A taskforce comprised of an expert group of 21 rheumatologists, radiologists and methodologists from 11 countries developed evidence-based recommendations on the use of imaging in the clinical management of both axial and peripheral spondyloarthritis (SpA). Twelve key questions on the role of imaging in SpA were generated using a process of discussion and consensus. Imaging modalities included conventional radiography, ultrasound, magnetic resonance imaging, computed tomography (CT), positron emission tomography, single photon emission CT, dual-emission x-ray absorptiometry and scintigraphy. Experts applied research evidence obtained from systematic literature reviews using MEDLINE and EMBASE to develop a set of 10 recommendations. The strength of recommendations (SOR) was assessed by taskforce members using a visual analogue scale. A total of 7550 references were identified in the search process, from which 158 studies were included in the systematic review. Ten recommendations were produced using research-based evidence and expert opinion encompassing the role of imaging in making a diagnosis of axial SpA or peripheral SpA, monitoring inflammation and damage, predicting outcome, response to treatment, and detecting spinal fractures and osteoporosis. The SOR for each recommendation was generally very high (range 8.9–9.5). These are the first recommendations which encompass the entire spectrum of SpA and evaluate the full role of all commonly used imaging modalities. We aimed to produce recommendations that are practical and valuable in daily practice for rheumatologists, radiologists and general practitioners.

ObjectivesTo develop a consensus-based ultrasound (US) definition and quantification system for synovitis in rheumatoid arthritis (RA).MethodsA multistep, iterative approach was used to: (1) evaluate the baseline agreement on defining and scoring synovitis according to the usual practice of different sonographers, using both grey-scale (GS) (synovial hypertrophy (SH) and effusion) and power Doppler (PD), by reading static images and scanning patients with RA and (2) evaluate the influence of both the definition and acquisition technique on reliability followed by a Delphi exercise to obtain consensus definitions for synovitis, elementary components and scoring system.ResultsBaseline reliability was highly variable but better for static than dynamic images that were directly acquired and immediately scored. Using static images, intrareader and inter-reader reliability for scoring PD were excellent for both binary and semiquantitative (SQ) grading but GS showed greater variability for both scoring systems (κ ranges: −0.05 to 1 and 0.59 to 0.92, respectively). In patient-based exercise, both intraobserver and interobserver reliability were variable and the mean κ coefficients did not reach 0.50 for any of the components. The second step resulted in refinement of the preliminary Outcome Measures in Rheumatology synovitis definition by including the presence of both hypoechoic SH and PD signal and the development of a SQ severity score, depending on both the amount of PD and the volume and appearance of SH.ConclusionA multistep consensus-based process has produced a standardised US definition and quantification system for RA synovitis including combined and individual SH and PD components. Further evaluation is required to understand its performance before application in clinical trials.

The paper explains the most important parameters for the use of colour and power Doppler in rheumatology. Recommendations for machine settings are given. The commonly encountered artefacts and their importance for image interpretation are explained.Most musculoskeletal ultrasound (US) is performed using grey-scale US, but newer US techniques include the use of Doppler US in the assessment of changes in tissue vascularisation that may occur in inflammatory conditions. 1-3 The Doppler evaluation provides useful clinical information regarding the presence or absence of flow. Guidelines have been suggested by the European League Against Rheumatism (EULAR) work group for the use of grey-scale US in musculoskeletal disease. 4 The guidelines address technical issues, training and standardisation of image acquisitions. However, no such guidelines exist for Doppler US. Standardisations of the methods for evaluating inflammation and the effect of the quality of the machine and image processing still need to be established.Correct interpretation of flow images requires knowledge of physical and technical factors that influence the Doppler signal. Artefacts caused by physical limitations of the modality or inappropriate equipment settings may result in displayed flow conditions that may differ considerably from the actual physiological situation. As a consequence, artefacts in Doppler imaging may be confusing and lead to misinterpretation of flow information.In this paper, we review colour Doppler and power Doppler (PD) US, as well as the artefacts and settings relevant for musculoskeletal US in rheumatology with focus only on soft tissue and joint inflammation. DOPPLER SIGNALThe Doppler effect is a change in wavelength (frequency) of sound resulting from motion of a source, receiver or reflector. As the US transducer is a stationary source and receiver, the Doppler effect arises from reflectors in motion-for all practical purposes these are the erythrocytes. When a pulse is reflected from erythrocytes, the frequency of the wave received differs from that, which is transmitted. This difference is known as the Doppler shift, named after the Austrian physicist and mathematician Chr. Andreas Doppler, who first described the phenomenon for light in 1843. 5There are two successive Doppler shifts involved. First, the sound from the stationary transmitting transducer is received by the moving erythrocytes. Second, the erythrocytes act as moving sources as they re-eradiate the US back toward the transducer, which is now the stationary receiver. These two Doppler shifts account for factor 2 in the Doppler equation:where: f D is the Doppler shift, f t is the transmitted frequency, f r is the received frequency, v is the blood velocity, h is the insonation angle (the angle between the US beam and the blood flow), and c is the speed of sound. The Doppler shift is thus directly proportional to the velocity of the flow, v, cosine to the insonation angle, h, and the transmitted frequency of the US, f t . 6 Pulsed DopplerThe Dopple...

