Whole-body MRI assessment of disease activity and structural damage in rheumatoid arthritis: first step towards an MRI joint count.

OBJECTIVE: The aim of this study was to investigate the ability of whole-body MRI (WBMRI) to visualize inflammation [synovitis, bone marrow oedema (BME) and enthesitis] and structural damage in patients with RA. METHODS: The 3T WBMR images were acquired in a head-to-toe scan in 20 patients with RA and at least one swollen or tender joint. Short Tau Inversion Recovery and pre- and post-contrast T1-weighted images were evaluated for readability and the presence/absence of inflammation (synovitis, BME and enthesitis) and structural damage (erosions and fat infiltrations) in 76 peripheral joints, 30 entheseal sites and in the spine. RESULTS: The readability was >70% for all individual joints, except for the most peripheral joints of the hands and feet. Synovitis was most frequent in the wrist, first tarsometatarsal, first CMC joints and glenohumeral joints (67-61%); BME in the wrist, CMC, acromioclavicular and glenohumeral joints (45-35%) and erosions in the wrist, MTP and CMC joints (19-16%). Enthesitis at ≥ 1 site was registered in 16 patients. BME was frequently seen in the cervical (20%) but not the thoracic and lumbar spine, while fat infiltrations and erosions were rare. The intrareader agreement was high (85-100%) for all pathologies. The agreement between WBMRI and clinical findings was low. CONCLUSION: Peripheral and axial inflammation and structural damage at joints and entheses was frequently identified by WBMRI, and more frequently than by clinical examination. WBMRI is a promising tool for evaluation of the total inflammatory load of inflammation (an MRI joint count) and structural damage in RA patients.

Patterns of magnetic resonance imaging bone erosion in rheumatoid arthritis--which bones are most frequently involved and show the most change?

OBJECTIVE: To investigate by magnetic resonance imaging (MRI) which bones in wrists and metacarpophalangeal (MCP) joints most frequently show bone erosions, and which most frequently demonstrate erosive progression, in early and established rheumatoid arthritis (RA). METHODS: MRI datasets from 258 RA patients [126 with early RA (disease duration < 6 months)] were analyzed, of whom 223, including 126 with early RA, had 1-year followup MRI. All patients had MRI of one wrist, whereas 86 patients had additional images of 2nd-5th MCP joints, and 46 patients additional images of the contralateral wrist. MRI were evaluated blinded by one reader, according to the OMERACT RA MRI scoring system (RAMRIS) for erosions, and presence/absence of erosions was noted in each bone, as was presence/absence of erosive progression. RESULTS: The capitate, ulna, lunate, triquetrum, and scaphoid were the 5 bones with both most frequent baseline erosions and most frequently demonstrated erosive progression. No bones were without erosions. Patterns of erosions and progression were similar in early and established RA. No major difference between dominant and nondominant wrists was detected. In the fingers, the 2nd-3rd MCP joint most frequently displayed erosions and erosive progression. CONCLUSION: The distribution and frequency of bone erosion and erosive progression as detected by MRI in RA wrists and MCP joints were identified. No pattern differences between early versus established disease and dominant versus nondominant sides were detected. No bones showed erosive progression. Thus, no self-evident simplification of the RAMRIS erosion score was identified. Bone involvement patterns may be considered, when joints are selected for MRI protocols for clinical trials and practice.

Update on research and future directions of the OMERACT MRI inflammatory arthritis group.

The OMERACT Magnetic Resonance Imaging (MRI) Task Force has developed and evolved the psoriatic arthritis MRI score (PsAMRIS) over the last few years, and at OMERACT 10, presented longitudinal evaluation by multiple readers, using PsA datasets obtained from extremity MRI magnets. Further evaluation of this score will require more PsA imaging datasets. As well, due to improved image resolution since the development of the original rheumatoid arthritis MRI scoring system (RAMRIS), the Task Force has worked on semiquantitative assessment of joint space narrowing, and developed a reliable method as a potential RAMRIS addendum, although responsiveness will need to be evaluated. One of the strengths of MRI is the ability to detect subclinical synovitis, so the group worked on obtaining low disease activity/clinical remission datasets from a number of international centers and presented cross-sectional findings. Subsequent longitudinal evaluation of this unique resource will be a major continuing focus for the group.

Bone edema on magnetic resonance imaging is an independent predictor of rheumatoid arthritis development in patients with early undifferentiated arthritis.

