Imagine this: over 13.5 billion milliliters of contrast media—enough to fill more than 5,000 Olympic-sized swimming pools—have been used in medical imaging for Medicare patients between 2011 and 2024. But here’s where it gets controversial: while these substances are essential for life-saving diagnoses, they’re also persistent pollutants that end up in our rivers, oceans, and even drinking water. A groundbreaking study published in JAMA Network Open on December 5 sheds light on this hidden environmental cost of modern healthcare.
Led by Dr. Florence Doo of the University of Maryland, Baltimore, the research team—including experts from the Harvey L. Neiman Health Policy Institute (HPI), NYU Langone, Oxford University, and Imperial College London—analyzed Medicare Part B claims data from 2011 to 2024. They focused on advanced imaging exams like CT and MRI scans, which rely on contrast agents containing iodine or gadolinium. These substances, while crucial for clarity in medical images, are non-renewable and not fully removed by standard wastewater treatment.
And this is the part most people miss: the study found that 169 million contrast-enhanced imaging exams were performed during this period, requiring a staggering 13.5 billion mL of contrast media. CT scans of the abdomen or pelvis alone accounted for 4.4 billion mL—the largest single contributor. For gadolinium-based agents, brain MRIs topped the list at 221 million mL. Even more concerning? Annual contrast use grew steadily from 2014 to 2019, with iodinated agents increasing by 5.2% and gadolinium agents by 3.5% year-over-year. While the COVID-19 pandemic caused temporary declines in 2020, usage rebounded sharply in 2021.
Dr. Doo emphasizes, ‘Contrast agents don’t just disappear after use. They accumulate in our environment, raising long-term ecological and public health concerns.’ Her team highlights actionable solutions, such as confirming the necessity of imaging orders, using weight-based dosing to avoid overuse, and adopting multiuse vial systems. Emerging technologies like biodegradable contrast alternatives and AI reduction algorithms show promise but remain experimental, requiring rigorous testing and regulatory approval.
Here’s the bold question: Should healthcare systems prioritize environmental stewardship alongside patient care? Dr. Doo argues, ‘We can’t ignore the environmental consequences of medical imaging. Contrast stewardship is a measurable way to align patient care with planetary health.’ But how far are we willing to go to balance these priorities? Share your thoughts in the comments—this is a conversation we can’t afford to ignore.
For the full report, visit https://www.doi.org/10.1001/jamanetworkopen.2025.47304.
Disclosure: Dr. Doo’s work was supported by grants from the National Institutes of Health Clinical and Translational Science Award Program and the Association of Academic Radiology Clinical Effectiveness in Radiology Research Academic Fund, partially funded by GE Healthcare (https://www.auntminnie.com/resources/vendors/company/15553507/ge-healthcare).
