MRI and ultrasonography for detection of early interphalangeal osteoarthritis.

OBJECTIVES: To assess the interest of MRI and ultrasonography (US) in identifying early and advanced interphalangeal (IP) OA. METHODS: We conducted a case-control study including patients with symptomatic hand OA (n=33) and young healthy volunteers (n=26). Proximal and distal IP joints were graded according to Kellgren and Lawrence (KL) grades. In OA patients, we separated IP joints into 2 groups: "at risk of OA" joints (potential early pre-radiographic OA joints, KL=0) and OA joints (KL=2-4). All IP joints from healthy participants were KL=0 and were considered strictly normal IP joints. Concurrently, synovitis, effusion, erosions, osteophytes, bone marrow lesions, cysts and cartilage space loss were graded by MRI and/or US. We assessed their prevalence, severity and diagnostic performance in hand OA and then compared normal IP joints from healthy participants and "at risk of OA" IP joints from OA patients as well as "at risk of OA" and OA IP joints from OA patients. RESULTS: The prevalence and grade of most MRI/US-detected lesions were higher in IP joints from OA patients than healthy participants. Except for osteophyte assessment, MRI seemed more sensitive than US. We found more MRI/US-detected lesions in "at risk of OA" IP joints than normal joints but also in OA than "at risk of OA" joints from OA patients. US appeared both sensitive and specific for detecting osteophytes in joints without radiographic abnormalities. CONCLUSIONS: MRI and US give good performance for detecting radiographic and pre-radiographic OA lesions and could be interesting tools to identify early hand OA.

Development of a new ultrasound scoring system to evaluate glandular inflammation in Sjögren's syndrome: an OMERACT reliability exercise.

OBJECTIVE: The aim of this exercise from the OMERACT Ultrasound subgroup on Sjögren's syndrome was to develop and assess the reliability of a consensus-based semiquantitative colour Doppler US scoring system for pathologic salivary gland vascularization in patients with primary Sjögren's syndrome (pSS). METHODS: Using the Delphi method, a colour Doppler semiquantitative scoring system for vascularization of bilateral parotid and submandibular glands was developed and tested in static images and on patients (9 pSS patients and 9 sonographers). Intra-reader and inter-reader reliability of grading the salivary glands were computed by weighted Cohen and Light's kappa analysis, respectively. RESULTS: The consensus-based semiquantitative score was: grade 0, no visible vascular signals; grade 1, focal, dispersed vascular signals; grade 2, diffuse vascular signals detected in <50% of the gland; grade 3, diffuse vascular signals in >50% of the gland. In static images, the intra- and inter-reader reliability showed excellent kappa values (95% CI) of 0.90 (0.87, 0.93) and 0.80 (0.74, 0.84), respectively, for all four salivary glands together. In patients, the intra- and inter-reader reliability for all four salivary glands together was kappa = 0.84 (0.73, 0.92) and 0.70 (0.64, 0.76), respectively. CONCLUSION: The consensus-based colour Doppler US scoring for the evaluation of salivary gland vascularization in pSS showed a good inter-reader reliability and excellent intra-reader reliability in static images and in patients. The clinical application of the developed scoring system should be tested in clinical settings.

Arthritis and enthesitis in the hip and pelvis region in spondyloarthritis - OMERACT validation of two whole-body MRI methods.

OBJECTIVE: To validate reliability, correlation and responsiveness of two whole-body MRI scores for the hip/pelvis region in spondyloarthritis. METHODS: Assessment of hip/pelvis inflammation in 4 multi-reader exercises using the OMERACT MRI Whole-body score for Inflammation in Peripheral joints and Entheses (MRI-WIPE) and Hip Inflammation Magnetic Resonance Imaging Scoring System (HIMRISS). RESULTS: In exercises 3-4 (11/20 cases, respectively; 9 readers) reliability was mostly good for the 3 best calibrated readers. Median pairwise single-measure ICC for status were 0.58-0.65 (WIPE-osteitis), 0.10-0.88 (HIMRISS-osteitis) and for status/change 0.38-0.72/0.52-0.60 (WIPE-synovitis/effusion) and 0.68-0.89/0.78-0.85 (HIMRISS-synovitis/effusion). SRM was 1.23 for WIPE-osteitis, while lower for WIPE-synovitis/effusion and HIMRISS. CONCLUSION: MRI-WIPE and HIMRISS may after further validation be useful in future spondyloarthritis trials.

