When most people think of diagnostic imaging, they think of X-rays, CT scans and MRIs, but the use of musculoskeletal ultrasound is becoming more popular for physical therapists. With most states having direct access laws, physical therapists are becoming primary care providers for musculoskeletal injuries. Despite a long history of therapists effectively using imaging in the military, and some managed care organizations like Kaiser Permanente in Northern California, in the United States PTs usually can't order X-rays, CT, or MRI scans. They can, however use musculoskeletal ultrasound.
A musculoskeletal ultrasound is very similar to the more common sonogram used during pregnancy. Both use sound waves to create an image of what's going on in the body in real time. Ultrasound can show a PT many structures in the body and can be used to help diagnose strains, sprains, inflammatory conditions like tendonitis or bursitis, nerve entrapments, and hernias.
Ultrasound is not popular with PTs just because they are limited in the ability to order other imaging. Research and clinical experience supports ultrasound as the preferred diagnostic test for many musculoskeletal injuries. Here are some benefits of ultrasound that support why:
- Ultrasound uses no radiation and has no known harmful effects on humans
- Real time imaging allows ultrasound to capture movement in the tissues, something x-ray, CT, and MRI can't do
- Ultrasound is widely available, and less expensive than most other types of imaging
- Ultrasound may provide greater detail of soft tissues like muscles, tendons, or joints
- Ultrasound can be used on people who can't have an MRI such as patients with pacemakers, and certain metallic implants
- Patients don't have to remain still for an ultrasound, meaning it can be easily used on people who are claustrophobic or nervous about other imaging types
With such a list of advantages, it seems that ultrasound is a great type of imaging technology. This is true, but it's not without a few drawbacks. These would include:
- Difficulty penetrating bones, and through large amounts of soft tissue, limiting the ability to see the deepest tissues in the body
- Ultrasound also has difficulty showing the internal structure of bones, making other techniques better for detecting suspected fractures