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Objective To perform region-based development of whole-body MRI through validation of knee region scoring systems in spondyloarthritis (SpA). Methods Assessment of knee inflammatory pathologies using 2 systems, OMERACT MRI Whole-body score for Inflammation in Peripheral joints and Entheses (MRI-WIPE) and Knee Inflammation MRI Scoring System (KIMRISS), in 4 iterative multi-reader exercises. Results In the final exercise, reliability was mostly good for readers with highest agreement in previous exercise. Median pairwise single-measure ICCs for osteitis and synovitis/effusion status/change were 0.71/0.48 (WIPE-osteitis), 0.48/0.77 (WIPE-synovitis/effusion), 0.59/0.91 (KIMRISS-osteitis) and 0.92/0.97 (KIMRISS-synovitis/effusion). SRMs were 0.74 (WIPE-synovitis/effusion) and 0.78 (KIMRISS-synovitis/effusion). Conclusion MRI-WIPE and KIMRISS may both be useful in SpA whole-body evaluation studies.

ObjectiveTo assess the diagnostic accuracy of radiography (X-ray, XR), CT and MRI of the sacroiliac joints for diagnosis of axial spondyloarthritis (axSpA).Methods163 patients (89 with axSpA; 74 with degenerative conditions) underwent XR, CT and MR. Three blinded experts categorised the imaging findings into axSpA, other diseases or normal in five separate reading rounds (XR, CT, MR, XR +MR, CT +MR). The clinical diagnosis served as reference standard. Sensitivity and specificity for axSpA and inter-rater reliability were compared.ResultsXR showed lower sensitivity (66.3%) than MR (82.0%) and CT (76.4%) and also an inferior specificity of 67.6% vs 86.5% (MR) and 97.3% (CT). XR +MR was similar to MR alone (sensitivity 77.5 %/specificity 87.8%) while CT+MR was superior (75.3 %/97.3%). CT had the best inter-rater reliability (kappa=0.875), followed by MR (0.665) and XR (0.517). XR +MR was similar (0.662) and CT+MR (0.732) superior to MR alone.ConclusionsXR had inferior diagnostic accuracy and inter-rater reliability compared with cross-sectional imaging. MR alone was similar in diagnostic performance to XR+MR. CT had the best accuracy, strengthening the importance of structural lesions for the differential diagnosis in axSpA.

Study Design: Efficacy study. Objectives: To elucidate the limitations of radiography in patients with spinal ankylosing disorders (SAD) with an emphasis on thoracolumbar injuries, which have been less focused upon. Methods: We searched our hospital’s emergency room database for patients who underwent a total spine computed tomography (CT) following a diagnosis of SAD on radiographs following a minor fall. A high-quality presentation containing 50 randomly situated anteroposterior + lateral radiographs was created. Of these, 24 contained a hyperextension type fracture diagnosed by CT. Twelve physicians—4 spine surgeons, 4 senior orthopedic residents and 4 junior orthopedic residents were requested to identify the pathologic radiographs and note the fracture level. Results: Fracture diagnosis stood at 65% for the best reader. When examining the different subgroups, the mean rate of diagnosis for spine surgeons was 55% and for orthopedic residents 32%. Mean diagnosis of thoracic fractures was 26%, of lumbar fractures was 55%, and for the entire thoracolumbar spine was 40%. The interobserver agreement (kappa coefficient) was found to be 0.37 for the entire group and 0.39 for spine surgeons. This finding was statistically significant. Conclusions: The simple radiograph is an inefficient modality for diagnosis of hyperextension type thoracolumbar fractures in patients with SAD. The poor interobserver agreement rate further amplifies this finding. Advanced imaging is recommended in these patients.

Objectives To validate in a large cohort with right-sided aorta the theory that thoracic right-sided flowing osteophytes in DISH results from a ‘protective’ effect of the pulsating descending left-sided thoracic aorta. Methods Chest CTs of patients with DISH and right-sided aorta and controls with DISH and left-sided aorta were evaluated and compared on each intervertebral space (IS) for the location of the aorta (right, left, centre) and the location of the osteophyte relative to the aorta (contralateral, ipsilateral, bilateral). Results The study and control cohorts included 31 and 35 subjects, respectively (male 22/9 and female 27/8; median age 64.8/65.3 years; P = 0.86). Osteophytes contralateral to the aorta’s location were recorded in the majority of ISs in both the study and control groups (47% and 60%, respectively; P > 0.05), while ipsilateral osteophytes were recorded in 6.9% and 7.7%, respectively (P = 0.002). Bilateral osteophytes located to the right and the left of the aorta were significantly more prevalent in the study group compared with the controls (17.2% and 5.4%, respectively; P = 0.04). Conclusions Aortic pulsation plays an important role in inhibiting the development of osteophytes and results in the majority of contralateral osteophytes on both right-sided and left-sided aortas. However, since both ipsilateral and bilateral osteophytes were not at all rare in both groups, other parameters, which are yet to be established, probably contribute to the location of osteophytes.

ObjectivesSpinal MRI is used to visualise lesions associated with axial spondyloarthritis (axSpA). The ASAS MRI working group (WG) updated and validated the definitions for inflammatory and structural spinal lesions in the context of axSpA.MethodsAfter review of the existing literature on all possible types of spinal MRI pathologies in axSpA, the group (12 rheumatologists and two radiologists) consented on the required revisions of lesion definitions compared with the existing nomenclature of 2012. In a second step, using 62 MRI scans from the ASAS classification cohort, the proposed definitions were validated in a multireader campaign by global (absent/present) and detailed (inflammation and structural) lesion assessment at the vertebral corner (VC), vertebral endplate, facet joints, transverse processes, lateral and posterior elements. Intraclass correlation coefficient (ICC) was used for analysis.ResultsRevisions were made for both inflammatory (bone marrow oedema, BMO) and structural (fat, erosion, bone spur and ankylosis) lesions, including localisation (central vs lateral), extension (VC vs vertebral endplate) and extent (minimum number of slices needed), while new definitions were suggested for the type of lesion based on lesion maturity (VC monomorphic vs dimorphic). The most reliably assessed lesions were VC fat lesion and VC monomorphic BMO (ICC (mean of all 36 reader pairs/overall 9 readers): 0.91/0.92; 0.70/0.67, respectively.ConclusionsThe lesion definitions for spinal MRI lesions compatible with SpA were updated by consensus and validated by a group of experienced readers. The lesions with the highest frequency and best reliability were fat and monomorphic inflammatory lesions at the VC.

Objectives To determine quantitative SI joint MRI lesion cut-offs that optimally define a positive MRI for inflammatory and structural lesions typical of axial SpA (axSpA) and that predict clinical diagnosis. Methods The Assessment of SpondyloArthritis international Society (ASAS) MRI group assessed MRIs from the ASAS Classification Cohort in two reading exercises where (A) 169 cases and 7 central readers; (B) 107 cases and 8 central readers. We calculated sensitivity/specificity for the number of SI joint quadrants or slices with bone marrow oedema (BME), erosion, fat lesion, where a majority of central readers had high confidence there was a definite active or structural lesion. Cut-offs with ≥95% specificity were analysed for their predictive utility for follow-up rheumatologist diagnosis of axSpA by calculating positive/negative predictive values (PPVs/NPVs) and selecting cut-offs with PPV ≥ 95%. Results Active or structural lesions typical of axSpA on MRI had PPVs ≥ 95% for clinical diagnosis of axSpA. Cut-offs that best reflected a definite active lesion typical of axSpA were either ≥4 SI joint quadrants with BME at any location or at the same location in ≥3 consecutive slices. For definite structural lesion, the optimal cut-offs were any one of ≥3 SI joint quadrants with erosion or ≥5 with fat lesions, erosion at the same location for ≥2 consecutive slices, fat lesions at the same location for ≥3 consecutive slices, or presence of a deep (i.e. >1 cm depth) fat lesion. Conclusion We propose cut-offs for definite active and structural lesions typical of axSpA that have high PPVs for a long-term clinical diagnosis of axSpA for application in disease classification and clinical research.

ObjectivesThe Assessment of SpondyloArthritis international Society (ASAS) MRI working group (WG) was convened to generate a consensus update on standardised definitions for MRI lesions in the sacroiliac joint (SIJ) of patients with spondyloarthritis (SpA), and to conduct preliminary validation.MethodsThe literature pertaining to these MRI lesion definitions was discussed at three meetings of the group. 25 investigators (20 rheumatologists, 5 radiologists) determined which definitions should be retained or required revision, and which required a new definition. Lesion definitions were assessed in a multi-reader validation exercise using 278 MRI scans from the ASAS classification cohort by global assessment (lesion present/absent) and detailed scoring (inflammation and structural). Reliability of detection of lesions was analysed using kappa statistics and the intraclass correlation coefficient (ICC).ResultsNo revisions were made to the current ASAS definition of a positive SIJ MRI or definitions for subchondral inflammation and sclerosis. The following definitions were revised: capsulitis, enthesitis, fat lesion and erosion. New definitions were developed for joint space enhancement, joint space fluid, fat metaplasia in an erosion cavity, ankylosis and bone bud. The most frequently detected structural lesion, erosion, was detected almost as reliably as subchondral inflammation (κappa/ICC:0.61/0.54 and 0.60/0.83) . Fat metaplasia in an erosion cavity and ankylosis were also reliably detected despite their low frequency (κappa/ICC:0.50/0.37 and 0.58/0.97).ConclusionThe ASAS-MRI WG concluded that several definitions required revision and some new definitions were necessary. Multi-reader validation demonstrated substantial reliability for the most frequently detected lesions and comparable reliability between active and structural lesions.

