Capillaroscopy is a non-invasive and safe tool which allows the evaluation of the morphology of the microcirculation. Since its recent incorporation in the 2013 American College of Rheumatology (ACR)/European League Against Rheumatism (EULAR) classification criteria for systemic sclerosis together with its assessed role to monitor disease progression, capillaroscopy became a 'mainstream' investigation for rheumatologists. Given its increasing use by a variety of physicians internationally both in daily practice to differentiate primary from secondary Raynaud's phenomenon, as well as in research context to predict disease progression and monitor treatment effects, standardisation in capillaroscopic image acquisition and analysis seems paramount. To step forward to this need, experts in the field of capillaroscopy/microcirculation provide in this very consensus paper their view on image acquisition and analysis, different capillaroscopic techniques, normal and abnormal capillaroscopic characteristics and their meaning, scoring systems and reliability of image acquisition and interpretation.

Introduction: In this study, we aimed to investigate ultrasonographic (US) changes suggestive of gouty arthritis in the hyaline cartilage, joints and tendons from asymptomatic individuals with hyperuricemia. Methods: We conducted a cross-sectional, controlled study including US examinations of the knees and first metatarsal-phalangeal joints (first MTPJs), as well as of the tendons and enthesis of the lower limbs. Differences were estimated by χ² or unpaired t-tests as appropriate. Associations were calculated using the Spearman's correlation coefficient rank test. Results: Fifty asymptomatic individuals with hyperuricemia and 52 normouricemic subjects were included. Hyperechoic enhancement of the superficial margin of the hyaline cartilage (double contour sign) was found in 25% of the first MTPJs from hyperuricemic individuals, in contrast to none in the control group (P < 0.0001). Similar results were found on the femoral cartilage (17% versus 0; P < 0.0001). Patellar enthesopathy (12% versus 2.9%; P = 0.01) and tophi (6% versus 0; P = 0.01) as well as Achilles enthesopathy (15% versus 1.9%; P = 0.0007) were more frequent in hyperuricemic than in normouricemic individuals. Intra-articular tophi were found in eight hyperuricemic individuals but in none of the normouricemic subjects (P = 0.003). Conclusions: These data demonstrate that morphostructural changes suggestive of gouty arthritis induced by chronic hyperuricemia frequently occur in both intra- and extra-articular structures of clinically asymptomatic individuals.

This study was designed to propose a simple "Fast Track algorithm" for capillaroscopists of any level of experience to differentiate "scleroderma patterns" from "non-scleroderma patterns" on capillaroscopy and to assess its inter-rater reliability. Based on existing definitions to categorise capillaroscopic images as "scleroderma patterns" and taking into account the real life variability of capillaroscopic images described standardly according to the European League Against Rheumatism (EULAR) Study Group on Microcirculation in Rheumatic Diseases, a fast track decision tree, the "Fast Track algorithm" was created by the principal expert (VS) to facilitate swift categorisation of an image as "non-scleroderma pattern (category 1)" or "scleroderma pattern (category 2)". Mean inter-rater reliability between all raters (experts/attendees) of the 8th EULAR course on capillaroscopy in Rheumatic Diseases (Genoa, 2018) and, as external validation, of the 8th European Scleroderma Trials and Research group (EUSTAR) course on systemic sclerosis (SSc) (Nijmegen, 2019) versus the principal expert, as well as reliability between the rater pairs themselves was assessed by mean Cohen's and Light's kappa coefficients. Mean Cohen's kappa was 1/0.96 (95% CI 0.95-0.98) for the 6 experts/135 attendees of the 8th EULAR capillaroscopy course and 1/0.94 (95% CI 0.92-0.96) for the 3 experts/85 attendees of the 8th EUSTAR SSc course. Light's kappa was 1/0.92 at the 8th EULAR capillaroscopy course, and 1/0.87 at the 8th EUSTAR SSc course. For the first time, a clinical expert based fast track decision algorithm has been developed to differentiate a "non-scleroderma" from a "scleroderma pattern" on capillaroscopic images, demonstrating excellent reliability when applied by capillaroscopists with varying levels of expertise versus the principal expert and corroborated with external validation.

Objective To investigate the potential of ultrasound (US) in the differential diagnosis between rheumatoid arthritis (RA) and psoriatic arthritis (PsA) at metacarpophalangeal (MCP) joints level. Methods 18 RA patients and 20 PsA patients with clinical involvement of MCP joints were included. All US examinations were performed by two rheumatologists investigating: presence of joint cavity widening (JCW), synovial fluid and/or synovial hypertrophy, peritenon extensor tendon inflammation (PTI) and intra-articular or peri-tendinous power Doppler (PD) signal. Results A total of 83 MCP joints in 18 RA patients were assessed. In all of these the authors found different degrees of JCW. 15 of 83 (18%) MCP joints showed synovial fluid, whereas 68 of 83 (82%) MCP joints showed synovial hypertrophy. In 72 of 83 (86.7%) MCP joints intra-articular PD was detected. No PTI pattern was found in these patients. In PsA patients, a total of 82 MCP joints in 20 patients were assessed. 54 of 82 (65.8%) MCP joints showed PTI pattern (p = 0.001). In 50 of these 54 (92.5%) MCP joints extra-articular PD signal was detected (p = 0.001). 28 of 82 (34.1%) MCP joints showed different degrees of JCW. 6 of 28 (21.4%) MCP joints presented synovial fluid, whereas 22 of 28 (78.5%) MCP joints showed synovial hypertrophy. In 8 of 82 (9.7%) MCP joints the JCW and PTI patterns were found contemporaneously. Conclusions Preliminary results demonstrate that PTI pattern is a higher characteristic of PsA, which suggests a potential role of US in the differential diagnosis between RA and PsA at MCP joints level.

Objective. To produce consensus-based definitions of the US elementary lesions in gout and to test their reliability in a web-based exercise. Methods. The process consisted of two steps. In the first step a written Delphi questionnaire was developed from a systematic literature review and expert international consensus. This collated information resulted in four statements defining US elementary lesions: double contour (DC), tophus, aggregates and erosion. The Delphi questionnaire was sent to 35 rheumatology experts in US, asking them to rate their level of agreement or disagreement with each statement. The second step tested the reliability by a web-exercise. US images of both normal and gouty elementary lesions were collected by the participants. A facilitator then constructed an electronic database of 110 images. The database was sent to the participants, who evaluated the presence/absence of US elementary lesions. A group of 20 images was displayed twice to evaluate intra-reader reliability. Results. A total of 32 participants responded to the questionnaires. Good agreement (>80%) was obtained for US definitions on DC, tophus, aggregates and erosion in the Delphi exercise after three rounds. The reliability on images showed inter-reader κ values for DC, tophus, aggregates, erosion findings of 0.98, 0.71, 0.54 and 0.85, respectively. The mean intra-reader κ values were also acceptable: 0.93, 0.78, 0.65 and 0.78, respectively. Conclusion. This, the first consensus-based US definition of elementary lesions in gout, demonstrated good reliability overall. It constitutes an essential step in developing a core outcome measurement that permits a higher degree of homogeneity and comparability between multicentre studies.