Experts call for more judicious use of contrast, highlighting environmental concerns
New data highlight the significant burden contrast media use places on the environment, prompting experts to call for more stringent use of these agents.
Published in JAMA Network Open, the research focused on contrast use in the Medicare population specifically. Experts found that those insured by Medicare received 13.5 billion milliliters of contrast media between 2011 and 2024. The majority of these scans used iodinated contrast, while another 5% utilized gadolinium-based contrast agents (GBCAs).
Authors of the paper expressed concern about these figures, cautioning that contrast agents do not simply disappear after their use and that excessive use can negatively affect the environment.
“Contrast agents are necessary for effective imaging, but they don’t disappear after use. Iodine and gadolinium are non-renewable resources that can enter wastewater and accumulate in rivers, oceans, and even drinking water,” noted lead author Florence Doo, MD, MA, director of innovation and assistant professor at the University of Maryland Medical Intelligent Imaging Center (UM2ii). “Quantifying which imaging exams use the most contrast helps us innovate thoughtful, practical contrast stewardship strategies to ensure patients continue to receive safe and high-quality imaging care.”
The team sought to identify patterns in contrast use that could guide mitigation tactics. To do this, they analyzed the U.S. Medicare Part B fee-for-service limited public claims data (2011 to 2024 Physician/Supplier Procedure Summary), which represents roughly two-thirds of the Medicare beneficiary population. They extracted data on patients, exam type, contrast type and amount of contrast used, in addition to reviewing how factors like COVID-19 have impacted contrast use over the last decade.
They found that between 2011 and 2024, Medicare beneficiaries underwent 169.3 million contrast-enhanced examinations across 82 CPT codes. CT exams of the abdomen and pelvis accounted for the most iodinated contrast use, at 4.4 billion mL during the time period studied. For GBCA use, MRI exams of the brain resulted in approximately 221 million mL.
The group observed a significant increase in contrast use after 2013; between 2014 and 2019, they noted a 5.2% year over year uptick for iodinated agents and 3.5% for gadolinium agents. During the height of COVID in 2020, these figures actually decreased (−9.6% for iodinated agents and −15.6% for GBCAs), before spiking again in 2021 and stabilizing in 2024.
For CT, 6 procedures accounted for 80% of iodinated contrast use, while 7 procedures were implicated for the majority of GBCA use.
The group suggested their findings highlight multiple opportunities to optimize contrast utilization and reduce its environmental impact.
“Incremental mitigation strategies include reducing inappropriate imaging orders, adopting weight-based dosing, and implementing recycling or multi-use vial systems,” the authors suggested. “Potentially transformative approaches like artificial intelligence-enabled virtual contrast imaging may eventually reduce contrast administration dependence.”
The team also touched on newer strategies that are still in developmental stages, such as biodegradable CT or MRI agents and ultrasonography microbubbles. These methods are still under clinical evaluation, but if proven safe and effective, the group believes they could help “simultaneously address chemical pollution, injection-related waste, and patient reaction risk and toxicity.”
Read more about the team’s findings here.
In addition to her background in journalism, Hannah also has patient-facing experience in clinical settings, having spent more than 12 years working as a registered rad tech. She began covering the medical imaging industry for Innovate Healthcare in 2021.