· Running the Numbers
· AIUM Offers Contrast-Enhanced Ultrasound Recommendations to FDA
· Tech Zoom: Monolithic Doppler Phase Shifter Geared Toward Portable Ultrasound
· University of South Carolina Begins Ultrasound Study

Running the Numbers

When in the scanning room, ultrasound users should break every 10 minutes for a brief period, according to Franklin Tessler, MD, CM, in the “Ask the Expert” section of the Society of Radiologists in Ultrasound (SRU) January 2007 newsletter. The question asked how to avoid injury while in the scanning room. Tessler?s other suggestions include:

  • avoid twisting your body;
  • don?t grip the transducer tightly; and
  • if you experience any pain or numbness, stop working immediately and seek professional attention.

For more information, visit www.sru.org.

?C. Vasko

AIUM Offers Contrast-Enhanced Ultrasound Recommendations to FDA

In 2005, the American Institute of Ultrasound in Medicine (AIUM), Laurel, Md, initiated discussions with the FDA to encourage the review and approval of ultrasound contrast agents. At that time, the FDA asked the AIUM to develop recommendations regarding contrast-enhanced ultrasound; AIUM distilled ideas from a July 2006 ultrasound contrast agent forum into its AIUM Recommendations for Contrast-Enhanced Liver Ultrasound Imaging Clinical Trials, presented to the FDA last November. Medical Imaging spoke with AIUM president Lennard Greenbaum, MD, about the details of the initiative.

Lennard Greenbaum, MD

MI:  What were the AIUM’s recommendations?

Greenbaum: We’re dealing specifically with using ultrasound contrast agents on the liver, and we divided that subject into several different areas. First, we felt that one had to identify appropriate endpoints for assessment of the efficacy of the contrast agents. We gave some examples of possible endpoints; one would be improved characterization of focal liver masses with contrast-enhanced ultrasound [CE-US] imaging, to determine whether a focal liver mass is benign or malignant compared with non-CE-US imaging. Another is improved ability to detect focal liver masses with CE-US imaging. Another would be a reduction in referral for further workup using other imaging or diagnostic procedures.

Second, another area focused on examination procedures, how the contrast agent should be prepared and administrated, the quality control of equipment, addressing qualified personnel, and the need for baseline imaging. We also had a section dealing with equipment, another dealing with training, and another dealing with safety.

MI:  What issues are the recommendations intended to address?

Greenbaum: One of the major problems that the FDA had in general was termed cross-platform reliability, meaning that if you go from one brand of ultrasound machine to another, or one brand of contrast agent to another, are there going to be marked differences? The FDA didn’t want to see that a contrast agent was machine-specific—that you got great results with Brand X, but with Brand Y, it didn’t work as well. They wanted to see that agents could be used across platforms, and what we were trying to do was eliminate or, if not eliminate, at least decrease variance going from platform to platform. We felt that involved trying to control the variables of the examination, the equipment, and the training of the people performing the examination.

MI:  What changes does the AIUM want to see?

Greenbaum: Well, the principal changes become very detailed. This document will be published in an upcoming issue of the Journal of Ultrasound in Medicine. In the equipment section, [we want] just some generalizations: If you’re going to use contrast agents, the equipment needs contrast-specific imaging modes that work on a low mechanical index; the performance requirements of the equipment need to be detailed. We had the three major ultrasound manufacturers—GE Healthcare, Philips Medical Systems, and Siemens Medical Solutions—provide us with information regarding how to set up their machines appropriately. There’s a lot of technical material as to capabilities that the equipment should have. Generally speaking, specific capabilities need to be present in order to achieve optimal results with contrast agents, and you need to make sure that the machines being used have those capabilities. Another important note under the equipment heading was that even though the technology is changing, if you started out with a certain level of equipment during a trial, you ought to stay on that level even if an advancement comes out.

MI:  What about changes in training and safety?

Greenbaum: For training of individuals, we emphasize the fact that there needs to be specific training in the use of contrast agents and setting up the machines, and that facilities may need to set up training centers in the initial stages to ensure that participants in trials all have at least the same basic level of training.