OBJECTIVE: To study magnetic resonance imaging (MRI) as a tool for early diagnosis of rheumatoid arthritis (RA) in patients with early undifferentiated arthritis (UA). METHODS: Patients (n = 116) without a specific rheumatologic diagnosis, but with ≥2 tender joints and/or ≥2 swollen joints among the metacarpophalangeal, proximal interphalangeal, wrist, or metatarsophalangeal (MTP) joints for >6 weeks but <24 months, underwent clinical, biochemical, conventional radiographic, and MRI examinations and were followed up for >12 months for the final diagnosis of RA or non-RA. Based on univariate analyses, clinical, biochemical, and imaging parameters were selected for inclusion as explanatory variables in multiple logistic regression analysis, with development of RA as the dependent variable. A prediction model was developed, and its performance was tested and compared with that of a previous model developed by van der Helm-van Mil et al (the vdHvM model). RESULTS: Of the 116 patients with early UA, 27 (23.3%) developed RA. When the prediction model was applied, which included as explanatory variables presence of hand arthritis, positivity for rheumatoid factor (RF), morning stiffness lasting >1 hour, and the Outcome Measures in Rheumatology Clinical Trials MRI summary score for bone edema in the MTP and wrist joints, the outcome of RA or non-RA was correctly identified in 82% of the patients (sensitivity 81%, specificity 82%). Another cutoff value for the prediction index in the model would allow a higher specificity (98%) and higher accuracy (83%), but lower sensitivity (36%). With the vdHvM model, RA/non-RA was predicted in 60.2% of the population. CONCLUSION: MRI evidence of bone edema in the MTP and wrist joints is an independent predictor of future RA in patients with early UA. A prediction model that includes the variables clinical hand arthritis, morning stiffness, positivity for RF, and bone edema on MRI in the MTP and wrist joints correctly identified the development or lack of development of RA in 82% of patients.

The OMERACT MRI inflammatory arthritis group: advances and future research priorities.

The OMERACT magnetic resonance imaging (MRI) in inflammatory arthritis group previously developed the rheumatoid arthritis MRI score (RAMRIS) for use in clinical studies, evaluated the use of extremity MRI, and initiated development of a psoriatic arthritis MRI score (PsAMRIS). At OMERACT 9 the group looked at clarifications of applying the RAMRIS, and presented data from a study examining how the contrast agent gadolinium affects RAMRIS outcomes. Much of the group's effort has been aimed at the iterative development of its PsA score, and reported exercises examining this score demonstrated encouraging results, allowing subsequent presentation of a preliminary PsAMRIS. The large amount of data presented were followed by discussions with the wider audience highlighting constructive suggestions for future research priorities, including further feasibility studies, understanding imaging remission, and further improvements to PsAMRIS.

Testing an OMERACT MRI scoring system for peripheral psoriatic arthritis in cross-sectional and longitudinal settings.

OBJECTIVE: Magnetic resonance imaging (MRI) is increasingly used to measure articular inflammation and damage in patients with psoriatic arthritis (PsA). We evaluated the reliability of a new OMERACT PsA MRI scoring system, PsAMRIS, in PsA fingers. METHODS: In 2 separate studies, MRI scans were obtained from patients with clinical evidence of synovitis or dactylitis of the fingers. For the first cross-sectional study, images were obtained at one timepoint. For the second longitudinal study, images were obtained at 2 timepoints, 6 weeks apart. Scans were scored using PsAMRIS in an international multireader setting, for synovitis, tenosynovitis, periarticular inflammation, bone edema, bone erosions, and bone proliferation. RESULTS: Global status scores from both datasets revealed moderate to high reliability for scoring most features, although reliability was poor for periarticular inflammation in the cross-sectional study. Change scores that reflected inflammatory activity also exhibited moderate to good reliability in the longitudinal exercise, despite there being very little absolute change in MRI synovitis or tenosynovitis observed in this dataset. At the distal interphalangeal joints, reliability for change scores was acceptable only for synovitis and tenosynovitis. CONCLUSION: Further development and testing of the PsAMRIS is planned to improve its performance as a clinical and research tool to identify and measure pathology in peripheral joint PsA.

The OMERACT psoriatic arthritis magnetic resonance imaging scoring system (PsAMRIS): definitions of key pathologies, suggested MRI sequences, and preliminary scoring system for PsA Hands.

This article describes a preliminary OMERACT psoriatic arthritis magnetic resonance image scoring system (PsAMRIS) for evaluation of inflammatory and destructive changes in PsA hands, which was developed by the international OMERACT MRI in inflammatory arthritis group. MRI definitions of important pathologies in peripheral PsA and suggestions concerning appropriate MRI sequences for use in PsA hands are also provided.