Diagnostic Imaging
November 2003

SONOGRAPHY

Handheld ultrasound creates new turf, practice challenges

Small devices redefine sonography's clinical use, but is the sono(stetho)scope ready?

Many radiologists have an uncertain idea of what the future holds, including the contents of the familiar physicians' black bag. In the primary-care physicians' bag of tricks, they may soon see a "sonoscope," a pocket-sized ultrasound scanner capable of delivering diagnostic information at the wave of a hand.

When the first handheld ultrasound systems appeared in the late 1990s, they captured the imagination of manufacturers and users alike. Some futurists even forecast the death of the stethoscope, or at least its mortal wounding. While the sonoscope now seems closer to clinical reality than ever, medical personnel have begun to wonder just how useful it will be.

Handheld ultrasound is still in its infancy. Systems already available are just as small and light as notepads, laptop computers, or briefcases, but they are nowhere close to what some radiologists visualize: a device as small as a stethoscope, with a little screen, that is no larger than a PDA.

Most clinicians and manufacturers make a distinction between portable ultrasound systems, which are laptoplike units weighing 10 to 30 pounds, and true handheld devices: pocket-sized imaging instruments that weigh no more than 3 pounds. The concept for both types, however, is the same-a miniaturized ultrasound scanner that can be easily carried and taken almost everywhere.

Among the top manufacturers are SonoSite, which markets the iLook, 180, SonoHeart, and Titan models; Medison, with the mysono 201, SonoAce, and new Pico; Philips with Optigo; and Terason with its SmartProbe and Terason Software.

"We serve five major core markets: radiology-including interventional radiology-ob/gyn, cardiology, surgery, and emergency medicine," said Dan Walton, vice president and general manager of SonoSite.

Other clinical areas where vendors have been focusing marketing efforts are urology, neurology, and phlebology. Interestingly, when these systems first saw the light, radiologists were not at the top of the vendors' list. Ob/gyns had long used ultrasound, and handheld systems seemed to fit in their clinical practice. While this market was originally a big part of SonoSite's portfolio, things have changed lately, said Dave Willis, director of global product strategy.

"Radiology has now become SonoSite's biggest market," he said.

Radiologists were skeptical about the handheld until they saw it in action, according to Willis. They tried out the device's diagnostic capabilities first. Then they figured out what kind of tasks they could perform with it. When they needed to visit outside clinics, for instance, they took the system with them. If they had to perform a simple ultrasound test on a patient two, three, or more floors upstairs, the big machine was left behind.

"The radiologists were the ones who drove us to consider putting pulsed-wave Doppler in our system," Walton said. "Then they asked for color and duplex, and we delivered. It's been a very active four years."

First-generation handheld ultrasound devices featured characteristic 2D gray-scale displays. Current-generation devices combine portability and ease of use with some of the high-end systems' most popular features, such as color and power Doppler, as well as linear, phased-array, and intravaginal probes. Medison's new handheld device, the Pico, includes black-and-white display; color, power, and spectral Doppler imaging; and even a 3D component, said marketing manager Jeff Johnson.

Powerful and innovative as they are, handheld ultrasound systems cannot yet match the power and image resolution capabilities of high-end systems. Still, nursing staff, interventional radiologists, and ER physicians in some large U.S. hospitals use these little machines to access vessels, place catheters, and perform thoracic aspirations. Obstetricians, too, sometimes use them in delivery rooms for placental localization.

CLINICAL APPLICATIONS

One of the first areas where portable or handheld ultrasound devices proved their value was the military, and it didn't happen by chance. Since the early 1990s, the Department of Defense has provided research grants that helped boost handheld R&D. More than 300 handheld systems have been used in Iraq and Afghanistan during the last year and a half, Walton said.

Researchers at Brooke Army Medical Center in Fort Sam Houston, TX, evaluated focused abdominal trauma sonography examinations using a handheld device in a field environment. They found this type of examination to be feasible. They also proved that real-time satellite transmission of the exam for remote clinical interpretation was possible (Prehosp Emerg Care 2003;7[3]:375-379).

Handheld ultrasound is making inroads in more traditional clinical scenarios as well. In settings such as the Medical College of Wisconsin, interventional radiologists and emergency physicians are the primary users.

"We are using handheld devices for vascular access, like peripherally inserted catheter line placement," said Dr. Francisco Quiroz, director of ultrasound at MCW.

