Geography affects imaging use rates
By Kate Madden Yee
AuntMinnie.com staff writer
December 4, 2008

CHICAGO - Whether it's a local imaging center trying to boost procedure volume to stay afloat in a tight market or a mighty organization like the U.S. Congress attempting to curb what it sees as skyrocketing healthcare spending, the use -- and overuse -- of medical imaging is under intense scrutiny.

Noninvasive diagnostic imaging makes up the majority of the total amount of imaging procedures performed every year in the U.S. But there have been few studies that examine whether diagnostic imaging rates vary from geographic area to geographic area or that track utilization growth by specialty in different regions.

Dr. Vijay Rao and colleagues at Thomas Jefferson University Hospital and the Center for Research on Utilization of Imaging Services (CRUISE) in Philadelphia explored how much variation in imaging utilization rates exists among different geographic regions of the U.S. The team presented its work at this week's RSNA meeting in Chicago, finding that there is a surprising amount of geographic variation in imaging use rates in the U.S., as well as considerable geographic variation in the rapidity of imaging utilization growth.

Who uses what, and where?

The team used the 2002-2006 Medicare Part B fee-for-service database; claims are categorized into 10 different geographic regions, each with a major city. The researchers calculated a utilization rate per thousand for all imaging services performed in each region and determined the proportion of these services that were performed by radiologists. The study also assessed utilization rates during this time frame among radiologists, cardiologists, primary care physicians, and surgeons.

In 2006, imaging utilization rates per thousand Medicare beneficiaries ranged from a high of 4,532 in the Atlanta region to a low of 2,901 in the Seattle region (a difference of 56%).

City Total imaging utilization by region, Medicare 2006 (per thousand) Atlanta 4,532 Dallas 4,262 New York City 4,219 Philadelphia 4,106 Chicago 4,093 Kansas City 3,850 Boston 3,830 San Francisco 3,830 Denver 3,371 Seattle 2,901

Radiologists' share of the imaging market ranged from a high of 69% in the Boston region to a low of 58% in the Atlanta region.

City Radiologists' percent share by region, Medicare 2006 Atlanta 58% Dallas 60% New York City 61% Philadelphia 66% Chicago 66% Kansas City 65% Boston 69% San Francisco 61% Denver 66% Seattle 66%

Between 2002 and 2006, the percent change in overall utilization rates ranged from 20% in New York City to 8% in Seattle.

City Percent change in overall utilization rates Atlanta 15% Dallas 15% New York City 20% Philadelphia 12% Chicago 16% Kansas City 13% Boston 14% San Francisco 11% Denver 13% Seattle 8%

Nonradiologists boost use rates

Of the four major specialty groups providing imaging, cardiologists showed the largest percentage increase during the time frame in all 10 geographic regions, ranging from 25% in Philadelphia to 53% in Boston.

"We found some correlation between use of imaging by radiologists and nonradiologists," Rao told AuntMinnie.com. "In regions that had higher utilization rates by nonradiologists, the overall use rate was higher as well."

Rao and her team suggested that a future study analyzing the use of MR, CT, and nuclear medicine separately could shed even more light on utilization patterns. And studying why some regions have lower imaging use than others could also prove insightful.

"Why is utilization so much lower in Seattle than in Atlanta?" Rao said. "If we dig a little deeper and try to understand what other factors contribute to these geographic variations, we could discover what some regions are doing to control use."

By Kate Madden Yee
AuntMinnie.com staff writer
December 4, 2008

Related Reading

Wake up, watch out: Coming trends in managing medical imaging, October 13, 2008

GAO: DRA cut 2007 imaging expenses by $1.7 billion, September 26, 2008

AHIP report touts RBMs to control imaging costs, July 29, 2008

GAO report on overutilization draws industry ire, July 15, 2008

Report: Payors putting squeeze on imaging overuse, July 11, 2008

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