By Kate Madden Yee, staff writer

November 30, 2010 -- CHICAGO - The use of CT in hospital emergency departments has increased at a higher rate than in other settings, which is bad news for associated radiation exposure, according to a study from Cincinnati Children's Hospital presented at the RSNA meeting.

The study was also published online today in Radiology (November 30, 2010).

David Larson, MD, and colleagues examined nationwide trends and factors associated with CT use in the emergency department using data from 1995 to 2007 National Hospital Ambulatory Medical Care Surveys. A mean of 30,044 visits were sampled for each year, and data were subcategorized according to multiple patient and hospital characteristics.

The team found that during the study time frame, the number of emergency room visits in which patients were imaged with CT increased 84% -- from 2.7 million to 16.2 million -- an average 16% increase per year. Of this growth, 3.3% was due to increased patient volume, while the remaining 12.7% was due to increased CT use, Larson said.

ED visits involving CT: 1995-2007 (in millions)
1995 2.7
1996 2.9
1997 3.3
1998 4.1
1999 4.8
2000 5.7
2001 6.5
2002 7.5
2003 8.5
2004 9.8
2005 12.3
2006 13.8
2007 16.2
Data courtesy of RSNA.
"This overall growth represents a 5.9-fold increase and a doubling time of approximately every 4.7 years," Larson told session attendees.

The percentage of CT procedures in the emergency department grew from 2.8% in 1995 to 13.9% in 2007 -- a 4.9-fold increase, a compound annual growth rate of 14.2%, and a doubling time of 5.2 years, Larson said. CT use in the emergency department increased the most among patients 65 years of age and older, going from 6.6% in 1995 to 25.2% in 2007.

And by 2007, the end point of the study's time frame, overall use of CT had not reached an inflection point -- that is, when growth acceleration of a technology becomes negative, according to Larson.

"We did not find evidence that the increased use of CT in the emergency department was tapering," he said. "It's impossible to predict when or at what level the overall use of CT in the ED will begin to level off."

The growth partially reflects new uses for CT that were rarely used in 1995, such as side/flank imaging, abdominal imaging, and imaging for chest pain, Larson told attendees: By 2007, these indications were the most common for CT. Use of CT for side or flank pain went from 0.4% in 1995 to 43.3% in 2007; abdominal imaging went from 2% to 33%; and use of CT for chest pain increased from 1.2% to 13.7%.

This upswing in CT use means higher radiation dose in the patient population, Larson warned.

"Our study didn't directly address radiation dose, but the evidence suggests that CT-associated radiation exposure in the emergency department likely has increased even more rapidly than the number of CT examinations performed," he said.

Larson's team suggested that inappropriate CT use will decrease as more sophisticated and evidence-based decision models that address patient benefit from the exam are used at the time the decisions are made.

By Kate Madden Yee staff writer
November 30, 2010

U.S. children's hospitals reduce CT exam volume, April 29, 2010

CDC report: MRI, CT, PET use spikes in physician offices, ER, February 18, 2010

Studies spotlight high CT radiation dose, increased cancer risk, December 14, 2009

Study shows CT use has increased, diagnostic yield has not, March 3, 2009

CT utilization spikes among nonradiologists, December 17, 2008

Copyright © 2010

Last Updated np 12/30/2010 5:00:32 PM

17 comments so far ...
12/1/2010 8:23:12 AM
John Cornell
I read, your article dated November 30, 2010 on Aunt Minnie entitled Study finds surge in emergency department use of CT. Although I agree with some of your findings, I strongly disagree that they represent any significant effect on the growth. The overwhelming reason for the increase growth is the spawning of radiology management companies hired by the insurance industry to precertify the study before it can be done in the less costly outpatient setting. This requirement has shunted tremendous numbers of studies through the emergency room where precertification is not or can not be required. Many ordering physicians will not expend the funds to have their own staff go through process to obtain the precertification but rather simply use the emergency room as if it were an outpatient setting. We now even see ambulatory care centers installing CT scanners as well because those centers are also exempt from the precertification requirement. All this in an effort to reduce insurance costs, but does it really?

John R. Cornell
Administrative Director
Spectrum Radiology Associates PLLC
1150 Youngs Road Suite 111
Williamsville, NY 14221
Telephone - 716-688-7615
Fax - 716-688-7592

12/1/2010 9:45:05 AM
Quote from
The overwhelming reason for the increase growth is the spawning of radiology management companies hired by the insurance industry to precertify the study before it can be done in the less costly outpatient setting.

I would love to see data on that statement.
Difficulty obtaining pre-cert is the "overwhelming reason" for increase in ED CT studies??? I think not.
CT heads on minimal trauma, CT PEs on every patient who is short of breath, and CT bellies on every guy who ate a bad taco last night ....that's the bulk of it.

12/1/2010 11:03:50 AM
At the hospitals where I work (3), outpt imaging due to precert issues comprises 0.0% of the increase in ER studies.
It comes partly from ER docs covering their behind or scanning patients who present with routine complaints.  The rest is due to the fact that CT is a damn accurate tool and is necessary in assessing pt symptoms.

12/1/2010 11:48:02 AM

It is almost all caused by ER docs and the overuse of protocols like D-dimer etc. ER is only about getting pts in and out - no time for good history and physical and actually practicing proper clinical medicine.

But, otoh, it is a very good tool and if I were a ER doc I would probably use the heck out of it also.

12/1/2010 11:58:37 AM
True or not, but ED docs I've spoken with claim that this does happen and with increasing frequency.

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