Meta-analysis: Test performance of ultrasonography for giant-cell arteritis

Background: Giant-cell arteritis is a diagnostic challenge. Purpose: To determine the diagnostic performance of ultrasonography for giant-cell arteritis. Data Sources: Studies published up to April 2004 in the MEDLINE, EMBASE, and Cochrane databases; reference lists; and direct contact with investigators. Study Selection: Studies in any language that examined temporal artery ultrasonography for diagnosis of giant-cell arteritis, enrolled at least 5 patients, and used biopsy or the American College of Rheumatology (ACR) criteria as the reference standard. Data Extraction: Two reviewers independently graded methodologic quality and abstracted data on sensitivity and specificity of ultrasonography for giant-cell arteritis. Diagnostic performance was determined for the halo sign, stenosis, or occlusion and for any of these ultrasonographic abnormalities. Data Synthesis: Weighted sensitivity and specificity estimates and summary receiver-operating characteristic (ROC) curve analysis were used. Twenty-three studies, involving a total of 2036 patients, met the inclusion criteria. The weighted sensitivity and specificity of the halo sign were 69% (95% Cl, 57% to 79%) and 82% (Cl, 75% to 87%), respectively, compared with biopsy and 55% (Cl, 36% to 73%) and 94% (Cl, 82% to 98%), respectively, compared with ACR criteria. Stenosis or occlusion was an almost equally sensitive marker compared with either biopsy (sensitivity, 68% [Cl, 49% to 82%]) or ACR criteria (sensitivity, 66% [Cl, 32% to 89%]). Consideration of any vessel abnormality nonsignificantly improved diagnostic performance compared with ACR criteria. Between-study heterogeneity was significant, but summary ROC curves were consistent with weighted estimates. When the pretest probability of giant-cell arteritis is 10%, negative results on ultrasonography practically exclude the disease (post-test probability, 2% to 5% for various analyses). Limitations: The primary studies were small and of modest quality and had considerable heterogeneity. Conclusion: Ultrasonography may be helpful in diagnosing giant-cell arteritis, but cautious interpretation of the test results based on clinical presentation and pretest probability of the disease is imperative.