Veins can be hard to visualize in some patients, such as those who have undergone chemotherapy. Handheld ultrasound is useful, facilitating the injection of contrast media for CT examinations in these patients, Quiroz said. ER physicians use the devices for abdominal aortic aneurysm screening, free fluid detection in the peritoneum in blunt trauma patients, and some ob/gyn-related emergency applications like ectopic pregnancies.

A University of Chicago study presented at the American Society of Echocardiography meeting in June showed how handheld ultrasound can help medical students. The trial suggested that the portable devices could enable them to refine their auscultatory skills. In addition, the study said, medical students could make better diagnoses than they would relying only on traditional techniques.

"The idea of using ultrasound is attractive," said principal investigator Dr. Jeanne M. DeCara, an assistant professor of medicine at the university's cardiology section. "It doesn't mean we have to throw our stethoscopes away. But we can enhance the diagnostic information we get at examination with handheld devices."

OPPORTUNITY OR THREAT?

The main advantages that both physicians and vendors attribute to handheld systems are portability and price. Handheld ultrasound can be used in any situation in which it is better to move the equipment rather than the patient, Quiroz said. Radiologists could go with a handheld or any other portable equipment to the intensive care unit, for example. Handhelds can be more easily managed in the limited space around patients who are intubated. Moving the little machines around doesn't disrupt the radiology department's workflow, as the bigger machines remain in place and operational.

Prices are relatively low, ranging from $10,000 to $33,000. These low prices and the scanners' portability concern some radiologists.

"As they get more portable and less expensive, we will see them being used more by specialties that traditionally have not used ultrasound before," said Dr. Lennard D. Greenbaum, president-elect of the American Institute of Ultrasound in Medicine.

Widespread availability could lead to lower reimbursements and a smaller market for the larger high-end machines often favored by radiologists. That could happen exactly when exciting developments in the field are taking place: Resolution is consistently being improved, and tissue harmonic and multidirectional imaging have recently been introduced, along with improvements in color-flow, 3D, and 4D imaging. Researchers are also waiting for approval of new contrast agents that could potentially enhance the role of ultrasound.

"There's a lot of development going on, and I would hate to see R&D diminish because of the proliferation of small, basic ultrasound units being utilized by numerous physicians," Greenbaum said.

Others are concerned about the potential for an increase in medical errors, as less qualified practitioners begin to use the devices.

"If the physicians doing it are not educated, they may make improper interpretations, and diseases, abnormalities, or cancers could be missed. If things are missed or inappropriately diagnosed, we are going to see an increase in lawsuits," said Dr. Barry Goldberg, director of the Thomas Jefferson University's Ultrasound Research and Education Institute.

Not all radiologists see the proliferation of inexpensive handhelds as a threat, however. Dr. Brian Garra, clinical director of ultrasound at the University of Vermont College of Medicine, contends that widespread ultrasound utilization could actually increase business. Physicians who use handhelds as adjuncts to the stethoscope during physical examinations may encounter questions or problems they cannot solve, and they may refer those patients to experienced sonologists.

"What I'm trying to do in our institution is focus our ultrasound offerings toward the high end, so we are going to start doing more high-performance tests," Garra said. "That's where you add value, when you can do something that nobody else can do."

EDUCATION AND REGULATION

Regulatory bodies such as the American College of Radiology do not yet have an official position on handheld ultrasound utilization, education, and training. The role of handheld ultrasound was on the agenda for discussion at the 13th annual meeting of the Society of Radiologists in Ultrasound in October.

A number of practitioners, including some outside of radiology, suggest an approach similar to that of some European nations. Primary-care physicians in the U.S. who wish to use ultrasound in the same way as their counterparts in Germany, for instance, should undergo the same type of training and certification, according to Greenbaum.

The physician's primary responsibility is to protect the public, he said. If someone, from any specialty, is using an ultrasound machine in any capacity, he or she ought to be appropriately trained and adept at using the equipment to avoid causing harm to patients.

The idea is bold, and it brings up more questions. Who's going to teach ultrasound in medical school? Many radiologists would like to know, since they are already struggling to teach their own residents during a well-documented staffing shortage. Others prefer to ponder the impact handheld devices will have on the specialty and on medicine as a whole.

"Whether I think it is a great idea, good or not for radiology, is irrelevant. It's going to happen," Garra said. "So I'm planning on it."