Superb microvascular imaging versus CT angiography for assessing disease activity in pediatric Takayasu arteritis: a...

To compare the value and consistency of superb microvascular imaging (SMI) and CT angiography (CTA) for assessing disease activity in pediatric Takayasu arteritis (TA), and to explore the feasibility of SMI as a non-invasive screening tool.

Forty-seven children with TA treated at our hospital between May 2019 and January 2025 were included. Disease activity was determined using the National Institutes of Health (NIH) criteria, and patients were classified into active (n = 26) and inactive (n = 21) groups. All patients underwent both SMI and CTA. The sensitivity, specificity, accuracy, and area under the ROC curve (AUC) of SMI grading and CTA for diagnosing TA activity were analyzed. Kappa tests were used to assess consistency with NIH criteria. Inter-observer agreement for SMI grading was also evaluated.

SMI grading was significantly higher in the active group than in the inactive group (Z = 5.388, p < 0.001). Using SMI grade ≥ II as the cutoff, SMI had a sensitivity of 84.62%, specificity of 95.24%, and accuracy of 89.36%. CTA had a sensitivity of 88.46%, specificity of 90.48%, and accuracy of 89.36%. The AUC values were 0.885 for SMI and 0.895 for CTA. SMI showed good consistency with NIH criteria (Kappa = 0.788), as did CTA (Kappa = 0.786). Inter-observer agreement for SMI grading was good (Kappa = 0.865, 95% CI: 0.777-0.953), with 43 of 47 cases (91.49%) showing complete concordance.

SMI and CTA demonstrate comparable diagnostic performance and high consistency in assessing disease activity in pediatric TA. Given its non-invasive nature, absence of radiation, no need for contrast agents, and repeatability, SMI is recommended as the preferred screening tool for long-term follow-up of disease activity in pediatric TA, with CTA reserved for cases where SMI suggests activity or when precise vascular assessment is needed.