Joint and entheseal inflammation in the knee region in spondyloarthritis - reliability and responsiveness of two OMERACT whole-body MRI scores.

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.

Recommendations for the pragmatic use of ultrasound in rheumatoid arthritis by the GEISPER French group.

OBJECTIVE: To develop recommendations for the appropriate use of ultrasound in the management of rheumatoid arthritis (RA) in routine practice based on data from the literature and of experts opinion. METHODS: Based on a systematic literature review, a scientific committee decided on themes and relevant questions to draw up an initial draft of recommendations. These recommendations were submitted to a group of experts in ultrasound in rheumatic and musculoskeletal diseases using a Delphi method, which produced preliminary recommendations. These were submitted to an expanded group of ultrasound experts for relevance, comprehensibility and comprehensiveness. The level of agreement of the experts were recorded during a face-to-face meeting. RESULTS: Following two rounds of the Delphi, a consensus was reached on three overarching principles, including definitions of joints, tendons and articular sites to be examined, and 10 recommendations. These recommendations underline the benefit of ultrasound for the diagnosis of RA in cases of inflammatory arthralgia or undifferentiated arthritis as well as in assessing the extent of initial structural and inflammatory damage. They also define the role of ultrasound during follow-up or when considering treatment reduction once clinical remission has been achieved. Lastly, they illustrate the utility of ultrasound in facilitating technical procedures. CONCLUSION: These 10 consensus-based recommendations should harmonize and optimize clinical practice and thus improve the management of RA patients.

Performance of serum apolipoprotein-A1 as a sentinel of Covid-19.

BACKGROUND: Since 1920, a decrease in serum cholesterol has been identified as a marker of severe pneumonia. We have assessed the performance of serum apolipoprotein-A1, the main transporter of HDL-cholesterol, to identify the early spread of coronavirus disease 2019 (Covid-19) in the general population and its diagnostic performance for the Covid-19. METHODS: We compared the daily mean serum apolipoprotein-A1 during the first 34 weeks of 2020 in a population that is routinely followed for a risk of liver fibrosis risk in the USA (212,297 serum) and in France (20,652 serum) in relation to a local increase in confirmed cases, and in comparison to the same period in 2019 (266,976 and 28,452 serum, respectively). We prospectively assessed the sensitivity of this marker in an observational study of 136 consecutive hospitalized cases and retrospectively evaluated its specificity in 7,481 controls representing the general population. RESULTS: The mean serum apolipoprotein-A1 levels in the survey populations began decreasing in January 2020, compared to the same period in 2019. This decrease was highly correlated with the daily increase in confirmed Covid-19 cases in the following 34 weeks, both in France and USA, including the June and mid-July recovery periods in France. Apolipoprotein-A1 at the 1.25 g/L cutoff had a sensitivity of 90.6% (95%CI84.2-95.1) and a specificity of 96.1% (95.7-96.6%) for the diagnosis of Covid-19. The area under the characteristics curve was 0.978 (0.957-0.988), and outperformed haptoglobin and liver function tests. The adjusted risk ratio of apolipoprotein-A1 for survival without transfer to intensive care unit was 5.61 (95%CI 1.02-31.0; P = 0.04). CONCLUSION: Apolipoprotein-A1 could be a sentinel of the pandemic in existing routine surveillance of the general population. NCT01927133, CER-2020-14.

Atlas of the OMERACT Heel Enthesitis MRI Scoring System (HEMRIS).

