Abdominal-Pelvic CTs Generally Used With Discretion in ED

James Brice

June 14, 2012

June 14, 2012 — A study involving more than 1 million Medicare patients indicates that abdominal-pelvic (AP) computed tomography (CT) is performed mainly on complex cases in the emergency department (ED).

Radiologists Richard Duszak Jr, MD, from Mid-South Imaging and Therapeutics and the University of Tennessee Health Science Center, Memphis, and colleagues established that 93.8% of CTAP procedures performed on Medicare patients in the ED were deemed highly complex, using current procedural terminology (CPT) billing codes assigned to the procedures. The remaining 6.2% involved less complexity, according to their study, which was published in the June issue of the Journal of the American College of Radiology.

The percentages translated into 61,204 CTAP studies for complex encounters and 4069 CTAP studies for cases involving less complex pathology, based on 1,081,000 ED encounters covered by Medicare in 2007.

The findings may not come as a surprise to ED physicians and radiologists, who have an intuitive understanding about the patterns of trauma, acute disease, and medical imaging applied in an ED setting, Dr. Duszak told Medscape Medical News. However, they helped document the reality of its use for skeptical policymakers and the general public, he said.

High-tech medical imaging, exemplified by multislice CT, has been under fire since an explosion of technological innovations beginning in the late 1990s greatly improved the speed, resolution, and diagnostic power of the technique. Also powered by rising magnetic resonance imaging (MRI) use, high-tech imaging became the largest single contributor to increased physician services costs for outpatient Medicare in the first half of the 2000s, according a 2006 Government Accountability Organization Report.

As exemplified by the analysis by Rebecca Smith-Bindman, MD, published in the June 13 issue of JAMA, CT has also drawn intensive interest because of its association with rapidly rising public exposure to medical radiation.

The current study indicates that CTAP is generally applied with discretion in the ED.

"If the contention is that physicians are using CT willy-nilly without appropriate discretion, we would see very high utilization in both low- and high-complexity patients," he said to Medscape Medical News. "In our experience and our practices, we understand utilization is truly higher in higher-complexity patients."

The Memphis group established that the differential use of CTAP in lower- vs higher-complexity encounters is highly significant (P < .001). Overall, 28.3% of ED visits covered by Medicare were coded as low-complexity cases; 774,599 cases (71.7%) were classified as high complexity.

Medicare use data were classified according to 5 CPT codes covering CTAP for ED patient evaluation and management. CPT codes 99281, 99282, and 99283 were applied to cases involving lower complexity, and CPT codes 99284 and 99285 identified higher-complexity cases.

Debunking Assumptions

The study's primary finding about the overwhelming likelihood of CTAP in highly complex cases argues against the belief that it is widely used in the ED for less-complex cases, Dr. Duszak noted.

According to the authors, the findings also contradict assertions that because of mispricing (for the multi-million-dollar CT scanners), medical imaging has been inappropriately expanded to lower-complexity patients.

For Alisa D. Gean, MD, a professor of radiology at the University of California, San Francisco, who also practices in the ED at San Francisco General Hospital, there is no question that CT for blunt polytrauma is the way to go.

"We are talking about life-saving issues in a lot of these cases," Dr. Gean told Medscape Medical News. "Radiation is really not a concern when you are saving a person's life."

CTPA serves as the equivalent of a radiological "1-stop shop" for acute AP pathology because of its easy accessibility, speed, resolution, and wide volumetric coverage, she said.

Some gastrointestinal specialists have proposed MRI as an alternative because of its high-contrast resolution and lack of ionizing radiation, but it is not as available as CT, is more cumbersome, and is more precarious when ED personnel do not know whether an uncommunicative patient is equipped with metallic stents or implants that would contraindicate MRI.

"You can't just put these patients in a magnetic field and hope nothing is going to go wrong," she said.

Still Need for Alternatives

However, the findings do not reduce the need for radiologists and ED physicians to look for alternative modalities for infants, children, and women who are especially vulnerable to induced cancers from ionizing radiation, Dr. Duszak said. Imaging tests should be tailored to optimize its clinical benefits and minimize radiation risk.

Appropriateness criteria from the American College of Radiology generally recommend diagnostic ultrasound in the ED for gallbladder disease and gynecologic pathology, especially in the presence of pregnancy, he noted. In addition to his practice in Memphis, Dr. Duszak is chair of the American College of Radiology Committee on Imaging Policy and Economics Research.

"This study doesn't in any way mitigate the need to encourage the profession to be a good steward of radiation safety," he said.

The study's limitations include that Medicare's research-identifiable files did not include actual patient records, making a timely examination of physician documentation impossible, according to the authors. This limitation was offset by the ability to aggregate imaging data from more than 1 million patients.

In addition, findings based on Medicare data do not apply to younger patients, who are likely to arrive in the ED with a substantially different profile of indications leading to CTPA than retirement-age adults.

The researchers also restricted their analysis to ED evaluation and management and CTAP claims for the same date of service. This policy minimized the erroneous capture of unrelated services, but it decreased the identification of coincident overnight services, such as CTAP at 10 pm and hospital discharge at 3 am, leading to different dates for CTAP and evaluation and management claims.

Dr. Duszak and Dr. Gean have disclosed no relevant financial relationships.

J Am Coll Radiol. 2012;9:409-413. Abstract

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