Objectives To report the discrepancies and agreements between US, MRI and radiography of the hand in PsA, and to compare the sensitivity and specificity of US and radiography to MRI as the gold standard imaging study in PsA. Methods All of the 100 prospectively recruited consecutive PsA patients underwent clinical assessment and concomitant radiographic, US and MRI studies of the MCP, PIP and DIP joints of one hand. Synovitis, flexor tenosynovitis, extensor paratenonitis, erosions and bone proliferations were identified and scored. All readers were blinded to clinical data, and agreement was calculated based on prevalence-adjusted bias-adjusted kappa (PABAK). Results The prevalence of synovitis, flexor tenosynovitis, extensor paratenonitis and erosions was similar for US and MRI, while that of bone proliferation was significantly increased in US and radiography compared with MRI (P Conclusion There is very good agreement between US and MRI for the detection of inflammatory changes in finger joints in PsA. US, radiography and MRI have a good-to-very good agreement for destructive changes.

Autoinflammatory disorders are commonly characterized by seemingly unprovoked systemic inflammation mainly driven by cells and cytokines of the innate immune system. In many disorders on this spectrum, joint and bone involvement may be observed and imaging of these manifestations can provide essential diagnostic information. This review aimed to provide a comprehensive overview of the imaging characteristics for major diseases and disease groups on the autoinflammatory spectrum, including familial Mediterranean fever (FMF), Behçet disease (BD), crystal deposition diseases (including gout), adult-onset Still’s disease (AoSD), and syndromatic synovitis, acne, pustulosis, hyperostosis, and osteitis (SAPHO)/chronic recurrent multifocal osteomyelitis (CRMO). Herein, we discuss common and distinguishing imaging characteristics, phenotypical overlaps with related diseases, and promising fields of future research.

Diffuse idiopathic skeletal hyperostosis (DISH) is a condition characterised by calcification and ossification of ligaments and entheses. The condition usually affects the axial skeleton, in particular, at the thoracic segment, though also other portions of the spine are often involved. DISH often involves also peripheral tendinous and/or entheseal sites either alone, or in association with the involvement of peripheral joints. At times, new bone formation involves the bone itself, but sometimes it involves joints not usually affected by osteoarthritis (OA) which result in bony enlargement of the epiphysis, joints space narrowing and a reduced range of motion. Because of the entheseal involvement, DISH can be mistaken for seronegative spondyloarthropathies or for a "simple" OA. Furthermore, other implications for the recognition of DISH include spinal fractures, difficult intubation and upper endoscopies, decreased response rates in DISH with concomitant spondyloarthritides, and increased likelihood to be affected by metabolic syndrome and cardiovascular diseases. This Atlas is intended to show the imaging finding in DISH in patients diagnosed with the condition by the Resnick classification criteria.

Sacroiliitis, inflammation of the sacroiliac joint (SIJ), may be associated with many rheumatic and nonrheumatic disorders. The diagnosis of sacroiliitis may be difficult in many patients, and awareness of its typical manifestations along with recognition of its diverse presentations and cognizance of the limitations of today's imaging modalities are critical to good clinical practice. This review presents the didactic approach to the early diagnosis of sacroiliitis in patients with suspected axial spondyloarthritis and other nosologic entities, discussing also differential interpretation of information acquired from patients' histories, physical examination, and imaging.

Background:Inflammation in peripheral joints and entheses is common in spondyloarthritis (SpA). Whole-body magnetic resonance imaging (WB-MRI) allows assessment of the overall inflammatory status of arthritis patients including joints and entheses. The OMERACT MRI Whole-body scoring system for Inflammation in Peripheral joints and Entheses (MRI-WIPE) [1] has been developed and validated for the entire body assessment, including the knee, but not separately validated for the knee joint region. Detailed MRI scoring systems exist for heels, hands and feet, but although knee arthritis is a key cause of functional impairment, no detailed scoring system has been validated for inflammatory arthritides. The Knee Inflammation MRI Scoring System (KIMRISS) [2] was developed and validated in osteoarthritis and demonstrated good reliability.Objectives:To perform region-based development of whole-body MRI through validation of two knee region scoring systems in SpA.Methods:Assessment of inflammation was performed in the knee region on sagittal WB-MRIs using 2 scoring systems, MRI-WIPE and KIMRISS (Figure 1), in 4 iterative multi-reader exercises. In the final exercise, images (psoriatic arthritis, axial and peripheral SpA) were obtained before and after TNF-inhibitor.Results:In the final exercise (exercise 4), reliability was mostly good for experienced readers with the overall highest interreader agreement in the previous exercise (exercise 3). Median pairwise single measure intraclass correlation coefficients for osteitis and synovitis/effusion for status/change were 0.71/0.48 (WIPE osteitis), 0.48/0.77 (WIPE synovitis/effusion), 0.59/0.91 (KIMRISS osteitis) and 0.92/0.97 (KIMRISS synovitis/effusion) (Table 1). Wilcoxon signed-rank test showed significant change in synovitis/effusion for both methods and they correlated significantly regarding status in osteitis (0.92, pTable 1.MRI-WIPE knee and KIMRISS interreader reliability for OMERACT exercises 3 and 4MRI-WIPE KneeKIMRISSOsteitisSynovitis/effusionOsteitisSynovitis/effusionVariablesNo. patientsType of scoreMean scoreICCMean scoreICCMean scoreICCMean scoreICCExercise 39 readers11Status3.6 (0-16)0.57 (-0.06-0.98)1.8 (0-4)0.47 (0.05-0.85)32.3 (1-224)0.87 (0.66-0.99)29.9 (11-60)0.34 (-0.62-0.87)11Change1.1 (-2-6)0.53 (0.03-0.90)0 (-2-1)0.32 (-0.13-0.76)27.7 (-9-131)0.58 (-0.30-0.96)-1.6 (-33-11)0.48 (-0.32-0.95)Exercise 33 readers11Status3.1 (0-16)0.83 (0.71-0.97)2.5 (0-5)0.59 (0.51-0.71)34.4 (0-233)0.89 (0.83-0.99)36.5 (16-78)0.59 (0.08-0.86)11Change0.9 (-3-6)0.72 (0.57-0.83)0 (-2-1)0.63 (0.49-0.76)19.3 (-23-86)0.46 (0.18-0.83)-1.8 (-45-17)0.89 (0.82-0.95)Exercise 49 readers10Change-0.25 (-4-5)0.38 (-0.35-0.94)-1.0 (-3-1)0.30 (-0.43-0.89)-0.45 (-37-65)0.26 (-0.86-0.97)-14.7 (-48-0.20)0.48 (-0.39-0.99)20Status2.9 (0-7)0.50 (-0.01-0.84)2.1 (0-4)0.44 (-0.21-0.79)15.2 (0-66)0.35 (-0.04-0.89)55.6 (1-122)0.54 (0.01-0.96)Exercise 43 readers10Change0.2 (-2-6)0.48 (0.16-0.66)-1.4 (-5-0)0.77 (0.70-0.82)5.8 (-27-111)0.92 (0.90-0.94)-20.7 (-65-28)0.97 (0.96-0.98)20Status2.3 (0-6)0.71 (0.60-0.80)2.7 (0-5)0.48 (0.42-0.57)11.4 (0-36)0.59 (0.39-0.71)69.4 (1-153)0.91 (0.87-0.93)Sum scores are mean (range) of the patients scores. ICC values are mean (range). ICC is 2-way mixed model, single measure, by absolute agreement.Conclusion:MRI-WIPE and KIMRISS may both be useful as part of modular whole-body evaluation in clinical studies.References:[1]Krabbe S et al. J Rheum. 2019;46(9):1215-21[2]Jaremko JL et al. RMD Open. 2017;3(1):e000355Acknowledgements:We thank CARE Aarthritis Limited (carearthritis.com) for help with setting up the web-based scoring interface, the scoring exercises, and the web-based meetings. We thank all who participated in the SIG (Special Interest Group) virtual OMERACT meeting 29 October 2020. HMO, GDM and PGC are supported in part by the National Institute for Health Research (NIHR) Leeds Biomedical Research Centre, United Kingdom. The views expressed in this study are those of the authors and not necessarily those of the NHS, the NIHR or the Department of Health.Disclosure of Interests:Marie Wetterslev: None declared, Walter P Maksymowych Speakers bureau: AbbVie, Janssen, Novartis, Pfizer and UCB, Consultant of: AbbVie, Boehringer Ingelheim, Celgene, Eli Lilly, Galapagos, Janssen, Novartis, Pfizer and UCB, Grant/research support from: AbbVie, Novartis, Pfizer and UCB, Robert G Lambert Consultant of: Parexel and Pfizer, Iris Eshed: None declared, Susanne Juhl Pedersen Speakers bureau: MSD, Pfizer, AbbVie, Novartis and UCB, Consultant of: AbbVie and Novartis, Grant/research support from: AbbVie, MSD, and Novartis, Maria Stoenoiu: None declared, Simon Krabbe: None declared, Paul Bird Speakers bureau: Janssen, Abbvie, UCB, Celgene, BMS, Novartis, Pfizer, Gilead, Eli-Lilly, Consultant of: Janssen, Abbvie, UCB, Celgene, BMS, Novartis, Pfizer, Gilead, Eli-Lilly, Violaine Foltz: None declared, Ashish Jacob Mathew: None declared, Frederique Gandjbakhch: None declared, Joel Paschke: None declared, Philippe Carron Speakers bureau: Pfizer, MSD, Novartis, BMS, AbbVie, UCB, Eli Lilly, Gilead and Celgene, Consultant of: Pfizer, MSD, Novartis, BMS, AbbVie, UCB, Eli Lilly, Gilead and Celgene, Grant/research support from: UCB, MSD and Pfizer, Gabriele De Marco: None declared, Helena Marzo-Ortega Speakers bureau: AbbVie, Celgene, Janssen, Lilly, Novartis, Pfizer, Takeda and UCB, Grant/research support from: Janssen and Novartis, Anna Enevold Fløistrup Poulsen: None declared, Jacob L Jaremko: None declared, Philip G Conaghan Speakers bureau: AbbVie, AstraZeneca, BMS, Eli Lilly, EMD Serono, Flexion Therapeutics, Galapagos, Gilead, Novartis, Pfizer and Stryker, Consultant of: AbbVie, AstraZeneca, BMS, Eli Lilly, EMD Serono, Flexion Therapeutics, Galapagos, Gilead, Novartis, Pfizer and Stryker, Mikkel Østergaard Speakers bureau: Abbvie, BMS, Boehringer-Ingelheim, Celgene, Eli-Lilly, Hospira, Janssen, Merck, Novartis, Pfizer, Regeneron, Roche, Sandoz, Sanofi and UCB, Consultant of: Abbvie, BMS, Boehringer-Ingelheim, Celgene, Eli-Lilly, Hospira, Janssen, Merck, Novartis, Pfizer, Regeneron, Roche, Sandoz, Sanofi and UCB, Grant/research support from: Abbvie, BMS, Boehringer-Ingelheim, Celgene, Eli-Lilly, Hospira, Janssen, Merck, Novartis, Pfizer, Regeneron, Roche, Sandoz, Sanofi and UCB

