AIUM white paper targets FDA’s contrast ultrasound approval

The American Institute of Ultrasound in Medicine unveiled a new strategy aiming at final FDA approval of contrast media for clinical ultrasound applications outside cardiology. The white paper outlining the plan appears in the June issue of the Journal of Ultrasound in Medicine. Though widely used around the world, particularly in the detection and characterization of liver tumors, contrast-enhanced sonography has been approved by the FDA only for a few cardiac imaging applications. The lack of approval not only causes the U.S. to lag behind the rest of the world, it may also be diminishing the quality of clinical care in this country, according to principal author Dr. Lennard D. Greenbaum, AIUM past president."Ask radiologists to look at a CT or an MRI of the liver without contrast. They are not going to be very happy about it," Greenbaum said. "Just like contrast material improves detection and differentiation of disease with those modalities, the same thing is true with ultrasound."The approval of ultrasound contrast agents could stimulate interest in the radiology community to get more involved in ultrasound. Contrast approval may not be critical for the survival of ultrasound as an imaging modality, but it is paramount for its development within the U.S. radiology community, he said.

The American Institute of Ultrasound in Medicine recommendations for contrast-enhanced liver ultrasound imaging clinical trials paper outlines a five-step approach:

• appropriate end points for the assessment of contrast media efficacy
• examination procedures that follow the indications of contrast manufacturers
• proper equipment and technical imaging settings
• safety guidelines
• personnel training requirements

The FDA has dealt with several issues related to contrast media in sonography. These include inconsistent outcomes across equipment platforms, insufficient training of some people performing the trials, and inappropriate use of technology. The AIUM wrote these guidelines at the FDA's behest to establish a framework that would give researchers a better chance of success with the FDA. The recommendations focused on the liver instead of other organs because of the abundant literature on the subject, Greenbaum said.

"We addressed all the issues that they were looking at: The training that's needed, the equipment, the setting up of the equipment . . . ," he said.Ultrasound contrast experts Dr. Stephanie Wilson and Peter Burns, Ph.D., from Canada and Dr. David Cosgrove from the U.K. also contributed to the paper. The FDA approved the document in November 2006. The AIUM is developing a clinical trial and looks at a couple of years before completion and FDA approval of the first contrast application in the liver, Greenbaum said. The U.S. has been blessed with the technology and the economics to be able to afford CT scans and MRI machines. However, there have been recent indications of increased radiation with CT and some toxic side effects from gadolinium. Having ultrasound using contrast agents as an alternative to these modalities would be a plus, he said."Ultrasound was the golden child in radiology in the late 70s and 80s and then started to become less popular as CT and MR came more to the forefront. I would like to see ultrasound regain a position of prominence within radiology, and contrast agents can help do that," he said. For more information from the Diagnostic Imaging archives:

Ultrasound's future in play: Will radiologists remain in the picture?

CE ultrasound broadens scope of clinical utility

Radiologists pledge to recapture sonography

Contrast's promising start gives way to slow adoption