Ultrasound provides alternative to MRI for some

January 20, 2017
Dr. Leah Davis with a patient
Dr. Leah Davis performs an MSK ultrasound on a patient’s shoulder. Photo provided

The pain in Theresa Haynes’ left shoulder was excruciating. The range of motion had deteriorated, and she was having trouble lifting her arm to get a cup from the cabinet or even pulling a shirt over her head. Rolling over in her sleep would wake her up with a start and a wince, and she was badly sleep deprived. It was affecting her mood and work. She knew she needed the magnetic resonance imaging (MRI) scan her orthopedist had ordered, but being severely claustrophobic made the simple test seem nearly an insurmountable task.

Finally, Haynes made her way to radiology, thinking she had adequately psyched herself up to get in the narrow capsule. But on the day of the test, the mere thought of being cooped up in that small tube for 40 minutes was more than she could bear. She got in and immediately asked to be taken out. 

She certainly wasn’t the first patient to make that request and wouldn’t be the last. It had just gotten the better of her. 

In an NIH study on MRIs and claustrophobia, a total of 95 patients (1.97 percent) suffered from claustrophobia and 59 (1.22 percent) prematurely terminated the examination due to claustrophobia.

All hope was not lost, however. She would be able to seek evaluation and diagnosis of her pain without undergoing an MRI, thanks to an increasingly important addition to the imaging arsenal, musculoskeletal ultrasound (MSK US), which has become a reliable alternative to MRI for some conditions. Many claustrophobic patients and those who have pacemakers, metal hardware, cochlear implants, certain aneurysm clips and other MRI-noncompatible implants may now have another option. 

MSK US produces images of joints, tendons, muscles and ligaments in the body and is useful in diagnosing tendon or muscle tears or strains, ligament sprains and other soft tissue conditions around joints.  A coworker mentioned to Haynes that MUSC had recently recruited a musculoskeletal radiologist who uses ultrasound to diagnose some conditions that previously had necessitated an MRI to launch a dedicated MSK ultrasound program at MUSC.

That day, Haynes made an appointment to see Leah Davis, DO, a diagnostic radiology specialist who joined the MUSC team in August, having relocated from Henry Ford Hospital in Detroit, Michigan, where she had completed her radiology residency and a fellowship in musculoskeletal radiology. Davis worked directly with Marnix van Holsbeeck, M.D., the respected director of musculoskeletal radiology in the Department of Radiology and director of radiology in the Department of Orthopaedic Surgery at Henry Ford. His influence on her career, she explained, was and continues to be invaluable.

“Ultrasound is increasingly being used for musculoskeletal applications, and Dr. Van Holsbeeck is recognized as one of the world’s leading authorities in MSK ultrasound,” she said. “He has been a great mentor. He is happy to see other institutions integrate MSK US into their programs and is glad to help make that happen.”

Here at MUSC, Bill Conway, M.D., Ph.D., division chief of MSK Radiology, has been a longtime advocate of MSK US, so the addition of ultrasound to MUSC’s nationally respected MSK radiology program is a perfect fit. 

Davis is versed in all facets of musculoskeletal imaging, including both diagnostic studies and ultrasound-guided treatments to relieve pain associated with nerve compression, calcific tendinitis and osteoarthritis. She is charged with introducing the many advantages of ultrasound — benefits that many may be unfamiliar with — to MUSC clinicians.

During Haynes’ appointment, Davis spent nearly 20 minutes carefully examining and imagining her shoulder. During the scan, Davis explained that there is no radiation output from the ultrasound equipment. It is safe and non-invasive and uses high frequency sound waves to produce high resolution, detailed images of the musculoskeletal system in real time. 

There Haynes sat on an examination table, free to move around and watch the screen, following along with what Davis was doing. Davis had to move Haynes’ arm into some painful positions during the examination.

“I am thrilled to be sitting here, not in a tube, being able to move around freely, without all that racket and confinement,” she told Davis. “You can twist my arm any way you’d like,” she said with a laugh.

“Many patients prefer the ultrasound,” Davis acknowledged. “They like that they can see the picture and that I can interact with them the entire time. I can point out tears or joint effusions. Also, dynamic imaging is one of the great advantages of ultrasound. MRI doesn’t allow for that type of diagnostic flexibility because the patient has to remain perfectly still during an MRI. Using ultrasound, I can actually move the patient’s arm into various positions and see what happens with the tendons during motion. I can place the probe on the exact spot where there is pain.”

“In some cases,” she continued, “small rotator cuff tears, which may be difficult to see well on MRI, become visible when you put the tendon under stress. Some of those tears may be missed or misdiagnosed as tendinosis on an MRI. While I scan, I can ask the patient to reproduce the motion that causes her the pain, and I am able to watch the soft tissues around the shoulder move; sometimes we can see soft tissue impingement. The ability to image dynamically is invaluable.”

Davis concluded that Haynes had tendinosis with a small bursal-sided tear in her left supraspinatus tendon and referred her to Shane Woolf, M.D., chief of MUSC Sports Medicine, who specializes in shoulder, knee and hip injuries and disorders.

“Orthopedic surgeons and sports medicine doctors are our natural partners,” Davis said, “and rheumatologists are also important clinical colleagues, because MSK US is also an important tool in the diagnosis and clinical follow-up of patients with inflammatory arthritis, particularly rheumatoid arthritis. It is very good at visualizing synovial thickening and synovial inflammation.”  

Ultrasound is primarily used for two important purposes: to guide the needle during real-time interventional procedures and to diagnose pathology in tendons, ligaments, muscles and nerves around joints. Davis is careful to point out, however, that MSK US does have some limitations. “Ultrasound does not see inside the joints well,” she said. “To see the structures inside any joint — labrum, capsular ligaments, anterior and posterior cruciate ligaments, cartilage defects — MRI is definitely the best.” So MSK US is not intended to be a replacement for MRI, but is a good alternative study or screening study for some conditions. “In some instances,” Davis added, “an MRI is still ordered after an ultrasound is done, but many times the ultrasound is sufficient to make a diagnosis.”

Therapeutic procedures performed via ultrasound include injecting or aspirating joints, performing steroid or anesthetic injections around nerves or tendons and biopsying soft tissue masses. Currently, Davis said, ultrasound is widely being used for these purposes all over the country by clinicians in many specialties.  

For diagnostic purposes, ultrasound is very good at evaluating the soft tissues around joints. In many cases, an ultrasound evaluation takes less time than an MRI, and ultrasound images actually have 4 to 5 times the resolution of MRI. Despite this, ultrasound is only being widely used in the United States at eight medical centers, while countries such as Europe, Asia and Canada — places where socialized health care exists — use it regularly for that purpose. MUSC is one of the eight sites where experts are trained to utilize ultrasound for diagnostic purposes.

Today, in this age of medical cost containment, ultrasound makes sense both clinically and economically and may be a more appropriate and practical imaging modality for some patients, Davis said.