Background While radiographic scoring of erosions and joint space narrowing (JSN) of the hand/wrist is standard to evaluate RA joint damage for regulatory approval of DMARDs, MRI is now also used to examine joint inflammation/damage in clinical trials. MRI field strength impacts feasibility, image quality and cost. Measurement methods initially used ≥1.0 tesla (T) MRI, requiring large machines and specialized space. Low field (<1.0T) MRI is now available and can be performed in a clinical office.

Objectives To report results of an SLR examining if Outcome Measures in Rheumatology Clinical Trials (OMERACT) RA MRI scoring (RAMRIS) is validated for low field (LF) images of RA wrist/hand.

Methods We searched PubMed with Cochrane hedge for articles from 1970 to Aug 2012 using search terms with relevant data. These included: demographics/RA features in adults, MRI field strength (<1.0 T), wrist/hand images assessing ≥1 joint features: synovitis, bone marrow edema (BME)/osteitis, erosions, JSN, tenosynovitis, as well as measurement method and validity evidence. We applied OMERACT validity definitions: face, criterion, content, construct, also assessing reliability, responsiveness, discrimination, and feasibility. Quality was assessed by Cochrane Handbook criteria, adapted for imaging research.

Results 35 LF MRI articles met criteria for extraction. RAMRIS was most often used, as with our previous SLR evaluating ≥1.0T MRI. Altogether, 16 articles using <1.0T/RAMRIS were analyzed, seeking validated MRI measures: 0.2T (13 articles, including 3 RCTs), 0.6T (2 articles), and 0.3T (1 article). 5 articles compared LF to high field (HF) MRI. Table 1 shows LF MRI validation data. Although not ideal, there is only indirect criterion validity for synovitis and erosions: 2 articles compared LF to HF MRI for synovitis and 2 others for erosions. One study provided good erosion score correlation between LF MRI and computed tomography, and another one with x-ray. Validating data with 0.2T included prediction of x-ray progression, sensitivity to change by 4 weeks, and intra/inter reliability for synovitis, BME, and erosions. Data currently lacking include discrimination for synovitis, BME, erosions, construct discriminant for erosions, and validation for JSN or tenosynovitis.

Number of articles providing validity data for RAMRIS measurement with LF MRI

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Conclusions Using a rigorous PRISMA-compliant SLR to examine low field MRI/RAMRIS of the RA wrist/hand, we found 0.2T MRI is partially validated to measure synovitis, BME/osteitis and erosions. To finalize validation, evidence for discrimination between treatment groups for synovitis, BME, erosions, and discriminant construct validity for erosions are needed.

Acknowledgements This work was supported by an unrestricted educational grant from Bristol Myers Squibb

Disclosure of Interest O. Troum Grant/research support from: Abbott, Amgen, Bristol Myers Squibb, Centocor, Novartis, Pfizer, Roche/Genentech, Consultant for: Abbott, Amgen, Centocor, Pfizer, Roche/Genentech, Speakers bureau: Abbott, Amgen, Bristol Myers Squib, Pfizer, Roche/Genentech, UCB, O. Pimienta Grant/research support from: Bristol Myers Squibb, T. Woodworth Grant/research support from: Bristol Myers Squibb, O. Morgacheva Grant/research support from: Bristol Myers Squibb, V. Ranganath Grant/research support from: Bristol Myers Squibb, NIH, UCB, Consultant for: UCB, D. Furst Grant/research support from: Abbott, Actelion, Amgen, Bristol Myers Squibb, Gilead, GSK, NIH, Novarts, Pfizer, Roche/Genentech, UCB, Consultant for: Abbott, Actelion, Amgen, Bristol Myers Squibb, Bogenldec, Centocor, Gilead, GSK, NIH, Novartis, Pfizer, Roche/Genentech, UCB, Speakers bureau: Abbott, Actelion, UCB (CME only)