Conservation strategies could greatly reduce contrast dye use amid shortage
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A global shortage of contrast dye for medical imaging has prompted experts at University of California, San Francisco to outline conservation strategies that would reduce the use of the agent by approximately 83%.
In a research letter published in JAMA, the authors discussed the ongoing shortage due to COVID-19-related supply chain issues.
“Contrast in general in the United States has been relatively inexpensive, and we have wasted it tremendously,” Rebecca Smith-Bindman, MD, UCSF professor in the department of epidemiology and biostatistics, said in an interview with Healio. “We haven’t really made thoughtful decisions about it. Whether or not there is a shortage, there is no reason to use more contrast than necessary.”
‘A profound worldwide shortage’
The global shortage of contrast dye began in April as a result of a pandemic-related supply chain disruption at GE Healthcare in Shanghai.
“Most of the GE contrast that we use for CT scans and angiograms passes through their Shanghai manufacturing plant, and during COVID shutdown that plant had to close. They were having significant delays at the port, which meant the contrast was not being delivered to them,” Smith-Bindman said. “Hospitals and imaging facilities don’t store very much contrast; they generally are in the practice of getting as much as is needed for a week or two. So, basically, all of a sudden, there was a profound worldwide shortage.”
Smith-Bindman and colleagues conducted a study modeling three conservation strategies separately and in combination with each other. They utilized a sample of 1.04 million CT scans in the UCSF International CT Dose Registry between Jan. 1, 2015, and March 11, 2021. This registry consists of CT scan data from 161 imaging facilities linked to 27 health care institutions.
The conservation strategies included using weight-based rather than fixed dosing (Model A), decreasing contrast dose while reducing tube voltage on scanners (Model B), and using nonenhanced CT instead of contrast-enhanced in cases where the diagnostic accuracy would not be compromised (Model C). They also studied a combination of models A and C, as well as a combination of all three models.
The researchers found replacing contrast-enhanced CT with nonenhanced CT resulted in a 78% decrease in contrast dye use.
“That was by far the most important strategy,” Smith-Bindman told Healio. “This applies to many patients with cancer, because for most types of cancer, you don’t actually need the contrast; you can see the cancer fairly well without the contrast. However, there are certain kinds of kidney cancers, as well as liver and pancreatic cancers, where you really need the contrast.”
Used individually, the strategy of weight-based dosing for abdomen, chest, cardiac, spine and extremity imaging reduced use of contrast dye by 10%, while lowering the tube voltage in suitable patients yielded a 25% reduction. These two strategies combined with forgoing contrast dye when possible led to a total reduction of 83%.
Smith-Bindman also noted that using single-use vials of contrast often results in wasted contrast dye, adding that multiuse vials could conserve contrast.
“There would be less waste,” she said. “It’s a bit nuanced, but it can have a big impact.”
Potential for lasting impact
Although COVID-19 and the current contrast dye shortage represent acute events that need to be addressed in a timely manner, Smith-Bindman said she hopes these crises can serve to underscore the long-term nature of the problem.
“This shortage brought to my attention — as well as to others’ attention — that there are opportunities to lower the use [of contrast dye],” she said. “The fact that we can attain sufficient accuracy without the use of contrast should really encourage us to do so when it’s appropriate.”
Smith-Bindman and her colleagues have been researching surveillance of patients with cancer and have noticed similar excess in that area.
“We do a lot of oversurveillance in general,” Smith-Bindman said. “We’re beginning to realize that some of this is just not necessary.”
Smith-Bindman said she hopes the results of the current study will have a lasting impact in terms of optimizing the use of contrast dye and avoiding waste.
“As painful as COVID has been, it’s definitely taught us some lessons,” she said. “One of the lessons is that we should think very carefully about how we use contrast and other medical imaging. We need to understand that, sometimes, less is more.”
For more information:
Rebecca Smith-Bindman, MD, can be reached at UCSF School of Medicine, 550 16th St., San Francisco, CA 94438; email: rebecca.smith-bindman@ucsf.edu.
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