OBJECTIVE: Assessment of enthesitis, a key feature in spondyloarthritis (SpA) and psoriatic arthritis (PsA), using objective and sensitive methods is pivotal in clinical trials. MRI allows detection of both soft tissue and intra-osseous changes of enthesitis. This article presents an atlas for the Outcome Measures in Rheumatology (OMERACT) Heel Enthesitis Magnetic Resonance ImagingMRI Scoring System (HEMRIS). METHODS: Following a preliminary selection of potential examples of each grade, as per HEMRIS definitions, the images along with detailed definitions and reader rules were discussed at web-based, interactive meetings between the members of the OMERACT MRI in Arthritis Working Group. RESULTS: Reference images of each grade of the MRI features to be assessed using HEMRIS, along with reader rules and recommended MRI sequences are depicted. CONCLUSION: The presented reference images can be used to guide scoring Achilles tendon and plantar fascia (plantar aponeurosis) enthesitis according to the OMERACT HEMRIS in clinical trials and cohorts in which MRI enthesitis is used as an outcome.

A simplified radiographic score effectively predicts radiographic progression of early arthritis in a large nationwide French cohort.

OBJECTIVE: Evaluating radiographic progression is a key component of the follow-up of patients with RA. Existing scores are ill-suited to everyday clinical practice. The objective here was to validate a new simplified radiographic score (SRS) for evaluating radiographic progression in patients with early arthritis. METHODS: Patients with arthritis of <6 months' duration were included in the large, prospective, nationwide, French ESPOIR cohort. Radiographs of the hands and feet were obtained at inclusion then 1 and 5 years later. The modified Sharp scores and SRS were determined by blinded readers. Interobserver reliability and intraobserver repeatability of each score, as well as agreement between the two scores, were assessed by computing the intraclass correlation coefficients. The rates of progression over the first year and the next 4 years were determined. RESULTS: The 506 patients with complete data for the first 5 years were included. At inclusion, the intraclass correlation coefficient between the two scores was good for erosions (0.715, P < 0.001), joint space narrowing (0.892, P < 0.001) and the total score (0.896, P < 0.001). Agreement between the two scores was also good for radiographic progression after 1 year (0.781, P < 0.001). The SRS had good positive and negative predictive values for slow and for rapid progression. SRS determination was less time consuming. CONCLUSION: The SRS is effective for monitoring radiographic progression in early arthritis and is easier to use and less time-consuming than the Sharp score. The usefulness of the SRS in clinical practice deserves further evaluation.

Optimization of ultrasonographic examination for the diagnosis of erosive Rheumatoid Arthritis in comparison to erosive hand Osteoarthritis.

OBJECTIVE: to determine thresholds and better scenario for the diagnosis of erosive rheumatoid arthritis (RA) by ultrasonography (US) in RA in comparison to osteoarthritic (OA) patients. METHODS: Patients, prospectively included, fulfilling ACR 1987; ACR/EULAR 2010 criteria for RA or hand OA criteria. Radiographic assessment (RX): Sharp erosion score, evaluated by two blinded readers and one adjudicator for discordant cases (number of eroded joints ≤ three). Definition of eroded RX RA: EULAR 2013 Definition. In US, erosions were scored on six bilateral joints (MCP2-3, 5; MTP2-3, 5) with a four-grade scale. RESULTS: A total of 168 patients were included: 122 RA (32 early RA < 2 years; 90 late RA ≥ 2 years); 46 OA patients. On RX: 42 RA patients (6 early; 36 late) and 5 OA patients have erosive diseases (sensitivity: 34.4%, specificity: 89.1%). On US, 95 RA patients (21 early; 78 late) and 12 OA patients have erosive diseases. Considering at least two joint facets eroded (threshold 1) or at least one joint facet eroded at grade 2 (threshold 2), sensitivities were good (68 and 72.1%), specificities excellent (89.1 and 100%). With only six targeted joint facets examined (6/30), sensitivities and specificities remained good (59.8 and 60.0%) and excellent (95.6 and 100%) with threshold 1 and 2 respectively. For all scenarios, agreement between RX and US for erosive RA was excellent ranged from 88.1% to 92.8%. CONCLUSION: US erosion assessment of six targeted joint facets detected 1.7 times more erosive RA patients than RX in late and early RA with good sensitivity and excellent specificity.

