Musculoskeletal ultrasound for ankylosing spondylitis A systematic review and meta-analysis

Objective: To clarify if musculoskeletal ultrasound (US) would give additional information for the clinical examination to diagnose and evaluate the activity of ankylosing spondylitis (AS). Methods: A literature search was performed in PubMed, Embase, Web of Science, the Cochrane Library, Sinomed, Chinese National Knowledge Infrastructure (CINK), and Wanfang databases from their inceptions to May 15, 2020. Studies that examined the musculoskeletal US, which detected sacroiliac joints in people with AS were included. The pooled analyses were performed using Meta Disc version 1.4 software. Results: A total of 9 studies encompassing 984 participants were included. Statistical analysis suggested an area under the curve (AUC) of 0.9259 (sensitivity 0.86, specificity 0.54) indicating that US had excellent diagnostic test accuracy for AS, an AUC of 0.6441 (sensitivity 0.87, specificity 0.51) indicating that the US did not have a good diagnostic test accuracy for AS activity. A subgroup analysis revealed that the AUC of power Doppler US (PDUS) and color Doppler US (CDUS) was 0.5000 and 0.9274, respectively, indicating that CDUS was superior to PDUS. Conclusion: US, especially CDUS, is a valid and reproducible technique for the diagnosis of AS. While the accuracy of AS activity evaluation of the US is not ideal. It may be considered for routine use as part of the standard diagnostic tools in AS.