Kay-Geert A. Hermann

Interobserver reliability of rheumatologists performing musculoskeletal ultrasonography: results from a EULAR “Train the trainers” course

Objective: To evaluate the interobserver reliability among 14 experts in musculoskeletal ultrasonography (US) and to determine the overall agreement about the US results compared with magnetic resonance imaging (MRI), which served as the imaging “gold standard”. Methods: The clinically dominant joint regions (shoulder, knee, ankle/toe, wrist/finger) of four patients with inflammatory rheumatic diseases were ultrasonographically examined by 14 experts. US results were compared with MRI. Overall agreements, sensitivities, specificities, and interobserver reliabilities were assessed. Results: Taking an agreement in US examination of 10 out of 14 experts into account, the overall κ for all examined joints was 0.76. Calculations for each joint region showed high κ values for the knee (1), moderate values for the shoulder (0.76) and hand/finger (0.59), and low agreement for ankle/toe joints (0.28). κ Values for bone lesions, bursitis, and tendon tears were high (κ = 1). Relatively good agreement for most US findings, compared with MRI, was found for the shoulder (overall agreement 81%, sensitivity 76%, specificity 89%) and knee joint (overall agreement 88%, sensitivity 91%, specificity 88%). Sensitivities were lower for wrist/finger (overall agreement 73%, sensitivity 66%, specificity 88%) and ankle/toe joints (overall agreement 82%, sensitivity 61%, specificity 92%). Conclusion: Interobserver reliabilities, sensitivities, and specificities in comparison with MRI were moderate to good. Further standardisation of US scanning techniques and definitions of different pathological US lesions are necessary to increase the interobserver agreement in musculoskeletal US.

Ustekinumab for the treatment of patients with active ankylosing spondylitis: results of a 28-week, prospective, open-label, proof-of-concept study (TOPAS)

Objective To evaluate efficacy and safety of ustekinumab in patients with ankylosing spondylitis (AS). Methods In this prospective, open-label, single-arm, proof-of-concept clinical trial (ClinicalTrials.gov identifier NCT01330901), ustekinumab in a dose of 90 mg was administered subcutaneously at baseline, week 4 and week 16 in 20 patients with active AS. Eligible patients were required to have a diagnosis of AS according to the modified New York criteria and an active disease defined as a Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) score of ≥4 despite previous non-steroidal anti-inflammatory drug (NSAID) treatment. The primary study endpoint was the proportion of patients reached the Assessment of SpondyloArthritis International Society 40 (ASAS40) response at week 24. Results At week 24, ASAS40 response was reached by 65% of the patients. ASAS20, ASAS5/6 and ASAS partial remission were observed in 75%, 50% and 30% of the patients, respectively. A ≥50% improvement of the BASDAI (BASDAI50) occurred in 55% of the patients. A total of 50% and 20% of the patients achieved the AS Disease Activity Score (ASDAS) clinically important improvement and major improvement, respectively. At week 24, 35% of the patients had an ASDAS inactive disease (ASDAS <1.3). Significant improvement of other patient-reported outcome parameters and active inflammation as detected by MRI as well as significant reduction of NSAIDs intake occurred during the treatment. Clinical response correlated with reduction of active inflammation on MRI and of serum C reactive protein level. Overall, ustekinumab was well tolerated. Conclusions In this prospective, open-label, proof-of-concept clinical trial, ustekinumab treatment was associated with a reduction of signs and symptoms in active AS and was well tolerated.

Both structural damage and inflammation of the spine contribute to impairment of spinal mobility in patients with ankylosing spondylitis

Objective To study the relationship between spinal mobility, radiographic damage of the spine and spinal inflammation as assessed by MRI in patients with ankylosing spondylitis (AS). Methods In this subanalysis of the Ankylosing Spondylitis Study for the Evaluation of Recombinant Infliximab Therapy cohort, 214 patients, representing an 80% random sample, were investigated. Only baseline data were used. MRI inflammation was assessed by the AS spinal MRI activity (ASspiMRI-a) score, structural damage by the modified Stoke AS Spine Score (mSASSS) and spinal mobility by the linear definition of the Bath Ankylosing Spondylitis Metrology Index (BASMI). Univariate correlations were calculated on baseline values using Spearman rank correlation. Independent associations between the variables of interest were investigated by multivariate linear regression analysis. Associations with clinical disease activity, C-reactive protein, disease duration, age, gender, body mass index and HLA-B27 status were also investigated. Subanalyses were performed according to disease duration. Results BASMI correlated moderately well with mSASSS (Spearmans ρ=0.6) and weakly with ASspiMRI-a (ρ=0.3). A best-fit model for BASMI included both mSASSS (regression coefficient (B)=0.865, p<0.001) and ASspiMRI-a (B=0.236, p=0.018). In patients with a disease duration ≤3 years, B was greater for ASspiMRI-a than for mSASSS (0.595 vs 0.380), while in patients with a disease duration >3 years B was greater for mSASSS than for ASspiMRI-a (0.924 vs 0.156). Conclusion Spinal mobility impairment in AS is independently determined both by irreversible spinal damage and by reversible spinal inflammation. Spinal mobility impairment is more influenced by spinal inflammation in early disease, and by structural damage in later disease.