Objective.The Outcome Measures in Rheumatology (OMERACT) Rheumatoid Arthritis (RA) Magnetic Resonance Imaging (MRI) scoring system (RAMRIS), evaluating bone erosion, bone marrow edema/osteitis, and synovitis, was introduced in 2002, and is now the standard method of objectively quantifying inflammation and damage by MRI in RA trials. The objective of this paper was to identify subsequent advances and based on them, to provide updated recommendations for the RAMRIS.Methods.MRI studies relevant for RAMRIS and technical and scientific advances were analyzed by the OMERACT MRI in Arthritis Working Group, which used these data to provide updated considerations on image acquisition, RAMRIS definitions, and scoring systems for the original and new RA pathologies. Further, a research agenda was outlined.Results.Since 2002, longitudinal studies and clinical trials have documented RAMRIS variables to have face, construct, and criterion validity; high reliability and sensitivity to change; and the ability to discriminate between therapies. This has enabled RAMRIS to demonstrate inhibition of structural damage progression with fewer patients and shorter followup times than has been possible with conventional radiography. Technical improvements, including higher field strengths and improved pulse sequences, allow higher image resolution and contrast-to-noise ratio. These have facilitated development and validation of scoring methods of new pathologies: joint space narrowing and tenosynovitis. These have high reproducibility and moderate sensitivity to change, and can be added to RAMRIS. Combined scores of inflammation or joint damage may increase sensitivity to change and discriminative power. However, this requires further research.Conclusion.Updated 2016 RAMRIS recommendations and a research agenda were developed.

Objective To evaluate the prevalence of sacroiliitis, the radiographic hallmark of inflammatory spondyloarthropathy, among patients diagnosed with fibromyalgia syndrome (FMS), using the current Assessment of SpondyloArthritis International Society (ASAS) criteria and magnetic resonance imaging. Methods Patients experiencing FMS (American College of Rheumatology 1990 criteria) were interviewed regarding the presence of spondyloarthritis (SpA) features and underwent HLA–B27 testing, C-reactive protein (CRP) level measurement, and magnetic resonance imaging examinations of the sacroiliac joints. FMS severity was assessed by the Fibromyalgia Impact Questionnaire and the Short Form 36 health survey. SpA severity was assessed by the Bath Ankylosing Spondylitis Disease Activity Index. Results Sacroiliitis was demonstrated among 8 patients (8.1%) and ASAS criteria for diagnosis of axial SpA were met in 10 patients (10.2%). Imaging changes suggestive of inflammatory involvement (e.g., erosions and subchondral sclerosis) were demonstrated in 15 patients (17%) and 22 patients (25%), respectively. The diagnosis of axial SpA was positively correlated with increased CRP level and with physical role limitation at recruitment. Conclusion Imaging changes suggestive of axial SpA were common among patients with a diagnosis of FMS. These findings suggest that FMS may mask an underlying axial SpA, a diagnosis with important therapeutic implications. Physicians involved in the management of FMS should remain vigilant to the possibility of underlying inflammatory disorders and actively search for such comorbidities.

Spondyloarthritis (SpA), a group of inflammatory diseases of which ankylosing spondylitis is the prototype, typically presents with inflammation of the sacroiliac joints (SIJ), or sacroiliitis1,2. The article by Ziegeler, et al in this issue of The Journal 3 describes the prevalence of periarticular sacroiliitis-like structural magnetic resonance imaging (MRI) changes of a patient population with low back pain and clinically suspected sacroiliitis. The authors’ main results provide important new insights into the MRI distribution pattern of periarticular fat metaplasia of the SIJ across different age groups in nonrheumatic subjects and numerous specific pathologic conditions. To date, MRI is considered the most sensitive and specific imaging modality for diagnosing and evaluating SIJ inflammation in patients with early disease4. The introduction of biological drugs such as the tumor necrosis factor-α receptor blocker group and their beneficial effect on SpA resulted in an accelerated use of MRI for early detection of sacroiliitis4,5. As a result, an increasing number of SIJ MRI are performed each year on patients with suspected sacroiliitis6. The main acute inflammatory finding detected on MRI, but not on radiographs, is periarticular bone marrow edema, or osteitis. Structural changes such as erosions, sclerosis, and ankylosis can be seen on pelvic radiographs and computed tomography in advanced, already established disease. However, like osteitis, periarticular fatty replacement, or fat metaplasia, is not seen on radiographs and can be reliably detected only on MRI. The Assessment of SpondyloArthritis international Society (ASAS) classification system for axial SpA (axSpA) is based on whether patients meet clinical or imaging criteria5, … Address correspondence to Prof. I. Eshed, Department of Diagnostic Imaging, Sheba Medical Center, Tel Hashomer 52621, Israel. E-mail: iriseshed{at}gmail.com

Objectives To investigate criteria for treatment response and remission in patients with axial SpA as assessed by whole-body magnetic resonance imaging (WB-MRI) of axial and peripheral joints and entheses during treatment with golimumab. Methods We performed an investigator-initiated cohort study of 53 patients who underwent WB-MRI at weeks 0, 4, 16 and 52 after initiation of golimumab. Images were assessed according to the Spondyloarthritis Research Consortium of Canada MRI SI joint inflammation index, Canada–Denmark MRI spine inflammation score and the MRI peripheral joints and entheses inflammation index. Results At weeks 4, 16 and 52, WB-MRI demonstrated an at least 50% reduction of MRI inflammation of the sacroiliac joints in 16, 29 and 32 (30%, 55% and 60%) patients, of the spine in 20, 30 and 31 (38%, 57% and 58%) patients and of peripheral joints and entheses in 8, 17 and 15 (15%, 32% and 28%) patients, respectively. The BASDAI50 response was achieved by 29, 31 and 31 (55%, 58% and 58%) patients, while ASDAS clinically important improvement (ASDAS-CII) was achieved by 37, 40 and 34 (70%, 75% and 64%) patients. WB-MRI remission criteria for spine, sacroiliac joints and peripheral joints and entheses were explored; total WB-MRI remission was attained by 2, 6 and 3 (4%, 11% and 6%) patients. At week 16, among 35 patients with an at least 50% reduction in the MRI Axial Inflammation Index (sacroiliac joint and spine inflammation), 29 (83%) achieved BASDAI50 and 35 (100%) achieved ASDAS-CII; among 16 patients with MRI axial inflammation non-response, 14 (88%) were BASDAI50 non-responders and 11 (69%) did not achieve ASDAS-CII. Conclusion WB-MRI demonstrated a significant reduction of inflammation in both the spine, sacroiliac joints and peripheral joints and entheses during golimumab treatment. Few patients achieved total WB-MRI remission. Combining spinal and sacroiliac joint inflammation in an MRI Axial Inflammation Index increased the ability to capture response. Trial registration ClinicalTrials.gov, http://clinicaltrials.gov, NCT02011386.

Objective.To assess the longitudinal reliability of the Outcome Measures in Rheumatology (OMERACT) Thumb base Osteoarthritis Magnetic resonance imaging (MRI) Scoring system (TOMS).Methods.Paired MRI of patients with hand osteoarthritis were scored in 2 exercises (6-mo and 2-yr followup) for synovitis, subchondral bone defects (SBD), osteophytes, cartilage assessment, bone marrow lesions (BML), and subluxation. Interreader reliability of delta scores was assessed.Results.Little change occurred. Average-measure intraclass correlation coefficients were good-excellent (≥ 0.71), except synovitis (0.55–0.83) and carpometacarpal-1 osteophytes/cartilage assessment (0.47/0.39). Percentage exact/close agreement was 52–92%/68–100%, except BML in 2 years (28%/64–76%). Smallest detectable change was below the scoring increment, except in SBD and BML.Conclusion.TOMS longitudinal reliability was moderate-good. Limited change hampered assessment.