Video clip assessment of a salivary gland ultrasound scoring system in Sjögren's syndrome using consensual definitions: an OMERACT ultrasound working group reliability exercise.

OBJECTIVE: To develop ultrasound (US) definitions and a US novel scoring system for major salivary gland (SG) lesions in patients with primary Sjögren's syndrome (pSS) and to test their intrareader and inter-reader reliability using US video clips. METHODS: Twenty-five rheumatologists were subjected to a three-round, web-based Delphi process in order to agree on (1) definitions and scanning procedure of salivary gland ultrasonography (SGUS): parotid, submandibular and sublingual glands (PG, SMG and SLG); (2) definitions for the elementary SGUS lesions in patients with Sjögren's syndrome; (3) scoring system for grading changes. The experts rated the statements on a 1-5 Likert scale. In the second step, SGUS video clips of patients with pSS and non-pSS sicca cases were collected containing various spectrums of disease severity followed by an intrareader and inter-reader reliability exercise. Each video clip was evaluated according to the agreed definitions. RESULTS: Consensual definitions were developed after three Delphi rounds. Among the three selected SGs, US assessment of PGs and SMGs was agreed on. Agreement was reached to score only greyscale lesions and to focus on anechoic/hypoechoic foci in a semiquantitative matter or, if not possible on a qualitatively (present/absent) evaluation of fatty or fibrous lesions. Intrareader reliability for detecting and scoring these lesions was excellent (Cohen's kappa 0.81) and inter-reader reliability was good (Light's kappa 0.66). CONCLUSION: New definitions for developing a novel semiquantitative US score in patients with pSS were developed and tested on video clips. Inter-reader and intrareader reliabilities were good and excellent, respectively.

Development and Validation of an OMERACT MRI Whole-Body Score for Inflammation in Peripheral Joints and Entheses in Inflammatory Arthritis (MRI-WIPE).

OBJECTIVE: To develop a whole-body magnetic resonance imaging (MRI) scoring system for peripheral arthritis and enthesitis. METHODS: After consensus on definitions/locations of MRI pathologies, 4 multireader exercises were performed. Eighty-three joints were scored 0-3 separately for synovitis and osteitis, and 33 entheses 0-3 separately for soft tissue inflammation and osteitis. RESULTS: In the last exercise, reliability was moderate-good for musculoskeletal radiologists and rheumatologists with previously demonstrated good scoring proficiency. Median pairwise single-measure/average-measure ICC were 0.67/0.80 for status scores and 0.69/0.82 for change scores; κ ranged 0.35-0.77. CONCLUSION: Whole-body MRI scoring of peripheral arthritis and enthesitis is reliable, which encourages further testing and refinement in clinical trials.

The OMERACT MRI in Enthesitis Initiative: Definitions of Key Pathologies, Suggested MRI Sequences, and a Novel Heel Enthesitis Scoring System.

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.

Ultrasonographic criteria for the diagnosis of erosive rheumatoid arthritis using osteoarthritic patients as controls compared to validated radiographic criteria.

OBJECTIVES: The aims of this study were to compare characteristics of radiography (RX) and ultrasound (US) erosive lesions in rheumatoid arthritis (RA) and osteoarthritis (OA) patients (prevalence, topography and severity), to determine thresholds for the diagnosis of erosive RA based on US and to evaluate the performance of US and RX to establish a diagnosis of erosive RA differentiated from hand OA. METHODS: Patients fulfilling ACR 1987 and/or ACR/EULAR 2010 criteria for RA or ACR hand OA criteria were prospectively included. A modified Sharp erosion score was assessed by two blinded readers and one adjudicator for discordant cases (number of eroded joints ≤ three). Erosions in US were scored on six bilateral joints (MCP2-3, 5; MTP2-3, 5) with a four-grade scale to calculate total US score for erosions (USSe). RESULTS: A total of 168 patients were included: 122 RA (32 early RA < 2 years; 90 late RA ≥ 2 years); 46 OA patients. On RX: 42 RA patients (6 early; 36 late) and 5 OA patients were eroded according to EULAR 2013 definition criteria with sensitivity at 34.4% and specificity at 89.1%. On US, 95 RA patients (21 early; 74 late) and 12 OA patients were eroded. Considering at least two joint facets eroded or at least one joint facet eroded at grade 2 on US, sensitivities were good (68-72.1%) and specificities excellent (89.1-100%). Agreement between RX and US was excellent (90-92%). The positive and negative likehood ratios were respectively 3.16 and 0.73 for radiography and 6.64 and 0.31 for US (for two facets eroded). CONCLUSION: USSe can differentiate RA from OA in erosive disease and detect two times more patients with erosive RA than RX with excellent specificity and agreement.

