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A controversial device: Opinions heat up about CAD; FDA keeps close watch, and radiologists should, too

Radiology Administrator's Compliance and Reimbursement Insider, February 1, 2008

To CAD or not to CAD? That is the question for those who use the equipment as a second pair of eyes.

John Smith, JD, MD, BA, a radiologist and partner at Hogan & Hartson in Washington, DC, who assists medical device companies with FDA regulations, is certain about one thing regarding computer-aided detection (CAD) systems: The FDA is watching closely.

“My crystal ball with the FDA is broken and has been for years,” says Smith. “But I would suspect what the FDA is going to do is increase, to some extent, its data requirements, and it’s particularly interested in the impact CAD has on clinical practices. The FDA takes its public health and safety role very seriously, and you can see why they’re concerned.”

Media scrutiny

Several articles and editorials that spoke unfavorably about CAD’s safety and financial implications for radiology facilities drew the FDA’s attention.

One of them—an article written by Joshua J. Fenton, MD, MPH, from the University of California, Davis in Sacramento, CA, and colleagues—sparked controversy about CAD.

CAD, approved for use by the FDA in 1998 and used at more than 30% of healthcare facilities, is used primarily to analyze digital mammograms and target questionable areas for the radiologist. Fenton and the other writers produced a survey, taken over four years and involving 429,000 mammograms and 2,351 cases of cancer at 43 facilities, that found the CAD technology did not help increase cancer detection.

It also leads, Fenton found, to more callbacks because of false-positive findings. That means more money out of the pockets of radiology facilities, which must account for additional fees and payments for diagnostic evaluations.

The implementation of CAD increased the sensitivity of cancer detection from 80.4% to 84%, Smith says. However, the rate of biopsy detection increased by 19.7%, which was statistically significant.

“As for the value of CAD, I’m on the fence,” says Leonard Berlin, MD, FACR, immediate past president of the Illinois Radiological Society and professor of radiology at Rush University Medical College in Skokie. “It helps occasionally, but my perception is that it is not of great value to most mammographers. Of course, we have to realize that the technology is still advancing, so perhaps CAD’s usefulness will increase in the future.”

Smith agrees that CAD’s a technological area that’s evolving.

“Certainly the technology’s gotten better,” he says. “The software is more sophisticated, and there’s more computing [involved]. Mammographies and x-rays to the chest, in many instances, now go directly to digital sources.”

FDA intervention

The FDA reviews CAD devices prior to their marketing in the United States and must either clear or approve the CAD device in order for the product to be legally marketed under the Federal Food, Drug, and Cosmetic Act, Smith says.

“Manufacturing facilities for devices that are approved for market under the premarket approval pathway must be inspected prior to that approval,” Smith says. “Following approval or clearance, the manufacturing of CAD devices is subject to the agency’s Quality System Regulation in a process that involves regular inspections of manufacturing facilities.”

The FDA staff that reviews CAD has seen a high turnover, Smith adds, making it unclear what the final results will be.

“With these new folks, it’s hard to compare the new reviewers to the old reviewers,” Smith says. “There are folks with different technological backgrounds, and all of this is combining to increase scrutiny.”

Smith says the FDA’s inquiries into CAD will not have an immediate effect on practicing radiologists. But it could eventually slow down the process of delivering CAD machines from the developer to the clinician, he says.

“Right now, it’s kind of a bunker-to-bunker approach,” Smith explains. “The FDA questions things on an individual basis. One gets the feeling [the] FDA is reevaluating its whole approach to CAD, and it may put in a more formal policy . . . for looking at this technology. It’s possible [it] may have to form an advisory committee of experts.”

As for the benefits of CAD, Smith says, “It’s the sanity check when you’re going through stacks and stacks of film. That’s where it’s made the most difference. Many radiologists do rely on CAD because they just want to make sure.”

Insider sources

Leonard Berlin, MD, FACR, immediate past president of Illinois Radiological Society and professor of radiology, Rush University Medical College, 9600 Gross Point Road, Skokie, IL 60076, 847/933-6111; Leonard_Berlin@rsh.net, www.illradsoc.org.

John Smith, JD, MD, BA, radiologist and partner, Hogan & Hartson, Washington, DC, 202/637-3638; jjsmith@hhlaw.com.

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