Objectives To define the elementary ultrasound (US) lesions in giant cell arteritis (GCA) and to evaluate the reliability of the assessment of US lesions according to these definitions in a web-based reliability exercise.
Methods Potential definitions of normal and abnormal US findings of temporal and extracranial large arteries were retrieved by a systematic literature review. As a subsequent step, a structured Delphi exercise was conducted involving an expert panel of the Outcome Measures in Rheumatology (OMERACT) US Large Vessel Vasculitis Group to agree definitions of normal US appearance and key elementary US lesions of vasculitis of temporal and extracranial large arteries. The reliability of these definitions on normal and abnormal blood vessels was tested on 150 still images and videos in a web-based reliability exercise.
Results Twenty-four experts participated in both Delphi rounds. From originally 25 statements, nine definitions were obtained for normal appearance, vasculitis and arteriosclerosis of cranial and extracranial vessels. The ‘halo’ and ‘compression’ signs were the key US lesions in GCA. The reliability of the definitions for normal temporal and axillary arteries, the ‘halo’ sign and the ‘compression’ sign was excellent with inter-rater agreements of 91–99% and mean kappa values of 0.83–0.98 for both inter-rater and intra-rater reliabilities of all 25 experts.
Conclusions The ‘halo’ and the ‘compression’ signs are regarded as the most important US abnormalities for GCA. The inter-rater and intra-rater agreement of the new OMERACT definitions for US lesions in GCA was excellent.
- giant cell arteritis
- systemic vasculitis
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SC and CDu contributed equally.
Contributors WAS, CDe, CDu and SC designed the study. CDe and CDu organised the Delphi exercise. WAS and SC organised the web-based exercise. SC build the database, collected all images and selected the study images. SC was responsible for data entry and data precession together with CAS, GC and SR who did the statistical analyses. WAS, CDu and SC wrote the manuscript. All authors contributed to the acquisition of data and have read and revised the manuscript.
Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.
Competing interests None declared.
Patient consent Not required.
Ethics approval Ethical approval for the web-based exercise was obtained from the Data Agency of the Southwest Hospital in Esbjerg, Denmark.
Provenance and peer review Not commissioned; externally peer reviewed.
Data sharing statement There are not additional unpublished data from the study.
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