Advancements in Imaging

Dr. Bakewell

Another guidance document contributor and speaker was Catherine Bakewell, MD, RhMSUS, a rheumatologist with Intermountain Medical Group in Salt Lake City. Dr. Bakewell explained that the information obtained via ultrasound, such as inflammation of the joints or enthesis, can increase the number of patients who qualify for a classification of PsA by the CASPAR classification criteria, as demonstrated by several studies.

Evaluating Disease Activity & Progression

In both RA and PsA, MSUS can be used to help evaluate current disease activity, informing decisions to escalate or de-escalate therapy. Example: MSUS with clinical examination confirms RA flares more effectively than clinical exam alone (moderate consensus). Similarly, sonographic features can inform the decision to escalate therapy in PsA (strong consensus).

Subclinical inflammation detected via MSUS also provides insights into clinical disease activity in both disease states, providing critical information for management. “Patients can have a clinically normal exam and in fact have ongoing synovitis,” said Dr. Bakewell. “But the converse can also be true. You can have a patient who has a swollen joint [but not active synovitis].”

Signs of synovitis on MSUS can help identify both patients with early and established RA who are at higher risk of radiographic progression and poorer patient-reported outcomes. Similarly, synovitis and enthesitis can also predict radiographic progression and worsening of patient-related outcomes in PsA. Dr. Kaeley pointed out that this approach can help clinicians form more tailored and effective interventions.

Specific Sites & Findings

For both disorders, a positive joint finding that demonstrates inflammation and supports a potential diagnosis of RA or PsA is a grayscale-type ultrasound graded ≥2 or a grayscale-type ultrasound graded ≥1 along with a power Doppler-type ultrasound graded ≥1 (both moderate consensus).

Detection of synovitis, tenosynovitis and erosions can aid in the diagnosis of early RA, reflected in a strong consensus statement. Tenosynovitis, specifically, can be an important predictor of the future development of RA, particularly in subjects with positive serology. These same ultrasound findings can be used to help predict risk of flare while on continued therapy or in response to medication tapering.

A related strong consensus statement was for the use of musculoskeletal ultrasound on the wrist joints and the second and third metacarpophalangeal and second and third proximal interphalangeal joints in RA. However, Dr. Kaeley emphasized, “The sonographer and clinician also need to address areas of concern based on clinical factors.” MSUS of these same joints can be used for treatment monitoring, as well as evaluation for remission, if applicable.