Background Whole-body MRI (WBMRI) is a promising tool for monitoring disease activity in inflammatory joint diseases. Earlier studies have shown good correlation with conventional MRI and scoring systems for WBMRI have been developed [1,2]. However, the validation of WBMRI is limited; no studies have evaluated the agreement between repeated scans (interscan agreement) and only few studies have evaluated the intra- and interreader agreement. Objectives To validate WBMRI by evaluating the interscan agreement in patients with psoriatic arthritis (PsA), rheumatoid arthritis (RA) and healthy controls (HC) and to evaluate the intra- and interreader agreement and determine the distribution of pathologies in the subjects. Methods WBMRI was performed twice with a one-week interval in 14 patients with PsA, 10 with RA and 16 HC. Coronal images of shoulders, hips, hands and ankles/feet, and sagittal images of knees, ankles, feet and spine were obtained (STIR and pre- and post-contrast T1 weighted spin echo images). Images were anonymized and read in pairs with unknown chronological order by experienced readers (peripheral: IE; spine: SK). WBMRI was scored for 83 peripheral joints and for 33 peripheral entheses according to the OMERACT WBMRI scoring system [1], and according to the CanDen MRI spine scoring system [2]. Ten image sets were re-anonymized for assessment of intra- and interreader agreement (peripheral and spine: MO). Agreement was calculated on lesion level by percentage exact agreement (PEA) and Cohen’s kappa with squared weights, and for sum scores by absolute agreement single-measure intraclass correlation coefficient (ICC). Results The age in the PsA/RA/HC was median (range) 48(31-68)/49(26-58)/35(23-54) years and the symptom duration 10(0-24)/7(3-24)/NA years. WBMRI of the spine and peripheral joints and entheses generally showed moderate to almost perfect interscan agreement with a PEA ranging from 95-100%, kappa ranging from 0.71-1.00 and ICC ranging from 0.95-1.00 (Table 1). Intra- and interreader agreement showed moderate to almost perfect agreement with few exceptions (Table 2). More lesions were found in patients than HC. PsA patients had more lesions in acromioclavicular and sternoclavicular joints, whereas RA patients had more hand lesions (Figure 1). PsA patients had more lesions in the spine (Figure 2). Conclusion WBMRI of the spine and peripheral joints and entheses showed very good interscan agreement, implying that repositioning between examinations does not markedly affect scoring of lesions. Intra- and interreader agreement showed moderate to almost perfect agreement. The distribution of findings in PsA, RA and HC was determined. References [1] Krabbe, et al., J Rheumatol, 2019 (in press) [2] Krabbe, et al., RMD Open, 2018;4;e000624. Disclosure of Interests Anna Enevold Floeistrup Poulsen: None declared, Mette Bjoerndal Axelsen: None declared, Rene Panduro Poggenborg: None declared, Iris Eshed: None declared, Simon Krabbe: None declared, Daniel Glinatsi: None declared, Jakob Mollenbach Moller: None declared, Mikkel Ǿstergaard Grant/research support from: Abbvie, Celgene, Centocor, Merck, Novartis, Consultant for: Abbvie, BMS, Boehringer-Ingelheim, Celgene, Eli Lilly, Hospira, Janssen, Merck, Novartis, Novo, Orion, Pfizer, Regeneron, Roche, and UCB, Speakers bureau: Abbvie, BMS, Boehringer-Ingelheim, Celgene, Eli Lilly, Hospira, Janssen, Merck, Novartis, Novo, Orion, Pfizer, Regeneron, Roche, and UCB

Background Follow up of the ASAS Classification Cohort (CC) indicated a high positive predictive value for the ASAS classification criteria derived from baseline patient and imaging data1. Moreover, diagnosis of axSpA was changed by the rheumatologist in only 11.2% of patients after 4.4 years. This has raised potential concerns regarding diagnostic ascertainment bias. Objectives To determine the evolution of MRI features of axSpA in ASAS-CC cases by central readers, whether this reflects diagnostic assignment by the rheumatologist, and the predictive utility of baseline MRI features of axSpA. Methods MR images were available from 108 cases in the ASAS-CC at baseline and follow up (mean 4.4 years) and also had a rheumatologist diagnosis at both time points. Eight readers from the ASAS MRI group recorded MRI lesions that comprised global assessment (MRI indicative of axSpA (yes/no), active and/or structural lesion typical of axSpA (yes/no) according to ASAS definitions), ASAS definition of positive MRI, and detailed scoring of lesions per SIJ quadrant (SPARCC SIJ method). MRI data from ≥2 readers and from the majority of readers (≥5/8) was used to calculate positive and negative predictive values (PPV, NPV). Results MRI was considered diagnostic of axSpA in 52/108 (48.1%) cases at baseline and in 47/86 (54.7%) diagnosed at baseline as axSpA by the rheumatologist. Change in MRI diagnosis was recorded in 10/108 (9.3%) of cases (2 from yes to no, and 4 from no to yes for axSpA) according to agreement by ≥2 readers and in only 3 cases according to ≥5/8 readers (Table 1). Change in rheumatologist diagnosis was recorded in 9/108 (8.3%), 2 of which had a change in MRI diagnosis. Baseline MRI lesions considered typical of axSpA had very high PPV for follow up diagnosis of axSpA (Table 2). Conclusion The infrequent change in diagnostic ascertainment of rheumatologists over follow up of the ASAS-CC is supported by this central reader evaluation of MRI scans. A positive MRI at baseline had very high PPV for a follow up diagnosis of axSpA. Reference [1] Sepriano et al. ARD 2016;75:1034-42 Disclosure of Interests Walter P Maksymowych Grant/research support from: AbbVie, Pfizer, Janssen, Novartis, Consultant for: AbbVie, Eli Lilly, Boehringer, Galapagos, Janssen, Novartis, Pfizer and UCB Pharma; Chief Medical Officer for Canadian Research and Education Arthritis, Xenofon Baraliakos Grant/research support from: AbbVie, Boehringer Ingelheim, Bristol-Myers Squibb, Celgene, Centocor, Chugai, Janssen, MSD, Novartis, Pfizer Inc, Roche and UCB, Grant/research support from: AbbVie, Pfizer, Merck Sharp & Dohme, UCB Pharma, Novartis, Consultant for: AbbVie, Bristol-Myers Squibb, Boehringer Ingelheim, Celgene, Chugai, Janssen Biologics, Novartis, Pfizer, UCB Pharma, Galapagos, Speakers bureau: AbbVie, Chugai, Janssen, Novartis, Pfizer, UCB Pharma, Manouk de Hooge: None declared, Iris Eshed: None declared, Susanne Juhl Pedersen: None declared, Ulrich Weber Consultant for: Abbvie, Joachim Sieper Consultant for: Abbvie, Bohringer Ingelheim, Janssen, Lilly, Merck, Mylan, Novartis, Pfizer, UCB., Speakers bureau: Abbvie, Bohringer Ingelheim, Janssen, Lilly, Merck, Mylan, Novartis, Pfizer, UCB., Stephanie Wichuk: None declared, Denis Poddubnyy Grant/research support from: AbbVie, Merck Sharp & Dohme, Novartis, Consultant for: AbbVie, Bristol-Myers Squibb, Janssen, Merck Sharp & Dohme, Novartis, Pfizer, UCB Pharma, Speakers bureau: AbbVie, Bristol-Myers Squibb, Janssen, Merck Sharp & Dohme, Novartis, Pfizer, Roche, UCB Pharma, Joel Paschke: None declared, Robert G Lambert Consultant for: Bioclinica, Parexel, Abbvie, Mikkel Ǿstergaard Grant/research support from: Abbvie, Celgene, Centocor, Merck, Novartis, Consultant for: Abbvie, BMS, Boehringer-Ingelheim, Celgene, Eli Lilly, Hospira, Janssen, Merck, Novartis, Novo, Orion, Pfizer, Regeneron, Roche, and UCB, Speakers bureau: Abbvie, BMS, Boehringer-Ingelheim, Celgene, Eli Lilly, Hospira, Janssen, Merck, Novartis, Novo, Orion, Pfizer, Regeneron, Roche, and UCB

The appendicular skeleton is frequently involved in patients with rheumatic diseases. Involved joints are affected by inflammation of the synovium and joint”s entheses. Imaging depicts joint derangement and generally mirrors the pathophysiology of the disease. MRI is considered the imaging modality of choice for the detection of acute joint inflammation as well as its structural sequela. Thus, MRI plays an important role in identifying, monitoring disease activity and the patient follow-up. The MRI features of inflammatory arthritis are well described, especially in the small appendicular joints of the hands and feet and include synovitis, erosions, osteitis, tenosynovitis and erosions. In the current presentation, the typical MRI properties of large joints arthritis in different rheumatic entities will be presented with special focus on the difference from inflammatory findings in smaller appendicular joints.: Disclosure of Interests: None declared

Early diagnosis of sacroiliitis may lead to preventive treatment which can significantly improve the patient's quality of life in the long run. Oftentimes, a CT scan of the lower back or abdomen is acquired for suspected back pain. However, since the differences between a healthy and an inflamed sacroiliac joint in the early stages are subtle, the condition may be missed. We have developed a new automatic algorithm for the diagnosis and grading of sacroiliitis CT scans as incidental findings, for patients who underwent CT scanning as part of their lower back pain workout. The method is based on supervised machine and deep learning techniques. The input is a CT scan that includes the patient's pelvis. The output is a diagnosis for each sacroiliac joint. The algorithm consists of four steps: (1) computation of an initial region of interest (ROI) that includes the pelvic joints region using heuristics and a U-Net classifier; (2) refinement of the ROI to detect both sacroiliiac joints using a four-tree random forest; (3) individual sacroiliitis grading of each sacroiliiac joint in each CT slice with a custom slice CNN classifier, and; (4) sacroiliitis diagnosis and grading by combining the individual slice grades using a random forest. Experimental results on 484 sacroiliiac joints yield a binary and a 3-class case classification accuracy of 91.9% and 86%, a sensitivity of 95% and 82%, and an Area-Under-the-Curve of 0.97 and 0.57, respectively. Automatic computer-based analysis of CT scans has the potential of being a useful method for the diagnosis and grading of sacroiliitis as an incidental finding.

