Arthritis, or joint inflammation, may cause irreversible damage and disability if left untreated. Experts say early and accurate diagnosis and treatment is critical to managing pain and improving joint function. Though ultrasound has been used in medicine since the 1940s, technological advances now make it possible to expedite relief for many of the 46-million Americans with arthritis.
“Ten years ago, it was difficult to distinguish enough detail in ultrasound images to make an accurate diagnosis of arthritis,” says UCLA rheumatologist John FitzGerald, MD, PhD. Ultrasound uses high-frequency sound waves to produce images that identify the distance, size and shape of objects inside the body. Compared to conventional X-rays, ultrasound is now the second most common form of diagnostic imaging, and may produce images that provide additional information.
“We can use ultrasound to identify inflammation, swelling or increased blood flow in a problem area or to see the crystals associated with gout,” he explains.
Based on that information, Dr. FitzGerald says, physicians can diagnose whether the arthritis is non-inflammatory (osteoarthritis), inflammatory (rheumatoid arthritis) or gouty (a form of arthritis that develops when uric acid crystals form in and around the joints, usually of the big toe) and determine if the condition is likely to cause serious problems.
“If someone has shoulder pain, for example, we need to figure out where the problem is,” Dr. FitzGerald says. “Ultrasound can help us determine if the swelling is in the rotator cuff joint or in the tendon attached to the joint. The location of the inflammation suggests one disease over another, but this information would be difficult to find with only a clinical exam.”
Because ultrasound provides real-time images, physicians can also use the technology for treatment, such as to guide placement of corticosteroids, which are anti-inflammatory hormones that temporarily relieve pain when injected into affected joints.
“We can make the diagnosis and treat the patient right there, with less pain and more accuracy,” Dr. FitzGerald says. “Most patients are very comfortable with ultrasound technology and prefer the convenience of being diagnosed and treated in our office rather than having to go to another place for an MRI or CT scan, and then return for treatment.”
Ultrasound has certain limitations. While it works well with skin, soft tissue and tendons, it is less accurate producing images of certain joints and unable to penetrate bone. Overall, however, ultrasound has proven useful in the diagnosis and treatment of arthritic conditions and may continue to be used to inform recommended treatment protocols.
“We’re still learning where best to use different types of therapies in arthritis patients,” Dr. FitzGerald says. “If we can eventually use ultrasound to predict whether certain treatments will work long term, we can improve treatment decision making and provide relief to patients much more quickly.”