Reliability assessment of the definition of ultrasound enthesitis in SpA: results of a large, multicentre, international, web-based study.

OBJECTIVES: To investigate the reliability of the OMERACT US Task Force definition of US enthesitis in SpA. METHODS: In this web exercise, based on the evaluation of 101 images and 39 clips of the main entheses of the lower limbs, the elementary components included in the OMERACT definition of US enthesitis in SpA (hypoechoic areas, entheseal thickening, power Doppler signal at the enthesis, enthesophytes/calcifications, bone erosions) were assessed by 47 rheumatologists from 37 rheumatology centres in 15 countries. Inter- and intra-observer reliability of the US components of enthesitis was calculated using Light's kappa, Cohen's kappa, Prevalence And Bias Adjusted Kappa (PABAK) and their 95% CIs. RESULTS: Bone erosions and power Doppler signal at the enthesis showed the highest overall inter-reliability [Light's kappa: 0.77 (0.76-0.78), 0.72 (0.71-0.73), respectively; PABAK: 0.86 (0.86-0.87), 0.73 (0.73-0.74), respectively], followed by enthesophytes/calcifications [Light's kappa: 0.65 (0.64-0.65), PABAK: 0.67 (0.67-0.68)]. This was moderate for entheseal thickening [Light's kappa: 0.41 (0.41-0.42), PABAK: 0.41 (0.40-0.42)], and fair for hypoechoic areas [Light's kappa: 0.37 (0.36-0.38); PABAK: 0.37 (0.37-0.38)]. A similar trend was observed in the intra-reliability exercise, although this was characterized by an overall higher degree of reliability for all US elementary components compared with the inter-observer evaluation. CONCLUSIONS: The results of this multicentre, international, web-based study show a good reliability of the OMERACT US definition of bone erosions, power Doppler signal at the enthesis and enthesophytes/calcifications. The low reliability of entheseal thickening and hypoechoic areas raises questions about the opportunity to revise the definition of these two major components for the US diagnosis of enthesitis.

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.

Entheseal involvement in patients with systemic lupus erythematosus: an ultrasound study.

Objectives: The main objective of this study is to explore the prevalence and distribution of entheseal US changes in a cohort of SLE patients, taking as controls a group including both PsA patients and healthy subjects. The secondary objective is to investigate the correlation between the US findings and the clinical and serological data in SLE patients. Methods: Clinical and US assessment of quadriceps, patellar and Achilles tendons, and plantar fascia entheses were performed by independent rheumatologists on 65 patients with SLE, 50 patients with PsA and 50 healthy subjects. US findings were identified according to the OMERACT definitions. In SLE patients, the correlation between the US changes and the clinical and laboratory findings was evaluated. Results: US revealed one or more abnormalities in at least one enthesis in 44 out of 65 SLE patients (67.7%), 47 out of 50 PsA patients (94.0%) and 22 out of 50 healthy subjects (44.0%). In SLE patients, US findings indicating active inflammation were significantly more frequently detected than in healthy subjects (P < 0.001). The distal enthesis of the patellar tendon was the most commonly involved. The presence of power Doppler signal at the enthesis was an independent predictor of SLE disease activity (SLEDAI-2k P < 0.001, ß = 0.52; musculoskeletal-BILAG P < 0.001, ß = 0.56). Conclusion: The burden of entheseal sonographic changes was significantly higher in SLE patients than in healthy subjects, especially as regards active inflammation. The presence of power Doppler signal at the enthesis may represent a potential biomarker of SLE disease activity.