BERN, Switzerland—High resolution grey-scale ultrasonography may help rheumatologists better measure response to rituximab (Rituxan®, Genentech-Biogen Idec) treatment among their rheumatoid arthritis (RA) patients, and this may just be the tip of the iceberg when it comes to the usefulness of ultrasound for monitoring response to RA therapy, according to a study in Rheumatology.1

“It seems very likely that [high resolution ultrasound] could become part of standard care in patients with RA and treatment with all sorts of disease modifying anti-rheumatic drugs, but this will take some more years.”—Hans-Rudolf Ziswiler, MD
“High resolution ultrasound is becom[ing] more and more accessible in modern European countries. Most centers and even some office based rheumatologists can offer it,” says lead study author Hans-Rudolf Ziswiler, MD, a rheumatologist at University Hospital in Bern, Switzerland. “Validating ultrasound as an assessment tool in RA is an ongoing process, actually mainly in research setting [but] it seems very likely that it could become part of standard care in patients with RA and treatment with all sorts of disease modifying anti-rheumatic drugs, but this will take some more years.”

Study compared high res grey-scale and color Doppler US

The new report focused on 23 RA patients who were treated with two 1000 mg infusions of rituximab. The researchers performed both high-resolution grey-scale and color-coded power Doppler ultrasonography at baseline and 6 months after treatment. The researchers also examined and scored the metacarpophalangeal joints and the proximal interphalangeal joints.

After therapy, median disease activity score as assessed by Disease Activity Score-28 (DAS28) improved from 5.03 to 3.56. This corresponded to a EULAR moderate response in 11 of 23 patients and a EULAR good response in another 6 patients.

US can monitor RA joint changes, cartilage thickness

Responders were able to taper off steroids without flaring. The mean grey-scale scores correlated with the swollen joint count at baseline and after 6 months. The mean grey-scale scores improved with treatment. Overall, the high resolution ultrasound provided evidence of significant reductions in synovial hyperplasia after rituximab treatment, but the power Doppler method did not show significant changes in synovial hyperplasia.

“It remains speculative whether more relevant information might be obtained by optimizing the power Doppler method,” the study authors write. The new study only viewed the palmar side of the finger joints with power Doppler, not the dorsal view. Other research has shown that power Doppler imaging may be effective from a dorsal view.

The same group recently found that ultrasonography can also assess cartilage thickness in finger joints.2

Translating research into practice: US in RA

The researchers suggested that the new ultrasound methods will readily transfer from bench to bedside.

“The ultrasound method of cartilage measurement was shown to be a promising alternative to radiographic methods for estimating cartilage,” they concluded. “In addition to being reliable and valid, this method has several practical advantages (e.g. efficiency and cost) that make it valuable for use in both research and clinical practice.”

References
1. Ziswiler HR, Aeberli D, Villiger PM, M?ller B. High-resolution ultrasound confirms reduced synovial hyperplasia following rituximab treatment in rheumatoid arthritis. Rheumatology. 2009; [epub ahead of print June 2, 2009].
2. M?ller B, Bonel H, Rotzetter M, et al. Measuring finger joint cartilage by ultrasound as a promising alternative to conventional radiograph imaging, Arthritis Care & Research. 2009;61:435-441.