December 5, 2025
New Study Reveals Millions of Liters of Medical Imaging Contrast Media Contribute to Environmental Pollution
A new study published in JAMA Network Open highlights the significant environmental footprint of medical imaging contrast agents, finding that Medicare patients alone received 13.5 billion milliliters of contrast media between 2011 and 2024. Conducted by researchers from the University of Maryland, Oxford University, Imperial College London, NYU Langone, and the Harvey L. Neiman Health Policy Institute, the study underscores the urgent need to address the environmental impact of these widely used diagnostic materials.
Key Findings from the new research included:
• 169 million contrast-enhanced imaging procedures were performed in the Medicare population over 13 years.
• Iodinated contrast agents (used in CT and CTA scans) accounted for more than 95% of the total volume (12.9 billion milliliters) with CT scans of the abdomen and pelvis alone contributing 4.4 billion milliliters.
• Gadolinium-based agents (used in MRI and MRA scans) were used less frequently but still totaled nearly 600 million milliliters, with brain MRI leading usage.
• Just a handful of procedure types accounted for 80% of all contrast use, suggesting clear targets for sustainability efforts.
“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,” explained lead author Florence Doo, MD, MA, Director of Innovation and Assistant Professor at the University of Maryland Medical Intelligent Imaging Center (UM2ii) in the Department of Diagnostic Radiology and Nuclear Medicine, and Faculty at the University of Maryland Institute for Health Computing. “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.”
Medical imaging contrast agents are critical for diagnosing disease, but they are also persistent pollutants. Conventional wastewater treatment does not fully remove them, raising concerns about long-term ecological and public health impacts. The authors discuss actionable mitigation strategies that include ensuring imaging orders are clinically appropriate, implementing weight-based dosing to avoid excess use, and recycling or multiuse vial systems. Additionally, contrast alternatives that are biodegradable or artificial intelligence reduction algorithms are an emerging technology that may reduce pollution.
“Our study shows that a small number of imaging procedures drive the majority of contrast use. Focusing on those highest-use imaging types make meaningful changes tractable and could significantly reduce health care’s environmental footprint,” said coauthor Elizabeth Rula, PhD, Executive Director of the Neiman Health Policy Institute. “Ensuring that contrast-enhanced imaging scans are only used when clinically appropriate according to American College of Radiology Appropriateness Criteria® is an important first step.”
“We can’t ignore the environmental consequences of medical imaging. Stewardship of contrast agents is a measurable and impactful way to align patient care with planetary health and should be an important part of broader health care sustainability efforts,” concluded Dr. Doo.
To arrange an interview with a spokesperson, contact Nichole Gonzalez at ngonzalez@neimanhpi.org.
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About the Harvey L. Neiman Health Policy Institute
The Harvey L. Neiman Health Policy Institute is one of the nation’s leading medical imaging socioeconomic research organizations. The Neiman Institute studies the role and value of radiology and radiologists in evolving health care delivery and payment systems and the impact of medical imaging on the cost, quality, safety and efficiency of health care. Visit us at www.neimanhpi.org and follow us on X, LinkedIn and Facebook.