Background:To date, the European Alliance of Associations for Rheumatology (EULAR) guidelines recommend X-ray (XR) as first line imaging in axial Spondyloarthritis (axSpA) and magnetic resonance imaging (MR) if the diagnosis cannot be established by XR and clinical features. However, much knowledge has been gained recently strengthening the applicability of MR for the detection of structural lesions and raising the question, whether XR is still necessary. Also, several publications used low-dose computed tomography (CT) as reference standard and imaging test.Objectives:In light of this complex diagnostic situation, the aim of this study was to compare the three major modalities, XR, MR and CT of SIJ, in their diagnostic performance of axSpA and differential diagnosis in a cohort of patients with low back pain using the final judgment of the rheumatologist as standard of reference.Methods:163 patients (89 with axSpA; 74 with degenerative diseases) underwent XR, CT and MR. Three blinded experts categorized the imaging into axSpA, other diseases or normal in 5 separate reading rounds (XR, CT, MR, XR+MR, CT+MR, respectively). The results were compared to the clinical diagnosis. Sensitivity and specificity values for axSpA and interrater reliability were compared.Results:XR showed lower sensitivity and specificity (66.3%/67.6% respectively) compared to MR (82.0%/86.5%) and CT (77.5%/97.3%). Sensitivity and specificity of XR+MR was similar to MR alone (77.5% / 87.8%). However, CT+MR was superior to MR alone (75.6% / 97.3%) (see Figure). CT had the best interrater reliability (kappa = 0.875) followed by MR (0.665) and XR (0.517). CR+MR reliability was similar (0.662) compared to MR alone, while CT+MR reliability (0.732) was superior.Figure 1.Frequency of positive and negative findings in radiography (XR), computed tomography (CT), magnetic resonance imaging (MR) and combinations and resulting diagnostic accuracy values. SE: Sensitivity, SP: Specificity, LR-/+: negative/positive likelihood ratio.Conclusion:In conclusion, XR is inferior to cross-sectional imaging and should be replaced by MR or CT for differential diagnosis. While MR is the most sensitive imaging technique, it lacks specificity when compared to CT. CT alone has high diagnostic accuracy, despite being insensitive to bone marrow lesions such as fatty metaplasia or osteitis. Adding CT to MR leads to an increase in specificity at a minor expense of sensitivity.References:[1]Sieper J, Rudwaleit M, Baraliakos X, et al. The Assessment of SpondyloArthritis international Society (ASAS) handbook: a guide to assess spondyloarthritis. Ann Rheum Dis. 2009;68 Suppl 2:ii1-44.[2]Mandl P, Navarro-Compán V, Terslev L, et al. EULAR recommendations for the use of imaging in the diagnosis and management of spondyloarthritis in clinical practice. Ann Rheum Dis. 2015;74(7):1327-39.[3]Diekhoff T, Hermann KA, Greese J, et al. Comparison of MRI with radiography for detecting structural lesions of the sacroiliac joint using CT as standard of reference: results from the SIMACT study. Ann Rheum Dis. 2017.[4]Diekhoff T, Greese J, Sieper J, Poddubnyy D, Hamm B, Hermann KA. Improved detection of erosions in the sacroiliac joints on MRI with volumetric interpolated breath-hold examination (VIBE): results from the SIMACT study. Ann Rheum Dis. 2018;77(11):1585-89.[5]Baraliakos X, Hoffmann F, Deng X, Wang YY, Huang F, Braun J. Detection of Erosions in Sacroiliac Joints of Patients with Axial Spondyloarthritis Using the Magnetic Resonance Imaging Volumetric Interpolated Breath-hold Examination. The Journal of rheumatology. 2019;46(11):1445-49.[6]Wu H, Zhang G, Shi L, et al. Axial Spondyloarthritis: Dual-Energy Virtual Noncalcium CT in the Detection of Bone Marrow Edema in the Sacroiliac Joints. Radiology. 2019;290(1):157-64.Disclosure of Interests:Torsten Diekhoff Speakers bureau: Canon MS, Roche, Novartis, MSD, Grant/research support from: Assessment of Spondyloarthritis International Society, Iris Eshed: None declared, Felix Radny: None declared, Katharina Ziegeler: None declared, Fabian Proft: None declared, Juliane Greese: None declared, Dominik Deppe: None declared, Robert Biesen: None declared, Kay-Geert Hermann: None declared, Denis Poddubnyy: None declared

Background:Whole-body MRI (WB-MRI) allows assessment of the overall inflammation in arthritis patients, including joint and entheses. To enhance the use of WB-MRI in clinical trials, the OMERACT MRI in Arthritis Working Group developed the OMERACT MRI Whole-body score for Inflammation in Peripheral joints and Entheses in inflammatory arthritis (MRI-WIPE) [1]. This has been validated for the entire body, including the hip/pelvis region, but not for each individual region. More detailed scoring systems exist for heels, hands and feet but although hip arthritis is a key cause of functional impairment in spondyloarthritis (SpA), no detailed scoring system has been published for use in SpA. The Hip Inflammation Magnetic Resonance Imaging Scoring System (HIMRISS) was developed and validated in osteoarthritis showing good reliability.Objectives:To validate reliability, correlation and responsiveness of two WB-MRI scores for the hip/pelvis region in SpA.Methods:Inflammation in the hip/pelvis region was assessed on coronal WB-MRIs in 4 iterative multi-reader exercises using MRI-WIPE for the hip/pelvis region and HIMRISS (Figure 1). In final exercises, images (axial/peripheral SpA and psoriatic arthritis) were obtained before and after TNF-inhibitor.Results:In final exercises reliability was mostly good for the best calibrated readers. Median single-measure intraclass correlation coefficients were 0.58-0.65 (WIPE osteitis), 0.10-0.88 (HIMRISS osteitis), 0.38-0.72/0.52-0.60 (WIPE synovitis/effusion) and 0.68-0.89/0.78-0.85 (HIMRISS synovitis/effusion) (Table 1). The methods correlated significantly for status in osteitis (0.72, p=0.019) and for synovitis/effusion status (0.83, p=0.003) and change (0.73, p=0.017) (Table 1). In exercise 4 Wilcoxon signed-rank test showed significant change in osteitis between timepoints using WIPE hip/pelvis and SRM was large (1.23), while lower for WIPE synovitis/effusion and HIMRISS.Table 1.MRI-WIPE hip/pelvis and HIMRISS interreader reliability for OMERACT exercises 3-4MRI-WIPE hip/pelvisHIMRISSOsteitisSynovitis/effusionOsteitisSynovitis/effusionVariablesNo. patients(cases)Type of scoreMeanscoreICCMeanscoreICCMeanscoreICCMeanscoreICCExercise 39 readers11Status2.3 (0-10)0.69 (0.23-0.93)1.4 (0-4)0.58 (-0.06-0.96)8.2 (1-60)0.84 (0.56-0.99)12.8 (3-25)0.52 (0.00-.91)11Change-0.2 (-1-1)NA-0.2 (-3-1)0.50 (0.10-0.87)-0.35 (-3-1)NA-1.8 (-17-10)0.50 (-0.05-0.89)Exercise 33 readers11Status1.8 (0-10)0.63 (0.46-0.93)1.7 (0-5)0.60 (0.34-0.80)6.6 (0-65)0.88 (0.77-0.94)12.8 (2-28)0.89 (0.87-0.91)11Change-0.12 (-1-1)NA-0.12 (-3-2)0.60 (0.48-0.83)-0.7 (-7-0)NA-1.6 (-21-8)0.78 (0.70-0.87)Exercise 49 readers10 (1-10)Status1.2 (0-4)0.21 (-0.39-0.91)1.1 (0-2)0.19 (-0.31-0.69)1.8 (0-6)0.07 (-0.17-0.83)16.4 (9-23)0.31 (0.00-0.89)10 (11-20)Status1.6 (0-6)0.51 (-0.08-0.99)1 (0-3)0.40 (-0.17-0.88)3.5 (1-8)0,08 (-0.21-0.95)11.2 (5-24)0.49 (0.00-0.94)10 11-20)Change-0.4 (-2-0)NA-0.39 (-2-0)0.22 (-0.68-0.83)-2.2 (-7-2)NA-5.2 (-18-0)0.57 (0.02-0.92)20 (1-20)Status1.4 (0-6)0.41 (-0.35-0.92)1.0 (0-3)0.27 (-0.07-0.75)2.7 (0-9)0.09 (-0.17-0.85)13.8 (5-25)0.45 (0.01-0.90)Exercise 43 readers10 (1-10)Status0.8 (0-4)0.29 (0.01-0.78)1.3 (0-2)-0.02 (-0.29-0.12)0.4 (0-2)-0.04 (-0.04-0.04)15.8 (5-26)0.73 (0.59-0.89)10 (11-20)Status1.8 (0-9)0.65 (0.52-0.76)1.2 (0-4)0.72 (0.62-0.81)1.7 (0-5)0.06 (-0.17-0.35)9.2 (2-26)0.68 (0.53-0.88)10 (11-20)Change-0.6 (-2-0)NA-0.5 (-3-1)0.52 (0.49-0.55)-0.2 (-2-1)NA-2.8 (-19-6)0.85 (0.82-0.88)20 (1-20)Status1.3 (0-9)0.58 (0.43-0.69)1.2 (0-4)0.38 (0.31-0.44)1.0 (0-5)0.10 (-0.09-0.33)12.5 (2-26)0.73 (0.69-0.77)Sum scores and ICCs are mean (range). ICC is 2-way mixed, single measure, by absolute agreement.Conclusion:MRI-WIPE and HIMRISS may be useful tools in modular WB-MRI evaluation of hip/pelvis inflammation in clinical trials in SpA.References:[1]Krabbe S et al. J Rheum. 2019;46(9):1215-21[2]Jaremko JL et al. J Rheum. 2019;46(9)1239-42Acknowledgements:We thank CARE Arthritis Limited (carearthritis.com) for help with setting up the web-based scoring interface, scoring exercises, and the web-based meetings. We acknowledge the contribution of SIG (Special Interest Group) participants at the virtual OMERACT meeting October 29, 2020. HMO, GDM and PGC are supported in part by the National Institute for Health Research (NIHR) Leeds Biomedical Research Centre, United Kingdom. The views expressed are those of the authors and not necessarily those of the NHS, the NIHR or the Department of Health.Disclosure of Interests:Marie Wetterslev: None declared, Robert G Lambert Consultant of: Parexel and Pfizer, Walter P Maksymowych Speakers bureau: AbbVie, Janssen, Novartis, Pfizer and UCB, Consultant of: AbbVie, Boehringer Ingelheim, Celgene, Eli Lilly, Galapagos, Janssen, Novartis, Pfizer and UCB, Grant/research support from: AbbVie, Novartis, Pfizer and UCB, Iris Eshed: None declared, Susanne Juhl Pedersen Speakers bureau: MSD, Pfizer, AbbVie, Novartis and UCB, Consultant of: AbbVie and Novartis, Grant/research support from: AbbVie, MSD, and Novartis, Paul Bird Speakers bureau: Janssen, Abbvie, UCB, Celgene, BMS, Novartis, Pfizer, Gilead, Eli-Lilly, Consultant of: Janssen, Abbvie, UCB, Celgene, BMS, Novartis, Pfizer, Gilead, Eli-Lilly, Maria Stoenoiu: None declared, Simon Krabbe: None declared, Ashish Jacob Mathew: None declared, Violaine Foltz: None declared, Frederique Gandjbakhch: None declared, Joel Paschke: None declared, Gabriele De Marco: None declared, Helena Marzo-Ortega Speakers bureau: AbbVie, Celgene, Janssen, Lilly, Novartis, Pfizer, Takeda and UCB, Grant/research support from: Janssen and Novartis, Philippe Carron Speakers bureau: Pfizer, MSD, Novartis, BMS, AbbVie, UCB, Eli Lilly, Gilead and Celgene, Consultant of: Pfizer, MSD, Novartis, BMS, AbbVie, UCB, Eli Lilly, Gilead and Celgene, Grant/research support from: UCB, MSD and Pfizer, Anna Enevold Fløistrup Poulsen: None declared, Jacob L Jaremko: None declared, Philip G Conaghan Speakers bureau: AbbVie, BMS, Eli Lilly, Flexion Therapeutics, Galapagos, Gilead, Novartis, Pfizer, Regeneron, Stryker, Consultant of: AbbVie, BMS, Eli Lilly, Flexion Therapeutics, Galapagos, Gilead, Novartis, Pfizer, Regeneron, Stryker, Mikkel Østergaard Speakers bureau: Abbvie, BMS, Boehringer-Ingelheim, Celgene, Eli-Lilly, Hospira, Janssen, Merck, Novartis, Pfizer, Regeneron, Roche, Sandoz, Sanofi and UCB, Consultant of: Abbvie, BMS, Boehringer-Ingelheim, Celgene, Eli-Lilly, Hospira, Janssen, Merck, Novartis, Pfizer, Regeneron, Roche, Sandoz, Sanofi and UCB, Grant/research support from: Abbvie, BMS, Boehringer-Ingelheim, Celgene, Eli-Lilly, Hospira, Janssen, Merck, Novartis, Pfizer, Regeneron, Roche, Sandoz, Sanofi and UCB