US appears to be a reproducible tool for evaluating and monitoring tenosynovitis in RA.

Objective: To assess the interobserver reliability of the main periarticular and intra-articular ultrasonographic pathologies and to establish the principal disagreements on scanning technique and diagnostic criteria between a group of experts in musculoskeletal ultrasonography. Methods: The shoulder, wrist/hand, ankle/foot, or knee of 24 patients with rheumatic diseases were evaluated by 23 musculoskeletal ultrasound experts from different European countries randomly assigned to six groups. The participants did not reach consensus on scanning method or diagnostic criteria before the investigation. They were unaware of the patients' clinical and imaging data. The experts from each group undertook a blinded ultrasound examination of the four anatomical regions. The ultrasound investigation included the presence/absence of joint effusion/synovitis, bony cortex abnormalities, tenosynovitis, tendon lesions, bursitis, and power Doppler signal. Afterwards they compared the ultrasound findings and re-examined the patients together while discussing their results. Results: Overall agreements were 91% for joint effusion/synovitis and tendon lesions, 87% for cortical abnormalities, 84% for tenosynovitis, 83.5% for bursitis, and 83% for power Doppler signal; k values were good for the wrist/hand and knee (0.61 and 0.60) and fair for the shoulder and ankle/foot (0.50 and 0.54). The principal differences in scanning method and diagnostic criteria between experts were related to dynamic examination, definition of tendon lesions, and pathological v physiological fluid within joints, tendon sheaths, and bursae. Conclusions: Musculoskeletal ultrasound has a moderate to good interobserver reliability. Further consensus on standardisation of scanning technique and diagnostic criteria is necessary to improve musculoskeletal ultrasonography reproducibility.

Objective. To standardize ultrasound (US) in enthesitis.Methods. An initial Delphi exercise was undertaken to define US-detected enthesitis and its core components. These definitions were subsequently tested on static images taken from spondyloarthritis patients in order to evaluate their reliability. Results. Excellent agreement (>80%) was obtained for including hypoechogenicity, increased thickness of the tendon insertion, calcifications, enthesophytes, erosions, and Doppler activity as core elementary lesions of US-detected enthesitis. US definitions were subsequently obtained for each elementary component. On static images, the intraobserver reliability showed a high degree of variability for the detection of elementary lesions, with kappa coefficients ranging from 0.13-1. The interobserver kappa values were variable, with the lowest kappa coefficient for enthesophytes (0.24) and the highest coefficient for Doppler activity at the enthesis (0.63). Conclusion. This is the first consensus-based US definition of enthesitis and its elementary components and the first step performed to ensure a higher degree of homogeneity and comparability of results between studies and in daily clinical work.

This task force has produced a consensus-based comprehensive and practical framework on standardised procedures for MSUS imaging in rheumatology.

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