Detection of Flares by Decrease in Physical Activity, Collected Using Wearable Activity Trackers in Rheumatoid Arthritis or Axial Spondyloarthritis: An Application of Machine Learning Analyses in Rheumatology.

OBJECTIVE: Flares in rheumatoid arthritis (RA) and axial spondyloarthritis (SpA) may influence physical activity. The aim of this study was to assess longitudinally the association between patient-reported flares and activity-tracker-provided steps per minute, using machine learning. METHODS: This prospective observational study (ActConnect) included patients with definite RA or axial SpA. For a 3-month time period, physical activity was assessed continuously by number of steps/minute, using a consumer grade activity tracker, and flares were self-assessed weekly. Machine-learning techniques were applied to the data set. After intrapatient normalization of the physical activity data, multiclass Bayesian methods were used to calculate sensitivities, specificities, and predictive values of the machine-generated models of physical activity in order to predict patient-reported flares. RESULTS: Overall, 155 patients (1,339 weekly flare assessments and 224,952 hours of physical activity assessments) were analyzed. The mean ± SD age for patients with RA (n = 82) was 48.9 ± 12.6 years and was 41.2 ± 10.3 years for those with axial SpA (n = 73). The mean ± SD disease duration was 10.5 ± 8.8 years for patients with RA and 10.8 ± 9.1 years for those with axial SpA. Fourteen patients with RA (17.1%) and 41 patients with axial SpA (56.2%) were male. Disease was well-controlled (Disease Activity Score in 28 joints mean ± SD 2.2 ± 1.2; Bath Ankylosing Spondylitis Disease Activity Index score mean ± SD 3.1 ± 2.0), but flares were frequent (22.7% of all weekly assessments). The model generated by machine learning performed well against patient-reported flares (mean sensitivity 96% [95% confidence interval (95% CI) 94-97%], mean specificity 97% [95% CI 96-97%], mean positive predictive value 91% [95% CI 88-96%], and negative predictive value 99% [95% CI 98-100%]). Sensitivity analyses were confirmatory. CONCLUSION: Although these pilot findings will have to be confirmed, the correct detection of flares by machine-learning processing of activity tracker data provides a framework for future studies of remote-control monitoring of disease activity, with great precision and minimal patient burden.

Longitudinal Reliability of the OMERACT Thumb Base Osteoarthritis Magnetic Resonance Imaging Scoring System (TOMS).

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.

Update on magnetic resonance imaging and ultrasound in rheumatoid arthritis.

Rheumatoid arthritis (RA) disease activity often remains difficult to assess and quantify accurately. As a result, numerous measures using various techniques to estimate clinical activity have been developed for clinical research and care. More objective imaging biomarkers for early detection and accurate, quantitative measurement of the disease burden are therefore of interest both for clinical use and for investigational studies. Two widely studied imaging biomarkers are magnetic resonance imaging (MRI) and ultrasound (US), imaging tests that are increasingly available to clinicians. While substantial and increasing evidence has been reported that these tools are valid and provide advantages in both clinical trials and clinical assessments, more information is needed to inform their appropriate use in routine clinical care. The goals of this review are to outline the current literature regarding each of these objective imaging tools, assess their strengths and limitations, and to clarify knowledge gaps to be filled before these techniques may be more optimally utilised.

Reliability of a consensus-based ultrasound definition and scoring for enthesitis in spondyloarthritis and psoriatic arthritis: an OMERACT US initiative.

