Carotid vasa vasorum detected by super-resolution ultrasound microvascular imaging in Takayasu's arteritis: a potential biomarker of disease activity and early treatment outcome

OBJECTIVES: To verify the ability of super-resolution ultrasound (SRUS) microvascular imaging in assessing Takayasu's arteritis (TAK) activity and predicting prognosis. METHODS: Between November 2023 and July 2024, 70 patients with TAK were consecutively included; disease activity was assessed per the 1990 American College of Rheumatology classification criteria (26 active, 44 inactive). B-mode ultrasound (US), conventional contrast-enhanced ultrasound (CEUS), and SRUS microvascular imaging examinations were performed at the carotid site with maximal wall involvement using the Resona A20 system equipped with a SL10-3U linear transducer. We compared diagnostic performance of individual markers and combined models for disease activity and evaluated deterioration-free survival with Kaplan-Meier analysis. RESULTS: Carotid vasa vasorum was detected by SRUS microvascular imaging in 14 patients (11 active, 3 inactive), while it was not observed in the remaining 56 cases (41 inactive, 15 active). Presence of vasa vasorum correlated strongly with disease activity (p<0.001), demonstrating 42.3% sensitivity, 93.2% specificity, and 74.3% accuracy. The prediction model constructed based on clinical and US characteristics demonstrated high accuracy in assessing TAK activity (area under the curve=0.900). Among 41 patients completing follow-up (17 active, 24 inactive; mean 8.7±2.7 months), patients with inactive TAK maintained stable disease (only 1 relapsed to active phase). Among patients with active TAK, those with vasa vasorum demonstrated significantly poorer outcomes: only 2/7 (28.6%) achieved remission versus 9/10 (90%) without vasa vasorum (p=0.036). CONCLUSIONS: SRUS detection of carotid vasa vasorum serves as a useful indicator for assessing the activity and severity of TAK.