Physical therapists are increasingly employing a new tool to better evaluate patients and their progress, while giving patients a clear image of how muscles and tendons work deep inside their body: ultrasound imaging.

Ultrasound gives clinicians the ability to measure and see internally and could be a "game changer" for therapists, said Theodore Croy, PT, PhD, OCS, MAJ, SP, an assistant professor at the U.S. Army-Baylor University Doctoral Program in Physical Therapy, at the Army Medical Department Center and School at Fort Sam Houston, Texas. "A picture is worth a thousand words and that holds true here," he said. "Ultrasound imaging may bring a whole new dimension to PT in terms of research, and practice and patient management."

Assessment and biofeedback

Ultrasound is used predominately by PTs to aid in the evaluation and clinical management of soft tissue, especially abdominal or paraspinal muscles, or in women’s health to see pelvic floor muscles related to incontinence problems, said Mary Fran Delaune, PT, MPT, director of the Practice Administration Department for the American Physical Therapy Association.

"As PTs, we have the ability to evaluate muscle function and performance. We have a sense of how long it takes tendons or muscles to recover, but that’s an average," Delaune said. "Through a combination of physical exam and ultrasound, physical therapists can direct interventions better and objectively measure tissue performance and healing. For example, in tendon repair, an ultrasound allows you to see the soft tissue moving as the patient moves. We can know better how and when to progress a patient further on his or her treatment plan."

Another important application of the technology by PTs is to provide valuable biofeedback to the patient in real time while the muscles and tendons are in motion, said Leslie Adrian, PT, MS, MPA, director of professional standards for The Federation of State Boards of Physical Therapy in Alexandria, Va. "PTs are using musculoskeletal imaging right there with their patients as a really good educational tool," she said. "It enables the PT to show the patient that with an adjustment in posture then this happens, or a muscle appears to be firing when you do this exercise. PTs are using the images as visual cues for their patients."

Such biofeedback can provide "additional means to self-correct," Croy said. "For example, the imaging enables patients to experience contracting a muscle in their abdomen or near the lumbar spine while they’re seeing it contract simultaneously."

A safe option for PTs

With decades of use on pregnant women, ultrasound imaging has proven to be safe and noninvasive, said Adrian. Ultrasound waves are nonionizing radiation, so they do not have the same risks as X-rays or other imaging, she wrote in her resource paper "Rehabilitative Sound Imaging," published last year on the FSBPT website.

While magnetic resonance imaging is commonly ordered by physicians, PTs cannot by law order such a test, Adrian said. "There are no state practice acts that currently allow PTS to order imaging such as X-ray, CT scan or MRI," she said. "PTs certainly use data from those physician-ordered images. Nothing precludes them from using that imagery. But there is no ability for PTs to write direct orders for those types of tests. We don’t have the authority at this point."

Adrian said PTs face a tough legislative battle if they attempt to change the rules in that area. "It will be seen by other professions as trying to increase our scope of practice," she said. "I think it will be met with opposition."

Ultrasound imaging, however, serves a wide assortment of healthcare practices, she said. To show its scope, in 2010 the American Institute of Ultrasound Medicine invited more than 55 professional groups, including APTA, to its ultrasound practice forum, she said. "Musculoskeletal imaging came from a multitude of different practices — no one is fighting over this," she said. "It has been a very collaborative, multi-disciplinary movement."

Also, ultrasound imaging is used within the traditional practice of PTs, Delaune pointed out. "We’ve always evaluated function and performance," she said. "We now have a new tool to see it better. This has always been part of our scope of practice. We use this tool to be more effective."

Croy agreed this is not out of the normal realm of physical therapy. "We’re not changing how we treat these patients by using ultrasound imaging," he said. "But in the future, we may be compelled to alter our assessment and exercise plan. Right now, there is more clinical and research work to be done, as well as practice guidelines to establish."

"The past eight to 10 years we’ve seen increasing clinical and research interest in ultrasound imaging for the identification of movement impairments in the musculoskeletal system — specifically at the lumbar spine and trunk muscles," Croy said. "In the next two to three years, we will likely see clinicians using ultrasound imaging for broader applications such as quantifying ankle or elbow laxity as well as identifying the effects of therapeutic interventions."

Costs decreasing

The popularity of ultrasound imaging among PTs is increasing as the technology goes down in price, said Delaune. "It’s growing as the technology becomes more accessible and affordable in a PT clinic," she said. "It’s becoming much more widespread."

Ultrasound software and probes ranges in price from $5,000 to $20,000, Croy said. "The most inexpensive versions have software and a USB ultrasound probe that connects to a computer," he said. "But that gives you a low imaging quality. Between $10,000 and $20,000 will get you a portable unit."

Manufacturers of the units include General Electric, SonoSite and Terason.

PTs will have to work at becoming proficient in ultrasound imaging techniques. "It requires considerable technical skill and knowledge of surface and cross-sectional anatomy — PTs have a lot to learn regarding the employment of this imaging capability in clinical practice," Croy said.

Several groups, including APTA, AIUM and the Society of Diagnostic Medical Sonography, offer continuing education and certification in ultrasound imaging for PTs. Physical therapy schools are starting to introduce it to their students also, Croy said. "Most schools don’t have formalized training in it, they merely expose their students to it," he said.

Experience in ultrasound is vital to be able to read the images correctly, Croy said. "It takes a lot of time to gain skills in using ultrasound imaging," he said. "There are professional risks in using ultrasound and not interpreting it properly. Clinicians should first do their homework in how it can be used and then use it for a specific, limited purpose, such as imaging the transversus abdominis and oblique muscles, or the lumbar multifidus with the intent of improving neuromuscular control of the spine and gain skills in a limited application before employing it in other anatomical areas or clinical applications."

If an ultrasound image shows anything abnormal, PTs need to refer the patient to an appropriate provider, Delaune said. "If it presents in a way that doesn’t fit what you’re trained to evaluate, you refer them on," she said. "Also make sure the patient understands your use of the technology and its focus and intent and how that may differ from other providers."

The future of ultrasound imaging in physical therapy is bright, Croy said. "It’s not for every PT office, but for the evaluation of musculoskeletal related disorders, ultrasound imaging has a place in the identification of movement-related impairments and results are promising," he said. "The capability to see these images is becoming increasingly affordable to a greater number of PTs, many are going to be eager to employ it. The combination of a skilled provider, a patient and a safe imaging modality within the PT setting could have quite an impact in the coming years." •

Teresa McUsic is a freelance writer.