Ultrasound Accurately Detects MRI-Confirmed Osteitis in RA

April 11, 2014

Ultrasound and MRI images confirm each other in detecting early rheumatoid arthritis of the hand and wrist, according to the first study to specifically test the question.

Kawashiri SY, Suzuki T, Nakashima Y, et al, Synovial inflammation assessed by ultrasonography correlates with MRI-proven osteitis in patients with rheumatoid arthritis. Rheumatology (2014) Mar 22. [Epub ahead of print]

Bone erosion in rheumatoid arthritis (RA) results from a combination of synovitis and osteitis in the joints. While only synovial inflammation can be directly seen on ultrasound (US), magnetic resonance imaging (MRI) clearly detects both synovitis and bone inflammation -- and can confirm joint damage, according to a small Japanese study.

Osteitis is the most specific MRI feature to predict the development of RA in people with early undifferentiated arthritis, the authors note. Therefore, MRI-confirmed osteitis could be a valuable early sign, together with synovitis detected by US.

The study of 30 consecutive patients meeting the 2010 European League Against Rheumatism (EULAR) criteria for RA and who were naïve to disease modifying antirheumatic drugs (DMARDs), compared images of hand and wrist joints taken with US and MRI.

The patients’ demographic and clinical characteristics showed that most were classified as having active, early-stage RA.

A total of 300 images of participants’ bilateral wrist joints (n=60) and the 2nd to the 5th metacarpal phalangeal (MCP) joints (n=240) were taken with systematic multi-planar Grey scale (GS) and power Doppler (PD) color ultrasound and by MRI.

A comparison of images from identical sites taken three days apart showed a clear correlation between high-grade synovitis and bone erosion seen on US and MRI-confirmed osteitis.

This is the first study to precisely examine this correlation.

MRI showed definite bone inflammation in 8.3% of the MCP joints and 48.3% of the wrist joints, with an increased prevalence at sites where grade 2 or 3 articular synovitis was earlier imaged by GS or Doppler US.

The RA MRI scoring system (RAMRIS) also confirmed osteitis in the joints of patients scoring positive for bone erosion on both types of ultrasound.