Comparison of halo and compression signs assessed by a high frequency ultrasound probe for the diagnosis of Giant Cell Arteritis

Abstract

Objective: To evaluate the diagnosis performances of halo and compression signs alone and combined, assessed by a high frequency 22-MHz probe, and test their agreement in giant cell arteritis (GCA).

Methods: In this cross-sectional study on patients suspected with GCA, halo sign was defined as hypo or iso-echogenic circumferential aspect of the vessel wall in transverse or longitudinal view; and compression sign was defined as visibility of the vessel wall upon transducer-imposed compression of the artery. Agreement of the two signs was tested using the Cohen's kappa statistic.

Results: A total of 80 patients (50% women) were included with a mean age of 74.4 years. Twenty participants (25%) were ultimately treated for GCA. Halo and compression signs have respective prevalences of 35% and 48%, with respective sensitivity and specificity of 80% and 80% for the halo sign; and 85% and 65% for the compression sign. The kappa coefficient for the global agreement of the two signs was 0.67 (95% confident interval: 0.54-0.85). Combination of the two signs give a sensitivity of 80% and a specificity of 81.7%.

Conclusion: Halo and compression signs assessed by a high frequency probe, show a good level of agreement for the diagnosis of GCA and improve ultrasound specificity when combined together.

Keywords: Giant cell arteritis; High-frequency probe; Ultrasound.