Technology gains outpace standards methodology

October 1, 2006

Imagers challenge consistency, convenience, and timeliness of Appropriateness Criteria

Imagers challenge consistency, convenience, and timeliness of Appropriateness Criteria

Accelerating changes in technology are forcing the American College of Radiology to make more frequent updates to its Appropriateness Criteria manual. But even when it does so, imagers say, technology adoption tends to occur ahead of the peer-reviewed literature that supports it.

Expert physician panels appointed to develop the criteria can hardly overlook recent technological advances and their clinical applications. But their challenge is to determine the best approach based on data, not on technical prowess, said Dr. Michael A. Bettmann, chair of the appropriateness criteria committee.

"The Appropriateness Criteria does not represent expert consensus. It is primarily designed to represent what studies prove," he said.

The guidelines include more than 160 topics ranging from cardiovascular to interventional radiology, women's imaging, and radiation oncology. The expert panels comprise more than 200 diagnostic and interventional radiologists, radiation oncologists, and nonradiology specialists.

The ACR used to evaluate the criteria every three to five years, but due to the pace of technological advances, updates are now performed annually. The ACR reviewed more than 30 topics last January and has updated about 100 or more since 2005.

Questions regarding the methodology behind the manual, specifically its timeliness and consistency, still linger, however.

Chest x-ray is one example. With a rating of nine points, it remains at the top of the Appropriateness Criteria chart for imaging studies of acute chest pain for suspected myocardial ischemia. Albeit the most widely available and cheapest imaging study ordered in acute chest pain, it is also probably the least helpful, said Dr. Michael Blaivas, an associate professor of emergency medicine at the Medical College of Georgia in Augusta.

Echocardiography may not be able to detect small lung nodules, but it does provide more information about heart condition and function, and, in many cases, it could be more useful than x-ray.

Multislice CT may also prove a cost-effective one-stop imaging test for chest pain. But the data to validate MSCT as the top imaging modality in this setting have yet to be published. As a result, MSCT remains at the bottom of the appropriateness table, Blaivas said.

Another apparent inconsistency in the criteria relates to detection of liver metastases. An increasing number of studies performed in Asia and Europe show contrast-enhanced ultrasound equivalent to MSCT for this application. CE-ultrasound is nowhere to be found in the respective Appropriateness Criteria table, however.

"Contrast-enhanced ultrasound does not pay nearly as well as CT or MRI, and many radiologists are not interested in ultrasound for that very reason," Blaivas said. "Second, it is harder to sit at home and read ultrasound scans. In many cases, you have to be there to do part of the scan for best results. Third, despite the great data, ultrasound contrast for the body is not FDA-approved at this time."

The criteria address changing times, Bettmann said. Some imaging modalities may not be available around the clock in some facilities. In such environments, imaging standards should keep up with resources. If a modality is unavailable, or if the expertise to perform it isn't present or results are equivocal, then physicians should consider appropriate alternatives.

"The criteria can serve as guidance for radiologists, medical students, residents, and referring clinicians as they consider what kind of imaging studies might be useful in any given clinical condition," he said.