Accuracy of Doppler ultrasound in the diagnosis of giant cell arteritis: a systematic review and meta-analysis.

BACKGROUND: Giant cell arteritis (GCA) is the most common primary systemic vasculitis in people 50 years of age and over, and it is considered a medical emergency due to the potential risk of permanent visual loss. Color Doppler ultrasound (CDU) of the temporal arteries is a rapid, noninvasive method to diagnose GCA. This study aims to determine the diagnostic accuracy of the halo sign in temporal arteries by CDU in people with suspected GCA. METHODS: The systematic literature review included the search for publications in the following electronic databases: PubMed, Embase, CENTRAL, LILACS, WHO ICTRP, ClinicalTrials.gov, gray literature up to December 2022, and no date or language restrictions were applied. We analyzed studies including patients over 50 years of age with suspected GCA evaluating CDU of temporal arteries as a diagnostic tool against clinical diagnosis as a standard reference. Paper titles and abstracts were selected by two investigators independently for all available records. The quality of the studies was assessed using the Quality of Diagnostic Accuracy Studies tool (QUADAS-2) and the R software (version 4.2.1) was used for data analysis. The protocol of this review is registered with PROSPERO (CRD42016033079). RESULTS: Twenty-two studies including 2893 participants with suspected GCA who underwent temporal artery CDU were evaluated. The primary analysis results showed a sensitivity of 0.76 [95% confidence interval (95 CI) 0.69-0.81] and specificity of 0.93 (95 CI 0.89-0.95) when the halo sign was compared to clinical diagnosis. The sensitivity value of 0.84 (95 CI 0.72-0.92) and specificity of 0.95 (95 CI 0.88-0.98) were found in five studies involving 1037 participants that analyzed the halo sign and temporal artery compression sign. A sensitivity of 0.86 (95 CI 0.78-0.91) and specificity of 0.95 (95 CI 0.89-0.98) were found in four studies with 603 participants where the halo sign was evaluated CDU on temporal and axillary arteries. CONCLUSION: The detection of the halo sign by CDU of temporal arteries has good accuracy for the diagnosis of cranial GCA. The compression sign in temporal arteries and the addition of axillary arteries assessment improves the diagnostic performance of CDU for GCA. TRIAL REGISTRATION: PROSPERO CRD42016046860.