Measurement of rheumatoid arthritis disease activity and damage using magnetic resonance imaging. Truth and discrimination: Does MRI make the grade?

Magnetic resonance imaging (MRI) is a tool with unprecedented capabilities. Rheumatoid arthritis (RA) abnormalities that can be measured with MRI incl ude erosions, articular cartilage thickness, synovial membrane volume, and pannus. However, as access to MRI increases, there is a risk that its use w ill not be evaluated using rigorous scientific measurement principles, We r eviewed published MRI measurement methods for RA and investigated whether t he methods were systematically evaluated for reliability, validity, and res ponsiveness to change - components of the OMERACT filter: Medline and Embas e databases were searched from 1966 to 1999. Titles and abstracts were scan ned to identify publications on MRI methods used to assess either disease a ctivity or damage in RA. A data extraction template was developed and 68 pe er reviewed publications from 40 research groups were appraised; 40 address ed RA disease activity, 4 RA damage, and 24 both activity and damage. Joint s most frequently assessed were knee (32 publications) and wrist (31 public ations). Ninety-one percent of publications evaluated either reliability or validity or responsiveness to change. Thirteen percent evaluated all 3 and only 9% evaluated none of these measurement properties. Validity was evalu ated in 85%. responsiveness to change in 37%, and reliability in 35% of pub lications. Only 12% of publications evaluated both intra and inter-reliabil ity. Few publications of MRI measures of disease activity or damage in RA m et the OMERACT filter for all measurement properties. It would be regrettab le if MRI measures are developed ad hoc, with little regard to consideratio ns of scaling, reliability: validity, and responsiveness to change, because this will severely limit their ability to confidently assess treatment eff icacy and prognostic indicators.