Symposium 5

Abstract

While magnetic resonance imaging (MRI) is the most established imaging modality to assess autoimmune myositis (AIM), there is a need for less expensive and more accessible tools. To analyze whether there is sufficient data from published literature to demonstrate that ultrasound presents good metric properties (truth, discrimination and feasibility) in AIM, the OMERACT ultrasound group for myositis performed a systematic literature review. The inclusion criteria required original research involving adult humans, reported in English, assessing ultrasound and elastography in patients with an AIM. Conference abstracts and computer-assisted diagnostics that focused on technique and not ultrasound domains were excluded. Approximately 2670 articles were identified. 41 full-text articles were included in the final analysis. There were 551 AIM patients studied. Eighteen studies (43.9%) had a control group, of which 15 (63.3%) were healthy controls. The age of participants (including controls) varied from 18 to 86 years, and most were females (59%). Diagnosis of AIM was largely biopsy-proven, although some were derived through clinical presentation, positive clinical imaging (ultrasound or otherwise) and/or electromyography and steroid responsiveness. The features examined with ultrasound in the 41 included articles consisted of: muscle echogenicity, bulk, atrophy, architecture, power Doppler, perfusion characteristics, shear wave modulus, shear wave velocity, elasticity index and fasciculations. 12 studies (29.2%) used quantitative methods to assess these characteristics, whilst others used semi-quantitative, dichotomous/binary and descriptive scoring systems. Criterion validity was met in 14 studies (12/14, 85.7%) and construct validity in 22 studies (22/25, 88.0%). Most published articles reported Level 3b to Level 5 evidence with varying degrees of bias. There was only one longitudinal study examining discrimination. Reliability and feasibility were under-reported. This was the first systematic review studying the utility of ultrasound in AIM, which suggested some evidence for criterion and construct validity. Further validation processes are underway.