Absolute counts of imaging studies have doubled since 2004

Examining imaging utilization history and trends, a study published in Current Problems in Diagnostic Radiology aimed to determine whether the number of imaging studies is increasing and why. 

The study found that while the absolute number of imaging studies performed in 2016 was twice the number of studies performed in 2004, the increase is attributable to a doubling in the number of active patients. These findings debunk common conjectures in the industry about a recent potential increase in reliance on imaging: There were 1.17 studies per active patient in 2004, and 1.15 studies per patient in 2016. 

“Although absolute counts of imaging studies more than doubled, the net change in per capita utilization over the study period was minimal,” wrote first author Kelvin L.S. Chan, MD, MS, of the Ohio State University Wexner Medical Center, and co-authors. “A likely interpretation is that population growth, demographic trends, and overall increase in general health care access may be the main drivers of the net changes in total imaging volume over this time period rather than system-wide physician ordering practices or ‘over-reliance’ on imaging.”

The study was based on retrospective data from a single, university-affiliated health system. The data represented more than 1.6 million unique patients representing over 5 million “active patient years.”

In all, total diagnostic exams rose by 6.8% per year and the active population size grew by 7.0% per year. After normalizing utilization rates, the study found that there was actually a drop in utilization of certain imaging categories, including a 20% decline in radiology and a 50% decline for nuclear medicine over the course of the 13-year study period.