Under safety, we emphasized that the safety record of the contrast-enhanced ultrasound agents has been excellent, and that after we did a review of the literature, complications or reactions appear to be less than what we see with other agents in other imaging modalities. CE-US is used around the world and has not shown any significant problems in Europe or Asia. So, the final conclusion was that the AIUM believes that implementation of these recommendations will decrease variance among sites and increase the likelihood of successful clinical trials.

Cat Vasko is associate editor of  Medical Imaging. For more information, contact .

Tech Zoom: Monolithic Doppler Phase Shifter Geared Toward Portable Ultrasound

A new demodulator and phase shifter from Analog Devices Inc, Norwood, Mass, boasts the ability to reduce board space by as much as 75% by replacing large crosspoint-switch matrices and analog delay lines typically employed in phased-array beam forming. With energy consumption of just 73 mW/channel—30% less than standard phase shifters—the AD8339 demodulator allows medical instrument manufacturers to provide CW Doppler capabilities in portable and battery-powered ultrasound equipment.

The power savings of the AD8339 demodulator and phase shifter from Analog Devices enables designers to increase the channel density of cart-based ultrasound systems.

Such variables as tissue density, fluid viscosity, and rate of fluid movement can create signals with exceptional dynamic range requirements when transmitting and receiving Doppler ultrasound signals. The dynamic range of the AD8339 is 158 dB/Hz; the system also features 22.5? phase steps, compensating for signal latency caused by physiological variables and ensuring accurate, time-aligned portable ultrasound images.

With a simple three-wire serial peripheral interface for digital control of channel selection and phase states by system computer commands, the AD8339 leverages a single synchronized common local oscillator input for all channels, enabling precise phase locking to the system clock.

The quad-programmable phase-shifter and demodulator will be available commercially in June for $11.95 in 1,000-piece quantities; it also is available in a 40-lead lead-frame chip-scale package.

?C. Vasko

University of South Carolina Begins Ultrasound Study

A new partnership between GE Healthcare, Waukesha, Wis, and the University of South Carolina (USC) School of Medicine, Columbia, SC, will test the educational and diagnostic potential of portable ultrasound devices. Beginning with the class of 2010, students at the School of Medicine will test GE Healthcare’s Logiq e ultrasound units, which are about the size of a laptop computer, weigh 10 pounds, and are designed for general diagnostic use.

“The Logiq e can be used at the bedside, and it has the capability to transfer high-quality digital images anywhere in the world over the Internet in minutes,” says Robert Honigberg, MD, global general manager of medical and clinical strategy at GE Healthcare. “It’s geared toward physical diagnosis and general exams.”

Honigberg explains that the partnership with USC is intended to proliferate the use of ultrasound through the next generation of medical professionals. “The goal is to validate that ultrasound can make a difference in the medical school curriculum, that it will increase scoring on testing—both for courses as well as the ability to make clinical decisions in their clerkships—by helping them understand spatial anatomical relationships. That data is all going to be captured and published. A key audience here is the Association of American Medical Colleges, and if that data looks positive, I think this is something that will definitely be exported to medical schools.”

Medical students at USC will learn about the benefits of ultrasound as a diagnostic tool in fields as different as family, preventive, and internal medicine; surgery; obstetrics and gynecology; and emergency medicine. An ultrasound curriculum has been added for students in their second, third, and fourth years. The program will be Web-based, allowing each student’s scores to be tracked over time.

“The ultrasound program at USC is de-signed as a vertical curriculum, so it starts in their first year and is employed immediately for their anatomy lectures,” Honigberg notes. “They’ll have their cadaver dissection, they’ll get their lecture, and then they’ll be able to go into the ultrasound laboratory and understand the anatomical relationships of what they’re learning. ? I think having this skill set can only make students more attractive.”

Students also will give feedback on the equipment’s design, and as GE Healthcare refines its portable ultrasound units, the models in use at USC will be refreshed. “It will be an iterative process,” Honigberg says. “And as the machine gets smaller and smaller, it will, of course, become more affordable. The target here is to have technology like this spread to primary care physicians and rural physicians on the front line.”

GE Healthcare also has established a similar relationship with another medical school; however, the company had not revealed its name at press time.

—C. Vasko