By Lynn Antonopoulos
Substituting iodinated contrast agents rather than relying on steroid premedication may safely prevent breakthrough allergic-like reactions in patients with a history of mild contrast reaction. It may also reduce imaging delays, according to research presented by Madeleine Sertic, MBBCh, BAO, of Massachusetts General Hospital, Mass General Brigham and Harvard Medical School, in Boston.
“Breakthrough allergic-like reactions to iodinated contrast media are uncommon when an alternative contrast agent is utilized, even in the absence of steroid premedication,” Dr. Sertic said. “Utilizing an alternative contrast agent decreased time from order placement to imaging by two hours.”
Dr. Sertic and her colleague, Daniel Glazer, MD, co-led the study as part of their respective institutions’ contrast safety committees. “With the growing body of evidence against premedication for patients with a history of mild contrast reactions, we began to question if our patients could be served better with contrast agent substitution,” Dr. Sertic said. “We launched a pilot, and the results have been promising so far.”
The study evaluated 25,395 contrast-enhanced CT scans performed in the emergency department setting between June 2024 and April 2025. Of these, 247 patients had a history of mild allergy to iodinated contrast media documented in the electronic health record. Only 24% of those cases specified the exact inciting agent.
From this group, 35 patients received iopamidol instead of steroid premedication and the original, inciting agent, iohexol. The mean time from order entry to exam completion was 2.7 hours for the substitution group compared with 4.7 hours for the premedication group.
Only one patient in the substitution group experienced a breakthrough reaction, which was mild and matched the severity of the initial reaction.“Breakthrough allergic-like reactions to iodinated contrast media are uncommon when an alternative contrast agent is utilized, even in the absence of steroid premedication. Utilizing an alternative contrast agent decreased time from order placement to imaging by two hours.”
Madeleine Sertic, MBBCh, BAO
The study also uncovered a surprising secondary benefit: improved clinician education and documentation accuracy.
Dr. Sertic noted that during the pilot program, distributing a tip sheet to ordering providers helped clarify patient histories. As a result, several providers identified that some patients had physiologic reactions, rather than true allergic-like reactions, improving the accuracy of documentation and reducing unnecessary premedication.
“Their reactions were appropriately re-classified in their charts, ensuring smoother and more accurate protocols for their future imaging studies,” Dr. Sertic said.
Despite their success, Dr. Sertic and her colleagues encountered challenges. “The majority of patients with a history of contrast reactions don’t have the specific agent documented,” she noted. “This prevented us from substituting the inciting agent and including those patients in our study.”
Additionally, consistent education across large, rotating staff populations proved difficult. “Ordering providers need to know about this change to practice patterns. Radiologists need to also know about the benefits of contrast agent substitution so they can answer questions appropriately,” she said. “Technologists have been taught that they are the last line of defense, so making sure we reach all staff members has been an ongoing challenge.”
Still, with just a single patient experiencing a breakthrough reaction, the early results have been encouraging. “This outcome has helped relieve underlying anxiety about the practice change, and overall adoption has been excellent,” Dr. Sertic said.
Access the presentation, “Contrast Agent Substitution As A Strategy to Decrease Risk of Breakthrough Allergic-Like Reactions: Results from Two Academic Medical Centers,” on demand at RSNA.org/MeetingCentral
© 2025 RSNA.
The RSNA 2025 Daily Bulletin is the official publication of the 110th Scientific Assembly and Annual Meeting of the Radiological Society of North America. Published online Sunday, November 30 — Thursday, December 4.
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