Radiologists Balance Quality and Safety with MR Contrast Agents
Concerns over the safety of gadolinium-based contrast agents (GBCAs) may be adversely affecting quality of care, according to presenters at a Wednesday session.
"The key question is, in an effort to avoid any adverse reactions from gadolinium-based MRI, have we compromised the quality of MR scans?" said Jeffrey C. Weinreb, M.D., of the Yale University School of Medicine in New Haven, Conn.
GBCAs improve MR image quality and increase diagnostic accuracy, but have been associated with nephrogenic systemic fibrosis (NSF), a disease that involves progressive, severe fibrosis of the skin and other organs, in patients with compromised kidney function. Since the first cases of NSF began appearing in 2006, screening for kidney function before MR imaging has become the standard of care, even though gadolinium-related NSF is extremely rare and not all types of GBCAs have been linked with the disease.
"Since the emergence of NSF and concerns over U.S. Food and Drug Administration warnings, the pendulum has probably swung too much in the direction of hypersensitivity to risk," said session moderator Thomas M. Grist, M.D., of the University of Wisconsin School of Medicine and Public Health in Madison.
During the session, "MRI Contrast Use: Have Quality and Safety Collided?", Dr. Weinreb and Martin R. Prince, M.D., Ph.D., professor of radiology at Cornell and Columbia Universities in New York City, discussed and debated the best approaches in five clinical cases that involved GBCAs.
In a case involving a kidney transplant patient, Dr. Prince raised the possibility of using non-contrast renal MR imaging, while Dr. Weinreb questioned the rationale of doing so many imaging studies with diminishing returns.
The case of a patient with a history of allergic reaction to a GBCA provoked a discussion of premedicating patients. Dr. Prince noted that the specific contrast-related allergic reactions that benefit from premedication are minor, and urged radiologists to pay attention to the contraindications listed in the contrast agent package inserts. For patients with a history of reaction to iodinated contrast agents, Dr. Prince recommended leaving in an IV line to speed delivery of medication in case of a reaction.
Both radiologists agreed that patients with cirrhosis and other liver diseases are largely safe to study with contrast-enhanced MR imaging, provided that their kidney function is sufficient.
"There is fairly compelling data that liver disease does not increase NSF risk, but liver disease does increase the risk of kidney disease, which has been associated with NSF," Dr. Weinreb said.
The two radiologists also debated the association between NSF and pro-inflammatory conditions. Dr. Prince's facility uses the presence of pro-inflammatory conditions as one of four risk factors considered in the decision making process, but Dr. Weinreb argued that people getting imaged are likely to be sick and in a pro-inflammatory state.
"In our practice it's not something we screen for and not something that would prevent us from using GBCAs," he said.
Late in the session, Dr. Prince asked Dr. Weinreb, "Why not pick an agent not associated with NSF and skip the screening?"
There are a number of reasons, Dr. Weinreb said. "For one, we don't know the patient's prior history," he said, adding that skipping the screening may become an FDA-supported option in the future.
In the end, the presenters emphasized the pivotal role of radiologists in keeping patients safe while providing them with optimal care. "With appropriate use of contrast agents and understanding of patient parameters, radiologists can reduce the likelihood of NSF," Dr. Grist concluded.