Background:The ASAS definition of a positive MRI for inflammation in the spine (ASAS-MRIspine+) is intended for classification of patients as having axSpA but is often misused for diagnostic purposes. This is problematic because bone marrow edema (BME) in the spine may occur in 20-40% of those with mechanical back disorders. The ASAS MRI group has generated updated consensus lesion definitions which have been validated on MRI spine images from the ASAS Classification Cohort.Objectives:We aimed to identify quantitative cut-offs based on numbers of vertebral corners that define ASAS-MRIspine+, there being two gold standards: A. majority central reader decision as to the presence of spine MRI findings consistent with axSpA B. rheumatologist expert opinion diagnosis of axSpA.Methods:Eight ASAS-MRI readers recorded MRI lesions in the spine according to recently updated ASAS definitions from 62 cases in an eCRF that comprises global assessment (MRI consistent with axSpA? (yes/no)), and detailed scoring of lesions for all sites in the spine. We calculated sensitivity and specificity for numbers of vertebral corners with BME where a majority of readers (≥5/8) agreed as to the presence of MRI findings consistent with axSpA. We selected cut-offs with ≥95% specificity. These cut-offs were analyzed for their predictive utility for rheumatologist diagnosis of axSpA by calculating positive and negative predictive values (PPV, NPV) and selecting cut-offs with PPV ≥95%. Both criteria were considered requirements for designation of MRI cut-offs defining ASAS-MRIspine+.Results:MRI findings consistent with axSpA were observed by majority read in 8 (20%) of 40 cases diagnosed with axSpA, and 0 (0%) of 19 cases without axSpA. Cut-offs achieving specificity of ≥95% for MRI findings consistent with axSpA were 4 vertebral corners (sensitivity 75%) for all cases, 3 vertebral corners (sensitivity 37.5%) for cases with ≥1 additional location with inflammation, 1 vertebral corner (sensitivity 62.5%) in cases with ≥2 vertebral corner fat lesions (Table 1). All of the above cut-offs also had very high PPV (≥95%) for diagnosis of axSpA in cases diagnosed by the rheumatologist (Table 2).Table 1.Majority readers agree MRI findings consistent with axSpA are present is the gold-standard external referenceMRI cut-offsSensitivity (95%CI)Specificity (95%CI)BME in ≥2 vertebral corners87.5 (47.3 - 99.7)87.0 (75.1 - 94.6)BME in ≥ 3 vertebral corners87.5 (47.3 - 99.7)94.4 (84.6 - 98.8)BME in ≥4 vertebral corners75.0 (34.9 - 96.8)98.2 (90.1 - 100.0)Cases with ≥1 additional non-corner site inflammatory lesionBME in ≥2 vertebral corners37.5 (8.5 - 75.5)94.4 (84.6 - 98.8)BME in ≥3 vertebral corners37.5 (8.5 - 75.5)98.2 (90.1-100.0)Cases with ≥2 vertebral corner fat lesionsBME in ≥1 vertebral corner62.5 (24.5 - 91.5)100.0 (93.4-100.0)BME in ≥2 vertebral corners62.5 (24.5 - 91.5)100.0 (93.4-100.0)Table 2.Predictive values of cut-offs for number of vertebral corners with BME according to the diagnostic ascertainment of the rheumatologistMRI cut-offsSensitivity (95%CI)Specificity (95%CI)PPVNPVMRI findings consistent with axSpA ≥any 2 readers52.5 (36.1 - 68.5)94.7 (74.0 - 99.9)95.5 (75.3 - 99.3)48.6 (40.2 - 57.2)MRI findings consistent with axSpA ≥majority read20.0 (9.1 - 35.6)100.0 (82.4 - 100.0)100.037.3 (33.7 - 40.9)BME in ≥ 4 vertebral corners17.5 (7.3 - 32.8100.0 (82.4 - 100.0)100.036.5 (33.3 - 39.9)Cases with ≥1 additional inflammatory lesionBME in ≥ 3 vertebral corners10.00 (2.8 - 23.7)100.00 (82.4 - 100.0)100.034.5 (32.2 - 36.9)Cases with ≥2 vertebral corner fat lesionsBME in ≥1 vertebral corner12.50 (4.2 - 26.8)100.00 (82.4 - 100.0)100.035.2 (32.6 - 37.9)Conclusion:A cut-off of BME in ≥4 vertebral corners, or ≥3 corners in the setting of additional inflammatory lesions at other locations or corner fat, are primary candidates for defining ASAS-MRIspine+. These cut-offs apply to typical patients referred to a rheumatologist with a high index of suspicion of axSpA and may not be appropriate in other populations.Disclosure of Interests:None declared