OBJECTIVES: To evaluate the reliability of consensus-based ultrasound (US) definitions of elementary components of enthesitis in spondyloarthritis (SpA) and psoriatic arthritis (PsA) and to evaluate which of them had the highest contribution to defining and scoring enthesitis. METHODS: Eleven sonographers evaluated 40 entheses from five patients with SpA/PsA at four bilateral sites. Nine US elementary lesions were binary-scored: hypoechogenicity, thickened insertion, enthesophytes, calcifications, erosions, bone irregularities, bursitis and Doppler signal inside and around enthesis. Kappa statistics were used to evaluate reliability. Sonographers were also asked to state which lesions can be considered as inflammatory or structural and should be included in the final definition of enthesitis. Only the lesions, scored as present in at least 75% of the entheses considered as having an enthesitis, were included in the final definition. RESULTS: The prevalence of detected lesions was quite low except for enthesophytes (55%) and bone irregularities (54%). Reliability ranged from poor to good (the lowest for thickened enthesis (kappa 0.1 (95% CI 0 to 0.7)) and the highest for enthesophytes (kappa 0.6 (95% CI 0.5 to 0.7)). When adjusted for low prevalence, kappa values increased for all lesions, with the best result observed for detecting Doppler signal at insertion (0.9) and for bursitis (0.8). The US components included in the final definition were hypoechogenicity, increased thickness at enthesis, erosions and calcifications/enthesophytes and Doppler signal at insertion. CONCLUSION: By using a consensus-based stepwise approach, a final reliable US score and definition of enthesitis in SpA/PsA were produced. Further studies are sought for implementing this score in clinical trials and practice.

Atlas for the OMERACT thumb base osteoarthritis MRI scoring system (TOMS).

This paper presents an atlas for the Outcome Measures in Rheumatology Clinical Trials (OMERACT) thumb base osteoarthritis MRI scoring system (TOMS). The atlas includes reference images of each grade of each feature that is assessed in TOMS (synovitis grade 0-3, subchondral bone defects grade 0-3, osteophytes grade 0-3, cartilage assessment grade 0-3, subluxation and bone marrow lesions grade 0-3) in the first carpometacarpal and scapho-trapezio-trapezoid joint. The presented reference images can be used to guide scoring of thumb base MRIs in patients with hand osteoarthritis according to the OMERACT TOMS.

Identification of calcium pyrophosphate deposition disease (CPPD) by ultrasound: reliability of the OMERACT definitions in an extended set of joints-an international multiobserver study by the OMERACT Calcium Pyrophosphate Deposition Disease Ultrasound Subtask Force.

OBJECTIVES: To assess the reliability of the OMERACT ultrasound (US) definitions for the identification of calcium pyrophosphate deposition disease (CPPD) at the metacarpal-phalangeal, triangular fibrocartilage of the wrist (TFC), acromioclavicular (AC) and hip joints. METHODS: A web-based exercise and subsequent patient-based exercise were carried out. A panel of 30 OMERACT members, participated at the web-based exercise by evaluating twice a set of US images for the presence/absence of CPPD. Afterwards, 19 members of the panel met in Siena, Italy, for the patient-based exercise. During the exercise, all sonographers examined twice eight patients for the presence/absence of CPPD at the same joints. Intraoberserver and interobserver kappa values were calculated for both exercises. RESULTS: The web-based exercise yielded high kappa values both in intraobserver and interobserver evaluation for all sites, while in the patient-based exercise, inter-reader agreement was acceptable for the TFC and the AC. TFC reached high interobserver and intraobserver k values in both exercises, ranging from 0.75 to 0.87 (good to excellent agreement). AC reached moderate kappa values, from 0.51 to 0.85 (moderate to excellent agreement) and can readily be used for US CPPD identification. CONCLUSIONS: Based on the results of our exercise, the OMERACT US definitions for the identification of CPPD demonstrated to be reliable when applied to the TFC and AC. Other sites reached good kappa values in the web-based exercise but failed to achieve good reproducibility at the patient-based exercise, meaning the scanning method must be further refined.