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February 25, 2008 Automated Breast Ultrasound — Increasing Sonography’s Reproducibility Combine the known benefit of ultrasound for breast cancer diagnosis with an automated image acquisition tool that can simplify the ultrasound process and help produce consistent results and you have what some physicians are calling the best thing since sliced imaging. The technology at the forefront of this reaction is SomoVu, an automated breast ultrasound system developed by U-Systems Inc. This system integrates an automated transducer arm, rather than the standard handheld probe, with a display workstation. The acquisition process allows the technologist to select individual diagnostic planes that are captured in an automated scan. The display workstation provides complete 3D renderings of transverse, sagittal, and coronal views. The coronal view is most unique because such an angle is not possible with 2D ultrasound. “It’s the icing on the cake,” says Dennis Yutani, MD, a radiologist at Memorial Hospital of Converse County in Douglas, Wyo. “Automated breast ultrasound takes what was a good imaging modality and makes it better.” Establishing Its Role “There’s no data that says this can replace other screening modalities,” Yutani says. “Automated breast ultrasound is an enhancement to the process and particularly helpful for women with dense breast tissue or women with breast implants. I would hesitate to say we should use this for screening until there is more data out.” From a procedural standpoint, the patient experience with automatic ultrasound begins in a similar fashion as standard handheld ultrasound. The difference starts once the device is secured and engaged and involves how the breast tissue images are acquired. As Thompson describes it, the ultrasound data are acquired with a 14-centimeter transducer that is larger than the approximately 4-centimeter handheld transducer used with most ultrasound equipment. “The larger transducer gives you a better spectral relationship,” Thompson says. “You can see more of the breast.” Sixty-Second Scan During the scanning process, the technologist watches the acquisition to ensure proper breast coverage and tissue contact. When the scan is complete, the technologist reviews images on the monitor, confirms the nipple location, and sends the images to the display station for the radiologist to review. This scan captures 350 ultrasound images that are then rendered and viewed in 3D. “The radiologist looks at the volume of data in its original planes in all views in three dimensions,” Thompson says. “The scan gives you a complete data set.” “With the 3D rendering,” Yutani adds, “there is a large volume of data. It slices like salami and then the data is reconstructed. That’s the biggest part. You can see the different perspectives of what’s going on in the breast. It’s the same anatomy, but you’re seeing it better.” Coronal View “The added benefit with automated breast ultrasound is the 3D look, particularly the coronal view,” she says. “That view is the most helpful. This is a view of the tissue from the skin to the chest wall.” Guingrich, a medical advisor for U-Systems, reported results of the first phase of the two-year clinical trial at RSNA 2006. In that study, the automated breast ultrasound system performance was compared with conventional handheld ultrasound results in 165 women who had first undergone mammograms. Findings with mammography and automated ultrasound agreed with mammography and handheld ultrasound in 94% of the 177 breasts analyzed. In an RSNA 2007 presentation, Guingrich discussed a trial in which the SomoVu device was evaluated to determine if the system could improve breast cancer diagnosis. In the study, women were first diagnosed using handheld ultrasound and then with automated ultrasound. In the end, Guingrich reported that the addition of 3D ultrasound imaging to the breast cancer diagnosis process could increase the chances of finding cancerous lesions. Consistent Exams “It’s more of an art and less science,” she says. “Our hope with this technology is to make it more of a science and less of an art.” Automation creates standardized views based on how the technology of the larger transducer scans a patient’s breast, with imaging parameters for the breast scan determined by the breast size. The technologist can easily repeat this process for follow-up scans, allowing for reproducible image quality and consistency. Images can be saved and reviewed later for comparison purposes. “Automation removes user variability,” Guingrich says. “With the handheld method, the view can be altered depending on the angle and how the transducer is held.” Repetitive Stress Yutani and Guingrich agree that this new technology doesn’t mean the end of handheld ultrasounds. “I still go back to the handheld ultrasound for another view if I see something after the automatic ultrasound is done,” Yutani says. Guingrich adds that automatic ultrasound provides a good overview of the breast tissue, but the handheld can be used for targeting one specific area for further review. “The handheld ultrasound provides a good evaluation for specificity, but when you’re looking for an overview, the automatic ultrasound provides a good view, particularly with dense breast tissue,” she says. “I’ll still use handheld for a correlation to compare with the automatic scan.” New View for Radiologists “It also takes some adapting to view in 3D,” he says. “People think in 3D, but they view in 2D. There is a learning curve. It depends on their experience using 3D. It varies individual to individual.” Guingrich agrees that physicians need to adjust to viewing images from three perspectives rather than one. “There are a lot of images there, with views obtained at different angles,” she says. “Once your eyes become accustomed to the slices, then the reviewing process goes pretty quickly. You have to be methodical. As you read more, you begin to apply your own pattern for viewing ultrasound slices. This is true with all modalities.” Guingrich gives one tip for technologists preparing the patient for an automated exam. “There is a learning curve for the technologists in applying the gel to the patient’s breast prior to scanning,” she says. “You need no air pockets. The more uniform the gel application, the better the view.” “From the technician’s standpoint, it’s pretty straightforward,” Yutani says. “For the radiologist, you’re looking at hundreds of slices. We’re still in the learning phase as far as knowing what the artifacts look like. To say you look at all views at 100% is generous. I focus on the initial view and the coronal view closely.” Quick Adoption “We have a board and an administration that believes in our mission statement: ‘Providing advanced medicine and home town care,’” Yutani says. Developing Automated Ultrasound Uses Thompson says U-Systems will develop more products focused on breast imaging, as well as complete existing clinical trials. “We’re continuing to focus on the breast,” he says. “There’s a long way to go. We have a continued interest with the discovery of disease in breast tissue.” “Ultrasound will never go away,” Guingrich adds. “Hopefully, there will be more acceptance of automated breast ultrasound and future integration with mammography. Hopefully, this will become more of a standard operating procedure than an exception.” — Kathy Hardy is a freelance writer and editor based in Phoenixville, Pa.
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