Background:Randomized controlled trials have targeted reducing the size of BML and degree of synovitis for the treatment of OA. We have developed the OMERACT Knee Inflammation MRI Scoring System (KIMRISS) and have recently refined it to maximize reliability and sensitivity to change. Innovations include electronic overlays for assessment of BML in 500 subregions, a web-based interface with direct online scoring, and real-time iterative calibration (RETIC) prior to reading exercises. Synovitis-effusion (S-E) is also scored on all consecutive sagittal slices on a web-based interface.Objectives:We aimed to test the feasibility, reliability, and responsiveness of KIMRISS versus an established method, MOAKS, in two multi-reader exercises.Methods:KIMRISS incorporates web-based graphic overlays for each of femur, tibia, and patella (range 0-500). S-E is recorded as the largest diameter perpendicular to the longest axis of this feature (range 0-100). All scores are pro-rated for a standardized number of MRI slices. In a pre-reading exercise for KIMRISS, readers scored sufficient cases in RETIC to attain scoring proficiency, pre-specified as an ICC of ≥0.80 and ≥0.70 for status and change scores of BML and S-E compared to developer reads. A new web-based scoring platform with overlays designating different subregions for scoring BML was developed for MOAKS. We compared reliability for status and change scores of BML and S-E in 2 international multi-reader exercises of baseline and one-year MRI scans from the Osteoarthritis Initiative: A. 4 expert readers and an OMERACT fellow scored 38 cases selected for MOAKS BML score ≥1. B. 7 expert readers and an OMERACT fellow scored 60 cases selected for MOAKS BML ≥3 and Kellgren-Lawrence (K-L) grade Results:For exercises A/B, subjects were 55.3%/ 26.7% male, mean(±SD) age 61.7(±9.1)/61.9(8.8) years, and radiographic K-L grade ≤2 in 39.4%/100%. Change was small in both exercises (Table 1.KIMRISS and MOAKS scores in Two International Multi-reader ExercisesMethodMRI featureScores mean (SD)SDC(% of max)P valueSRMBaselineOne-year Follow upChangeEXERCISE AMOAKSBML3.6 (2.9)3.4 (2.3)-0.2 (1.9)1.0 (2.2%)0.72-0.11Synovitis-effusion1.3 (0.8)1.5 (0.8)0.2 (0.4)0.4 (13.3%)0.0170.5KIMRISSBML15.7 (13.3)21.2 (22.5)5.5 (15.3)5.6 (1.1%)0.0220.36Synovitis-effusion21.8 (12.0)24.3 (11.9)2.5 (7.4)2.8 (2.8%)0.0430.34EXERCISE BMOAKSBML4.2 (2.6)3.7 (2.4)-0.5 (2.1)1.1 (2.4%)0.083-0.24Synovitis-effusion1.2 (0.7)1.3 (0.8)0.0 (0.5)0.4 (13.3%)0.590.0KIMRISSBML18.0 (17.5)15.9 (14.3)-2.1 (12.3)5.9 (1.2%)0.19-0.17Synovitis-effusion21.8 (9.3)22.9 (10.8)1.1 (7.1)2.2 (2.2%)0.250.15Intra-class Correlation Coefficients (95%CI)MethodMRI featureExercise AExercise BKIMRISS statusKIMRISS changeBML0.86 (0.78-0.92)0.88 (0.81-0.93)0.80 (0.70-0.87)0.72 (0.64-0.80)MOAKS statusMOAKS changeBML0.71 (0.46-0.85)0.76 (0.64-0.85)0.67 (0.56-0.77)0.69 (0.60-0.78)KIMRISS statusKIMRISS changeSynovitis-effusion0.88 (0.81-0.93)0.87 (0.79-0.92)0.75 (0.52-0.86)0.87 (0.82-0.91)MOAKS statusMOAKS changeSynovitis-effusion0.66 (0.4-0.79)0.52 (0.36-0.67)0.65 (0.52-0.75)0.48 (0.37-0.60)Conclusion:The KIMRISS method for scoring BML and Synovitis-Effusion scores highly for feasibility and demonstrates consistently high reliability when compared to MOAKS. Further validation for responsiveness is necessary in cases with greater change in MRI features than in the OAI dataset.Disclosure of Interests:None declared.

Purpose To investigate the current role of WB-MRI for rheumatic inflammatory diseases in clinical practice using a survey addressed to musculoskeletal radiologists. Methods A survey composed of 61 questions, subdivided in three sections, demographics (five questions), application of WB-MRI for inflammatory musculoskeletal diseases in adults and children (28 questions: 7 open and 21 multiple choice for each subgroup) was distributed via the European Society of Musculoskeletal Radiology (ESSR) from July 2 to December 31, 2018 to radiologists working in academic, private, and public workplaces. Comparisons among the different workplaces were performed using the Chi-squared and the Kruskal-Wallis test for nominal and ordinal data, respectively (p Results Seventy-two participants out of the 1779 (4%) members of the ESSR with 10.4 ± 7.9 years of experience in musculoskeletal imaging, replied to at least one question. 30.6% and 12.3% of the respondents performed at least 50 WB-MRI examinations per year in adults and children, respectively. The most frequent indications were myositis in adults and chronic recurrent multifocal osteomyelitis (CRMO) in children, the latter mostly in academic centers (p = 0.013). The ESSR Arthrits Subcommitte's protocol was applied by half of the participants and especially radiologists working in private practice used it for adults (p = 0.025). Contrast medium was rarely used for adults particularly by academics (p = 0.04). Diffusion Weighted Imaging was applied for children mostly in private practice (p = 0.01) although, overall, it plays a marginal role. Scoring systems were rarely used. Ongoing research is limited. Conclusion WB-MRI is not routinely applied for musculoskeletal inflammatory diseases. The most frequent indications are myositis and CRMO.

Background:Heterogeneity is a hallmark of psoriatic arthritis (PsA), which is reflected in diverse clinical, imaging and molecular features that may reflect disease course and response to treatment. We hypothesized that specific molecular pathways underlie the various manifestations of PsA.Objectives:To create a model for accurate and biologically meaningful sub-phenotyping of PsA using imaging and molecular data. Specifically, we aimed to identify imaging sub-phenotypes in patients with PsA and determine their association with whole blood mRNA expression markers.Methods:55 patients with PsA ready to initiate treatment for active disease were prospectively recruited. An ultrasound assessment of the extent of musculoskeletal inflammation in 64 joints, 34 tendons and 16 entheses was performed. Sonographic inflammation (in greyscale and Doppler) of the following domains was graded for: a) synovitis; b) peri-tendonitis; c) tenosynovitis; and d) enthesitis. A global inflammatory score was calculated for each tissue domain. Peripheral blood was profiled with RNAseq, and gene expression data were obtained. Analyses were performed in two stages: 1) Unsupervised cluster analysis was performed using hierarchial and k-means to define imaging sub-phenotypes in PsA that reflected the predominant tissue involved; 2) Principal component analysis with ellipses was used to determine the association between imaging-defined clusters and peripheral blood gene expression profile.Results:The patients could be divided into 3 groups based on unsupervised hierarchical and k-means clustering of images indicating the predominant involved tissue (Figure 1): 1) Enthesitis predominant (N=13 [24%]); 2) Peri-tendonitis predominant (N=11 [20%]); 3); Synovitis predominant (N=31 [56%]). Patients in the synovitis predominant group had more nail involvement, while those in the peri-tendonitis group had the highest number of clinically active joints (Table 1). Unsupervised clustering of gene expression data identified three clusters that partially overlapped with the imaging clustering (Figure 2). Overall, 344 genes were differentially expressed (pTable 1.Clinical Features by Imaging ClusteringVariableEnthesitis predominantcluster(N=13)Peritendonitis predominant cluster(N=11)Synovitis predominant cluster(N=31)Age (years)47 (14)49 (16)45 (20)Sex: Female8 (61.5%)5 (45.5%)15 (48.4%)PsA duration (years)1.2 (1.5)1.6 (11.5)0.8 (3.7)BMI29.4 (6.8)25 (8.1)26.1 (8.4)Nail lesions3 (23.1%)5 (45.5%)17 (54.8%)PASI1.2 (2.7)1.2 (3.2)2.8 (7.8)Tender joint count6 (9)11 (5)3 (6)Swollen joint count2 (6)10 (7)3 (6)Dactylitis3 (23.1%)4 (36.4%)7 (22.6%)Enthesitis count3 (3)1 (4)0 (2)Enthesitis12 (92.3%)7 (63.6%)15 (48.4%)hsCRP2.9 (8.8)8.5 (21.5)3.6 (9.4)Median (IQ range) and frequencies (%)Bolded=Statistically different between the 3 groups (pConclusion:We identified three different imaging clusters based on the predominant tissue involved in patients with active PsA. Distinct gene expression profiles may underlie these imaging clusters seen in PsA.Acknowledgments:The study was supported by a Discovery Grant from the National Psoriasis Foundation.Disclosure of Interests:Lihi Eder Grant/research support from: Abbvie, Lily, Janssen, Amgen, Novartis, Consultant of: Janssen, Speakers bureau: Abbvie, Lily, Janssen, Amgen, Novartis, Quan Li: None declared, Sara Rahmati: None declared, Iris Eshed: None declared, Proton Rahman Grant/research support from: Janssen and Novartis, Consultant of: Abbott, AbbVie, Amgen, BMS, Celgene, Lilly, Janssen, Novartis, and Pfizer., Speakers bureau: Abbott, AbbVie, Amgen, BMS, Celgene, Lilly, Janssen, Novartis, Pfizer, Igor Jurisica Grant/research support from: IBM, Vinod Chandran Grant/research support from: Abbvie, Celgene, Consultant of: Abbvie, Amgen, Bristol-Myers Squibb, Celgene, Eli Lily, Janssen, Novartis, Pfizer, UCB, Employee of: Spouse employed by Eli Lily

Objective.To develop and validate an enthesitis magnetic resonance imaging (MRI) scoring system for spondyloarthritis/psoriatic arthritis, using the heel as model.Methods.Consensus definitions of key pathologies and 3 heel enthesitis multireader scoring exercises were done, separated by discussion, training, and calibration.Results.Definitions for bone and soft tissue pathologies were agreed. In the final exercise, median pairwise single-measures intraclass correlation coefficients (ICC; patient-level) for entheseal inflammation status/change scores were 0.83/0.82 for all readers. For radiologists and selected rheumatologists, ICC were 0.91/0.84 and quadratic-weighted κ (lesion-level) 0.57–0.91/0.45–0.81.Conclusion.The proposed definitions and Heel Enthesitis Scoring System (HEMRIS) are reliable among trained readers and promising for clinical trials.