MRI of enthesitis of the appendicular skeleton in spondyloarthritis

Entheses are sites where tendons, ligaments, joint capsules or fascia attach to bone. Inflammation of the entheses (enthesitis) is a well-known hallmark of spondyloarthritis (SpA). As entheses are associated with adjacent, functionally related structures, the concepts of an enthesis organ and functional entheses have been proposed. This is important in interpreting imaging findings in entheseal-related diseases. Conventional radiographs and CT are able to depict the chronic changes associated with enthesitis but are of very limited use in early disease. In contrast, MRI is sensitive for detecting early signs of enthesitis and can evaluate both soft-tissue changes and intraosseous abnormalities of active enthesitis. It is therefore useful for the early diagnosis of enthesitis-related arthropathies and monitoring therapy. Current knowledge and typical MRI features of the most commonly involved entheses of the appendicular skeleton in patients with SpA are reviewed. The MRI appearances of inflammatory and degenerative enthesopathy are described. New options for imaging enthesitis, including whole-body MRI and high-resolution microscopy MRI, are briefly discussed.

Descriptions of spinal MRI lesions and definition of a positive MRI of the spine in axial spondyloarthritis: a consensual approach by the ASAS/OMERACT MRI study group

Objective The aim of this study was to define characteristic MRI findings in the spine of patients with axial spondyloarthritis (SpA) and provide a definition of a positive spinal MRI for inflammation and structural changes. Methods Technical details of spinal MRI and the description of spinal lesions of both inflammation and structural changes were discussed in consecutive meetings of 10 experts of the Assessment in SpondyloArthritis international Society (ASAS). The discussions aimed at a broad consensus on definitions of ‘a positive spinal MRI’ for both types of lesions and were backed up by a systematic literature search. Results A total of six different types of lesions were described for inflammation—anterior/posterior spondylitis, spondylodiscitis, arthritis of costovertebral joints, arthritis of zygoapophyseal joints and enthesitis of spinal ligaments—and another four for structural changes—fatty deposition, erosions, syndesmophytes and ankylosis. In the literature review, four relevant papers were identified. Anterior/posterior spondylitis and fat depositions at vertebral edges were considered as the most typical findings in SpA. Based on expert consensus and taking the literature review into consideration, a positive spinal MRI for inflammation was defined as the presence of anterior/posterior spondylitis in ≥3 sites. Evidence of fatty deposition at several vertebral corners was found to be suggestive of axial SpA, especially in younger adults. ASAS members (n=56) approved these definitions by voting in January 2010. Conclusions This consensus statement gives clear descriptions of disease-related spinal lesions and of definitions of a positive spinal MRI for inflammatory lesions (spondylitis) and structural changes (fat deposition). These definitions can be used to describe findings of spinal MRI in patients with SpA in daily practice and clinical studies.

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.

First clinical evaluation of sagittal laser optical tomography for detection of synovitis in arthritic finger joints

Objective: To identify classifiers in images obtained with sagittal laser optical tomography (SLOT) that can be used to distinguish between joints affected and not affected by synovitis. Methods: 78 SLOT images of proximal interphalangeal joints II–IV from 13 patients with rheumatoid arthritis were compared with ultrasound (US) images and clinical examination (CE). SLOT images showing the spatial distribution of scattering and absorption coefficients within the joint cavity were generated. The means and standard errors for seven different classifiers (operator score and six quantitative measurements) were determined from SLOT images using CE and US as diagnostic references. For classifiers showing significant differences between affected and non-affected joints, sensitivities and specificities for various cut off parameters were obtained by receiver operating characteristic (ROC) analysis. Results: For five classifiers used to characterise SLOT images the mean between affected and unaffected joints was statistically significant using US as diagnostic reference, but statistically significant for only one classifier with CE as reference. In general, high absorption and scattering coefficients in and around the joint cavity are indicative of synovitis. ROC analysis showed that the minimal absorption classifier yields the largest area under the curve (0.777; sensitivity and specificity 0.705 each) with US as diagnostic reference. Conclusion: Classifiers in SLOT images have been identified that show statistically significant differences between joints with and without synovitis. It is possible to classify a joint as inflamed with SLOT, without the need for a reference measurement. Furthermore, SLOT based diagnosis of synovitis agrees better with US diagnosis than CE.

