Definitions and reliability assessment of elementary ultrasound lesions in giant cell arteritis: a study from the OMERACT Large Vessel Vasculitis Ultrasound Working Group

Abstract

ObjectivesTo 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.MethodsPotential 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.ResultsTwenty-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.ConclusionsThe ‘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.

EULAR recommendations for the use of imaging in large vessel vasculitis in clinical practice

“…Recently, it has been defined by an Outcome Measures in Rheumatology  (OMERACT) working group as a ‘homogenous, hypoechoic wall thickening that is well delineated towards the luminal side that is visible both in longitudinal and transverse planes, most commonly concentric in transverse scans’ 26. The ‘halo’ sign at temporal arteries revealed a pooled sensitivity of 77% and a pooled specificity of 96% as compared with the clinical diagnosis of GCA 12.…”

Clinical Applicability of Ultrasound in Systemic Large Vessel Vasculitides

“…The standardization of the definitions and reliability testing by the Outcome Measures in Rheumatology (OMERACT) Ultrasound Working Group on large vessel vasculitis was per formed in order to expand the use of ultrasound in GCA and alleviate skepticism around the method . In a recent study by Chrysidis et al, in which international expert consensus was obtained using specific OMERACT methodology, the authors concluded that to a high degree ultrasound images and videos of inflamed temporal and axillary arteries can reliably document the characteristics (halo and compression signs) and diagnostic abnormalities in patients in whom GCA is suspected .…”

Op0210 false Positives of Ultrasound in Giant Cell Arteritis. Some Diseases Can Also Have Halo Sign

“…Background: Giant cell arteritis (GCA) is the most common systemic vasculitis in the elderly. The halo sign has been shown as an accepted valid test in the diagnosis of GCA in trained units [1][2] . However, to further improve the specificity, the sonographer should know some pathologies that can mimic halo signs since they also produce a hypoechoic increase of the arterial wall thickness.…”

“…Background: Color duplex ultrasonography (CDU) is recommended as first line of imaging in patients suspected for cranial GCA [1]. However, extra-cranial involvement without temporal artery involvement is found in up to 40% of GCA patients [2].…”