Diagnostic imaging utilization slows

The dramatic growth of Medicare-related medical imaging utilization-which drew the attention of rate-cutting federal policymakers and the wrath of politicians on Capitol Hill in the mid-2000s-has ended, according to a study from Thomas Jefferson University in Philadelphia. 

The year 2005 represented a turning point in that chapter for modern cross-sectional imaging, according to Dr. David Levin, a professor of radiology at Thomas Jefferson. By sifting through Medicare Part B data, Levin and Dr. Vijay Rao, the university’s radiology chair, found the compound annual growth rate for noninvasive diagnostic imaging increased 1.4% per year from 2005 to 2008, compared with 4.1% from 1998 to 2005.

“There was a dramatic flattening,” Levin said while presenting his findings Wednesday at the 2010 RSNA meeting.

The moderating trend was stronger among diagnostic radiologists than for physicians who own and operate medical imaging equipment, Levin said. An expert in physician self-referral, Levin has repeatedly singled out the controversial practice for fueling wasteful and unnecessary utilization growth.

For all forms of noninvasive diagnostic imaging, the average annual growth rate among radiologists was 0.8% from 2005 to 2008, compared with 3.4% annually from 1998 to 2005. The average annual growth rates for all other physicians for the two periods were 1.8% and 6.6%, respectively.

“Nonradiologists are basically in the business of self-referring, so it is not surprising to see that their utilization continues to grow at twice the rate of radiologists’,” he said.

By individual modality, Levin and Rao found the spectacular growth rate of CT through the first half of the 2000s slowed only slightly from 2005 to 2008, mainly because of its expanded use in emergency medicine. The number of nuclear medicine procedures, including PET, per 1000 Medicare beneficiaries actually declined slightly from 2005 to 2008, while the growth trend for MRI flattened. The utilization rate for general x-ray has changed little since the 1990s.

The same trends emerged when Levin and Rao focused on outpatient imaging. Growth rates for all modalities fell, with CT, MR, and nuclear medicine all seeing rate reductions since 2005. The CT growth rate dropped from an annual average of 9.5% in the 1998 to 2005 period to an annual average of 4.3% between 2005 and 2008. MRI procedure growth rates dropped from 13.1% to 1.9% and nuclear medicine procedure growth rates from 13.6% to 0.6% in the two time time periods.

Levin dismissed the possibility of a link between slowing growth and the Medicare rate cuts for cross-sectional medical imaging that were enacted in 2007 as part of the federal Deficit Reduction Act. He did not propose his own theory for the trend.

Publication of the results is pending in the American Journal of Roentgenology, Levin said.