Takayasu arteritis is characterised by disturbances of B cell homeostasis and responds to B cell depletion therapy with rituximab

Introduction Takayasu arteritis (TA) is a large vessel vasculitis involving the aorta and its major branches. T cell-mediated autoimmunity is thought to play a major role in its pathogenesis, while the role of B cells is still unclear. Methods B cell subsets in the peripheral blood of 17 patients with TA were analysed and compared with nine patients with active systemic lupus erythematosus (SLE) and nine healthy controls by flow cytometry. Based on these findings, three patients with active refractory TA were treated with B cell depletion therapy (BCDT) using monoclonal anti-CD20 antibodies (rituximab). Results The absolute number and frequency of peripheral blood CD19+/CD20−/CD27high antibody-secreting cells in patients with active TA was significantly higher than in healthy donors. As in active SLE, the majority of these cells are newly generated plasmablasts which significantly correlated with TA activity. Three patients with active refractory TA and expansion of plasmablasts were successfully treated with BCDT, which resulted in remission. Conclusion Disturbances of B cell homeostasis may be critical in TA. Circulating plasmablasts could be a useful biomarker of disease activity and a tool for selecting appropriate candidates for BCDT. B cells and plasmablasts/plasma cells may therefore represent novel targets for effective therapies for TA.

MRI inflammation at the vertebral unit only marginally predicts new syndesmophyte formation: a multilevel analysis in patients with ankylosing spondylitis

Objective To investigate the relationship between MRI inflammation at the vertebral unit and the formation and growth of syndesmophytes at the same vertebral unit. Methods An 80% random sample of the ASSERT database was analysed. MRI were scored using the ankylosing spondylitis (AS) spinal MRI activity score (at baseline, 24 and 102 weeks) and spinal x-rays were scored using the modified Stoke AS spine score (at baseline and 102 weeks). Data were analysed at the patient level and the vertebral unit level using a multilevel approach to adjust for within-patient correlation. Results There was a slightly increased probability of developing syndesmophytes in vertebral units with MRI activity, which was maintained after adjustment for within-patient correlation (per vertebral unit level) and treatment, and after further adjustment for potential confounders, resulting in significant OR ranging from 1.51 to 2.26. Growth of existing syndesmophytes at the vertebral unit level was not associated with MRI activity. At the patient level only a trend for an association was observed. Conclusion MRI inflammation in a vertebral unit slightly increases the propensity to form a new syndesmophyte in the same vertebral unit, but does not predict the growth of already existing syndesmophytes. Despite this association, the large majority of new syndesmophytes developed in vertebral units without inflammation. The subtle association at the vertebral unit level did not translate into an association at the patient level.

Responsiveness of the Ankylosing Spondylitis Disease Activity Score (ASDAS) and clinical and MRI measures of disease activity in a 1-year follow-up study of patients with axial spondyloarthritis treated with tumour necrosis factor α inhibitors

Objectives To investigate construct validity and responsiveness of the novel ankylosing spondylitis (AS) disease activity score (ASDAS) in patients with spondyloarthritis (SpA). Methods In a 46-week prospective longitudinal multicentre study of 60 patients with SpA (80% men, median age 40 years (range 21–62)) treated with tumour necrosis factor α (TNFα) inhibitors (infliximab, n=41; etanercept, n=13; adalimumab, n=6), the responsiveness of ASDAS, conventional clinical measures of disease activity and treatment response and the Berlin MRI sacroiliac joint (SIJ) and lumbar spine inflammation scores were compared. Results After 22 weeks, 58.3% of the patients were clinical responders (50% or 20 mm reduction in the Bath AS Disease Activity Index (BASDAI)). At baseline, clinical responders had significantly higher median (range) ASDAS than non-responders (4.15 (1.98–6.04) vs 2.99 (2.05–6.19), p=0.008). Changes in ASDAS correlated with changes in clinical measures of disease activity (including BASDAI (ρ=0.76) and C-reactive protein (CRP) (0.79)), MRI SIJ inflammation (0.46) and MRI total inflammation scores (0.34). Patients with higher BASDAI or Assessment of SpondyloArthritis International Society (ASAS) responses obtained more profound reductions in ASDAS. ASDAS had the highest responsiveness with an effect size of 2.04 and a standardised response mean of 1.45, whereas BASDAI (effect size 1.86; standardised response mean 1.36) and CRP (effect size 0.63; standardised response mean 0.70) were less responsive. Linear regression showed that a change in BASDAI of 20 mm or 50% corresponded to a change in ASDAS of 1.38 and 1.95, respectively. Conclusion ASDAS demonstrates construct validity and high responsiveness during treatment with TNFα inhibitors in patients with SpA. The proposed thresholds for disease activity and treatment response need further validation. Trial registration number NCT00133315.