy/acute renal failure, so in the past, gadolinium has been preferred for patients with kidney disease. Consequently, patients with kidney disease have often received MRAs with gadolinium to visualize their blood vessels.
All this has changed. Over the last year, an increasing numbers of cases of NSF have been identified and a strong link to gadolinium has been made. NSF is a condition which is similar to scleroderma, in which abnormal fibrous tissue accumulates in the skin, muscle, and internal organs. Eventually, NSF can lead to severe disability or death.
The FDA has added a "black box" warning to the labels of gadolinium-based contrast agents to emphasize the risk of NSF. The risk appears to be greatest for patients with severe decreased kidney function (glomerular filtration rate 2). For patients with severe kidney disease, gadolinium-based contrast agents should be used only when absolutely necessary. In some situations, physicians may choose to perform an angiogram or CT scan with iodine-based contrast rather than perform an MRI with gadolinium.
The full text of the FDA's information for health care professionals is here.