Sacroiliitis, inflammation of the sacroiliac joint (SIJ), may be associated with many rheumatic and nonrheumatic disorders. The diagnosis of sacroiliitis may be difficult in many patients, and awareness of its typical manifestations along with recognition of its diverse presentations and cognizance of the limitations of today's imaging modalities are critical to good clinical practice. This review presents the didactic approach to the early diagnosis of sacroiliitis in patients with suspected axial spondyloarthritis and other nosologic entities, discussing also differential interpretation of information acquired from patients' histories, physical examination, and imaging.

Magnetic resonance imaging (MRI) is a technique that utililises powerful magnets and radiofrequency to produce 3-dimentional images. MRI does not involve ionising radiation and has superb tissue resolution, enabling excellent delineation of anatomy as well as pathology in joints. This article briefly reviews the technical principle of magnetic resonance and discusses advantages and disadvantages of the technique, with particular attention to rheumatologic imaging. New information is summarised concerning the use of contrast media, dynamic, contrast-enhanced MRI, diffusion-weighted imaging, cartilage imaging and whole-body MRI.

Juvenile spondyloarthritis may be present in at least 3 subtypes of juvenile idiopathic arthritis according to the classification of the International League of Associations for Rheumatology. By contrast with spondyloarthritis in adults, juvenile spondyloarthritis starts with inflammation of peripheral joints and entheses in the majority of children, whereas sacroiliitis and spondylitis may develop many years after the disease onset. Peripheral joint involvement makes it difficult to differentiate juvenile spondyloarthritis from other juvenile idiopathic arthritis subtypes. Sacroiliitis, and especially spondylitis, although infrequent in childhood, may manifest as low back pain. In clinical practice, radiographs of the sacroiliac joints or pelvis are performed in most of the cases even though magnetic resonance imaging offers more accurate diagnosis of sacroiliitis. Neither disease classification criteria nor imaging recommendations have taken this advantage into account in patients with juvenile spondyloarthritis. The use of magnetic resonance imaging in evaluation of children and adolescents with a clinical suspicion of sacroiliitis would improve early diagnosis, identification of inflammatory changes and treatment. In this paper, we present the imaging features of juvenile spondyloarthritis in juvenile ankylosing spondylitis, juvenile psoriatic arthritis, reactive arthritis with spondyloarthritis, and juvenile arthropathies associated with inflammatory bowel disease.

Background Patients with predominantly axial spondyloarthritis (axSpA) may also have inflammation of peripheral joints and entheses. Using a whole-body MRI (WBMRI) approach, peripheral joints and entheses can be assessed objectively and followed during treatment. Objectives To describe the localization and extent of inflammation of peripheral joints and entheses by WBMRI in patients with axSpA initiating TNF-inhibitor therapy, and to assess treatment-induced changes. Methods Fifty-three patients that fulfilled the ASAS criteria for axSpA were included. MRI of SIJs and spine and WBMRI of peripheral joints and entheses were performed at baseline and 4/16/52 weeks after starting TNF inhibitor treatment. 75 peripheral joints and 30 peripheral entheses were scored in chronological order by an experienced musculoskeletal radiologist (IE). Osteitis, synovitis and entheseal soft tissue inflammation were scored separately [0(none)/1(mild)/2(moderate/severe)]. A WBMRI peripheral joint and enthesis index (WBMRI index) was derived by summing scores of all peripheral lesions. Results Median age (IQR/range) was 35 years. (28–44/22–73); median symptom duration was 5 years. (3–13/0–31); 53% were male. Baseline median WBMRI index (n=53) was 7,4–14; 0–40 after 52 weeks (n=46) 4 (2–9; 0–26). WBMRI index decreased mean 0.6 at week 4 (p=0.17, paired t-test), 2.3 at week 16 (p In univariate analysis, WBMRI index at week 52 was associated with age (2.5 higher per 10 years increase in age, p In univariate analysis, higher age was not significantly associated with change in WBMRI index, but when adjusted for baseline WBMRI index, higher age was associated with a less prominent reduction in WBMRI index (+0.9 per 10 years increase in age). Conclusions Inflammation of peripheral joints and entheses decreased over time in a cohort of patients with predominantly axSpA. Most patients had WBMRI index above zero during follow-up, and this was related to age and involved sites prone to osteoarthritis. Thus, the WBMRI Index may capture both disease activity related to axSpA and age-related degenerative changes. Disclosure of Interest None declared

Background There has been substantial progress in the characterisation of MRI lesions in the sacroiliac joints (SIJ) and spine in axial spondyloarthritis (axSpA) since the last consensus-based descriptive reports from ASAS1,2. There is as yet a lack of international consensus on standardised definitions of all the lesions reported to date. Consequently, the ASAS MRI group was convened to generate a consensus update. Objectives To evaluate the literature describing the spectrum of MRI lesions in axSpA and to generate a consensus update on standardised definitions. Methods The literature pertaining to MRI lesion definitions in axSpA was discussed at 3 meetings of the ASAS MRI group attended by 26 investigators. The group reviewed the literature for MRI lesion definitions and decided by consensus which definitions would be retained, which required modification, and which required a new definition. Results For definitions denoting signs of activity in the SIJ, there are no revisions to the most current ASAS definition of a positive MRI1. Definitions for capsulitis and enthesitis are revised. A new definition, joint space enhancement, denotes increased signal on contrast-enhanced images in the joint space of the cartilaginous portion of the SIJ. This replaces the term ‘synovitis’ and a separate definition describes what constitutes joint space fluid. For structural change in the SIJ, the definition for sclerosis is unchanged. Revised definition for a fatty lesion incorporates characteristics typical of axSpA, and for erosion requires both loss of cortical bone as well as adjacent marrow matrix. A new definition, fat metaplasia in the joint space (‘backfill’), denotes the reparative change on a T1W image at the site of erosion when signs of activity recede. The new definition for ankylosis stresses the continuity of bright marrow signal across the joint space. Spinal lesion definitions are divided into those that occur in defined central and lateral sagittal slices. The revised definition of a vertebral corner inflammatory lesion divides this into a regular (type A) and dimorphic (type B) lesion. A new definition for corner erosion requires both loss of cortical bone as well as adjacent marrow matrix. New definitions for new bone growth require bright signal on T1W images extending from the vertebral corner marrow or endplate, which may (ankylosis) or may not (bone spur) be continuous with the adjacent vertebra. Conclusions The ASAS MRI group has generated a consensus based update on MRI lesions in axSpA. References [1] Lambert, et al. Ann Rheum Dis2016;75:1958–1963. [2] Hermann, et al. Ann Rheum Dis2012;71:1278–1288. Disclosure of Interest None declared

Background Magnetic resonance imaging (MRI) allows objective assessment of inflammation in peripheral joints and entheses. MRI scoring systems have until now focused on assessing specific parts of the musculoskeletal system in detail, e.g. the Rheumatoid Arthritis MRI Scoring System (RAMRIS), which is applied to wrist and metacarpophalangeal joints and adjacent tendon sheaths. The interest in a whole-body MRI approach is growing as modern MRI scanners now permit whole-body scanning within an acceptable time frame, and future improvements in MRI hardware and pulse sequences are expected to improve scan time and image resolution further. Objectives To develop a whole-body MRI scoring system for inflammation of peripheral joints and entheses and to investigate its feasibility and reliability. Methods Definitions of the key pathologies and locations for assessment have been agreed upon in the OMERACT MRI Working Group1. In a first round in June 2017, 9 readers (AJM/DG/FG/IE/MO/PB/SJP/SK/WPM) scored MR images of 2 patients with spondyloarthritis using a draft web-based scoring system. Results were discussed and the scoring system was slightly modified. Hereafter, in a second round in October 2017, 14 MRI readers (3 musculoskeletal radiologist (IE/JLJ/RGL) and 11 rheumatologists with varying exposure to MRI (AJM/DG/FG/MS/MO/PB/RP/SJP/SK/VF/WPM), scored 5 similar patients by the modified scoring system. Using a semiquantitative scale 0–3 (none/mild/moderate/severe), synovitis and osteitis were scored separately for 83 joints, and soft tissue inflammation and osteitis were scored separately for 33 entheses. Discrepancies between readers were discussed during an online meeting to obtain consensus, to train inexperienced readers, and to identify potential pitfalls when applying the scoring system. Results Inter-reader reliability was overall moderate for joint scores and poor for enthesis scores; however, among the 3 musculoskeletal radiologists, enthesis scores were as reliable as joint scores (Table). Reliability did not improve between the first and second round, possibly because patients with several very conspicuous inflammatory lesions were selected as cases in the first round. Conclusions It is feasible to perform online multi-reader scoring exercises of whole-body MRI using a web-based scoring interface. MRI readers need to be further trained and calibrated in the semiquantitative scoring approach used to increase inter-reader reliability. Reference [1] Ostergaard M, et al. J Rheumatol2017;44:1699–1705. Disclosure of Interest None declared