The halo sign in cranial giant cell arteritis (GCA) may be accurately diagnosed using color Doppler ultrasound (CDU) of the temporal arteries, according to findings of a systematic review and meta-analysis published in Advances in Rheumatology.
It is known that GCA is the most common primary systemic vasculitis among adults aged 50 years and older.
Researchers from Universidade Federal de São Paulo in Brazil conducted a study to evaluate whether the halo sign of the temporal arteries detected by CDU was an accurate diagnostic tool.
Researchers searched publication databases, including PubMed, Embase, CENTRAL, and ClinicalTrials.gov, through December 2022 for studies using CDU to diagnose suspected GCA.
A total of 22 studies including 2893 patients were identified for the analysis.
The pooled sensitivity of the halo sign in temporal arteries observed by CDU for GCA diagnosis was 0.76 (95% CI, 0.69-0.81; I2=88.7%), the specificity was 0.93 (95% CI, 0.89-0.95; I2=82.9%), the positive likelihood ratio was 10.15 (95% CI, 6.42-16.31), the negative likelihood ratio was 0.26 (95% CI, 0.20-0.35), and the area under the curve (AUC) was 0.91.
These data indicated that in a hypothetical population of 1000 individuals, 857 would have been accurately diagnosed by CDU and receive appropriate treatment, 103 would have a false-negative result, and 40 would have a false-positive result.
In a subset of studies that included a CDU device with a frequency of at least 15 MHz, the sensitivity and specificity for diagnosing GCA were 0.84 (95% CI, 0.75-0.89) and 0.93 (95% CI, 0.85-0.97), respectively.
A subset of studies used additional or alternative CDU markers for diagnosing GCA. Four studies evaluated the halo sign in both the temporal and axillary arteries, which had a sensitivity of 0.86 (95% CI, 0.78-0.91; I2=69.6%), specificity of 0.95 (95% CI, 0.89-0.98; I2=65.7%), and an AUC of 0.94. Five studies used the compression sign in temporal arteries, which had a sensitivity of 0.84 (95% CI, 0.72-0.92; I2=87.7%), specificity of 0.95 (95% CI, 0.88-0.98; I2=86.3%), and an AUC of 0.97. Four studies used both the halo sign and flow abnormalities in the temporal arteries, which had a sensitivity of 0.71 (95% CI, 0.56-0.82; I2=84.9%), specificity of 0.89 (95% CI, 0.82-0.94; I2=75.5%), and an AUC of 0.92.
A major limitation of the analysis was the high heterogeneity observed between studies.
The study authors concluded, “This systematic review and meta-analysis showed that the halo sign detected by the CDU of the temporal arteries has a good diagnosis performance for GCA.”
In general, accuracy of GCA diagnosis can be improved by using the compression sign and by evaluating the halo sign of axillary arteries. Incorporating blood flow abnormalities did not contribute to better GCA diagnostic accuracy.
Nakajima E, Moon FH, Junior NC, Macedo CR, de Souza AWS, Iared W. Accuracy of Doppler ultrasound in the diagnosis of giant cell arteritis: a systematic review and meta‑analysis. Adv Rheumatol. 2023;63(1):5. doi:10.1186/s42358-023-00286-3