Dive Brief:

• Usage rates for computed tomography, magnetic resonance imaging, ultrasound and nuclear medicine imaging have continued to rise in both the United States and Ontario, Canada, despite concerns about overuse that have led to efforts by physician groups to curb the amount of imaging in medicine, according to a large study published Tuesday in the Journal of the American Medical Association.
• Researchers at the University of California Davis, University of California San Francisco and Kaiser Permanente analyzed patterns of imaging use from more than 135 million exams conducted between 2000 and 2016.
• The findings suggest that neither financial incentives nor the campaign to reduce the use of medical imaging have been completely effective, the study authors said.

Dive Insight:

Efforts such as the "Choosing Wisely" campaign launched in 2012 by the American Board of Internal Medicine Foundation and endorsed by 85 professional medical societies attempted to address potential overuse of diagnostic testing. The campaign urged physicians to discuss with patients whether an imaging study is necessary, as well as potential risks. CMS has also reduced reimbursement rates for some scans to discourage overuse.

Still, the new study found imaging rates were significantly higher in 2016 than in 2000 for all scan types except nuclear medicine in seven healthcare systems in the United States and Ontario. From 2000 to 2016, CT and MRI rates continued to increase among adults, but at a slower pace in more recent years.

Imaging rates for CT among adults and older adults increased most rapidly in the early 2000s. In adults, annual growth in CT was 11.6% at U.S. sites from 2000 to 2006 and 9.2% in Ontario from 2000 to 2007. In older adults, annual growth was 9.5% in both the United States (2000-2006) and Ontario (2000-2007).

Growth slowed from 2006 to 2013, down 0.5% among adults and up 0.9% among older adults (2006-2014) in the United States and up 1.3% among adults (2007-2013) and 3.4% among older adults (2007-2016) in Ontario. But growth reaccelerated in recent years for most groups, rising 3.7% among adults in 2013 to 2016 and 5.2% among older adults in 2014 to 2016 in the United States and 3.7% among adults in Ontario from 2013 to 2016.

MRI use patterns among adults and older adults in the U.S. healthcare systems and Ontario were similar to those seen for CT. One notable exception to the rising usage rates observed in the study was a decline in CT use in children in recent years.

"Although most physicians are aware that imaging tests are frequently overused, there are not enough evidence-based guidelines that rely on a careful consideration of the evidence, including information on benefits and harms that can inform their testing decisions," said lead author Rebecca Smith-Bindman, UCSF professor of radiology, epidemiology and biostatistics, and obstetrics and reproductive medicine. "In the absence of balanced evidence, the default decision is to image."

The study's findings come amid a prediction for a sharp rise in precision medical imaging in the next decade, driven by technological advances such as image-based 3D printing, according to analysts at Frost and Sullivan.